Beam bridge without middle partition, hanging formwork and negative bending moment tooth block and design method thereof

Abstract

The present invention proposes a beam bridge without a central partition, without a hanging formwork, and without a negative bending moment tooth block, and a design method thereof. The beam bridge includes a prefabricated main beam, a wet joint, a lower structure, and a pier top crossbeam above the lower structure. The concrete bridge decks of adjacent prefabricated main beams are connected by a wet joint. The design method of the above beam bridge includes the following steps: S1, initial design of the main beam; S2, calculation of the non-uniform deflection of the main beam and the indirect transverse stress of the bridge deck; S3, calculation of the direct transverse stress of the bridge deck; S4, crack resistance verification of the bridge deck; S5, optimization of bridge parameters to reduce the stress on the driving surface; S6, completion of the beam bridge design. The beam bridge and its design method effectively solve the problem that the existing beam bridge without a central partition is prone to longitudinal cracking at the joints, and realizes the suspension tension without the wet joint hanging formwork of the bridge deck and the negative bending moment beam, and has better mechanical properties and better economic, environmental and social benefits, which can facilitate the promotion and application of such bridges in various types of highways, railways and municipal engineering.

Description

Technical Field

[0001] The invention relates to the technical field of assembled bridges, and in particular to a beam bridge free of a central partition, a hanging formwork, and negative bending moment tooth blocks and a design method thereof. Background Art

[0002] Prior art

[0003] like Figure 1 , Figure 2 As shown in the figure, conventional prefabricated bridges with concrete decks are still the main structural form of existing and under-construction bridges in China due to their significant cost advantages. However, there are still the following difficulties in prefabricated construction:

[0004] The first difficulty is that the wet joint work of the middle diaphragm (i.e. all the transverse diaphragms not at the pier top) is large and the construction quality is poor. (1) The wet joint of the middle diaphragm needs to be suspended in the air by the construction workers for on-site construction, which has great safety risks and slow construction speed; (2) Figures 1-2 Taking the commonly used concrete T-beam bridge (single span 40m, half bridge width 12.75m) as an example, each span needs to be equipped with 3 to 5 middle partitions in the longitudinal direction of the bridge, and each middle partition has 4 to 5 wet joints. For each middle partition, personnel and equipment need to be suspended from the wet joints of the bridge deck between each beam to weld steel bars, set up suspension formwork, pour concrete, and remove the suspension formwork. The φ25 to φ28 thick steel bars are difficult to position and have poor welding quality. In addition, the on-site workload is very large and the suspension construction is inconvenient, which significantly reduces the efficiency of prefabricated construction.

[0005] The second difficulty is that the wet joint formwork of the bridge deck is large and the cost of measures is high. (1) Before pouring, the wet joint of the bridge deck needs to be used as an upper and lower passage for the construction of the wet joint of the middle partition, so its width needs to be set to a larger value, resulting in the concrete of the wet joint being calculated only as wet weight but not sharing the dead load, resulting in a significant waste of material performance; (2) The large number of middle partitions means that the wet joint of the bridge deck needs to be set up over the entire length of the bridge, so the amount of cast-in-place work is large; (3) When the bridge deck adopts wet joints, a large number of suspended formworks need to be set up, which significantly reduces the efficiency of assembly construction; (4) When demolding the wet joint formwork of the bridge deck, it is necessary to set up a ground bracket or frequently lift personnel to recover the formwork, or the formwork can only be left to fall to the ground, resulting in a high loss rate. For high piers or bridges across the river, permanent bottom formwork or a special suspension platform is required to recover the formwork, which significantly increases the cost of on-site measures.

[0006] The third difficulty is that the negative bending moment beam needs to be anchored to the tooth block and suspended in the air for tensioning. (1) Because the precast concrete bridge deck of the prefabricated bridge is usually thin (generally 16 to 20 cm thick), the negative bending moment beam cannot be directly anchored in the reserved grooves on the bridge deck. Instead, tooth blocks need to be set under the bridge deck for anchoring, which poses a high safety risk and slows the construction speed. (2) The tensioning and anchoring of the negative bending moment beam of each beam requires a high-altitude suspension platform to be set up at the wet joints of the bridge deck on both sides. The construction measures are expensive, the suspension construction is inconvenient, and the efficiency of prefabricated construction is significantly reduced. In addition, the construction quality of high-altitude operations and narrow spaces is difficult to guarantee.

[0007] It can be seen that the above problems significantly increase the on-site man-hours, measures costs and safety risks of prefabricated bridges. When applied to cross-line bridges, the impact on existing traffic is particularly significant, and the cost will increase significantly when using steel structure bridges. It can be seen that whether it is a concrete or steel structure prefabricated bridge, its actual assembly efficiency and benefits still need to be improved.

[0008] Some researchers have tried to improve the first difficulty, but there are still major shortcomings: (1) In the Chinese invention patent "CN201610162690-Reinforced concrete T-beam bridge and its construction method", the steel structure bolt connection and transverse prestressed tendons are tensioned on site to achieve the connection between the prefabricated diaphragms. Although the cast-in-place wet joint operation of the diaphragms is avoided, the connection between the concrete structures through the steel structure actually requires a very high prefabrication accuracy (concrete vibration can easily cause a certain deviation of the embedded steel structure), and there are problems such as significantly increased material costs, still unable to avoid high-altitude suspension operations, very low adaptability to the errors of the on-site prefabricated beam positioning coordinates and elevations, and not suitable for bridges other than single-track railway bridges that usually require more than two T-beams to be arranged in the transverse direction of the bridge; (2) The utility model patent "CN202121598690-A transverse prefabricated simply supported T-beam without wet joints" adopts a combined tooth structure (that is, the so-called tongue-and-groove joint, such as dry type The connection between prefabricated diaphragms also faces higher prefabrication accuracy requirements, and the existing prefabrication technology level is difficult to meet in actual processing and manufacturing, and the driving dynamic performance and structural seismic performance are very low; (3) Chinese invention patent "CN202010213138-A new prefabricated T-beam structure and widening method convenient for later widening and transformation" and utility model patent "CN202122232380-A steel-concrete composite simply supported T-beam bridge" also have similar problems in the above-mentioned prior art; (4) Chinese invention patent "CN201711444345-A T-beam suspended work platform structure and T-beam diaphragm construction method" has made certain improvements to the suspended work platform for the wet joints of the diaphragms of conventional T-beam bridges, which has not substantially solved the problems of low safety, large workload and low efficiency caused by the large amount of high-altitude suspension construction required for the wet joints of the diaphragms of conventional T-beam bridges.

[0009] As for the second difficulty, some researchers have also tried to improve it, but there are still major deficiencies: (1) In the Chinese invention patents "CN201610092674-A prefabricated T-beam and construction method" and "CN202111335794-A prefabricated T-beam structure and construction method that is easy to assemble", the prefabricated bridge deck is connected through the reserved holes and the embedded steel bars on the top surface of the web. Although the cast-in-place wet joint operation of the bridge deck is avoided, the embedded steel bars on the top surface of the web are not connected due to the production error of the steel cage and the vibration of the concrete. This makes it difficult to accurately position the bridge deck according to the design requirements. This structure is equivalent to designing each T-beam wing plate to be connected in a manner similar to sleeve grouting. Based on the experience of sleeve grouting, it is known that this design method will bring a huge workload of construction positioning and steel bar deviation correction, so it is difficult to implement. (2) The Chinese invention patent "CN201710890164-A precast concrete T-beam transverse connection joint structure and construction method" adopts the method of staggered arrangement of steel bars at the wet joints of the bridge deck and anchoring them separately to reduce the wet joints. The welding operation of the joint steel bars is still not solved, but the problem of the need for hanging formwork and casting has not been solved; (3) The Chinese invention patent "CN202111335795-A connection structure of a non-bonded prefabricated assembled T-beam" adopts a method similar to bolt connection to overlap the wing plates between the two prefabricated T-beams. This is also difficult to avoid the problem that when the concrete structure is connected through the steel structure, a very high prefabrication accuracy is actually required (it is difficult to accurately position the steel cage, and the concrete vibration is easy to cause a certain deviation of the embedded steel structure), and an additional suspension platform is required to carry out the wing plate connection operation or remove the connection bracket under the wing plate, which further increases the on-site operation time and measures The cost; (4) The utility model patent "CN201920685632-A hanging basket structure for prefabricated erection of small box beam cross-line bridge wet joint construction" has made certain improvements to the suspended formwork for the wet joint of the bridge deck of the conventional T-beam bridge, but has not substantially solved the problems of large workload, high measures cost, and low efficiency of formwork and demoulding in the wet joint construction of the bridge deck of the conventional T-beam bridge.

[0010] For the third difficulty, some researchers have also tried to improve it, but there are still major shortcomings: (1) Although the Chinese invention patent "CN202010306429-Construction method of prestressed concrete beam negative moment zone bridge structure" avoids the difficulties of hole reservation, steel bundle perforation and casting holes in the traditional post-tensioning prestressing process, its process is not simple and requires a large amount of ultra-high performance concrete (UHPC) for on-site casting, which significantly increases the material cost, makes UHPC difficult to maintain on-site, and is not practical; (2) The Chinese invention patent "CN202121443136-A T-beam detachable pier top negative moment anchor plate fixing structure" improves the anchor plate of the negative moment beam and reduces the difficulty of later anchor sealing construction, but does not solve the fundamental problem of negative moment beam construction of conventional T-beam bridges. The problem is the nature of the problem; (3) Regarding the Chinese invention patents "CN201911176619-A hanging basket for negative bending moment construction in a limited space in the middle beam of a T-beam and its use method", "CN202110420161-A negative bending moment tensioning device and tensioning method for high pier T-beams" and the utility model patents "CN201821214280-A T-beam negative bending moment reinforcement tensioning and steel box beam flange plate weld painting operation table", "CN201911176619-A hanging basket for negative bending moment construction in a limited space in the middle beam of a T-beam and its use method", they are all improvements on the negative bending moment beam construction suspension platform, but they have not essentially solved the problems of low working performance of the negative bending moment beam of conventional T-beam bridges, high construction measures costs, multiple suspension times, high safety risks, slow construction speed, and difficulty in ensuring construction quality.

[0011] Technical issues

[0012] If the design of prefabricated bridges with concrete bridge decks without central partitions, hanging formwork, and negative bending moment tooth blocks can be safely and reliably realized, it will be the most ideal way to completely solve the above problems. In a few expressway projects built in China in the 1990s, T-beam bridges without central diaphragms were also used on a large scale. However, the reality is: as described on page 54 of the monograph "100 Questions on Bridge Design (Second Edition)" and the paper "Analysis of Defects of T-beam Bridges without Central Diaphragms and Evaluation of Reinforcement Effects", after long-term operation of these bridges, a large number of longitudinal cracks appeared in the bridge pavement at the interface between the new and old concrete joints of the bridge deck. The fundamental reason is that the existing design and calculation methods are not perfect when applied to such bridges, and fail to accurately calculate the stress state of the bridge deck after the central diaphragm is removed. Because according to Article 4.2 of the current Chinese standard "JTG 3362-2018 Highway Reinforced Concrete and Prestressed Concrete Bridge and Culvert Design Code" and the bridge deck design method in "Bridge Engineering", when calculating the bridge deck stress, the upper edge of the bridge deck joint interface should be in a compressive stress state in the transverse direction of the bridge, so it is impossible to explain why cracks occur there. It can be seen that the shortcomings of the existing design method have resulted in the failure to make corresponding improvements or reasonable reinforcement of the bridge deck after the central partition of this type of bridge was cancelled, which ultimately caused a large number of defects. The final solution was as described in the "Defect Analysis and Reinforcement Effect Evaluation of T-beam Bridges without Central Cross Beams", which was to improve the defects by re-adding central partitions.

