A beam joint structure for prefabricated beam bridges, prefabricated beam bridges and their construction methods

Abstract

This invention belongs to the field of design and construction technology of continuous simply supported beam bridges, specifically relating to a beam joint structure in prefabricated beam bridges, a prefabricated beam bridge, and a construction method. The beam joint structure of this invention comprises, from top to bottom, a simply supported beam structure and a rigidly connected structure along the neutral axis. The rigidly connected structure is located at the neutral axis of the beam end section and is rigidly connected to the main beams on both sides. Under the action of beam end rotation, the tensile strain at the upper and lower edges of the rigidly connected structure is reduced by tens of times compared to the existing continuous bridge deck structure, essentially preventing cracking. The simply supported beam structure is simply supported on the two side flanges. The top surface of the simply supported beam structure will not crack and is directly subjected to wheel impacts, effectively avoiding the frequent pavement damage at continuous sections of the bridge deck in the prior art. Simultaneously, through the ingenious design of multiple inclined planes and pipes in the drainage system, water flows through the concrete structure, avoiding tensile cracking zones at various points. Therefore, the waterproofing performance of this invention is significantly higher than that of the existing continuous bridge deck structure.

Description

Technical Field

[0001] This invention belongs to the field of design and construction technology of continuous simply supported beam bridges, specifically relating to the beam joint structure of prefabricated beam bridges, prefabricated beam bridges and construction methods. Background Technology

[0002] In theory, simply supported beam bridges are the most economical bridge type suitable for the prefabricated construction of small-span bridges on various urban roads and highways of all grades, offering faster construction speeds and lower project costs compared to continuous beam bridges. However, in reality, simply supported beam bridges have 2 to 3 times more expansion joints than continuous beam bridges. At high speeds, vehicles are prone to bouncing at these expansion joints, severely impacting ride comfort. Furthermore, expansion joints are the most vulnerable components in bridge engineering, requiring monthly cleaning and often having a service life as low as 2 to 3 years. Therefore, the frequent maintenance required for expansion joints significantly reduces road traffic performance.

[0003] To reduce the number of expansion joint devices in the aforementioned simply supported beam bridges, continuous simply supported beam bridges have emerged and have been widely used in China for over 20 years. For example... Figure 7 The general structure of a continuous simply supported beam bridge consists of a section of L9 in length, rigidly connected to the two adjacent simply supported main beams, within the reinforced concrete pavement layer 33 on the top surface of the beam joint 32 between the first and second main beams (including T-beams, small box girders, large box girders with a single span, steel-concrete composite beams, etc.). Below this section is a thin asphalt layer 331 covered with a plastic film. A transverse longitudinal slit 333, 2-3 cm deep, is cut into the top surface of this section and filled with asphalt mastic. The pavement reinforcement 332 in the cast-in-place leveling layer 33 extends through the range of the "continuous bridge deck structure". Because the thickness of the "continuous bridge deck structure" is generally consistent with the cast-in-place leveling layer, its flexural stiffness at the structural joints is much lower than that of the adjacent simply supported main beam. Therefore, a continuous simply supported beam bridge has horizontal deformation and force transmission performance close to that of a continuous beam bridge, as well as smooth driving performance at the pier tops. However, unlike continuous beam bridges, it does not generate excessive negative bending moments at the pier tops, requiring a large number of prestressed tendons to resist them. The continuous bridge deck structure only needs to be designed and reinforced according to the specifications for ordinary reinforced concrete members to meet the verification requirements. However, in reality, years of experience have shown that... Figure 7 The actual performance of existing continuous bridge deck technology, represented by the example of continuous bridge deck bridges, differs greatly from the theoretical performance. Its durability, waterproofing, ride comfort, and seismic performance are all significantly lower than those of continuous beam bridges. The performance disadvantages of existing continuous simply supported beam bridges in the operation phase have exceeded their advantages in construction period and cost. As a result, this technology has been gradually phased out in most small and medium span prefabricated bridges and is currently only used in a few skewed, curved, widened, or irregularly shaped bridges.

[0004] The reasons for this are that existing bridge deck continuity technologies (including authorized invention patents CN201110000647, CN201210588176, CN201510060304, CN201911383159, CN202110271685, etc.) have the following four significant problems:

[0005] Firstly, durability: Bridges need to withstand vertical loads such as the weight of vehicles and pedestrians, horizontal loads such as overall temperature rise and fall and braking forces, local effects such as wheel impacts and gradual temperature changes, forced horizontal and vertical displacements such as soil displacement and uneven settlement of piers, vertical displacement deformation caused by asynchronous elastic compression of rubber bearings, and horizontal and vertical seismic forces. All these loads and deformations are transmitted to the continuous sections of the bridge deck, inevitably causing cracks in the reinforced concrete structure at these points. The instant these concrete cracks appear, they often tear the adjacent waterproofing layer and a certain thickness of asphalt layer. Furthermore, the asphalt material itself may have gaps, allowing rainwater and sewage to seep in and erode the continuous reinforcing steel at the cracks. This is especially true for bridges like... Figure 8 When the main girder deflects under various forces, causing a rotation at the girder end, and this rotation is transmitted to the continuous structure of the bridge deck, although the internal force at the upper edge of the continuous structure is relatively small, the stress still far exceeds the tensile strength of the concrete. Therefore, cracks will inevitably appear at this location. Figure 9 The concrete at the cracks suffers from reduced strength due to cracking and internal micro-damage. This area directly bears the stress concentration caused by repeated impacts from wheel loads. Combined with the effects of temperature and other localized factors, this leads to further crack development and amplification, exceeding specification limits and even causing breakage. This stress then reflects onto the overlying waterproof layer and asphalt pavement, causing fatigue cracking of the road surface. This situation cannot be quantitatively calculated or predicted by existing specifications, theories, and experimental research, which is the fundamental reason why continuous bridge deck technology has failed to solve this persistent problem despite years of application. Furthermore, in more unfavorable circumstances, such as... Figure 10 When bridge piers settle unevenly, cracks will appear at the lower edge of the continuous bridge deck structure. Once these cracks connect, they will significantly accelerate the deterioration of the continuous bridge deck structure. Especially under overall cooling, the continuous bridge deck structure is under axial tension, and its cracks may increase uncontrollably. In actual operation, some bridges have even developed significant cracking at the continuous sections of the deck within a year of opening to traffic. Therefore, compared to continuous beam bridges, which are less prone to cracking at the pier tops due to the presence of negative moment prestressed tendons, the durability of existing simply supported continuous beam bridges is significantly lower than that of continuous beam bridges.

[0006] Secondly, there's the issue of waterproofing: After the aforementioned durability problems occur, rainwater and sewage will directly seep into the cracks in the continuous structure of the bridge deck, causing extensive corrosion and expansion of the reinforcing steel, further exacerbating the cracks and reducing durability. Furthermore, once through cracks form, rainwater and sewage will directly seep into and flow into the pier caps and supports below, affecting the durability of the substructure. Currently, water damage to existing continuous simply supported beam bridges has become a common problem; statistics show that over 70% of bridges in Zhejiang Province suffer from this type of damage. Therefore, the waterproofing performance of existing continuous simply supported beam bridges is significantly lower than that of continuous beam bridges.

[0007] Thirdly, there's the issue of ride comfort: After the aforementioned durability and waterproofing problems occur, the asphalt pavement at the continuous structure of the bridge deck will suffer severe damage such as cracking, edge chipping, potholes, and breakage. The bouncing phenomenon will be even more pronounced than at expansion joints, posing a significant safety hazard at high speeds. In actual operation, it has been found that without timely repairs, a "bouncing at every point" situation will occur. However, the maintenance and replacement of structures at the continuous bridge deck are significantly more difficult than at expansion joints, severely impacting the traffic performance of this type of bridge. Therefore, the ride comfort of a continuous simply supported beam bridge after long-term operation cannot be guaranteed technically and can only be improved through enhanced management and maintenance. This is its fundamental disadvantage compared to continuous beam bridges.