[0013] Therefore, there is an urgent need for a structure and a design method that can effectively solve the problem of longitudinal cracking of the bridge deck in the existing partition-free beam bridge, so as to avoid the problem of a large number of longitudinal cracks occurring at the interface between the new and old concrete joints of the bridge deck of the T-beam bridge without a partition after long-term operation. Summary of the invention

[0014] In order to solve the above problems, the present invention proposes a beam bridge without a central partition, without a hanging formwork, and without a negative bending moment tooth block, and a design method thereof, and provides the structure of an assembled beam bridge without a central partition and a design calculation method thereof, which effectively solves the problem of longitudinal cracking at the joints of the bridge deck in the beam bridge without a central partition, and realizes the elimination of a hanging formwork for wet joints of the bridge deck and the elimination of negative bending moment beam suspension tensioning, which is convenient for the actual design and promotion and application of such bridges.

[0015] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0016] A beam bridge without a middle diaphragm, without a hanging formwork, and without a negative bending moment tooth block and a design method thereof, wherein the beam bridge without a middle diaphragm, without a hanging formwork, and without a negative bending moment tooth block comprises a prefabricated main beam, a wet joint, a pier top cross beam, and a lower structure; adjacent prefabricated main beams are connected by the wet joints, the pier top cross beams are connected to the prefabricated main beams, and the pier top cross beams are arranged above the lower structure;

[0017] The prefabricated main beam comprises a web and a concrete bridge deck; adjacent concrete bridge decks are connected by the wet joint, the contact surface between the concrete bridge deck and the wet joint is a joint interface, and the web is integrally formed with the concrete bridge deck;

[0018] Based on the beam bridge without middle partition, hanging formwork and negative bending moment tooth block, the design method of the beam bridge includes the following steps:

[0019] S1. Design of initial structural parameters of precast main beams: Based on the statistical data of the structural dimensions of built beam bridges, the cross-sectional form, maximum span L, and cross-sectional inertia moment I of the precast main beams are assumed; the thickness of the concrete bridge deck at the joint interface is assumed to be T1, the thickness of the concrete bridge deck at the web is assumed to be T2, and the number of precast main beams arranged in the transverse direction of the beam bridge is assumed to be J; the webs are numbered from left to right in the transverse direction as 1#, 2#, 3#, ..., (N-1)#, N#, and the transverse distance between the center lines of the webs at both ends of the beam bridge in the transverse direction is D;

[0020] S2. Calculation of indirect transverse stress of concrete bridge deck: According to the actual support conditions, the load is set at the outermost part of the transverse direction of the beam bridge, and the non-uniform deflection {△ n},{△ n}={△1,△2,△3,…,△ N-1 ,△ N}, △1, △2, △3, …, △ N-1 ,△ N are the vertical deflections of the webs No. 1#, 2#, 3#, ..., (N-1)#, and N#, respectively; a section is taken along the longitudinal direction of the beam bridge, and the bottom of the webs of the section are assumed to be vertical rigid supports, and △1, △2, △3, ..., △4 are applied to the bottoms of the webs No. 1#, 2#, 3#, ..., (N-1)#, and N# one by one. N-1 ,△ N The forced displacement is used to calculate the indirect transverse stress σ on the top surface of the concrete bridge deck. b1 ;

[0021] S3. Calculation of direct transverse stress of concrete bridge deck: Assuming that the bottom of the web is vertically rigidly supported, the load is set at the outermost part of the transverse direction of the beam bridge, and the direct transverse stress σ on the top surface of the concrete bridge deck is calculated. b2 ;

[0022] S4. Crack resistance calculation of the top surface of the concrete bridge deck: The most unfavorable transverse stress σ on the top surface of the concrete bridge deck b According to the indirect transverse stress σ b1 and direct transverse stress σ b2Superposition calculation, that is, σ b =σ b1 +σ b2 ;

[0023] If σ at the joint interface b ≥f tjp , f tjp is the fatigue tensile strength at the joint interface, then go to step S5;

[0024] If σ at the joint interface b <f tjp , then go to step S6;

[0025] S5, increase T1 and / or T2 and / or J and / or I and / or reduce L, return to step S2, and perform crack resistance calculation on the top surface of the concrete bridge deck again;

[0026] S6. Complete the remaining design in the conventional way: apply multi-lane, multi-vehicle live loads and other design loads in the conventional influence line method, determine the configuration of the steel bars and steel strands in the precast main beam according to the most unfavorable full-bridge internal force state under the bridge design load combination and the conventional structural design method to complete the beam bridge design.

[0027] The technical principle and effect of the above invention are: when the load is biased to the outermost side, each prefabricated main beam will deflect downward and the deflection values ​​are △1, △2, △3, ..., △ N-1 ,△ N are different, but due to the presence of the middle partition, the vertical deflection difference between each prefabricated main beam and the adjacent prefabricated main beam is basically the same (△1-△2≈△2-△3≈…≈△ N-1 -△ N ), that is, the shape of the top surface of the bridge deck after deflection is still close to the plane. However, when there is no middle partition, the vertical deflection difference will be significantly different, that is, there will be obvious non-uniform deflection {△ n The non-uniform deflection causes the bridge deck to have a large curvature and a relatively arched deformation, which causes the top surface of the bridge deck, especially the upper edge of the joint interface, to produce an indirect tensile stress σ in the transverse direction of the bridge. b1 , the direct tensile stress σ caused by the transverse bending moment generated when the indirect tensile stress acts directly on the load b2 After superposition, it should not exceed f at the joint interface tjp To avoid cracking on the upper edge (which is not considered in the existing design method when calculating the bridge deck, σ b Too large is also the direct cause of longitudinal cracks on the driving surface of the T-beam bridge without a central partition in the prior art). By increasing T1, T2, J or I, or by reducing L, σ b Controlled below f tjpThe whole bridge design can be completed subsequently using the same conventional calculation method as the beam bridge with a central partition.

[0028] Preferably, when setting the load in S2, the load of a single car or train is set at the leftmost side of the transverse direction of the beam bridge, and the distance between the load and the leftmost end of the beam bridge meets the requirements of the specifications; when setting the load in S3, the load of a single vehicle is set at the leftmost side of the transverse direction of the beam bridge, and the distance between the load and the leftmost end of the beam bridge meets the requirements of the specifications.

[0029] Preferably, for the cross section of the concrete bridge deck with a longitudinal width of a0, the σ in step S2 is b1 =M b1 / W b , W b is the section modulus of the concrete bridge deck section with longitudinal width a0, M b1 is the indirect transverse bending moment of the concrete bridge deck section with longitudinal width a0;

[0030] M b1 =M b1max d y / (D / 2), d y M is the transverse distance of the section from the centerline of the leftmost web; b1max =E c I bmax / R eq , I bmax =a0·[max(T1,T2)] 3 / 12, E c is the elastic modulus of the concrete bridge deck, R eq For △1, △2, △3, ..., △ N-1 ,△ N The equivalent curvature radius of the concrete bridge deck under the forced displacement; R eq =(D / 2) 2 / (2△ g ),△ g is the relative camber; when N is an odd number, g =△ (N+1) / 2 -(△1+△ N ) / 2, when N is an even number△ g =(△ N / 2 +△ N / 2+1 ) / 2-(△1+△ N ) / 2.

[0031] The technical principle and effect of the above invention are as follows: the non-uniform deflection of each prefabricated main beam causes the bridge deck to produce a relatively arched deformation, so σ b1 It is positively correlated with the curvature of the bridge deck, so combined with Figure 5 The equivalent curvature radius R of the bridge deck in the present invention is eq From the calculation diagram, we can see that: since the deformation of the bridge structure in actual operation is still small, it can be assumed that the upper edge of the cross section of the bridge deck after arching is an arc, so the curvature radius R of the arc eq =(D / 2) / sinβ, according to the principle of small angle approximation, sinβ≈β; further according to the chord tangent angle theorem, β=2α, according to the equal angle theorem of parallel lines, α=θ; finally, according to the principle of small angle approximation, θ≈tanθ=△ g / (D / 2), combining the above formulas, we can get R eq =(D / 2) 2 / (2△ g ). At the same time, because the deformation of the bridge deck still belongs to the small displacement theory, the relative camber △ g ≈Vertical deflection of the bridge deck at the transverse centerline of the entire bridge - the average of the vertical deflections of the No. 1 and No. N webs.

[0032] Preferably, the non-uniform deflection {△ n}={m n}w, w is the vertical deflection generated when assuming that one of the prefabricated main beams of the beam bridge bears the load in step S2 alone; {m n} is the set of transverse distribution coefficients of all the prefabricated main beams when loaded according to S2, {m n}Calculated according to the rigid plate method, the equivalent moment of inertia of the longitudinal unit width bridge deck in the rigid plate method is beq =F(D / (N-1)) 3 / (48E c w eq ), E c is the elastic modulus of the concrete bridge deck, F is the unit force, w eq is the equivalent flexibility;

[0033] w eq Calculation method: Assume the concrete bridge deck between the center lines of the webs 1 and 2 as a simply supported beam supported at the webs. When F is applied at the mid-span of the simply supported beam, the mid-span vertical deflection calculated by conventional structural mechanics methods or finite element modeling is w eq .

[0034] The technical principle and effect of the above invention are as follows: the calculation error of the transverse distribution coefficient generally has little effect on the longitudinal force of the prefabricated main beam, but has a great influence on the indirect transverse stress σ of the bridge deck of the beam bridge without a central partition. b1The calculation has a great influence; in practice, the stiffness of the bridge deck often changes along the transverse direction of the bridge, but the stiffness of the bridge deck in the rigid-connected plate method can only be considered as a fixed value, which is bound to bring about a large error; therefore, the bridge deck with variable stiffness can be approximated as a bridge deck with equal stiffness as a simply supported beam based on the displacement equality under unit force to solve its equivalent moment of inertia I beq , and I beq Used in calculations using the rigid plate method.

[0035] Preferably, the non-uniform deflection {△ n}, the finite element model of the whole bridge is established according to the conventional Hambly beam grid method, and the width of the virtual crossbeam in the model is the actual working width a of the longitudinal direction of the concrete bridge deck, a=max{(a1+2h p )+D / (N-1) / 3, 2D / (N-1) / 3}, a1 is the longitudinal bridge-to-ground dimension of the heaviest wheel of the vehicle load, h p is the total thickness of the leveling layer and the pavement layer above the concrete bridge deck; a single car or train load is set to the leftmost position, and the non-uniform deflection {△ n}.

[0036] The technical principle and effect of the above invention are as follows: when the vehicle load is applied as lane load, the concentrated force of the lane load is very large, while the actual wheel load is a uniform force with a certain width and will spread to the bridge deck within a certain range in the longitudinal direction, resulting in a large difference between the deformation and stress of the virtual beam of the conventional beam grid method under the concentrated force of the lane load and the actual situation. Considering the effect of the calculation error of the vertical deflection on the indirect lateral stress σ of the bridge deck of the beam bridge without a central partition, the calculation error of the vertical deflection on the indirect lateral stress σ of the bridge deck of the beam bridge without a central partition is as follows: b1 Therefore, when modeling a beam bridge without a central partition according to the beam grid method, the virtual crossbeam width is taken as the actual working width a of the bridge deck in the longitudinal direction of the bridge, which can effectively reduce the calculation error of the vertical deflection and the bridge deck stress.

[0037] Preferably, the σ in S3 is calculated b2 When the longitudinal mid-span of the beam bridge is a segment with a longitudinal width of a0, the bottom of the web in the segment is assumed to be a vertical rigid support, the heaviest axis of a single vehicle load is set at the leftmost side of the segment, and the transverse bridge upward edge stress σ at each section of the segment is calculated according to conventional structural mechanics methods or finite element modeling. b22 ; σ at each cross section b2 =σ b22 a0 / a n , when the cross section is located between the n#th web and the (n+1)#th web n =min{(a1+2h p)+D / (N-1) / 3,2D / (N-1) / 3}+(n-1)D / (N-1) / 3, otherwise a n =(a1+2h p )+2d c , a1 is the longitudinal bridge dimension of the heaviest wheel of the vehicle, h p is the total thickness of the leveling layer and the paving layer above the concrete bridge deck, d c It is the distance from the leftmost edge of the leftmost wheel contacting the ground to the centerline of the leftmost web of the vehicle load.

[0038] The technical principle and effect of the above invention are as follows: in the actual full bridge force, when the vehicle load is located between the first web and the second web, the longitudinal width of the bridge deck between the two webs that actually bears the vehicle load is a. n ; When the effect of vehicle load spreads to between the 2# web and the 3# web, the longitudinal width of the bridge deck that actually bears the vehicle load will be further enlarged; the same can be said when the section is between the n# web and the (n+1)# web; therefore, based on the geometric relationship, it is diffused at a 45° angle and is biased towards safety, and can be calculated using the above formula.

[0039] Preferably, in S4, only the σ at the mid-span position of the maximum span in the longitudinal direction of the concrete bridge deck is calculated. b , and only the joint interface at a distance d from the center line of the leftmost web is checked; when J is an odd number, d is the distance from the center line of the leftmost web in the transverse direction of the bridge to the left joint interface of the (J+1) / 2-th precast main beam; when J is an even number, d is the distance from the center line of the leftmost web in the transverse direction of the bridge to the right joint interface of the J / 2-th precast main beam.

[0040] The technical principle and effect of the above invention are as follows: the mid-span deflection at the maximum span in the longitudinal direction of the bridge is the maximum vertical deflection of the entire bridge, and at this time, the non-uniform deflection effect between the prefabricated main beams is also the most obvious, that is, σ b Usually, the design is controlled at the mid-span position at the maximum span in the longitudinal direction; while the maximum bending moment of the bridge deck caused by non-uniform deflection usually occurs at the center line of the entire bridge in the transverse direction and decreases toward both sides. Therefore, only the joint section closest to this point, that is, the joint interface at a distance d from the center line of the leftmost web, can be checked.

[0041] Preferably, f described in S4 tjp =γ j γ p ·min(f ty ,f tj ), f ty is the design value of concrete tensile strength of the precast main beam, f tj is the design value of concrete tensile strength of the wet joint, γj is the tensile strength correction factor of concrete at the joint interface, γ p is the correction factor for concrete fatigue tensile strength.

[0042] The technical principle and effect of the above invention are as follows: there is a transition layer with a high water-cement ratio at the interface between the new and old concrete, which is easy to form a cement mortar matrix with relatively loose pores, and the initial damage of the old concrete during roughening and the shrinkage stress of the new concrete also affect the stress performance at the interface, so the tensile strength of the concrete at the joint interface must be reduced. At the same time, considering that the bridge bears live loads for a long time and the stress on the bridge deck changes repeatedly from tension to compression, the fatigue effect should be considered to further correct the tensile strength of the concrete, which can generally be taken as γ j =0.49,γ p =0.6.

[0043] Preferably, a cantilever plate is provided at the transverse end of the prefabricated main beam, and the transverse net distance of the cantilever plates between adjacent prefabricated main beams does not exceed 60 cm. A pad is provided above the cantilever plate, and the pad is connected to the wet joint to form an overall common force.

[0044] The technical principle and effect of the above invention are as follows: after the partition-free design method is implemented, it is no longer necessary to have personnel go up and down from the bridge deck joint to apply the partition, so the cantilever plate can be preset and only a small clearance can be left between the cantilever plate and the adjacent prefabricated main beam, thereby greatly reducing the amount of cast-in-place engineering of the wet joint, avoiding the performance waste caused by the wet joint concrete being unable to bear its own wet weight, and the prefabricated main beam of the beam bridge without a partition can have a large bending stiffness at the same amount of concrete, thereby saving steel. At the same time, after placing small pieces of thin pads one by one on the cantilever plate, protection can be formed and used as a permanent bottom formwork, thereby completing the steel bar connection and cast-in-place operation of the wet joint, and the thin pads can also be prefabricated with concrete materials and form a whole with the wet joint concrete and bear force together, which will not lead to an increase in engineering volume and waste of material performance.

[0045] Preferably, there are no less than 2 prefabricated main beams in the longitudinal direction of the bridge, and the adjacent prefabricated main beams in the longitudinal direction of the bridge are connected by negative bending moment beams, and min(T1, T2)≥20cm. Anchoring grooves are preset on the concrete bridge deck, and the negative bending moment beams are anchored in the anchoring grooves.

[0046] The technical principle and effect of the above invention content are: after the center partition is eliminated according to the above design method, there is no need for personnel to go up and down the bridge deck joints to thread, tension and anchor the negative bending moment beams, and the bridge deck thickness of the center partition-free beam bridge is thicker than that of the conventional prefabricated beam bridge, so the negative bending moment beams can be anchored directly on the bridge deck in the reserved grooves of the thicker bridge deck.

[0047] Preferably, the concrete bridge deck of the prefabricated main beam is provided with bridge deck holes arranged at intervals in the longitudinal and transverse directions of the bridge, and bridge deck cross ribs are provided between the longitudinally adjacent bridge deck holes, and the bridge deck cross ribs are provided with shear reinforcements arranged at intervals along the transverse direction of the bridge.

[0048] The technical principles and effects of the above invention are as follows: after holes are set in the bridge deck, the stiffness of the bridge deck can be significantly improved without increasing the dead load weight, thereby reducing the non-uniform deflection effect and reducing the tensile stress on the top surface of the bridge deck, while greatly reducing the amount of transverse steel bars in the bridge deck; after cross ribs of the bridge deck are set between the holes, the cross ribs can form an I-shaped section together with the bridge decks above and below the nearby holes to bear the wheel load, and the reinforcement of the bridge deck can be designed according to the conventional I-section beam. Compared with the stress state of the bridge deck as a rigid truss when there is no cross ribs of the bridge deck, the calculation and reinforcement workload can be significantly simplified.

[0049] Preferably, the prefabricated main beam also includes a closed box-section structure, a bottom plate is provided at the bottom of the web, the bottom plate, the web and the concrete bridge deck form the closed box-section structure, and the transverse end of the concrete bridge deck is provided with an end thickened portion, and the end thickened portion is connected to the wet joint.

[0050] Preferably, the transverse end of the concrete bridge deck is provided with an end slope, the end thickened portion includes a thickened portion slope and a thickened portion plane, the thickened portion slope is connected to the wet joint, the slope of the thickened portion slope is not greater than 1.00, and T1>T2.

[0051] The technical principle and effect of the above invention are as follows: after the joint interface is thickened, the non-uniform deflection effect is not significantly reduced, but because the section stiffness and thickness are close to the cubic relationship, the bending stiffness of the section at this location is significantly increased, thereby significantly reducing the tensile stress at the joint interface. After the end bevel is set, the shear stiffness and shear bearing capacity of the new and old concrete joint interface can be significantly improved, and the upward development of the cracks at the lower edge of the interface can be blocked to a certain extent. When the slope of the thickened portion is not greater than 1.00, it can facilitate the transmission of the lateral stress of the bridge deck and reduce the influence of stress concentration.

[0052] Preferably, a bottom plate is provided at the bottom of the web of the prefabricated main beam, an end thickening portion is provided at the transverse end of the concrete bridge deck, and the bridge deck transverse ribs are provided between the web and the end thickening portion. The bridge deck transverse ribs are located below the concrete bridge deck and are arranged at intervals along the longitudinal direction of the concrete bridge deck.

[0053] Preferably, the concrete bridge deck is connected to the bridge deck transverse ribs, and the thickness T1 of the concrete bridge deck at the joint interface includes the cross-sectional thickness of the concrete bridge deck and the cross-sectional thickness of the bridge deck transverse ribs, and T1 ≥ 30 cm.

[0054] The technical principle and effect of the above invention are as follows: the bridge deck and the transverse ribs below form a T-shaped section. When the section height increases, its stiffness increases nearly cubically, which can significantly reduce the non-uniform deflection effect. At the same time, the tensile stress at the joint interface can be reduced by significantly increasing the bending stiffness.

[0055] Preferably, the web of the prefabricated main beam comprises a steel structure, and the side surfaces of the web are provided with web vertical ribs arranged at intervals along the longitudinal direction of the beam bridge, and the top ends of the web vertical ribs are connected to the bridge deck.

[0056] Preferably, the web vertical ribs and the bridge deck transverse ribs are at the same longitudinal bridge position to resist the transverse deformation transmitted by the bridge deck transverse ribs.

[0057] The technical principle and effect of the above invention are: when the web of the prefabricated main beam is a steel structure, the deformation transmitted from the transverse ribs of the bridge deck will significantly reduce the local stability of the web, so corresponding vertical ribs of the web need to be set to offset the adverse effects of the transverse ribs of the bridge deck.

[0058] The beneficial effects of the present invention are summarized as follows:

[0059] The present invention proposes a beam bridge without a middle partition, a hanging formwork, or a negative bending moment tooth block and a design method thereof, and its beneficial effects include:

[0060] 1. No central partition: The present invention proposes a beam bridge without a central partition and its design method. In the present invention, by eliminating the transverse partitions outside the pier top, the problem of a large number of high-altitude suspended construction of a large number of central partition wet joints in conventional assembled beam bridges is avoided, which greatly enhances the construction safety, greatly reduces the amount of on-site work, and significantly improves the assembly construction efficiency. At the same time, the design method of the present invention clarifies the non-uniform deflection effect of the beam bridge without a central partition, and clarifies that the most unfavorable lateral stress of the bridge deck of the beam bridge without a central partition is the indirect tensile stress σ at the upper edge of its joint interface under the non-uniform deflection effect. b1 and the direct tensile stress σ under the direct action of vehicle load b2 The calculation method of the most unfavorable transverse stress on the top surface of the bridge deck of this type of bridge is given by superposition. Finally, by controlling the most unfavorable transverse stress of the bridge deck of the beam bridge without a central partition below the fatigue tensile strength at the concrete joint interface, the safety and reliability of the structural design is ensured, and the problem of longitudinal cracking of the driving surface of the beam bridge without a central partition at the joint that may be caused by the design according to the existing technology is effectively avoided.

[0061] 2. No need to hang formwork for wet joints of bridge decks: The present invention does not require personnel to go up and down from the bridge deck joints to construct the middle partition and negative bending moment beam. The wet joint width can be designed to be as narrow as possible, and a cantilever plate structure is set at the transverse end of the concrete bridge deck in the prefabricated main beam, and the small-sized pad on the top is used to achieve complete no-hanging and no-removal of formwork for the entire bridge. Therefore, the present invention can avoid the problem of large-scale hanging formwork casting and demolding for wet joints of bridge decks of conventional assembled beam bridges, and has a smaller amount of concrete cast-in-place, greatly saves the cost of wet joint construction measures, and significantly improves the efficiency of assembly construction.

[0062] 3. High-altitude suspended construction without negative bending moment bundles: The present invention directly anchors the negative bending moment bundles in the thicker bridge deck, and there is no need to set a large number of tooth blocks under the bridge deck for prestressed anchoring. This avoids a large number of high-altitude suspended tensioning operations of the negative bending moment bundles of conventional prefabricated beam bridges, greatly enhances construction safety, greatly saves the cost of suspension construction measures, significantly saves tensioning man-hours, improves the prestressed tensioning operation space and working environment, and better guarantees construction quality.

[0063] 4. Better mechanical properties: Compared with conventional prefabricated beam bridges with concrete bridge decks, the wet joint width of the bridge deck of the present invention can be significantly reduced, thereby reducing the impact of the unfavorable situation that the post-cast concrete and longitudinal steel bars at the wet joints cannot be taken into account in the longitudinal force due to the low reliability of the joints between the new and old concrete. At this time, the width of the bridge deck of the prefabricated main beam can be made larger, and the longitudinal stiffness of the prefabricated main beam is greater, thereby having better longitudinal force performance.

[0064] 5. More beautiful bridge appearance: The present invention eliminates a large number of dense middle partitions, and has better permeability and appearance along the bridge direction than conventional prefabricated beam bridges; in addition, after eliminating a large number of exposed large-volume anchoring teeth, the linear smoothness and aesthetics of the beam body can be improved.