[0008] Fourthly, seismic performance: To minimize the bending moment generated by the main beam under vertical loads, continuous bridge deck structures should reduce their vertical bending stiffness as much as possible. However, this reduction in vertical bending stiffness weakens their seismic performance under vertical seismic forces. Existing continuous bridge deck structures with the same thickness as the cast-in-place concrete pavement have insufficient vertical bending stiffness to guarantee the seismic performance of the entire bridge. Therefore, more and more expensive seismic isolation bearings or other measures are required to enhance seismic resistance. This situation partially offsets the original cost advantage of continuous simply supported beam bridges, resulting in lower economic applicability in areas with high seismic requirements. Therefore, compared to continuous beam bridges, which improve the overall integrity and seismic performance of the entire bridge by using wet joints at the pier tops with the same height as the main beam section and prestressed tendons to achieve rigid connections, the seismic performance of existing continuous simply supported beam bridges is significantly lower. Summary of the Invention

[0009] In response to the four problems mentioned above that have remained unresolved in existing technologies for a long time, this invention provides a beam joint structure for prefabricated beam bridges, a prefabricated beam bridge and a construction method. Starting from the fundamental issue of the overall bridge structural system, it solves the four major problems of existing technologies and has better economic benefits.

[0010] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0011] A beam joint structure for prefabricated beam bridges is disclosed. The beam joint structure connects adjacent main beams along the bridge direction. The beam joint structure is located at the joint between a first main beam and a second main beam. From top to bottom, the beam joint structure comprises a simply supported beam structure for the bridge deck and a rigid connection structure for the neutral axis. The simply supported beam structure is located in the flange area. The rigid connection structure for the neutral axis is rigidly connected to both the first and second main beams. The absolute value of the vertical height difference between the top and bottom surfaces of the rigid connection structure and the neutral axis of the beam end section of the first main beam does not exceed 0.25H0. ​​The absolute value of the vertical height difference between the top and bottom surfaces of the rigid connection structure and the neutral axis of the beam end section of the second main beam does not exceed 0.25H0. ​​The maximum thickness H4 of the rigid connection structure is ≤0.3H0, where H0 is the maximum beam height of either the first or second main beam.

[0012] Specifically, the simply supported beam structure of the bridge deck is not in direct contact with the main beams on both sides and the reinforced concrete pavement layer thereon, and there are no horizontally continuous steel bars connected to it. The bottom surface of the simply supported beam structure of the bridge deck is composed of one or more flat surfaces.

[0013] The technical principles and effects of the above invention are as follows: (1) The neutral axis rigid connection structure is located at the neutral axis of the beam end section. The horizontal deformation caused by the beam end rotation angle is close to 0. Therefore, under the action of the beam end rotation angle, the tensile strain of the upper and lower edges of the neutral axis rigid connection structure is reduced by more than 10 times compared with the existing bridge deck continuous structure. Its tensile stress can be completely controlled within the design value of the tensile strength of concrete, thereby greatly reducing the damage caused by the beam end rotation angle caused by vertical loads such as the weight of cars and people. Basically, no cracks will be generated, and the durability is significantly improved; (2) Since the neutral axis rigid connection structure is set at the neutral axis of the beam end section, it can also reduce the bearing friction resistance generated during the overall temperature rise and fall relative to the lever arm of the neutral axis rigid connection structure, and play a better role in transmitting the overall temperature rise and fall and braking force. (3) Based on the above advantages, the neutral axis rigid connection structure also has better seismic performance under horizontal and vertical seismic forces. Since the bridge deck simply supported beam structure above it generally will not be damaged after a major earthquake, the damage to the neutral axis rigid connection structure can be repaired while maintaining bridge deck traffic. In addition, its thickness can be designed to be thicker than the existing bridge deck continuous structure to further improve seismic performance without affecting its durability. (4) After the bridge deck simply supported beam structure is separated from the main beams and reinforced concrete pavement on both sides, the stress is close to that of a simply supported beam. This structure is mainly responsible for bearing the local load of the wheels. Its cracks will only appear from the lower edge of the simply supported beam and will not produce through cracks from the upper and lower edges. Therefore, it will not cause pavement damage and affect the smoothness of driving.

[0014] Preferably, the longitudinal dimension F1 of the beam joint is ≥30cm.

[0015] The technical principle and effect of the above invention are as follows: When the longitudinal dimension F1 of the beam joint is greater than or equal to 30cm, the neutral axis rigid connection structure has a certain degree of flexibility, and also ensures that there is enough space for personnel to construct the neutral axis rigid connection structure. At the same time, it reduces the total length of the main beam and the calculated span, and significantly saves the amount of concrete and steel used in the main beam.

[0016] Preferably, the neutral axis of the beam end section is parallel to the zero normal stress line, which is the line connecting all points in the section at a distance H0 from the support centerline along the bridge direction where the normal stress is 0 under the self-weight of the main beam.

[0017] The technical principle and effect of the above invention are as follows: First, the beam end is a very short cantilever beam segment outside the support range, so the internal force of the beam end section is very small, and its rotation angle and neutral axis are basically consistent with the section at the support centerline; in addition, calculation and analysis revealed that under uniformly distributed load, the actual neutral axis of the section within H0 range on both sides of the support centerline of the simply supported beam deviates significantly from the theoretical centroid. It can be seen that due to the influence of the local effect of the support, the strain distribution of the simply supported beam at the support section does not satisfy the plane section assumption and the neutral axis cannot be determined by the centroid. The amplitude of the beam end rotation angle is the result of the cumulative deformation of all sections within the entire span of the main beam. Therefore, after comprehensive consideration, it is most appropriate to select the section at H0 distance from the support centerline to determine the neutral axis of the beam end section.

[0018] More preferably, the neutral axis of the beam end section is a horizontal straight line along the transverse direction of the bridge, and the vertical coordinate z of the neutral axis of the beam end section in the spatial rectangular coordinate system is... q4 Determine z using the following formula: q4 =[z q1 *L1+z q2 *(L-L1)] / L, where L is the total length of the main beam, z is the length of the main beam, and L is the length of the main beam. q1 Let L1 be the vertical coordinate of the equivalent centroid of the mid-span section, L2 be the total length of beam segments with the same shape as the mid-span section along the entire length of the main beam, and z be the vertical coordinate of the equivalent centroid of the mid-span section. q2 Here is the vertical coordinate of the equivalent centroid of the section at a distance H0 from the support centerline;

[0019] The formula for calculating the vertical coordinate of the equivalent centroid of the above section is:

[0020] z q =(z1*A1+z2*A2*E) c2 / E c1 +0.5*z3*A3*E c3 / E c1 ) / (A1+A2+0.5*A3),

[0021] In the formula z q For z q1 or z q2 z1, z2, and z3 are respectively z q1 or zq2 The centroid vertical coordinates of the main beam section, reinforced concrete pavement layer section, and asphalt pavement layer section at the corresponding cross-sections, A1, A2, and A3, respectively, are z... q1 or z q2 The area of ​​the main beam section, the reinforced concrete pavement layer section, and the asphalt pavement layer section at the corresponding cross-section, E c1 E c2 E c3 z q1 or z q2 The elastic modulus of concrete at the corresponding cross-section of the main beam, the elastic modulus of concrete at the cross-section of the reinforced concrete pavement, and the elastic modulus of asphalt.

[0022] The technical principles and effects of the above invention are as follows: (1) Due to the variability of bridge cross-section and load and the spatial effect of the stress on the whole bridge, the line connecting all points where the normal stress in the longitudinal direction of the cross-section at the center line H0 of the support is 0 generally deviates from the straight line and has a certain vertical position. In order to simplify the calculation and facilitate the design, it can be approximated as a horizontal straight line along the transverse direction of the bridge; (2) Because the main beam of the bridge has a uniform cross-section in a large range on both sides of the mid-span and a variable cross-section in a small range on both sides of the pier top, and the amplitude of the beam end rotation angle is the result of the cumulative deformation of all cross-sections in the entire span of the main beam, the vertical coordinate z of the equivalent neutral axis at the beam end is determined. q4 The equivalent centroid z of the cross-section within the entire bridge area should be taken into account. q The effects of inconsistency; (3) The upper edge of a simply supported beam is compressed under vertical load, so the reinforced concrete pavement and asphalt pavement at non-pier tops generally do not crack. This is a significant characteristic that distinguishes simply supported beams from continuous beams. Therefore, when determining the equivalent centroid z of the cross section, q It is necessary to take into account the influence of reinforced concrete pavement layer and asphalt pavement layer; (4) Considering that there is no steel reinforcement connection between asphalt pavement layer and reinforced concrete pavement layer, the cross-sectional strain in asphalt pavement layer is somewhat different from the plane section assumption. At the same time, considering the influence of long-term wear of asphalt pavement layer, after analysis, its cross-sectional area is reduced by 0.5 to more accurately account for its influence on the equivalent centroid z of the cross section. q The impact of calculations.