[0065] 6. Better social, environmental and economic benefits: The beam bridge without central partition, hanging formwork and negative bending moment tooth block of the present invention completely avoids the high-altitude suspension operation of the central partition and negative bending moment beam of the conventional assembled beam bridge, which significantly saves man-hours, reduces the impact on the traffic under the bridge and nearby, and significantly improves the social benefits. The thin pads at the small-volume wet joints prevent leakage and act as a permanent bottom formwork to bear the force together with the cast-in-place wet joints, thus avoiding a large number of demolding operations and damage to the formwork caused by forced demolding, and also improves the environmental benefits to a certain extent. The economic benefits are significantly improved by completely eliminating the amount of steel bars in the central partition, greatly reducing the amount of steel bars in the transverse direction of the bridge deck, completely eliminating the suspension and tensioning facilities of the negative bending moment beam, and completely eliminating all wet joint suspension formwork and high-altitude demolding operations.

[0066] In summary, the present invention avoids the problem of a large number of middle partitions and a large number of high-altitude suspension construction of the middle partition wet joints required in conventional assembled beam bridges by designing a beam bridge structure without a middle partition. In addition, in the design and calculation process of the beam bridge, it is considered that the beam bridge will have obvious non-uniform deflection when there is no middle partition. Therefore, the indirect tensile stress σ at the upper edge of the joint interface of the beam bridge is reduced. b1 and direct tensile stress σ b2 The superposition is used to check the crack resistance of the top surface of the bridge deck to avoid cracking of the driving surface during the use of the beam bridge.

[0067] Furthermore, based on the beam bridge structure without a central partition, the present invention avoids the need for a large number of hanging formwork casting and demolding operations for the wet joints of the bridge deck of a conventional prefabricated beam bridge by arranging cantilever plates and pads at the transverse ends of the prefabricated main beams, thereby reducing the amount of on-site construction, avoiding a large number of high-altitude operations during the construction process, improving the safety factor of the construction process, and significantly increasing construction efficiency.

[0068] Furthermore, based on the above-mentioned beam bridge structure, the present invention anchors the negative bending moment beam in the concrete bridge deck of the beam bridge. Through this structural design, the beam bridge no longer needs personnel to go up and down from the bridge deck joints to thread, tension and anchor the negative bending moment beam, thereby further improving the construction safety of the beam bridge and its design method, improving the working environment of the construction personnel, and improving the construction quality.

[0069] Therefore, the beam bridge and design method of the present invention without central partition, hanging formwork and negative bending moment tooth block are new assembled beam bridges and design methods that are safer, more economical, more applicable and more beautiful than the prior art, and can be widely used in the construction of various highways, railways and municipal bridges. BRIEF DESCRIPTION OF THE DRAWINGS

[0070] Figure 1 It is a longitudinal section view along the center line of the web of a conventional prefabricated bridge using a concrete bridge deck in the background technology of the present invention;

[0071] Figure 2 It is a standard cross-sectional view of a conventional concrete T-beam bridge in the background technology of the present invention;

[0072] Figure 3 It is a cross-sectional schematic diagram of a beam bridge without a central partition according to the present invention;

[0073] Figure 4 It is a schematic diagram for calculating the most unfavorable transverse stress on the top surface of the bridge deck of the beam bridge without a central partition according to the present invention;

[0074] Figure 5 is the equivalent curvature radius R of the bridge deck in the present invention eq Schematic diagram of calculation;

[0075] Figure 6 It is a schematic diagram of the longitudinal section structure of the beam bridge without middle partition, hanging formwork and negative bending moment tooth block of the present invention;

[0076] Figure 7 It is a schematic diagram of the cross-sectional structure of a beam bridge without a middle partition, without a hanging formwork, and without a negative bending moment tooth block according to the present invention;

[0077] Figure 8 1 is a schematic diagram of the cross-sectional structure of a beam bridge without a central partition and a hanging formwork using a honeycomb bridge deck in Example B1;

[0078] Fig. 9 1 is a schematic diagram of the cross-sectional structure of a beam bridge without a central partition and a hanging formwork using a thick-slit bridge deck in Example B2;

[0079] Fig.10 1 is a schematic diagram of the cross-sectional structure of a beam bridge without a central partition and a hanging formwork using a transverse rib type bridge deck in Example B3;

[0080] Fig.11 is a plate-shell-solid finite element model of a conventional T-beam bridge in Example C;

[0081] Fig.12 is the transverse stress distribution on the top surface of the bridge deck of the conventional T-beam bridge in Example C, where the unit is MPa;

[0082] Fig.13 is the lateral stress on the top surface of the bridge deck of a conventional T-beam bridge without a center diaphragm in Example C, in which the unit is MPa;

[0083] Fig.14 is the Hambly beam grid method finite element model of the conventional T-beam bridge without a diaphragm in Example C;

[0084] Fig.15 is the non-uniform deflection of each prefabricated main beam of the conventional T-beam bridge without a central partition in Example C, and the unit in the figure is mm;

[0085] Fig.16 is the maximum transverse stress at the upper edge of the joint interface when the T-beam bridge without a central partition in Example C is designed according to solid bridge decks of different thicknesses;

[0086] Fig.17 is the maximum longitudinal bending moment of the precast main beam when the T-beam bridge without a central partition in Example C is designed according to solid bridge decks of different thicknesses;

[0087] Fig.18 The plate-shell-solid finite element model and calculation results of the T-beam bridge without a central partition plate using a honeycomb bridge deck in Example C;

[0088] Fig.19 is the maximum lateral distribution coefficient of the precast main beam under different bridge configurations in Example C;

[0089] Fig. 20 is a photo of a scaled test specimen of a conventional T-beam bridge in Example C;

[0090] Fig.21 is a photo of a scaled test specimen of a T-beam bridge without a central partition plate using a honeycomb bridge deck in Example C;

[0091] Fig. 22 is a photograph of a full-scale segment specimen of a T-beam bridge without a central partition using a honeycomb bridge deck in Example C;

[0092] Fig.23 This is a photo of a full-scale segment specimen of the conventional T-beam bridge in Example C.

[0093] Description of reference numerals:

[0094] 1. Prefabricated main beam; 11. Web plate; 111. Web plate vertical rib; 12. Concrete bridge deck; 121: Cantilever plate; 122. Pad plate; 123. Bridge deck hole; 124. Bridge deck transverse rib; 125. End thickening part; 1251. End inclined surface; 1252. Thickening part inclined surface; 1253. Thickening part plane; 126. Non-arched bridge deck cross-section upper edge; 127. Arched bridge deck cross-section upper edge; 13. Bottom plate; 14. Middle partition plate wet joint;

[0095] 2. Wet seams; 21. Seam interfaces;

[0096] 3. Pier top beam; 31. Middle partition; 4. Lower structure;

[0097] 5. Negative bending moment beam; 51. Anchoring notch; 52. Negative bending moment gear block; P. Wheel load. DETAILED DESCRIPTION

[0098] The present invention is further described in detail below in conjunction with test examples and specific implementation methods. However, this should not be understood as the scope of the above subject matter of the present invention being limited to the following embodiments, and all technologies realized based on the content of the present invention belong to the scope of the present invention.

[0099] Example A

[0100] like Figure 3-Figure 7 As shown, the present invention provides a design method for a beam bridge without a middle partition, a hanging mold, or a negative bending moment tooth block, and the design method for a beam bridge without a middle partition, a hanging mold, or a negative bending moment tooth block comprises the following steps:

[0101] S1. Design of initial structural parameters of precast main beam 1: Based on the statistical data of the structural dimensions of the built beam bridge, the cross-sectional form, maximum span L, and cross-sectional inertia moment I of the precast main beam 1 are assumed; the thickness of the concrete bridge deck 12 at the joint interface 21 is assumed to be T1, the thickness of the concrete bridge deck 12 at the web 11 is assumed to be T2, and the number of precast main beams 1 arranged in the transverse direction of the beam bridge is assumed to be J; the webs 11 are numbered 1#, 2#, 3#, ..., (N-1)#, N# from left to right in the transverse direction, and the transverse distance between the center lines of the webs 11 at both ends of the transverse direction of the beam bridge is D;

[0102] S2. Calculation of indirect transverse stress of concrete bridge deck 12: According to the actual support conditions, the load is set at the outermost part of the transverse direction of the beam bridge, and the non-uniform deflection {△ n},{△ n}={△1,△2,△3,…,△ N-1 ,△ N}, △1, △2, △3, …, △ N-1 ,△ N are the vertical deflections of the webs 11 No. 1#, 2#, 3#, ..., (N-1)#, and N#, respectively; a section is taken along the longitudinal direction of the beam bridge, and the bottom of the webs 11 of the section is assumed to be a vertical rigid support, and △1, △2, △3, ..., △4 are applied to the bottom of the webs 11 No. 1#, 2#, 3#, ..., (N-1)#, and N#, one by one. N-1 ,△ N The forced displacement is calculated to obtain the indirect transverse stress σ on the top surface of the concrete bridge deck 12 at this time. b1 ;

[0103] S3. Calculation of direct transverse stress of concrete bridge deck 12: Assuming that the bottom of web 11 is vertically rigidly supported, the load is set at the outermost part of the transverse direction of the beam bridge, and the direct transverse stress σ on the top surface of concrete bridge deck 12 is calculated. b2 ;

[0104] S4. Crack resistance calculation of concrete bridge deck 12: The most unfavorable transverse stress σ on the top surface of concrete bridge deck 12 b According to the indirect transverse stress σ b1 and direct transverse stress σ b2 The superposition calculation, that is, σ b =σ b1 +σ b2 ;

[0105] If σ at the joint interface 21 b ≥f tjp , f tjp is the fatigue tensile strength at the joint interface 21, then go to step S5;

[0106] If σ at the joint interface 21 b <f tjp , then go to step S6;

[0107] S5, increase T1 and / or T2 and / or J and / or I and / or reduce L, return to step S2, and perform crack resistance calculation of the concrete bridge deck 12 again;

[0108] S6. Complete the remaining design in the conventional way: Apply multi-lane, multi-vehicle live loads and other design loads in the conventional influence line method, determine the configuration of the steel bars and steel strands in the precast main beam 1 based on the most unfavorable full-bridge internal force state under the bridge design load combination and the conventional structural design method to complete the beam bridge design.

[0109] Based on the above design method, the present invention proposes a beam bridge without a central partition, without a hanging formwork, and without a negative bending moment tooth block, which includes a precast main beam 1, a wet joint 2, a pier top beam 3 and a lower structure 4; adjacent precast main beams 1 are connected by a wet joint 2, the pier top beam 3 is arranged below the precast main beam 1, and the pier top beam 3 is arranged above the lower structure 4; the precast main beam 1 includes a web 11 and a concrete bridge deck 12, adjacent concrete bridge decks 12 are connected by a wet joint 2, the contact surface between the concrete bridge deck 12 and the wet joint 2 is a joint interface 21, and the web 11 and the concrete bridge deck 12 are integrally formed.

[0110] In this embodiment, the present invention takes into account the obvious non-uniform deflection of the beam bridge when there is no intermediate partition 31 during the design process, so the indirect tensile stress σ of the beam bridge at the upper edge of the joint interface 21 is b1 and direct tensile stress σ b2 The crack resistance of the top surface of the bridge deck is checked by superposition to avoid the phenomenon of cracking of the driving surface of the beam bridge during use. In the design process according to the prior art, when calculating the beam bridge without the central partition 31, the designers did not take into account that there is a significant difference in the vertical deflection difference between the adjacent precast main beams 1 of the beam bridge without the central partition 31 under the condition of load. Each precast main beam 1 will produce non-uniform deflection, and the non-uniform deflection of the precast main beam 1 will usually cause the bridge deck of the beam bridge to have a larger curvature and a relatively arched deformation, which will cause indirect tensile stress in the transverse direction of the bridge at the joint interface 21 of the bridge deck. The superposition of the indirect tensile stress and the direct tensile stress caused by the direct action of the load causes a large number of longitudinal cracks to appear on the driving surface of the existing beam bridge without the central partition 31 during use. In the existing design, when the designer does not consider the existence of indirect tensile stress, when designing the beam bridge without the central partition 31, when the load is biased to the outermost side, each prefabricated main beam 1 will produce deflection and the deflection values ​​are △1, △2, △3, ..., △ N-1 ,△ Nare different, but when the middle partition 31 exists, the vertical deflection difference between each prefabricated main beam 1 and the adjacent prefabricated main beam 1 is basically the same (△1-△2≈△2-△3≈…≈△ N-1 -△ N ), that is, the shape of the top surface of the bridge deck after deflection is still close to the plane, while the vertical deflection differences when there is no middle partition 31 will be significantly different, that is, there will be obvious non-uniform deflection {△ n}. Therefore, without considering the indirect tensile stress σ caused by non-uniform deflection b1 In this case, the f at the joint interface 21 of the beam bridge without the middle partition 31 designed according to the prior art tjp , that is, the fatigue tensile strength, is not enough to resist the most unfavorable lateral stress σ on the top surface of the bridge deck b Because its σ b In fact, it is the indirect tensile stress σ caused by non-uniform deflection b1 The direct tensile stress σ caused by the transverse bending moment generated when the load acts directly b2 of superposition.

[0111] In the design method proposed by the present invention, the indirect tensile stress σ caused by non-uniform deflection is taken into account. b1 In the case of σ, by increasing T1 and / or T2 and / or J and / or I and / or reducing L, the tensile stress at the joint interface 21 of the beam bridge can be reduced, thereby achieving b Controlled below f tjp level, avoiding the occurrence of σ b Compared with the situation that the fatigue tensile strength of the beam bridge is too large, the bridge deck will crack longitudinally. The design scheme proposed by the present invention clarifies the non-uniform deflection effect of the beam bridge without the middle partition 31, and clarifies that the most unfavorable transverse stress of the bridge deck of the beam bridge without the middle partition 31 is the indirect tensile stress σ under the non-uniform deflection effect. b1 and the direct tensile stress σ under the direct action of vehicle load b2 The most unfavorable value appears at the upper edge of the bridge deck joint interface 21, and the anti-cracking calculation method of the top surface of the bridge deck of this type of bridge is given. Finally, by substituting the most unfavorable transverse stress σ b Control the fatigue tensile strength f at the concrete joint interface 21 tjp The safety and reliability of the structural design is ensured, and the problem of longitudinal cracking of the running surface at the joints of the 31-beam bridge without a central partition that may be caused by the design according to the existing technology is effectively avoided, which facilitates the actual design and promotion and application of such bridges.

[0112] Furthermore, the load set in S2 is set at the leftmost side of the transverse direction of the beam bridge within the scope of the specification requirements, and the load set in S3 is set at the leftmost side of the transverse direction of the beam bridge within the scope of the specification requirements. In this embodiment, when the beam bridge is applied to bridge construction in different countries or regions, the specifications of the region are correspondingly adopted according to the specifications of each region, and when the load is arranged at the leftmost side, the specific position of the arrangement is adaptively adjusted according to the requirements of the specifications of each region.

[0113] In a preferred embodiment, see Figure 5 , σ of step S2 b1 =M b1 / W b , taking the cross section of the concrete bridge deck 12 with a longitudinal width of a0 as an example, W b is the section modulus of the concrete bridge deck 12 section with longitudinal width a0, M b1 is the indirect transverse bending moment of the concrete bridge deck 12 section with longitudinal width a0; M b1 =M b1max d y / (D / 2), d y M is the transverse distance of the cross section from the center line of the leftmost web 11; b1max =E c I bmax / R eq , I bmax =a0·[max(T1,T2)] 3 / 12, E c is the elastic modulus of the concrete bridge deck 12, R eq For △1, △2, △3, ..., △ N-1 ,△ N The equivalent radius of curvature of the concrete bridge deck 12 under the forced displacement; R eq =(D / 2) 2 / (2△ g ),△ g is the relative camber; therefore, when N is an odd number, g =△ (N+1) / 2 -(△1+△ N ) / 2, when N is an even number△ g =(△ N / 2 +△ N / 2+1 ) / 2-(△1+△ N ) / 2.

[0114] In this embodiment, the non-uniform deflection produced by each prefabricated main beam 1 causes the bridge deck of the beam bridge to produce a relatively arched deformation, so the indirect transverse stress σ on the concrete bridge deck 12 is b1 is positively correlated with the curvature of the bridge deck. Figure 5Equivalent curvature radius R of the middle bridge deck eq From the calculation diagram, we can see that: since the deformation of the bridge structure in actual operation is still small, it is assumed that the upper edge 126 of the cross section of the bridge deck without arching is a plane, and the upper edge 127 of the cross section of the arched bridge deck is an arc, so the curvature radius R of the arc eq =(D / 2) / sinβ, according to the principle of small angle approximation, sinβ≈β; further according to the chord tangent angle theorem, β=2α, according to the equal angle theorem of parallel lines, α=θ; finally, according to the principle of small angle approximation, θ≈tanθ=△ g / (D / 2), combining the above formulas, we can get R eq =(D / 2) 2 / (2△ g ). At the same time, because the deformation of the bridge deck still belongs to the small displacement theory, the relative camber △ g ≈Vertical deflection of the bridge deck at the transverse centerline of the entire bridge - the average of the vertical deflections of the No. 1 and No. N webs 11.

[0115] Further, in step S2, the non-uniform deflection {△ n}={m n}w, w is the vertical deflection generated when one of the prefabricated main beams 1 of the assumed beam bridge bears the load in step S2 alone; {m n} is the set of load lateral distribution coefficients of all precast main beams 1 when loaded according to S2, {m n}Calculated according to the rigid plate method, the equivalent moment of inertia of the longitudinal unit width bridge deck in the rigid plate method is beq =F(D / (N-1)) 3 / (48E c w eq ), E c is the elastic modulus of the concrete bridge deck 12, F is the unit force, w eq is the equivalent flexibility. eq Calculation method: Assume that the concrete bridge deck 12 between the center lines of the No. 1 and No. 2 webs 11 is a simply supported beam supported at the webs 11. When F is applied at the mid-span of the simply supported beam, the mid-span vertical deflection calculated by conventional structural mechanics methods or finite element modeling is w eq .

[0116] In this embodiment, the non-uniform deflection {△ n}, the calculation error of the transverse distribution coefficient generally has little effect on the longitudinal force calculation of the precast main beam 1, but it has an impact on the indirect transverse stress σ of the bridge deck of the beam bridge without a central partition 31. b1The calculation has a great impact; and in practice, the stiffness of the bridge deck often varies along the transverse direction of the bridge, and the stiffness of the bridge deck calculated by the rigid plate method can only be considered as a fixed value, which will undoubtedly bring a large error in the design process. Therefore, in the design method provided by the present invention, based on the equal displacement under the action of unit force, the variable stiffness bridge deck is approximately calculated as a bridge deck of equal stiffness as a simply supported beam to solve the equivalent moment of inertia I beq , and its equivalent moment of inertia is applied to the process of calculating the set of load lateral distribution coefficients of all precast main beams 1 according to the rigid plate method, so as to reduce the calculation error of non-uniform deflection in the design process and further improve the calculation accuracy of non-uniform deflection in the design method.

[0117] In another embodiment, the non-uniform deflection {△ n The finite element model of the whole bridge can be established according to the conventional Hambly beam grid method. The width of the virtual crossbeam in the model is the actual working width a of the longitudinal direction of the concrete bridge deck 12, a=max{(a1+2h p )+D / (N-1) / 3, 2D / (N-1) / 3}, a1 is the longitudinal bridge-to-ground dimension of the heaviest wheel of the vehicle load, h p is the total thickness of the leveling layer and the pavement layer above the concrete bridge deck 12; the load of a single car or train is set to the leftmost position to calculate the non-uniform deflection {△ n}.

[0118] In this implementation, when the vehicle or train load is applied as lane load, the concentrated force of the lane load is very large, while the actual wheel load P is a uniform force with a certain width and will spread to the bridge deck within a certain range in the longitudinal direction. This results in a large difference between the deformation and stress of the virtual beam of the conventional Hambly beam grid method under the concentrated force of the lane load and the actual situation. b1 Therefore, when modeling a 31-beam bridge without a central partition according to the beam grid method, the virtual beam width in the model is taken as the actual working width a of the bridge deck in the longitudinal direction of the bridge. This can effectively reduce the calculation error of the vertical deflection and the bridge deck stress.

[0119] Furthermore, if Figure 4 As shown in the figure, a segment with a longitudinal width of a0 is taken at the longitudinal mid-span of the beam bridge. The bottom of the web 11 in the segment is assumed to be a vertical rigid support. The heaviest axis of a single vehicle or train load is set at the leftmost side of the segment. The transverse bridge upward edge stress σ at each section of the segment is calculated according to conventional structural mechanics methods or finite element modeling. b22 ; σ at each cross section in step S3 b2 =σ b22 a0 / a n, when the cross section is located between the n#th web 11 and the (n+1)#th web 11 n =min{(a1+2h p )+D / (N-1) / 3,2D / (N-1) / 3}+(n-1)D / (N-1) / 3, otherwise a n =(a1+2h p )+2d c , a1 is the longitudinal bridge dimension of the heaviest wheel of the vehicle, h p is the total thickness of the leveling layer and the paving layer above the concrete bridge deck 12, d c It is the distance between the leftmost edge of the leftmost wheel contacting the ground and the center line of the leftmost web 11.

[0120] In this embodiment, in the actual full bridge force, when the vehicle load is located between the first web 11 and the second web 11, the longitudinal width of the bridge deck between the two webs 11 that actually bears the vehicle load is a. n ; When the effect of the vehicle load spreads between the 2# web 11 and the 3# web 11, the longitudinal width of the bridge deck that actually bears the vehicle load will be further enlarged; the same can be said when the section is between the n# web 11 and the (n+1)# web 11; therefore, based on the geometric relationship and the diffusion at a 45° angle and for safety considerations, it can be calculated according to the above formula.

[0121] Furthermore, in step S4, only the mid-span position σ of the maximum span in the longitudinal direction of the concrete bridge deck 12 is calculated. b , and only the crack resistance calculation is performed on the joint interface 21 at a distance d from the center line of the leftmost web 11; when J is an odd number, d is the distance from the center line of the leftmost web 11 in the transverse direction to the left joint interface 21 of the (J+1) / 2th precast main beam 1; when J is an even number, d is the distance from the center line of the leftmost web 11 in the transverse direction to the right joint interface 21 of the J / 2th precast main beam 1.

[0122] In this embodiment, the mid-span deflection at the maximum span in the longitudinal direction of the bridge is the maximum vertical deflection of the entire bridge. At this time, the non-uniform deflection effect between the prefabricated main beams 1 is also the most obvious, that is, the most unfavorable transverse stress σ on the top surface of the concrete bridge deck 12 of the beam bridge b It usually appears at the mid-span position of the maximum span in the longitudinal direction of the beam bridge, that is, only the σ at the mid-span position of the maximum span in the longitudinal direction of the concrete bridge deck 12 needs to be controlled. bis a smaller value. In addition, the maximum bending moment of the bridge deck caused by non-uniform deflection usually occurs at the center line of the entire bridge in the transverse direction and decreases toward both sides. Therefore, only the joint section closest to this point can be checked, that is, the joint interface 21 at a distance d from the center line of the leftmost web 11. Therefore, it is only necessary to ensure that the σ of the joint section closest to the transverse center line at the mid-span position of the concrete bridge deck 12 in the longitudinal direction is b <f tjp , it can be ensured that the beam bridge without the central partition 31 will not experience the common longitudinal cracking when designed according to the prior art during use.

[0123] In a preferred embodiment, f in S4 tjp =γ j γ p ·min(f ty ,f tj ), f ty is the design value of concrete tensile strength of precast main beam 1, f tj is the design value of concrete tensile strength of wet joint 2, γ j is the tensile strength correction factor of concrete at the joint interface 21, γ p is the correction factor for concrete fatigue tensile strength.

[0124] In this embodiment, since there is a transition layer with a high water-cement ratio at the interface between the new and old concrete, a cement mortar matrix with relatively loose pores is easily formed, and the initial damage of the old concrete during roughening and the shrinkage stress of the new concrete also affect the stress performance at the interface, so the tensile strength of the concrete at the joint interface 21 must be reduced accordingly. At the same time, considering that the bridge bears live loads for a long time and the stress on the bridge deck changes repeatedly from tension to compression, the fatigue effect should be considered to further correct the tensile strength of the concrete; generally, the tensile strength correction coefficient of the concrete at the joint interface 21 is γ j =0.49, concrete fatigue tensile strength correction factor γ p =0.6, thus ensuring the safety of the beam bridge during use, avoiding over-presetting the fatigue tensile strength at the joint interface 21 of the concrete bridge deck 12, and further ensuring that the beam bridge will not have longitudinal cracks on the driving surface of the traditional 31T beam bridge without a central partition during use.