[0023] Preferably, the neutral axis rigid connection structure includes a first cantilever slab and a second cantilever slab arranged opposite to each other. The first cantilever slab is prefabricated integrally with the first main beam, and the second cantilever slab is prefabricated integrally with the second main beam. A slab joint is formed between the first cantilever slab and the second cantilever slab. A post-cast concrete slab is provided in the area above the first cantilever slab and the second cantilever slab. Several sets of truss reinforcement bars are pre-embedded at the ends of the main beam. The several sets of truss reinforcement bars are arranged at intervals along the transverse direction of the bridge.

[0024] Preferably, each group of truss reinforcement bars includes a first truss reinforcement bar and a second truss reinforcement bar arranged opposite to each other, and the first truss reinforcement bar and the second truss reinforcement bar arranged opposite to each other are connected by connecting reinforcement bars.

[0025] Specifically, the left end of the first truss reinforcement is embedded in the first main beam, and the lower part of the first truss reinforcement near the post-cast concrete slab is embedded in the first cantilever slab, while the upper part extends into the post-cast concrete slab; similarly, the right end of the second truss reinforcement is embedded in the second main beam, and the lower part of the second truss reinforcement near the post-cast concrete slab is embedded in the second cantilever slab, while the upper part extends into the post-cast concrete slab.

[0026] Preferably, a bottom formwork is also erected on the joint between the first cantilever slab and the second cantilever slab. The bottom formwork is not removed after the post-cast concrete slab is constructed and shares the load with it.

[0027] Preferably, the top surface of the post-cast concrete slab has a structure with high sides and low center, and the sides are located close to the main beam.

[0028] The technical principles and effects of the above invention are as follows: (1) Under the action of beam end rotation, the lower edge of the neutral axis rigid connection structure is compressed and the upper edge is tensile. The use of precast cantilever slabs as post-cast bottom formwork will not cause the problem of easy cracking at the interface between new and old concrete. The bottom formwork can also be made of concrete materials and does not need to be disassembled after the post-cast concrete slab is completed; (2) The truss reinforcement can also serve as the load-bearing reinforcement during construction, the connection reinforcement between the interface between new and old concrete, and the shear reinforcement during uneven settlement of the pier and earthquake resistance; (3) The cantilever slab and truss reinforcement can form a combined structure, which greatly improves the vertical bending stiffness and allows construction personnel to walk directly. (4) The construction error of the precast length of the main beam can be eliminated by setting the longitudinal slab joint, ensuring that the second main beam is not easily damaged by collision with the first main beam when it is erected, and also leaving space for the drainage pipe to pass through; (5) The cantilever slab can be poured when the beam end side cantilever slab is initially set, so as not to produce the interface performance problem of new and old concrete; (6) When the top surface of the post-cast concrete slab is a structure with high on both sides and low in the middle, it can facilitate the smooth collection of the fine water flow that seeps into the bridge deck simple support beam structure to the low place for easy drainage.

[0029] Preferably, both the first main beam and the second main beam have end beams between their webs, and the surface of the end beams near the beam joints is flush with the end face of the neutral axis rigid connection structure and is rigidly connected to each other.

[0030] The technical principle and effect of the above invention are as follows: the rigid connection between the neutral shaft and the end beam can effectively transmit horizontal force and spread it to the entire main beam, avoiding the adverse effects caused by force transmission only at the web.

[0031] Preferably, the truss reinforcement bars are spaced apart only at the end beam positions in the transverse direction of the bridge, and no pre-embedding is required at the web position.

[0032] The technical principle and effect of the above invention are as follows: The end face of the web of the main beam is generally occupied by a large space of the anchorage zone of the prestressed tendons. In order to avoid the pre-embedded truss steel bars causing inconvenience in anchoring the prestressed tendons, truss steel bars are not arranged in the web. However, there are still connecting steel bars in this place to ensure the stress of the neutral axis rigid connection structure itself.

[0033] Preferably, the wing plate end of the first main beam is provided with a downwardly inclined first groove, and the wing plate end of the second main beam is provided with a downwardly inclined second groove. The bridge deck simply supported beam structure is disposed between the first groove and the second groove. The bridge deck simply supported beam structure includes, from bottom to top, an elastic bottom formwork and a simply supported beam plate. The simply supported beam plate is a cast-in-place reinforced concrete structure. A soft partition layer is vertically disposed between the simply supported beam plate and the wing plates on both sides to separate it from the wing plates of the main beam.

[0034] Preferably, the thickness H of the simply supported beam slab is... 51 The thickness is greater than the thickness of the reinforced concrete pavement layer on the top surface of the wing plate.

[0035] Preferably, elastic pads are further provided on both sides of the elastic bottom formwork along the bridge direction. The bottom surface of the elastic pads contacts the top surface of the wing plate at the first or second groove, and the top surface of the elastic pads contacts the bottom surface of the simply supported beam structure of the bridge deck. The vertical projection range of the elastic pads includes the vertical centerline of the main beam support, and the length L of the elastic pads along the bridge direction is... 53 It is less than the longitudinal length of the support.

[0036] The technical principles and effects of the above invention are as follows: (1) The simply supported beam slab adopts a reinforced concrete structure and can be cast in place at the same time as the reinforced concrete pavement layer without adding extra procedures, processes and construction period; (2) After the flange is provided with a groove at the end of the beam, the thickness of the simply supported beam slab can be designed to be a larger value, and since the simply supported beam slab itself is a simply supported structure, it will not cause an increase in the internal force transmitted from the main beam, and has better stress performance; (3) The elastic pad, elastic bottom formwork and soft partition layer separate the simply supported beam slab from the main beam and the cast-in-place reinforced concrete pavement layer, ensuring that the internal force at the end of the main beam will not be transmitted to the simply supported beam slab and cause its upper edge to crack; (4) The upper edge upturn value generated by the beam end corner at the vertical center line of the support is close to 0, so the upturn value of the simply supported beam slab caused by the elastic pad falling near the center line of the support is very small, so it does not affect the smoothness of driving.

[0037] Preferably, the bridge deck simply supported beam structure and the wing plate structure below are vertically connected by a number of limiting tension bars, which are spaced apart along the transverse direction at the center line section of the support.

[0038] In a further preferred embodiment, a sleeve is provided outside the limiting anti-pull-out reinforcement, and the sleeve passes sequentially from the wing plate through the elastic pad to the simply supported beam plate along the cross-section of the support center line.

[0039] The technical principles and effects of the above invention are as follows: (1) The limiting anti-pull reinforcement mainly ensures that the simply supported beam slab does not undergo excessive vertical displacement under the action of force majeure such as earthquakes. Its cross-sectional bending stiffness is very small, so it will basically not transmit the beam end rotation deformation; (2) The sleeve can ensure that the limiting anti-pull reinforcement is not eroded by the fine water seeping into the soft partition layer.

[0040] Preferably, both the reinforced concrete pavement layer on the top surface of the wing plate and the simply supported beam structure of the bridge deck are provided with a protruding structure. The length direction of the protruding structure is transverse to the bridge and the width direction is longitudinal to the bridge. The protruding structure separates the asphalt pavement layer and its top surface is flush with the asphalt pavement layer. The soft partition layer is located in the protruding structure and is provided along the length direction of the protruding structure.

[0041] In a further preferred embodiment, along the bridge direction, an asphalt pavement layer is provided between adjacent protruding structures, and the top surface of the protruding structure is flush with the top surface of the asphalt pavement layer.

[0042] The technical principle and effect of the above invention are as follows: the soft partition layer has raised structures of reinforced concrete on both sides, which avoids the asphalt from being sheared, lifted or chipped when the asphalt pavement layer is directly covered on the soft partition layer, and at the same time serves as a stable base for the side of the asphalt layer.

[0043] More preferably, the elastic modulus of the elastic pad is greater than that of the elastic bottom mold; the elastic modulus of the elastic bottom mold does not exceed 1 / 100 of the elastic modulus of the simply supported beam plate.

[0044] Preferably, the elastic pad is generally made of rubber, the elastic bottom mold is generally made of foam, the soft partition layer is made of soft, waterproof material, generally asphalt mastic or polyurethane waterproof sealant, and the raised structure is generally made of steel fiber reinforced concrete.

[0045] Before constructing the soft partition layer, a rigid partition board (usually a thin aluminum plate or plastic plate) can be pre-embedded. After the initial setting of the cast-in-place concrete of the reinforced concrete pavement layer and the simply supported beam slab, the rigid partition board can be removed and then the soft partition layer can be filled in.