[0125] Example B

[0126] See also Figure 3-Figure 10Based on the above-mentioned design method of a beam bridge without a center partition, without a hanging formwork, and without a negative bending moment tooth block, the present invention also provides a beam bridge without a center partition, without a hanging formwork, and without a negative bending moment tooth block. The design method of a beam bridge without a center partition, without a hanging formwork, and without a negative bending moment tooth block, the present invention also provides a beam bridge without a center partition, without a hanging formwork, and without a negative bending moment tooth block, which includes a prefabricated main beam 1, a wet joint 2, a pier top crossbeam 3 and a lower structure 4; adjacent prefabricated main beams are connected by wet joints, the pier top crossbeam is arranged below the prefabricated main beam, and the pier top crossbeam is arranged above the lower structure; the prefabricated main beam includes a web 11 and a concrete bridge deck 12, adjacent concrete bridge decks are connected by wet joints, the contact surface between the concrete bridge deck and the wet joint is a joint interface 21, and the web and the concrete bridge deck are integrally formed.

[0127] In this embodiment, by eliminating the diaphragms outside the pier top, the high-altitude suspension construction problem of a large number of wet joints 14 of a large number of middle diaphragms 31 of conventional assembled beam bridges is avoided, which greatly enhances the construction safety, greatly reduces the amount of on-site work, and significantly improves the assembly construction efficiency. In addition, compared with the traditional beam bridge with middle diaphragms 31, this beam bridge eliminates a large number of dense middle diaphragms 31, and has better permeability and appearance in the longitudinal direction of the bridge than conventional assembled beam bridges.

[0128] like Figure 7 As shown, a cantilever plate 121 is provided at the transverse end of the precast main beam 1, and the transverse net distance of the cantilever plates 121 between adjacent precast main beams 1 does not exceed 60 cm. A pad 122 is provided above the cantilever plate 121, and the pad 122 is connected to the wet joint 2 to form an overall common force.

[0129] In this embodiment, the beam bridge designed without the middle partition 31 does not require personnel to go up and down from the bridge deck joint to apply the middle partition 31 during the construction of the beam bridge. Therefore, the cantilever plate 121 can be preset and only a small clearance can be left between the adjacent prefabricated main beam 1, thereby greatly reducing the amount of cast-in-place engineering of the wet joint 2, avoiding the performance waste caused by the wet joint 2 concrete being unable to bear its own wet weight, and the prefabricated main beam 1 of the beam bridge without the middle partition 31 can have a large bending stiffness under the same amount of concrete, thereby reducing the amount of steel used in the construction process and improving economy. At the same time, placing small pieces of thin pads 122 one by one above the cantilever plate 121 can form protection on the prefabricated main beam 1 and serve as a permanent bottom mold, thereby completing the steel bar connection and cast-in-place operation of the wet joint 2, and the thin pads 122 can also be prefabricated with concrete materials and form a whole with the wet joint 2 concrete, so as to bear the force together, which not only saves the amount of engineering, but also avoids the waste of material performance, and further improves the practicality of the beam bridge. Since the beam bridge does not need to have personnel go up and down from the bridge deck joint to construct the middle partition 31 and the negative bending moment beam 5, the width of the wet joint 2 can be designed to be as narrow as possible, and the cantilever plate 121 structure is set at the transverse end of the concrete bridge deck 12 in the prefabricated main beam 1, and the small-sized pad 122 above is used to achieve the complete formwork-free and formwork-free operation of the entire bridge. Therefore, the beam bridge can avoid the problem of a large number of formworks required for pouring and removing the wet joints 2 of the bridge deck of conventional assembled beam bridges, and has a smaller amount of concrete cast-in-place, greatly saves the cost of wet joint 2 construction measures, and significantly improves the efficiency of assembly construction.

[0130] In a preferred embodiment, the prefabricated main beam 1 also includes a negative bending moment beam 5 and an anchoring groove 51; there are no less than two prefabricated main beams 1 in the longitudinal direction of the bridge, and the adjacent prefabricated main beams 1 in the longitudinal direction of the bridge are connected by the negative bending moment beam 5, and min (T1, T2) ≥ 20 cm, and the concrete bridge deck 12 is preset with an anchoring groove 51, and the negative bending moment beam 5 is anchored in the anchoring groove 51.

[0131] In this embodiment, after the beam bridge is designed without the middle diaphragm 31, it is not necessary for personnel to go up and down from the bridge deck joint to thread, tension and anchor the negative bending moment beam 5. The thickness of the bridge deck of the beam bridge without the middle diaphragm 31 is thicker than that of the conventional prefabricated beam bridge, so the negative bending moment beam 5 can be anchored in the reserved notch of the thicker bridge deck directly above the bridge deck, thereby realizing the structural design of the surface negative bending moment tooth block 52. By directly anchoring the negative bending moment beam 5 in the thicker bridge deck, it is no longer necessary to set a large number of tooth blocks under the bridge deck for prestressed tensioning and anchoring, avoiding a large number of high-altitude suspension tensioning operations of the negative bending moment beam 5 of the conventional prefabricated beam bridge, greatly enhancing the construction safety, greatly saving the cost of suspension construction measures, significantly saving tensioning man-hours, improving the prestressed tensioning operation space and working environment, and better ensuring the construction quality.

[0132] Example B1 - Honeycomb bridge deck: Figure 8 As shown, the present invention provides a honeycomb bridge deck structure, wherein the prefabricated main beam 1 also includes bridge deck transverse ribs 124, and the concrete bridge deck 12 is provided with bridge deck holes 123 evenly spaced in the longitudinal and transverse directions of the bridge, and bridge deck transverse ribs 124 are provided between longitudinally adjacent bridge deck holes 123, and the bridge deck transverse ribs 124 are provided with shear steel bars spaced along the transverse direction of the bridge.

[0133] In this embodiment, the evenly spaced bridge deck holes 123 can significantly improve the stiffness of the bridge deck without increasing the dead load, thereby reducing the non-uniform deflection effect and reducing the tensile stress on the top surface of the bridge deck, while greatly reducing the amount of steel bars used in the transverse direction of the bridge deck. Bridge deck cross ribs 124 are provided between the longitudinally adjacent bridge deck holes 123. The bridge deck cross ribs 124 and the bridge deck near the bridge deck holes 123 form an I-shaped section to jointly bear the wheel load. The bridge deck reinforcement can be designed according to the conventional I-shaped cross-section beam. Compared with the stress state of the bridge deck as a rigid truss without the bridge deck cross ribs 124, the calculation and reinforcement workload of the bridge deck reinforcement can be significantly simplified.

[0134] Example B2 - Thick seam bridge deck: In a preferred embodiment, see Fig. 9 The present invention provides a thick seam type bridge deck structure, wherein the prefabricated main beam 1 further comprises a closed box section structure, a bottom plate 13 is provided at the bottom of the web 11, the bottom plate 13, the web 11 and the concrete bridge deck 12 form a closed box section structure, and an end thickening portion 125 is provided at the transverse end of the concrete bridge deck 12, and the end thickening portion 125 is connected to the wet joint 2. An end inclined surface 1251 is provided at the transverse end of the concrete bridge deck 12, and the end thickening portion 125 comprises a thickening portion inclined surface 1252 and a thickening portion plane 1253, and the thickening portion inclined surface 1252 is connected to the wet joint 2, and the slope of the thickening portion inclined surface 1252 is not greater than 1.00, and T1>T2.

[0135] In this embodiment, after the joint interface 21 is thickened, the non-uniform deflection effect is not significantly reduced, but because the cross-sectional stiffness and thickness are close to the cubic relationship, the bending stiffness of the cross section at this location is significantly increased, thereby significantly reducing the tensile stress at the joint interface 21. After the end bevel 1251 is set, the shear stiffness and shear bearing capacity of the new and old concrete joint interface 21 can be significantly improved, and the upward development of the cracks at the lower edge of the interface can be blocked to a certain extent. When the slope of the thickened portion bevel 1252 is not greater than 1.00, it can facilitate the transmission of the lateral stress of the bridge deck and reduce the influence of stress concentration.

[0136] Example B3 - transverse rib bridge deck, see Fig. 9The present invention provides a transverse rib type bridge deck structure, wherein a bottom plate 13 is provided at the bottom of the web 11, an end thickening portion 125 is provided at the transverse end of the concrete bridge deck 12, and a bridge deck transverse rib 124 is provided between the web 11 and the end thickening portion 125, and the bridge deck transverse rib 124 is located below the concrete bridge deck 12 and is arranged at intervals along the longitudinal direction of the concrete bridge deck 12. The concrete bridge deck 12 is connected to the bridge deck transverse rib 124, and the thickness T1 of the concrete bridge deck 12 at the joint interface 21 includes the cross-sectional thickness of the concrete bridge deck 12 and the cross-sectional thickness of the bridge deck transverse rib 124, and the thickness T1 is ≥ 30 cm.

[0137] In this embodiment, the design of the transverse rib bridge deck allows the bridge deck and the transverse ribs below to form a T-shaped section. As the section height increases, its stiffness increases by nearly three times, which can significantly reduce the non-uniform deflection effect. At the same time, the tensile stress at the joint interface 21 can be reduced by significantly increasing the bending stiffness.

[0138] Further, in a preferred embodiment, the web 11 includes a steel structure, and the side of the web 11 is provided with web vertical ribs 111 arranged at intervals along the longitudinal direction of the beam bridge, and the top ends of the web vertical ribs 111 are connected to the deck. The web vertical ribs 111 are at the same longitudinal position as the bridge deck transverse ribs 124 to resist the transverse deformation transmitted by the bridge deck transverse ribs 124.

[0139] In this embodiment, when the web 11 of the prefabricated main beam 1 is a steel structure, the deformation transmitted from the bridge deck transverse ribs 124 will significantly reduce the local stability of the web 11, so the web vertical ribs 111 are correspondingly arranged to offset the adverse effects caused by the bridge deck transverse ribs 124.

[0140] Example C

[0141] In order to verify the technical effect of the present invention, a prefabricated prestressed concrete simply supported T-beam bridge (referred to as conventional T-beam bridge, cross-section structure as shown in FIG. 1 ) with a span of 40 m and a width of 12.75 m, which is currently commonly used in highway bridges in China, was used. Figure 2 ) as an example, conventional T-beam bridges are provided with middle partitions 31 at 1 / 2L, 3 / 8L and 5 / 8L, and a single span has a total of 3 middle partitions 31. The number of precast main beams 1 arranged in the transverse direction of the conventional T-beam bridge is J=5, and their webs 11 are numbered 1#, 2#, 3#, 4#, 5# from left to right in the transverse direction, and the corresponding precast main beams 1 are also numbered 1#, 2#, 3#, 4#, 5#. The precast main beams 1 and wet joints 2 are both made of concrete with strength grade C50, and their tensile strength design value f ty =f tj=1.83MPa. The beam height of the precast main beam 1 is 2.5m, and the transverse distance between the center lines of the leftmost web 11 and the rightmost web 11 is 4×2.55=10.2m. The bridge deck thickness at the joint interface 21 of the conventional T-beam bridge is T1=0.2m, and the bridge deck thickness at the web 11 is T2=0.25m; the wet joint 2 is 0.8m wide, and the web 11 is 0.2m thick. The full-bridge refined plate-shell-solid finite element model of the conventional T-beam bridge is established as follows: Fig.11 As shown. Fig. 20 As shown in the figure, the scaled test specimen was used to calibrate the refined plate-shell-solid finite element model of the conventional T-beam bridge, so that the errors of various stress and deformation indicators of the two were within 5%. Then, a single highway Class I vehicle load was arranged on the left side in the transverse direction and at the point where the vertical deflection of the whole bridge is the largest in the longitudinal direction. The transverse stress of the top surface of the bridge deck in the range of 1 / 2L to 5 / 8L in the longitudinal direction was calculated as follows: Fig.12 As shown, it can be seen that the maximum tensile stress on the upper edge of the joint interface 21 is σ b (3) =0.46MPa <f tjp =γ j γ p ·min(f ty ,f tj )=0.49×0.6×1.83=0.54MPa, that is, the upper edge of the joint interface 21 of the conventional T-beam bridge will not crack.