[0046] The technical principles and effects of the above invention are as follows: (1) The elastic pad is generally made of rubber material and the elastic bottom mold is generally made of foam. The elastic modulus of the former is much greater than that of the latter. Therefore, the latter basically does not participate in the stress and ensures that the deformation of the simply supported beam slab is close to that of the simply supported beam so as to clarify its stress and reinforcement; (2) The soft partition layer is generally made of asphalt mastic or polyurethane waterproof sealant. Its elastic modulus is very low and it has a certain fluidity. When the corner deformation occurs at the beam end, it can achieve self-compactment and sealing waterproof.

[0047] Preferably, the thickness H of the elastic bottom mold at the end section of the main beam is... 52 The following inequalities must be satisfied:

[0048] H 52 ≥(L3-F1) / 2*tan[max(θ1,θ2)];

[0049] Where L3 is the longitudinal distance between the center lines of the supports at both ends of the beam joint, and θ1 and θ2 are the rotation angles at the support center line sections of the first and second main beams under the assumption of plane sections and the most unfavorable load combination of the ultimate limit state of bearing capacity in the current bridge code.

[0050] The technical principle and effect of the above invention are as follows: the elastic bottom formwork can be completed or removed in a simply supported beam slab, because its elastic modulus is significantly lower than that of the concrete. After the main beam end rotates, the thickness H of the elastic bottom formwork at the main beam end section is [not specified]. 52 The value ≥(L3-F1) / 2*tan[max(θ1,θ2)] can guarantee that the beam end rotation angle will not cause the simply supported beam slab to warp upwards. The specific derivation is as follows (refer to Figure A-2): According to the geometric similarity relationship, the upward warping value Δ at the upper edge of the beam end is known. z1 ≈ Value of upward tilt of the neutral axis at the beam end face △ z2 Considering the large vertical bending stiffness of the beam segment outside the support centerline, the centroid of the beam end section can be considered to rotate upwards along a circular arc trajectory around the centroid of the support section. According to the principle of small-angle approximation, the upward tilt value of the neutral axis of the beam end face is Δ. z2 ≈D0*sinβ≈D0*tanβ, where D0 is the distance from the support centerline to the beam end, and β is the rotation angle of the beam end neutral axis plane; further, according to the plane section assumption, the support centerline is perpendicular to the beam neutral axis plane, that is, θ=β, θ is the rotation angle of the support section, and D0=(L3-F1) / 2; therefore, in order to ensure that the distance from the upper edge of the main beam end section to the lower edge of the simply supported beam slab is not less than the largest of the upward tilt values ​​of the upper edge of the beam end produced by the first main beam and the second main beam, it can be proved by combining the above formulas that H 52 H must be satisfied 52 ≥△ z1 ≈(L3-F1) / 2*tan[max(θ1,θ2)].

[0051] Preferably, the beam joint structure further includes a drainage system, which includes a first drainage pipe and a second drainage pipe. The first drainage pipe is located at the bottom of the simply supported beam structure of the bridge deck, and the second drainage pipe is located at the bottom of the rigid connection structure of the neutral axis.

[0052] Preferably, a set of first drainage pipes is provided at the lowest point of the cross slope of the wing plate. The first drainage pipes are respectively provided on the bottom surface of the first groove and the second groove, and the first drainage pipes are inclined towards one side of the beam joint.

[0053] More preferably, the first drainage pipe is located at the end of the beam joint.

[0054] Preferably, the drainage system further includes a wing plate cantilever plate waterstop and a water guide plate. The wing plate cantilever plate waterstop is located below the wing plate cantilever plate and slopes towards the web. The water guide plate is located at the junction of the post-cast concrete slab and the beam end, and the water guide plate is arranged along the transverse direction of the post-cast concrete slab.

[0055] Preferably, a water collection well is provided at the joint between adjacent cantilever slabs at the lowest point of the cross slope of the neutral shaft rigid connection structure. The water collection well extends from the top surface to the bottom surface of the neutral shaft rigid connection structure and is connected to the second drainage pipe. The water guide plate can guide the water flow to the water collection well and drain it away through the second drainage pipe.

[0056] Preferably, the inclined bottom surfaces of the first groove and the second groove are both first inclined surfaces, and the inclined top surface of the post-cast concrete slab is a second inclined surface. The first inclined surface and the second inclined surface can guide the water flow to the collection well and drain it away through the second drainage pipe.

[0057] The technical principle and effect of the above invention are as follows: by combining the first inclined plane, the second inclined plane and the corresponding drainage pipes, waterstops and water guides, the fine water flow that seeps into the soft partition layer can be quickly discharged into the drainage network without falling onto the bridge pier. The concrete structure that the water flow may pass through avoids the possible tensile cracking areas of the concrete structure, so it will not affect the durability of the structure. At the same time, the joint between the new and old concrete of the neutral axis rigid connection structure and the main beam will not be invaded by water, thus ensuring the durability of the entire beam joint structure.

[0058] A prefabricated beam bridge includes N piers spaced apart, N-1 precast main beams are erected on the N piers, and beam joint structures as described above are provided between adjacent main beams along the bridge direction.

[0059] A construction method for a prefabricated beam bridge includes the following steps:

[0060] Step 1: In this step, the prefabricated structure is built on the completed piers and supports according to the construction design drawings of the prefabricated beam bridge. During the prefabrication of the main beam, the end of the wing plate is provided with a groove for installing the simply supported beam structure of the bridge deck. The end of the main beam and the end face of the end crossbeam are prefabricated with cantilever slabs and truss reinforcement respectively. Limiting pull-out reinforcement, sleeves and elastic pads are pre-embedded at the center line of the support.

[0061] Step 2: This step involves the construction of the neutral axis rigid connection structure and corresponding drainage facilities at the beam joint. First, place the bottom formwork above the joint of the cantilever slab and install the water collection well and the second drainage pipe. Install connecting steel bars between the opposite truss steel bars. After pouring the concrete slab, install the water guide plate on the top after the concrete has initially set.

[0062] Step 3: This step involves the construction of the simply supported beam structure of the bridge deck and the corresponding drainage facilities. First, install the waterstop strip of the cantilever plate of the wing plate at the bottom of the wing plate, then install the first drainage pipe and the elastic bottom formwork. After installing the rigid partition plate, pour concrete for the reinforced concrete pavement layer and the simply supported beam plate. After the concrete has initially set, remove the rigid partition plate and fill it with the soft partition layer.

[0063] Step 4: This step involves the construction of the subsequent bridge deck structure, including the sequential construction of the bridge deck waterproofing layer, asphalt pavement layer, and other bridge deck facilities on the top surface of the reinforced concrete pavement layer and the simply supported beam slab, ultimately completing the overall construction of the prefabricated beam bridge.

[0064] The technical principles and effects of the above invention are as follows: (1) By adopting the construction method of the present invention, the neutral axis rigid connection structure can be completely free of formwork, and the construction personnel can walk directly on the cantilever slab to complete the reinforcement binding and cast-in-place operation of the cast-in-place concrete slab; (2) The bridge deck simply supported beam structure and the reinforced concrete pavement layer are constructed at the same time without adding extra procedures, processes and construction period; (3) Compared with continuous beam bridges, it saves two major time-consuming procedures: tensioning of negative bending moment bundles at the pier top and a large number of dense reinforcement connection operations in the limited space at the wet joint at the pier top, which greatly reduces the construction difficulty, saves construction measures costs and shortens the construction period.

[0065] Compared with existing continuous simply supported beam bridges, the beneficial effects of this invention are summarized as follows, addressing the four long-standing unresolved problems described in the background section:

[0066] I. Enhanced Durability: This invention features a rigid neutral axis connection structure at the neutral axis of the beam ends of the main beams on both sides. This structure can better transmit horizontal loads such as overall temperature rise and fall, and braking force. Furthermore, it is designed to prevent cracking under the influence of beam end rotation caused by vertical loads such as the weight of vehicles and pedestrians. It also incorporates a simply supported beam structure for the bridge deck, which is isolated from the main beams on both sides and the reinforced concrete pavement. This ensures that the top surface of the simply supported beam structure will not crack, and that any cracked areas will not be directly impacted by vehicle wheels. Therefore, it completely avoids the phenomenon of pavement damage requiring frequent maintenance. As a result, the durability of this invention is significantly higher than that of the existing continuous bridge deck structure.