[0142] Furthermore, if all three intermediate partitions 31 of the conventional T-beam bridge are removed, the calculation shows that the transverse stress on the top surface of the bridge deck in the range of 1 / 2L to 5 / 8L in the longitudinal direction of the conventional T-beam bridge without intermediate partitions 31 is as follows: Fig.13 As shown, it can be seen that the tensile stress at the upper edge of the joint interface 21 at a distance d = 4.225m from the center line of the leftmost web 11 is the largest, and its value is σ b (0) =0.93MPa>f tjp It can be seen that after long-term operation, the upper edge of the joint of the conventional T-beam bridge without the middle partition 31 will crack on a large scale, and the moment of cracking is easy to tear the bridge deck waterproof coating and even part of the asphalt layer; and when the wheel load directly acts on the wet joint 2, the tensile stress at the lower edge of the joint interface 21 is also significantly greater than f tjp Therefore, the lower edge of the joint is also prone to cracking. Therefore, the conventional T-beam bridge without a central partition 31 is a stress mode in which both the upper and lower edges of the joint may be pulled and cracked, and the cracks are easy to penetrate each other at the interface. Eventually, under the long-term repeated effects of direct impact of wheels and environmental factors (rainwater erosion, steel bar rust expansion, winter freezing and thawing, and deicing salt corrosion), reflective cracks appear on the asphalt surface layer. This is the fundamental reason for the defects of the 31-inch T-beam bridge without a central partition built in China in the 1990s.

[0143] See also Figure 14-15 In order to verify the design method of the beam bridge without middle partition, hanging formwork and negative bending moment tooth block of the present invention, a finite element model of the Hambly beam grid method of a conventional T beam bridge without middle partition 31 is established as follows Fig.14 The width of the virtual beam in the model is the actual working width a of the bridge deck in the longitudinal direction, and because the total thickness of the leveling layer and the pavement layer above the bridge deck is 0.18m, a=max{(a1+2h p )+D / (N-1) / 3,2D / (N-1) / 3}=max{(0.2+2×0.18)+2.55 / 3,2×2.55 / 3}=1.70m. Fig.14 As shown, according to the method of the present invention, the non-uniform deflection {△ n}, where △1 = -10.02mm, △2 = -6.34mm, △3 = -3.23mm, △4 = -1.40mm, △5 ​​= -0.25mm; g =△3-(△1+△5) / 2=-3.23-(-10.02+-0.25) / 2=1.905mm, then R eq =(D / 2) 2 / (2△ g ) = (4 × 2550 / 2) 2 / (2×1.905)=6.8268e6mm. Further, taking the longitudinal width of the bridge deck a0=1m, we can calculate I bmax =a0·[max(T1,T2)] 3 / 12=(1000×250 3 ) / 12=1.3021e9mm 4 , so we get M b1max =E c I bmax / R eq =3.45e4×1.3021e9 / 6.8268e6 / 10 6 =6.58kN·m, so M b1 =M b1max d y / (D / 2)=6.58×4225 / (4×2550 / 2)=5.45kN·m, σ b1 =M b1 / W b =5.45e6 / ((1000×200 2) / 6)=0.82MPa. A longitudinal a0=1m wide segment is selected at the longitudinal mid-span of the bridge. The bottoms of all webs 11 of the segment are assumed to be vertical rigid supports. The heaviest axis of a single vehicle load is arranged on the left side. The upper edge stress σ at each section of the bridge deck is calculated using conventional structural mechanics methods. b22 =0.37MPa; and the joint interface 21 at a distance d=4.225m from the center line of the leftmost web 11 is located between the second web 11 and the third web 11, then a n =min{(a1+2h p )+D / (N-1) / 3,2D / (N-1) / 3}+(n-1)D / (N-1) / 3=a2=min{(0.2+2×0.18)+2.55 / 3,2×2.55 / 3}+(2-1)×2.55 / 3=1.41+2.55 / 3=2.26m, so the σ b2 =σ b22 a0 / a n =0.37×1 / 2.26=0.16MPa. From the above, we can get σ b =σ b1 +σ b2 =0.82+0.16=0.98MPa, it can be seen that the σ calculated by the design method of the beam bridge without the middle partition 31 of the present invention is b It is close to the result of the refined plate-shell-solid finite element model (0.93MPa) and is slightly safer; therefore, the beam bridge design method without central partition, hanging formwork, and negative bending moment tooth block proposed in the present invention can be used for the actual design of such bridges and greatly simplifies the calculation workload.

[0144] like Fig.16 and 17 As shown, further, by adopting the beam bridge without middle partition 31 of the present invention and its design method, the thickness of T1 is increased from 20 cm to 60 cm by 5 cm increments and the bridge deck is kept as a solid slab, and the load arrangement is kept consistent with the conventional T beam bridge with middle partition 31, the maximum transverse stress change at the upper edge of the bridge deck joint interface 21 at the longitudinal mid-span is calculated as follows: Fig.16 It can be seen that the transverse tensile stress on the upper edge of the joint interface 21 decreases with the increase of the bridge deck thickness; when the bridge deck T1 is thickened to 40cm, the maximum tensile stress on the upper edge of the joint interface 21 (σ b =0.44MPa) is lower than f tjp (0.54MPa) and with the middle diaphragm 31 (0.46MPa), so the lateral force of the solid bridge deck at this thickness is slightly better than that of the beam bridge with the middle diaphragm 31. Fig.17The longitudinal bending moment variation of a 31T beam bridge without a central partition under a single lane eccentric load is given. It can be seen that after thickening the bridge deck, the unevenness of the longitudinal bending moment variation of the 31T beam bridge without a central partition is reduced, indicating that after thickening the bridge deck, in addition to increasing the bridge deck section modulus W at the joint, b It directly reduces the joint stress and indirectly reduces the indirect lateral bending moment M by reducing the degree of non-uniform deflection. b1 , thus reducing the joint stress of the bridge deck. In addition, when the thickness is increased to 40cm, the bending stiffness of the bridge deck section increases by 8 times compared with the original design of 20cm, and the longitudinal bending moments of the 1# and 2# precast main beams 1 of the T-beam bridge without the middle partition 31 are both smaller than those of the 1# and 2# precast main beams 1 with the middle partition 31, that is, more bending moments are allocated to the 3# to 5# precast main beams 1; it can be predicted that the internal forces of the outermost beams (1# and 5# precast main beams 1) and the secondary outer beams (2# and 4# precast main beams 1) designed according to the most unfavorable envelope of multiple lanes will be smaller than those of the T-beam bridge with the middle partition 31, that is, the longitudinal force of the T-beam bridge without the middle partition 31 of this thickness under vehicle load is also better than that of the T-beam bridge with the middle partition 31 (however, considering that the ratio of the vehicle load effect to the total effect in the longitudinal calculation of the concrete beam bridge is not large, the difference in longitudinal force with or without the middle partition 31 will not be very large).

[0145] Therefore, when the deck of the above-mentioned T-beam bridge without the central partition 31 is thickened to 40cm, the stress on the longitudinal beam and the deck under the vehicle load is better than that of the T-beam bridge with the central partition 31. However, the effect of the constant load is significantly increased at this time, and the comprehensive benefit may not be economical. Therefore, holes are set at intervals in the longitudinal and transverse directions of the 40cm thick solid deck, that is, a honeycomb deck is used, and a deck transverse rib 124 is provided between the longitudinally adjacent deck holes 123; at the same time, a cantilever plate 121 is provided at the transverse end of the precast main beam 1, and the transverse net distance of the cantilever plate 121 between the two adjacent precast main beams 1 is 4cm. A pad 122 prefabricated with M50 grade mortar is provided above the cantilever plate 121. The pad 122 forms a whole with the wet joint 2 concrete and bears stress together. At this time, the maximum tensile stress at the upper edge of the honeycomb deck joint interface 21 calculated by the design method of the present invention is σ b =0.48MPa, still lower than f tjp (0.54MPa), that is, at this time, the upper edge of the joint interface 21 will not crack, and the stress is basically the same as that of the 40cm solid bridge deck and the 31T beam bridge with a middle partition. Fig.21 As shown in the figure, a scaled test specimen was made for the above-mentioned T-beam bridge without central partition using honeycomb bridge deck, and a refined plate-shell-solid finite element model of the whole bridge calibrated based on the test data was established. The transverse stress results of the mid-span section were calculated as shown in Fig.18 As shown, the maximum tensile stress on the upper edge of the joint interface 21 is 0.45 MPa, which is consistent with the σ calculated by the design method of the present invention.b This further proves that the method of the present invention is sufficiently accurate and relatively safe.

[0146] Finally, for different bridge structures in this embodiment, the maximum lateral distribution coefficients {m n}(Take the envelope value under 1 to 3 lanes load) Fig.19 It can be seen that the transverse distribution coefficient of the T-beam bridge without central partition using honeycomb bridge deck is basically the same as that of the 40cm solid deck, indicating that the force transmission performance of the solid bridge deck has not been significantly changed after the holes are set; and the transverse distribution coefficient of the outermost beam of the T-beam bridge without central partition using honeycomb bridge deck is significantly reduced compared with the conventional T-beam bridge, while the second outer beam is basically the same, indicating that it has better longitudinal force performance than the conventional T-beam bridge. Fig. 22 and Fig.23 As shown, in order to verify the anti-cracking effect at the wet joint 2 of the above-mentioned T-beam bridge without a central partition and the stress-bearing performance of the cantilever plate 121 and the pad 122, a full-scale segment test specimen was made and static loading was carried out, and compared with the full-scale segment specimen test of the conventional T-beam bridge; during the static loading process, cracks appeared in the joint interface 21 of the conventional T-beam bridge when the load was loaded to 87.5kN, while no cracks appeared in the joint interface 21 when the T-beam bridge without a central partition was loaded to the destruction load of 335.2kN. It can be seen that the anti-cracking performance of the wet joint 2 of the T-beam bridge without a central partition is much higher than that of the conventional T-beam bridge, and the combined stress-bearing performance of the cantilever plate 121 and the pad 122 is also sufficiently safe and reliable.

[0147] In this embodiment, Fig. 20 is a photo of a scaled test specimen of a conventional T-beam bridge. Fig. 20 The scaled test specimen shown in the figure is used to calibrate the refined plate-shell-solid finite element model of the full bridge of a conventional T-beam bridge with a center partition 31, so as to compare and verify the reason why the joint interface 21 of the conventional T-beam bridge is prone to cracking in the absence of the center partition 31.

[0148] Fig.21 is a scaled test specimen of a T-beam bridge without a central partition plate using a honeycomb bridge deck in Example C. Fig.21 The scaled test specimen shown in the figure is used to test a T-beam bridge without a central partition. Based on the test data, a refined plate-shell-solid finite element model of the full-bridge T-beam bridge without a central partition using a honeycomb bridge deck is calibrated, and the maximum tensile stress at the upper edge of the joint interface 21 at the mid-span section is calculated and then compared with the σ obtained by the design method of the present invention. b The comparison is to verify the accuracy and safety of the design method of the present invention.

[0149] Fig. 22 is a photograph of a full-scale segment specimen of a T-beam bridge without a central partition using a honeycomb bridge deck in Example C, Fig.23is a photograph of a full-scale segment specimen of a conventional T-beam bridge in Example C, for comparison Fig. 22 and Fig.23 It can be seen from the static loading test data of full-scale segment specimens that the crack resistance of the honeycomb bridge deck joints of the T-beam bridge without a central partition is much higher than the 20 cm thick solid bridge deck of the conventional T-beam bridge, and the combined stress performance of the cantilever plate 121 and the pad 122 is safe and reliable.