[0067] II. Superior Waterproofing: Through the ingenious design of multiple inclined planes and drainage pipes, this invention can quickly drain the fine water flow that seeps into the soft partition layer into the drainage network without falling onto the lower pier and cap beam structure. The concrete structures that the water flow may pass through all avoid their respective tensile cracking zones, and the joints between the new and old concrete of the neutral axis rigid connection structure and the main beam will not be invaded by water. Therefore, it will not affect the structural durability, and it will not cause the phenomenon in the prior art where a large number of stressed steel bars rust and expand due to water immersion in cracks, thus aggravating crack development. Therefore, the waterproofing of this invention is significantly higher than that of the existing bridge deck continuous structure.

[0068] III. More Reliable Driving Comfort: The present invention, through the coordinated design of the neutral shaft rigid connection structure, the simply supported beam structure of the bridge deck, and the drainage system, ensures the durability and waterproofness of each structure at the beam joints throughout its service life, and avoids damage to the asphalt pavement at the beam joints. Thus, at the technical level, it can fully guarantee the driving comfort and safety of the bridge after long-term operation. Therefore, the driving comfort of the present invention is significantly more reliable than that of the existing continuous bridge deck structure.

[0069] IV. Enhanced Seismic Performance: The neutral axis rigid connection structure in this invention, due to its location in a position less affected by cross-sectional rotation and the inclusion of internal truss reinforcement, exhibits superior seismic performance under both horizontal and vertical seismic forces. Its thickness can be designed to be greater than that of existing continuous bridge deck structures to further enhance seismic performance without significantly impacting durability. Furthermore, after a major earthquake, the simply supported beam structure of the bridge deck above the neutral axis rigid connection structure generally remains intact, allowing for repairs of any damage to the neutral axis rigid connection structure while maintaining bridge traffic flow. Therefore, the seismic performance of this invention is significantly stronger than that of existing continuous bridge deck structures.

[0070] V. Superior Economic Benefits: The beam joint width of the present invention can be designed to be significantly larger than that of the prior art, thereby reducing the total length of the main beam and the calculated span, significantly saving the amount of concrete and steel used in the main beam, and saving the direct construction cost of the bridge; at the same time, it also greatly reduces the damage to the beam joint structure and the inspection and maintenance of the bridge deck pavement, saving the indirect operating cost of the bridge; therefore, the economic benefits of the present invention are significantly better than those of the existing bridge deck continuous structure.

[0071] Furthermore, compared with existing continuous beam bridges, the present invention also has the following beneficial effects:

[0072] I. Faster construction speed: The simply supported beam bridge of the present invention eliminates two major time-consuming processes: tensioning the negative moment bundles at the pier top and connecting a large number of dense steel bars in the limited space at the wet joint at the pier top. This greatly reduces the construction difficulty and saves the construction period, thus having a faster construction speed compared to continuous beam bridges.

[0073] II. Lower Construction Costs: The simply supported beam bridge of this invention has a clear stress distribution, fully retaining the cost advantages of conventional simply supported beam bridges compared to continuous beam bridges. This includes a significant reduction in the total amount of steel reinforcement and concrete while slightly increasing the steel strands. Furthermore, the elimination of the need for pre-reserved negative moment strand teeth and slots also saves on prefabrication mold costs. At the same time, the elimination of negative moment strand tensioning at the pier top and the significant reduction in on-site work at the wet joint at the pier top also greatly save on direct construction cost. Therefore, it has lower construction costs compared to continuous beam bridges.

[0074] III. Superior Social and Environmental Benefits: The simple-supported beam bridge of this invention shortens the construction period, thereby reducing interference with existing traffic and nearby residents under the bridge. It is more suitable for the construction environment and requirements of prefabricated bridges, and therefore has superior social and environmental benefits compared with continuous beam bridges.

[0075] In summary, this invention is a new type of prefabricated bridge beam joint structure and construction method that is safer, more economical, practical, durable and reliable than existing technologies, and can be widely used in various types of highway and municipal bridges. Attached Figure Description

[0076] Figure 1 This is a longitudinal elevation view of the beam joint structure between prefabricated beam bridges according to the present invention.

[0077] Figure 2 This is a cross-sectional view (AA) of the beam joint structure between prefabricated beam bridges according to the present invention.

[0078] Figure 3 This is a BB cross-sectional view of the beam joint structure between prefabricated beam bridges according to the present invention.

[0079] Figure 4 This is a CC sectional view of the beam joint structure between prefabricated beam bridges according to the present invention.

[0080] Figure 5 This is the overall structural concept of the prefabricated beam bridge of the present invention;

[0081] Figure 6 The diagram shows the steps of the construction method for the prefabricated beam bridge of the present invention; (a is a state diagram of construction step 1, b is a state diagram of construction step 2, c is a state diagram of construction step 3, d is a state diagram of construction step 4, and e is a state diagram of construction step 5).

[0082] Figure 7 This is a schematic diagram of the longitudinal elevation of an existing continuous simply supported beam bridge.

[0083] Figure 8 This is a schematic diagram of the beam end rotation angle of an existing continuous simply supported beam bridge after the main beam deflects downward.

[0084] Figure 9 A schematic diagram of cracks at the beam end corners of an existing continuous simply supported beam bridge.

[0085] Figure 10 A schematic diagram of cracks in an existing continuous simply supported beam bridge under uneven settlement of the piers.

[0086] Figure Labels

[0087] 1-First main girder, 2-Second main girder, 121-Support, 122-Web plate, 123-End crossbeam, 124-Wing plate, 1241-Groove, 3-Main girder, 31-Pier, 32-Beam joint, 33-Reinforced concrete pavement layer, 34-Bridge deck waterproofing layer, 35-Asphalt pavement layer, 36-Expansion joint, 4-Neutral axis rigid connection structure, 41-Cantilever slab, 411-Slab joint, 42-Truss reinforcement, 43-Bottom formwork, 44-Connecting reinforcement, 45-Post-cast concrete slab 46-Neutral axis of beam end section; 5-Simply supported beam structure of bridge deck; 51-Simply supported beam slab; 511-Protruding structure; 52-Elastic bottom formwork; 53-Elastic pad; 54-Limiting pull-out reinforcement; 541-Sleeve; 55-Soft partition layer; 551-Rigid partition plate; 6-Drainage system; 61-First inclined plane; 62-First drainage pipe; 63-Wing plate cantilever plate waterstop; 64-Water guide plate; 65-Second inclined plane; 66-Water collection well; 67-Second drainage pipe. Detailed Implementation

[0088] The present invention will be further described in detail below with reference to experimental examples and specific embodiments. However, this should not be construed as limiting the scope of the above-mentioned subject matter of the present invention to the following embodiments; all technologies implemented based on the content of the present invention fall within the scope of the present invention.

[0089] Example 1

[0090] This embodiment provides a beam joint structure for prefabricated beam bridges, such as... Figure 1-4 As shown, the beam joint structure is used to connect adjacent main beams along the bridge direction. The beam joint structure is located at the beam joint 32 between the first main beam 1 and the second main beam 2. The longitudinal dimension F1 of the beam joint 32 is ≥30cm. The beam joint 32 is constructed from top to bottom as follows: a simply supported beam structure 5 and a neutral axis rigid connection structure 4. The simply supported beam structure 5 is located in the flange 124 area. The neutral axis rigid connection structure 4 is rigidly connected to the first main beam 1 and the second main beam 2 respectively. The absolute value of the vertical height difference between the top and bottom surfaces of the neutral axis rigid connection structure 4 and the neutral axis 46 of the beam end section of the first main beam 1 does not exceed 0.25H0. ​​The absolute value of the vertical height difference between the top and bottom surfaces of the neutral axis rigid connection structure 4 and the neutral axis 46 of the beam end section of the second main beam 2 does not exceed 0.25H0. ​​The maximum thickness H4 of the neutral axis rigid connection structure 4 is ≤0.3H0, where H0 is the maximum beam height of the first main beam 1 or the second main beam 2. The simply supported beam structure 5 of the bridge deck does not directly contact the main beams on both sides and the reinforced concrete pavement layer 33 on them, and there are no horizontally continuous steel reinforcement connections. The bottom surface of the simply supported beam structure 5 of the bridge deck is composed of one or more flat surfaces.

[0091] Specifically, the neutral axis 46 of the beam end section is parallel to the zero normal stress line, which is the line connecting all points in the section at a distance H0 from the center line of support 121 along the bridge direction where the normal stress is 0 under the action of the main beam's self-weight.

[0092] The neutral axis 46 of the beam end section is a horizontal straight line along the transverse direction of the bridge, and the vertical coordinate z of the neutral axis of the beam end section in the spatial rectangular coordinate system is... q4 Determine z using the following formula: q4 =[z q1 *L1+z q2 *(L-L1)] / L, where L is the total length of the main beam, z is the length of the main beam, and L is the length of the main beam. q1 Let L1 be the vertical coordinate of the equivalent centroid of the mid-span section, L2 be the total length of beam segments with the same shape as the mid-span section along the entire length of the main beam, and z be the vertical coordinate of the equivalent centroid of the mid-span section. q2 The vertical coordinate of the equivalent centroid of the section at H0, a distance from the centerline of support 121;

[0093] The formula for calculating the vertical coordinate of the equivalent centroid of the above section is:

[0094] z q =(z1*A1+z2*A2*E) c2 / E c1 +0.5*z3*A3*E c3 / E c1 ) / (A1+A2+0.5*A3),

[0095] In the formula zq For z q1 or z q2 z1, z2, and z3 are respectively z q1 or z q2 The centroid vertical coordinates of the main beam section, reinforced concrete pavement layer section, and asphalt pavement layer section at the corresponding cross-sections, A1, A2, and A3, respectively, are z... q1 or z q2 The area of ​​the main beam section, the reinforced concrete pavement layer section, and the asphalt pavement layer section at the corresponding cross-section, E c1 E c2 E c3 z q1 or z q2 The elastic modulus of concrete at the corresponding cross-section of the main beam, the elastic modulus of concrete at the cross-section of the reinforced concrete pavement, and the elastic modulus of asphalt.

[0096] In this embodiment, the neutral axis rigid connection structure 4 includes a first cantilever slab 41 and a second cantilever slab 41 arranged opposite to each other. The first cantilever slab 41 is prefabricated integrally with the first main beam 1, and the second cantilever slab 41 is prefabricated integrally with the second main beam 2. A slab joint 411 is formed between the first cantilever slab 41 and the second cantilever slab 41. A post-cast concrete slab 45 is provided above the first cantilever slab 41 and the second cantilever slab 41. Several sets of truss steel bars 42 are pre-embedded at the ends of the main beam, and the several sets of truss steel bars 42 are arranged at intervals along the transverse direction of the bridge. A bottom formwork 43 is also erected on the slab joint 411 between the first cantilever slab 41 and the second cantilever slab 41. The bottom formwork 43 is not removed after the post-cast concrete slab 45 is constructed and shares the load with it. The top surface of the post-cast concrete slab 45 has a structure with high sides and low center, and the sides are close to the main beam.

[0097] Each set of truss reinforcement bars 42 includes a first truss reinforcement bar and a second truss reinforcement bar arranged opposite each other, and the first truss reinforcement bar and the second truss reinforcement bar arranged opposite each other are connected by connecting reinforcement bars 44. Specifically, the left end of the first truss reinforcement bar is embedded in the first main beam 1, and the portion of the first truss reinforcement bar near the post-cast concrete slab 45 is embedded in the first cantilever slab 41 at the bottom and extends into the post-cast concrete slab 45 at the top; similarly, the right end of the second truss reinforcement bar 42 is embedded in the second main beam 2, and the portion of the second truss reinforcement bar 42 near the post-cast concrete slab 45 is embedded in the second cantilever slab 41 at the bottom and extends into the post-cast concrete slab 45 at the top.

[0098] Both the first main beam 1 and the second main beam 2 have end crossbeams 123 between their webs 122. The surface of the end crossbeams 123 near the beam joint 32 is flush with the end face of the neutral axis rigid connection structure 4 and is rigidly connected to each other. Several groups of truss reinforcement bars 42 are spaced apart only at the end crossbeams 123 in the transverse direction of the bridge, and no pre-embedding is required at the web 122.

[0099] The first main beam 1 has a downwardly inclined first groove 1241 at the end of its wing plate, and the second main beam has a downwardly inclined second groove 1241 at the end of its wing plate. The bridge deck simply supported beam structure 5 is disposed between the first groove 1241 and the second groove 1241. The bridge deck simply supported beam structure includes, from bottom to top, an elastic bottom formwork 52 and a simply supported beam plate 51. The simply supported beam plate 51 is a cast-in-place reinforced concrete structure. A soft partition layer 55 is vertically disposed between the simply supported beam plate 51 and the wing plates on both sides to separate it from the wing plates of the main beam. The thickness H51 of the simply supported beam plate 51 is greater than the thickness of the reinforced concrete pavement layer 33 on the top surface of the wing plate.

[0100] In this embodiment, the thickness H of the elastic bottom mold 52 at the beam end section of the main beam is... 52 The following inequalities must be satisfied:

[0101] H 52 ≥(L3-F1) / 2*tan[max(θ1,θ2)];

[0102] Where L3 is the longitudinal distance between the centerlines of the supports 121 at both ends of the beam joint 32, and θ1 and θ2 are the rotation angles at the centerline sections of the supports 121 generated by the first main beam 1 and the second main beam 2 under the assumption of plane section and the most unfavorable load combination of the ultimate limit state of bearing capacity in the current bridge code.

[0103] Elastic pads 53 are also provided on both sides of the elastic bottom formwork 52 along the bridge direction. The bottom surface of the elastic pad 53 contacts the top surface of the wing plate at the first groove 1241 or the second groove 1241, and the top surface of the elastic pad 53 contacts the bottom surface of the simply supported beam structure of the bridge deck. The vertical projection range of the elastic pad 53 includes the vertical centerline of the main beam support 121, and the length L53 of the elastic pad 53 along the bridge direction is less than the length of the support 121 along the bridge direction. The elastic modulus of the elastic pad 53 is greater than that of the elastic bottom formwork 52; the elastic modulus of the elastic bottom formwork 52 does not exceed 1 / 100 of the elastic modulus of the simply supported beam plate 51. The elastic pad 53 is generally made of rubber material, and the elastic bottom formwork 52 is generally made of foam material; the soft partition layer 55 is made of soft, waterproof material, generally asphalt mastic or polyurethane waterproof sealant; the raised structure 511 is generally made of steel fiber reinforced concrete.

[0104] Before constructing the soft partition layer 55, a rigid partition board 551 (usually a thin aluminum plate or plastic plate) can be pre-embedded. After the initial setting of the cast-in-place concrete of the reinforced concrete pavement layer 33 and the simply supported beam slab 51, the board can be removed and the soft partition layer 55 can be filled in.

[0105] The simply supported beam structure 5 of the bridge deck is vertically connected to the wing plate structure below by a number of limiting tension bars 54. The limiting tension bars 54 are spaced apart along the transverse direction at the center line section of the support 121. More specifically, the limiting tension bars 54 are also provided with sleeves 541, which are arranged sequentially from the wing plate, through the elastic pad 53, to the simply supported beam plate 51 along the center line section of the support 121.

[0106] At the junction of the reinforced concrete pavement layer 33 on the top surface of the wing plate 124 and the simply supported beam structure of the bridge deck, both are provided with raised structures. The length direction of the raised structure is transverse to the bridge direction, and the width direction is longitudinal to the bridge direction. The raised structure interrupts the asphalt pavement layer 35, and its top surface is flush with the asphalt pavement layer 35. The soft partition layer 55 is located within the raised structure and is arranged along the length direction of the raised structure. In the longitudinal direction, an asphalt pavement layer 35 is provided between adjacent raised structures 511, and the top surface of the raised structure 511 is flush with the top surface of the asphalt pavement layer 35.

[0107] Example 2

[0108] This embodiment discloses a beam joint structure for prefabricated beam bridges. Its structure is basically the same as that of Embodiment 1, as shown in Figures 1-4. The difference lies in that, based on Embodiment 1, the beam joint 32 structure further includes a drainage system 6. The drainage system 6 includes a first drainage pipe 62 and a second drainage pipe 67. The first drainage pipe 62 is located at the bottom of the simply supported beam structure of the bridge deck, and the second drainage pipe 67 is located at the bottom of the rigid connection structure 4 of the neutral axis. A set of first drainage pipes 62 is positioned opposite each other at the lowest point of the wing plate's cross slope. The first drainage pipes 62 are respectively located on the bottom surfaces of the first groove 1241 and the second groove 1241, and are inclined towards one side of the beam joint 32.

[0109] The drainage system 6 also includes a wing plate cantilever plate waterstop 63 and a water guide plate 64. The wing plate cantilever plate waterstop 63 is located below the wing plate cantilever plate and slopes towards the web plate 122. The water guide plate 64 is located at the position where the post-cast concrete slab 45 connects with the beam end. The water guide plate 64 is arranged on the post-cast concrete slab 45 along the transverse direction of the bridge.