[0150] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. The design method of a beam bridge without a central partition, hanging formwork, or negative bending moment, characterized in that: The beam bridge without middle diaphragm, hanging formwork and negative bending moment tooth block comprises a prefabricated main beam, a wet joint, a pier top cross beam and a lower structure; the adjacent prefabricated main beams are connected by the wet joint, the pier top cross beam is arranged below the prefabricated main beam, and the pier top cross beam is arranged above the lower structure; The prefabricated main beam comprises a web and a concrete bridge deck, the adjacent concrete bridge decks are connected by the wet joint, the contact surface between the concrete bridge deck and the wet joint is a joint interface, and the web is integrally formed with the concrete bridge deck; Based on the beam bridge without middle partition, hanging formwork and negative bending moment tooth block, the design method of the beam bridge includes the following steps: S1. Initial structural parameter design of prefabricated main beam: Based on the statistical data of the structural dimensions of the existing beam bridges, it is assumed that the cross-sectional form and maximum span of the prefabricated main beam L , Section moment of inertia I ; Assume that the thickness of the concrete bridge deck at the joint interface is T 1. The thickness of the concrete bridge deck at the web is T 2. Assume that the number of prefabricated main beams arranged in the transverse direction of the beam bridge is J ; The webs are numbered 1#, 2#, 3#, ..., ( N -1)#、 N #, the transverse distance between the center lines of the webs at both ends of the beam bridge is D ; S2. Calculation of indirect transverse stress of concrete bridge deck: According to the actual support conditions, the load is set at the outermost part of the transverse direction of the beam bridge, and the non-uniform deflection {△ n },{△ n }={△1,△2,△3,…,△ N-1 ,△ N }, △1, △2, △3, …, △ N-1 ,△ N They are No. 1#, No. 2#, No. 3#, ..., ( N -1)#、 N The vertical deflection of the web plate #; the longitudinal length along the longitudinal direction of the beam bridge is a 0, the bottom of the web of the segment is assumed to be a vertical rigid support, for No. 1, No. 2, No. 3, ..., ( N -1)#、 N The bottom of the web described in # is applied with △1, △2, △3, ..., △ N-1 ,△ N The forced displacement is σ b1 = M b1 / W b The indirect transverse stress of the top surface of the concrete bridge deck in the transverse direction of the bridge is calculated. σ b1 ; For the vertical width a 0 of the cross section of the concrete bridge deck, W b is the section modulus of the cross section of the concrete bridge deck, M b1 is the indirect transverse bending moment of the cross section of the concrete bridge deck; M b1 = M b1max d y / ( D / 2), d y is the transverse distance from the cross section of the concrete bridge deck to the center line of the leftmost web; M b1max = E c I bmax / R eq , I bmax = a 0·[max( T 1, T 2)] 3 / 12, E c is the elastic modulus of the concrete bridge deck, R eq For △1, △2, △3, ..., △ N-1 ,△ N The equivalent curvature radius of the concrete bridge deck under the forced displacement; R eq =( D / 2) 2 / (2△ g ),△ g is the relative camber; N When it is an odd number g =△ (N+1) / 2 -(△1+△ N ) / 2, when N When it is an even number g =(△ N / 2 +△ N / 2+1 ) / 2-(△1+△ N ) / 2; S3. Calculation of direct transverse stress of concrete bridge deck: Assuming that the bottom of the web is vertically rigidly supported, the load is set at the outermost part of the transverse direction of the beam bridge, and the direct transverse stress on the top surface of the concrete bridge deck is calculated. σ b2 ; S4. Crack resistance calculation of concrete bridge deck: The most unfavorable transverse stress on the top surface of the concrete bridge deck σ b According to indirect transverse stress σ b1 Direct transverse stress σ b2 The superposition calculation is σ b = σ b1 + σ b2 ; If the joint interface σ b ≥ f tjp , f tjp is the fatigue tensile strength at the joint interface, then go to step S5; If the joint interface σ b < f tjp , then go to step S6; S5, increase T 1 and / or T 2 and / or J and / or I and / or reduce L , return to step S2 and perform crack resistance calculation of the concrete bridge deck again; S6. Complete the remaining design in the conventional way: apply multi-lane, multi-vehicle live loads and other design loads in the conventional influence line method, determine the configuration of the steel bars and steel strands in the precast main beam according to the most unfavorable full-bridge internal force state under the bridge design load combination and the conventional structural design method to complete the beam bridge design.

2. The design method of a beam bridge without a central partition, hanging formwork, or negative bending moment according to claim 1 is characterized in that: The load set in S2 is set at the leftmost side of the transverse direction of the beam bridge within the scope required by the specification, and the load set in S3 is set at the leftmost side of the transverse direction of the beam bridge within the scope required by the specification.

3. The design method of a beam bridge without a central partition, hanging formwork, or negative bending moment gear block according to claim 1 is characterized in that: The non-uniform deflection {△ n }={ m n } w , w is the vertical deflection generated when assuming that one of the prefabricated main beams of the beam bridge bears the load in step S2 alone; m n } is the set of load lateral distribution coefficients of all the prefabricated main beams when loaded according to S2, { m n }Calculated according to the rigid plate method, the equivalent moment of inertia of the longitudinal unit width bridge deck in the rigid plate method is I beq = F ( D / ( N -1)) 3 / (48 E c w eq ), E c is the elastic modulus of the concrete bridge deck, F is the unit force, w eq is the equivalent flexibility; w eq The calculation method is as follows: the concrete bridge deck between the center lines of the webs No. 1 and 2 is assumed to be a simply supported beam supported at the webs, and the F The mid-span vertical deflection calculated by conventional structural mechanics methods or finite element modeling is w eq .

4. The design method of a beam bridge without a central partition, hanging formwork, or negative bending moment according to claim 1 is characterized in that: The non-uniform deflection {△ n The finite element model of the whole bridge can be established according to the conventional Hambly beam grid method, and the width of the virtual beam in the model is the actual working width of the concrete bridge deck in the longitudinal direction of the bridge. a , a =max{( a 1+2 h p )+ D / ( N -1) / 3, 2 D / ( N -1) / 3}, a 1 is the longitudinal dimension of the heaviest wheel of the vehicle load towards the ground, h p is the total thickness of the leveling layer and the pavement layer above the concrete bridge deck; the load of a single car or train is set to the leftmost position to calculate the non-uniform deflection of the precast main beam {△ n }.

5. The design method of a beam bridge without a central partition, hanging formwork, or negative bending moment according to claim 1 is characterized in that: The longitudinal width of the beam bridge at the longitudinal mid-span is a 0, the bottom of the web in the segment is assumed to be a vertical rigid support, the heaviest axis of a single vehicle or train load is set at the leftmost side of the segment, and the transverse bridge upward edge stress at each section of the segment is calculated according to conventional structural mechanics methods or finite element modeling σ b22 ; The σ b2 = σ b22 a 0 / a n , when the section is located at n #The web and the ( n +1)# between the webs a n =min{( a 1+2 h p )+ D / ( N -1) / 3,2 D / ( N -1) / 3}+( n -1) D / ( N -1) / 3, otherwise a n =( a 1+2 h p )+2 d c , a 1 is the longitudinal bridge-to-ground dimension of the heaviest wheel on the vehicle. h p is the total thickness of the leveling layer and the paving layer above the concrete bridge deck, d c It is the distance from the leftmost edge of the leftmost wheel contacting the ground to the centerline of the leftmost web of the vehicle load.

6. The design method of a beam bridge without a central partition, hanging formwork, or negative bending moment gear block according to claim 1 is characterized in that: In step S4, only the mid-span position of the maximum span in the longitudinal direction of the concrete bridge deck is calculated. σ b , and only for the distance from the centerline of the leftmost web d Carry out crack resistance calculation on the joint interface at the position; when J When is an odd number, d From the center line of the leftmost web of the transverse bridge to the ( J +1) / 2 pieces of the distance between the left side joint interface of the prefabricated main beam; when J When is an even number, d From the centerline of the leftmost web to the J / 2 pieces are the distance between the right side joint interfaces of the prefabricated main beams.

7. The design method of a beam bridge without a central partition, hanging formwork, or negative bending moment according to claim 1 is characterized in that: As described in S4 f tjp = γ j γ p ·min( f ty , f tj ), f ty is the design value of the concrete tensile strength of the precast main beam, f tj is the design value of concrete tensile strength of the wet joint, γ j is the tensile strength correction factor of concrete at the joint interface, γ p is the correction factor for concrete fatigue tensile strength.

8. The design method of a beam bridge without a central partition, hanging formwork, or negative bending moment tooth block according to claim 1 is characterized in that: A cantilever plate is provided at the transverse end of the prefabricated main beam, and the transverse net distance of the cantilever plates between adjacent prefabricated main beams does not exceed 60 cm. A pad is provided above the cantilever plate, and the pad is connected to the wet joint to form an overall common force.

9. The design method of a beam bridge without a central partition, hanging formwork, or negative bending moment gear block according to claim 1 is characterized in that: The prefabricated main beam also includes a negative bending moment beam and an anchoring notch; the prefabricated main beam has no less than 2 pieces in the longitudinal direction of the bridge, and the adjacent prefabricated main beams in the longitudinal direction of the bridge are connected by the negative bending moment beam, and min( T 1, T 2) ≥20cm, the concrete bridge deck is preset with the anchoring notch, and the negative bending moment beam is anchored in the anchoring notch.

10. The design method of a beam bridge without a central partition, hanging formwork, or negative bending moment according to any one of claims 1 to 9, characterized in that: The prefabricated main beam also includes bridge deck transverse ribs. The concrete bridge deck is provided with evenly spaced bridge deck holes in the longitudinal and transverse directions. The bridge deck transverse ribs are provided between the longitudinally adjacent bridge deck holes. The bridge deck transverse ribs are provided with shear reinforcement bars spaced along the transverse direction.

11. The design method of a beam bridge without a central partition, hanging formwork, or negative bending moment tooth block according to any one of claims 1 to 9, characterized in that: The prefabricated main beam also includes a closed box-section structure, a bottom plate is arranged at the bottom of the web, the bottom plate, the web and the concrete bridge deck form the closed box-section structure, and the transverse end of the concrete bridge deck is provided with an end thickening portion, and the end thickening portion is connected to the wet joint.

12. The design method of a beam bridge without a central partition, hanging formwork, or negative bending moment tooth block according to claim 11 is characterized in that: The transverse end of the concrete bridge deck is provided with an end inclined surface, the end thickened portion includes a thickened portion inclined surface and a thickened portion plane, the thickened portion inclined surface is connected to the wet joint, and the slope of the thickened portion inclined surface is not greater than 1.00, and T 1> T 2.

13. The design method of a beam bridge without a central partition, hanging formwork, or negative bending moment according to any one of claims 1 to 9, characterized in that: A bottom plate is provided at the bottom of the web, an end thickening portion is provided at the transverse end of the concrete bridge deck, and a bridge deck transverse rib is provided between the web and the end thickening portion. The bridge deck transverse rib is located below the concrete bridge deck and is arranged at intervals along the longitudinal direction of the concrete bridge deck.

14. The design method of a beam bridge without a central partition, hanging formwork, or negative bending moment tooth block according to claim 13 is characterized in that: The concrete bridge deck is connected to the bridge deck transverse rib, and the thickness of the concrete bridge deck at the joint interface T 1 includes the cross-sectional thickness of the concrete bridge deck and the cross-sectional thickness of the bridge deck transverse ribs, T 1≥30cm.

15. The design method of a beam bridge without a central partition, hanging formwork, or negative bending moment tooth block according to any one of claims 1 to 9, characterized in that: The web plate comprises a steel structure, and the side surface of the web plate is provided with web plate vertical ribs arranged at intervals along the longitudinal direction of the beam bridge, and the top ends of the web plate vertical ribs are connected to the concrete bridge deck.

16. The design method of a beam bridge without a central partition, hanging formwork, or negative bending moment according to claim 15, characterized in that: The prefabricated main beam also includes a bridge deck transverse rib, and the transverse end of the concrete bridge deck is provided with an end thickened portion, and the bridge deck transverse rib is arranged between the web and the end thickened portion. The web vertical rib is at the same longitudinal position as the bridge deck transverse rib to resist the lateral deformation transmitted by the bridge deck transverse rib.

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