[0110] Specifically, a water collection well 66 is provided at the joint 411 between adjacent cantilever slabs 41 at the lowest point of the cross slope of the neutral shaft rigid connection structure 4. The water collection well 66 extends from the top surface to the bottom surface of the neutral shaft rigid connection structure 4 and is connected to the second drainage pipe 67. The water guide plate 64 can guide the water flow to the water collection well 66 and drain it away through the second drainage pipe 67.

[0111] The inclined bottom surfaces of the first groove 1241 and the second groove 1241 are both first inclined surfaces 61, and the inclined top surface of the post-cast concrete slab 45 is a second inclined surface 65. The first inclined surface 61 and the second inclined surface 65 can guide the water flow to the water collection well 66 and drain it away through the second drainage pipe 67.

[0112] Example 3

[0113] This embodiment discloses a prefabricated beam bridge, such as Figure 5 As shown, the bridge includes N piers 31 spaced apart, and N-1 precast main beams are erected on the N piers 31. The beam joint 32 structure described in Embodiment 1 or Embodiment 2 is provided between adjacent main beams along the bridge direction.

[0114] Example 4

[0115] A construction method for prefabricated beam bridges, such as Figure 6 As shown, it includes the following steps:

[0116] Step 1: In this step, the prefabricated structure is constructed on the completed piers 31 and supports 121 according to the construction design drawings of the prefabricated beam bridge. During the prefabrication of the main beam, the end of the wing plate is provided with a groove 1241 for installing the simply supported beam structure of the bridge deck. The end of the main beam and the end face of the end crossbeam 123 are respectively prefabricated with cantilever slabs 41 and truss reinforcement 42. Limiting pull-out reinforcement 54, sleeves 541 and elastic pads 53 are pre-embedded at the center line of the support 121.

[0117] Step 2: This step involves the construction of the neutral axis rigid connection structure 4 at beam joint 32 and the corresponding drainage facilities. First, place the bottom formwork 43 above the joint 411 of the cantilever slab 41 and install the water collection well 66 and the second drainage pipe 67. Install the connecting steel bars 44 between the opposite truss steel bars 42. After pouring the concrete slab 45, install the water guide plate 64 on the top after the concrete has initially set.

[0118] Step 3: This step involves the construction of the simply supported beam structure of the bridge deck and the corresponding drainage facilities. First, install the cantilever plate waterstop 63 at the bottom of the wing plate, then install the first drainage pipe 62 and the elastic bottom formwork 52. After installing the rigid partition plate 551, pour concrete at the position of the reinforced concrete pavement layer 33 and the position of the simply supported beam plate 51. After the concrete has initially set, remove the rigid partition plate 551 and fill in the soft partition layer 55.

[0119] Step 4: This step involves the construction of the subsequent bridge deck structure, including the sequential construction of the bridge deck waterproofing layer 34, asphalt pavement layer 35, and other bridge deck facilities on the top surface of the reinforced concrete pavement layer 33 and the simply supported beam slab 51, ultimately completing the overall construction of the prefabricated beam bridge.

[0120] In the technical solution of the present invention, the construction method of the present invention can realize the complete formwork-free operation of the neutral axis rigid connection structure, and the construction personnel can walk directly on the cantilever slab to complete the reinforcement binding and cast-in-place operation of the cast-in-place concrete slab; (2) the bridge deck simply supported beam structure and the reinforced concrete pavement layer are constructed at the same time without adding extra procedures, processes and construction period; (3) compared with continuous beam bridge, it saves the two major time-consuming procedures of tensioning the negative bending moment bundle at the pier top and the large number and dense reinforcement connection operations in the limited space at the wet joint at the pier top, greatly reducing the construction difficulty, saving construction measures costs and shortening the construction period.

[0121] The above description is only a preferred embodiment of the present invention and is 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 within the protection scope of the present invention.

Claims

1. A fabricated beam gap construction between beam bridges, the beam gap construction being used to connect main beams arranged adjacent to each other in the bridge direction, the beam gap construction being arranged in the position of a beam gap (32) between a first main beam (1) and a second main beam (2), characterized in that The beam gap structure comprises a deck simply supported beam structure and a neutral axis rigid joint structure (4) from top to bottom in turn, the deck simply supported beam structure is arranged in the wing plate area, the neutral axis rigid joint structure (4) is rigidly connected with the first main beam (1) and the second main beam (2) respectively, the vertical height difference absolute value of the top surface and the bottom surface of the neutral axis rigid joint structure (4) and the neutral axis of the beam end section of the first main beam (1) is not more than 0.25H0, the vertical height difference absolute value of the top surface and the bottom surface of the neutral axis rigid joint structure (4) and the neutral axis of the beam end section of the second main beam (2) is not more than 0.25H0, the maximum thickness H4 of the neutral axis rigid joint structure (4) is less than or equal to 0.3H0, and H0 is the maximum beam height of the first main beam (1) or the second main beam (2).

2. The fabricated beam gap construction between beam bridges according to claim 1, characterized in that, The beam gap (32) has a bridge longitudinal size F1 of not less than 30cm.

3. The fabricated beam gap construction between beam bridges according to claim 1, characterized in that, The beam end section neutral axis is parallel to the zero normal stress line, and the zero normal stress line is a line connecting all points with zero normal stress in the section under the action of the self weight of the main beam and at a distance H0 from the bridge center line in the bridge longitudinal direction.

4. The fabricated beam gap construction between beam bridges according to claim 1, characterized by, The beam end section neutral axis is a horizontal straight line along the transverse bridge direction, and the vertical coordinate z of the beam end section neutral axis in the space rectangular coordinate system q4 is determined as follows: z q4 = [z q1 * L1 + z q2 * (L - L1) ] / L, formula 1) In formula 1), L is the full length of the girder, z q1 is the vertical coordinate of the equivalent centroid of the cross section at the midspan, L1 is the total length of the girder section in the range of the full length of the girder that is consistent with the cross section at the midspan, z q2 is the vertical coordinate of the equivalent centroid of the cross section at the center line H0 of the support; The calculation formula of the vertical coordinate of the equivalent centroid of the section is: z q = (z1*A1+z2*A2*E c2 / E c1 +0.5*z3*A3*E c3 / E c1 ) / (A1+A2+0.5*A3), equation 2) In formula 2), z q is z q1 or z q2 , z1, z2, z3 are z q1 or z q2 the vertical coordinates of the centroid of the main beam section, the reinforced concrete pavement section, and the asphalt pavement section at the corresponding section, A1, A2, A3 are z q1 or z q2 the areas of the main beam section, the reinforced concrete pavement section, and the asphalt pavement section at the corresponding section, E c1 , E c2 , E c3 are z q1 or z q2 the elastic modulus of the concrete of the main beam section, the elastic modulus of the concrete of the reinforced concrete pavement section, and the asphalt elastic modulus at the corresponding section.

5. The fabricated beam gap construction between beam bridges according to claim 1, characterized by, The neutral axis rigid joint structure (4) comprises oppositely arranged first and second cantilever plates (41), the first cantilever plate (41) is integrally prefabricated with the first main beam (1), the second cantilever plate (41) is integrally prefabricated with the second main beam (2), a plate gap (411) is formed between the first and second cantilever plates (41), a post-poured concrete plate (45) is arranged in the area above the first and second cantilever plates (41), a plurality of groups of truss steel bars (42) are embedded in the main beam end portion, and the plurality of groups of truss steel bars (42) are arranged at intervals in the transverse bridge direction.

6. The fabricated beam gap construction between beam bridges according to claim 5, characterized in that, Each group of truss steel bars (42) comprises oppositely arranged first and second truss steel bars (42), and the first and second truss steel bars (42) are connected by connecting steel bars (44).

7. The fabricated beam gap construction between beam bridges according to claim 6, characterized in that, The left end of the first truss steel bar is embedded in the first main beam, the lower part of the part of the first truss steel bar close to the post-poured concrete plate is embedded in the first cantilever plate, and the upper part of the part of the first truss steel bar close to the post-poured concrete plate extends into the post-poured concrete plate; similarly, the right end of the second truss steel bar is embedded in the second main beam, the lower part of the part of the second truss steel bar close to the post-poured concrete plate is embedded in the second cantilever plate, and the upper part of the part of the second truss steel bar close to the post-poured concrete plate extends into the post-poured concrete plate.

8. The fabricated beam gap construction between beam bridges according to claim 6, characterized in that, The top surface of the post-poured concrete plate (45) has a structure of high in the middle and low on both sides.

9. The fabricated beam gap construction between beam bridges according to claim 5, characterized in that, The end cross beams (123) are arranged between the webs (122) of the first main beam (1) and the second main beam (2), the surfaces of the end cross beams (123) close to the beam gap (32) are flush with the end surfaces of the neutral axis rigid joint structure (4) and are rigidly connected with each other.

10. The fabricated beam gap joint of claim 9, wherein, The plurality of groups of truss steel bars (42) are arranged at intervals only at the positions of the end cross beams (123) in the transverse bridge direction.

11. The fabricated beam gap construction between beam bridges of claim 1, wherein, The wing plate end of the first main beam (1) is provided with a downwardly inclined first groove (1241), the wing plate end of the second main beam is provided with a downwardly inclined second groove (1241), the deck simple supported beam structure is arranged between the first groove (1241) and the second groove (1241), and the deck simple supported beam structure sequentially comprises an elastic bottom die (52) and a simple supported beam plate (51) from bottom to top, the simple supported beam plate (51) is a cast-in-place reinforced concrete structure, and a soft partition layer (55) for partitioning the main beam wing plate is arranged between the simple supported beam plate (51) and the wing plates on both sides in the vertical direction.

12. The fabricated beam gap joint of claim 11, wherein, The thickness H of the simply supported slab (51) 51 The thickness of the reinforced concrete pavement (33) above the top surface of the slab.

13. The fabricated beam gap joint of claim 11, wherein, Elastic pads (53) are also arranged on both sides of the elastic bottom die (52) in the bridge direction, the bottom surface of the elastic pads (53) is in contact with the top surface of the wing plate at the first groove (1241) or the second groove (1241), the top surface of the elastic pads (53) is in contact with the bottom surface of the bridge deck simply supported beam structure, the vertical projection range of the elastic pads (53) contains the vertical center line of the main beam support (121), and the bridge direction length L 53 of the elastic pads (53) is less than the bridge direction length of the support (121).

14. The fabricated beam gap joint of claim 11, wherein, A plurality of limiting anti-uplift bars (54) are connected in the vertical direction between the deck simple supported beam structure and the wing plate structure below, and the limiting anti-uplift bars (54) are arranged in the transverse bridge direction at the support (121) center line section position.

15. The fabricated beam gap joint of claim 14, wherein, The limiting anti-uplift bars (54) are further provided with sleeve pipes (541) outside, and the sleeve pipes (541) sequentially penetrate the wing plate, the elastic pad plate (53) and the simple supported beam plate (51) along the support (121) center line section.

16. The fabricated beam gap joint of claim 11, wherein, The joint positions of the reinforced concrete pavement layer (33) on the top surface of the wing plate and the deck simple supported beam structure are both provided with protruding structures, the length direction of the protruding structures is the transverse bridge direction, the width direction is the in-bridge direction, the protruding structures partition the asphalt pavement layer (35), the top surface of the protruding structures is flush with the asphalt pavement layer (35), the soft partition layer (55) is located in the protruding structures, and the soft partition layer (55) is arranged in the length direction of the protruding structures.

17. The fabricated beam gap joint of claim 16, wherein, In the in-bridge direction, the asphalt pavement layer (35) is arranged between adjacent protruding structures (511), and the top surface of the protruding structures (511) is flush with the top surface of the asphalt pavement layer (35).

18. The fabricated beam gap joint of claim 13, wherein, The elastic modulus of the elastic pad plate (53) is greater than the elastic modulus of the elastic bottom die (52), and the elastic modulus of the elastic bottom die (52) is not more than 1 / 100 of the elastic modulus of the simple supported beam plate (51).

19. The fabricated beam gap joint of claim 11, wherein, The thickness H of the elastic bottom die (52) at the girder end section 52 satisfies the following inequality: H 52 ≥ (L3 - F1) / 2 * tan[max(θ1, θ2)]; Wherein, L3 is the in-bridge distance of the center line of the support (121) at both ends of the beam joint (32), θ1 and θ2 are the rotation angle values of the support (121) center line section of the first main beam (1) and the second main beam (2) respectively under the assumption of the plane section and the most unfavorable load combination of the bearing capacity limit state of the current bridge specification.

20. The fabricated beam gap joint of claim 11, wherein, The beam joint (32) further comprises a drainage system (6), the drainage system (6) comprises a first drainage pipe (62) and a second drainage pipe (67), the first drainage pipe (62) is arranged at the bottom position of the deck simple supported beam structure, and the second drainage pipe (67) is arranged at the bottom of the neutral axis rigid joint structure (4).

21. The fabricated beam gap joint of claim 20, wherein, A group of first drainage pipes (62) are oppositely arranged at the lowest point of the wing plate transverse slope, the first drainage pipes (62) are arranged on the bottom surfaces of the first groove (1241) and the second groove (1241) respectively, and the first drainage pipes (62) are arranged to be inclined to one side of the beam joint (32).

22. The fabricated beam gap joint of claim 20, wherein, The drainage system (6) further comprises a wing cantilever stop water belt (63) and a water guide plate (64), the wing cantilever stop water belt (63) is arranged below the wing cantilever and points to the web (122), the water guide plate (64) is arranged at the position where the post-cast concrete slab (45) is connected with the beam end, and the water guide plate (64) is arranged on the post-cast concrete slab (45) in the transverse bridge direction.

23. The fabricated beam gap joint of claim 20, wherein, The position of the slab joint (411) between the adjacent cantilever slabs (41) at the lowest point of the neutral axis rigid joint structure (4) is also provided with a water collecting well (66), the water collecting well (66) penetrates from the top surface to the bottom surface of the neutral axis rigid joint structure (4) and communicates with the second drainage pipe (67), and the water guide plate (64) can guide the water flow to the water collecting well (66) and drain away through the second drainage pipe (67).

24. The fabricated beam gap joint of claim 20, wherein, The inclined bottom surface of the first and second grooves (1241) is a first inclined surface (61), the inclined bottom surface of the post-cast concrete slab (45) is a second inclined surface (65), and the first inclined surface (61) and the second inclined surface (65) can guide the water flow to the water collecting well (66) and drain away through the second drainage pipe (67).

25. A fabricated beam bridge comprising N piers (31) arranged at intervals, N-1 precast main beams being erected on the N piers (31), characterized in that, The beam joint structure of any one of claims 1-24 is arranged between the adjacent main beams in the longitudinal direction of the bridge.

26. A construction method of a fabricated beam bridge, characterized by, The method comprises the following steps: Step 1: In this step, the prefabricated structure is built on the completed pier (31) and support (121) according to the construction design drawing of the fabricated beam bridge, wherein, in the prefabrication process of the main beam, the end of the wing plate is provided with a groove (1241) for installing the simply supported beam structure of the bridge deck, and the end of the main beam and the end surface of the end cross beam (123) are respectively prefabricated with a cantilever slab (41) and a truss steel bar (42); a limiting uplift resisting bar (54), a sleeve (541) and an elastic pad (53) are embedded at the position of the center line of the support (121); Step 2: In this step, the neutral axis rigid joint structure (4) and the corresponding drainage facilities at the beam joint (32) are constructed, first, the bottom formwork (43) is placed above the slab joint (411) of the cantilever slab (41) and the water collecting well (66) and the second drainage pipe (67) are installed, and the connecting steel bar (44) is installed between the opposite truss steel bars (42); the post-cast concrete slab (45) is poured, and after the initial setting of the concrete, the water guide plate (64) is installed on the top; Step 3: In this step, the simply supported beam structure of the bridge deck and the corresponding drainage facilities are constructed, first, the wing cantilever stop water belt (63) is installed at the position of the bottom of the wing plate, then the first drainage pipe (62) and the elastic bottom formwork (52) are installed, after the hard partition plate (551) is installed, the concrete pouring of the steel reinforced concrete paving layer (33) position and the simply supported beam slab (51) position is carried out, after the initial setting of the concrete, the hard partition plate (551) is removed and the soft partition layer (55) is filled. Step 4: In this step, the subsequent bridge deck structure is constructed, including the construction of the bridge deck waterproof layer (34), the asphalt paving layer (35) and other bridge deck facilities on the top surface of the steel reinforced concrete paving layer (33) and the simply supported beam slab (51) in sequence, and finally the overall construction of the fabricated beam bridge is completed.

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