Continuous simply supported track beam bridge and construction method

Abstract

The application discloses a simply-supported track beam bridge with continuous running surface and a construction method, and is applied to the technical field of simply-supported track beam bridge design and construction. The simply-supported track beam bridge comprises track beams erected on piers, rigid rigid joint structures and present tension prestressing components. Preformed prestressing beams are pre-buried in the track beams. The adjacent track beams are connected through the rigid rigid joint structures. The top surface and the side surface of the rigid joint structures correspond to the top surface and the side surface of the track beams respectively and are flush. The rigid joint structures provide running surfaces and supports for running wheels, guide wheels and stabilizing wheels to pass through the third structure joint. The present tension prestressing components comprise present tension prestressing beams arranged in the track beams. The construction method is a construction method of the simply-supported track beam bridge and comprises rigid rigid joint structure construction and tensioning processes. The application can effectively reduce the beam end corner and the lifting effect of the simply-supported beam, strengthens the anti-seismic, anti-torsion, anti-lateral tilting, anti-fatigue and durability of the whole bridge, realizes smooth transition between the two-span track beams, and reduces the construction difficulty.

Description

Technical Field

[0001] This invention relates to the field of design and construction technology of simply supported track beam bridges for straddle-type monorail transit, and particularly to a simply supported track beam bridge with a continuous running surface and its construction method. Background Technology

[0002] Straddle-type monorails are a transportation system where the train body, equipped with rubber tires, straddles a track beam, which simultaneously supports, guides, and stabilizes the train. This type of rail transit is generally used in low- to medium-capacity urban rail transit systems. For example... Figure 1 As shown, the top surface of the track beam of the straddle-type monorail is for the running wheels of the straddle-type monorail vehicle to travel on, and the sides are for the guide wheels and stabilizing wheels to travel on. Its track beam is both a load-bearing structure and a running track. Therefore, it is required to achieve millimeter-level precision in prefabrication, erection and bridge alignment in both horizontal and vertical directions. However, it is difficult to guarantee the precision requirements of the track beam by on-site cast-in-place construction. Therefore, the construction method of "factory prefabrication, on-site assembly and partial cast-in-place" is generally the main method.

[0003] Currently, only a few straddle-type monorail lines have been built or are in operation in Chongqing, Yinchuan, Liuzhou, Wuhu, and other cities. The structural systems of their bridge spans include three types: simply supported beam systems, continuous beam systems, and continuous rigid frame systems. However, each system has some long-standing unresolved problems that limit the widespread application of straddle-type monorails. Based on analysis, the advantages and shortcomings of each system are summarized as follows:

[0004] The advantages of a simply supported beam system are: (1) No secondary internal forces are generated under the effects of foundation settlement, concrete shrinkage and creep, and temperature; (2) The difficulty of controlling the alignment during on-site erection is low, and the alignment adjustment is relatively convenient. After the bridge is completed, the alignment can be adjusted for each span; (3) The on-site construction difficulty is low, the construction procedures are few, and the construction speed is fast, making it very suitable for prefabricated assembly construction. Its disadvantages are: (1) Poor overall integrity, low stiffness, and poor resistance to earthquakes, tilting, and torsion; (2) Many expansion joint devices with high unit prices, poor driving comfort, and high tire wear; (3) The large corner of the beam end of the simply supported beam results in a relatively smaller span compared to the continuous beam, denser piers, and difficulty in avoiding underground pipelines, resulting in a less aesthetically pleasing appearance; (4) Many expansion joint devices and supports, resulting in a large workload for maintenance and repair.

[0005] II. The advantages of the continuous beam system are: (1) good integrity, high stiffness, and certain seismic and torsional resistance; (2) fewer beam joints, good driving comfort, and low tire wear; (3) moderate span, and good coordination between pier height and span; (4) fewer expansion joint devices and fewer supports, resulting in a moderate workload for maintenance. Its disadvantages are: (1) secondary internal forces will be generated under the action of uneven settlement of the foundation; (2) rigid wet joints with dense steel strands and steel strands need to be cast in place at the top of the middle pier, resulting in a large amount of steel connection work and low efficiency of prefabricated assembly construction; (3) the large proportion of live load borne by the track beam leads to the difficulty of controlling the tensile stress in the negative bending moment zone. If the negative bending moment zone cracks, the maintenance is difficult and seriously affects the driving comfort; (4) if the support layout is not carefully analyzed and calculated, the horizontal force borne by a single pier may be much greater than that of other piers, resulting in excessive horizontal displacement at the top of the pier and affecting the smoothness of driving.

[0006] III. The advantages of continuous rigid frame system are: (1) good integrity, high stiffness, strong seismic and torsional resistance; (2) fewer beam joints, good driving comfort, and low tire wear; (3) moderate span, good coordination between pier height and span; (4) fewer expansion joint devices and supports, and less maintenance workload; (5) longitudinal horizontal force is borne by multiple piers, which can reduce the horizontal displacement of pier top and the number of lower pile foundations. Its disadvantages are: (1) the structural system is greatly affected by uneven settlement of foundation, concrete shrinkage and creep, temperature and other effects; (2) it is necessary to cast in place the steel reinforcement and dense steel strand rigid wet joints at the top of the middle pier, the steel reinforcement connection work is large, and the prefabrication and assembly construction efficiency is low; (3) the live load ratio of the track beam is too large, which makes it difficult to control the tensile stress in the negative bending moment zone. If the negative bending moment zone cracks, the maintenance is difficult and it seriously affects the driving comfort; (4) the alignment control requirements are very high. It needs to be adjusted in place once before the bridge is completed. The alignment cannot be adjusted after the bridge is completed. Summary of the Invention

[0007] In theory, simply supported beam systems offer faster construction speeds and lower project costs, making them the most economical bridge type for the prefabricated construction of bridge spans in straddle-type monorail transit. Therefore, addressing the long-standing unresolved issues of existing simply supported beam systems, this invention provides a simply supported track beam bridge with a continuous running surface and its construction method. Starting from the fundamental issue of the overall bridge structure, it solves the four major shortcomings of existing simply supported beam systems and offers higher reliability, applicability, and economic benefits.

[0008] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0009] A simply supported track beam bridge with a continuous running surface includes a first track beam and a second track beam erected adjacent to each other on piers, and a rigid connection structure at the running wheel and guide wheel. Both the first and second track beams are precast concrete structures. Precast prestressed tendons are embedded and anchored within the first and second track beams, respectively. The beam width B of the first and second track beams is ≤100cm. The rigid connection structure is located in the upper middle part of a first structural joint between the first and second track beams, with a longitudinal dimension F1 ≥30cm. The top surface of the rigid connection structure is flush with the top of the first and second track beams. The rigid connection structure is rigidly connected to both the first and second track beams, and the maximum vertical dimension H4 of the connection surface satisfies: H4 ≤ max(H1, H2) / 4, where H1 is the maximum beam height of the first track beam and H2 is the maximum beam height of the second track beam; prestressed prestressed components connected to both ends are pre-installed in the first and second track beams along the longitudinal direction of the bridge; the prestressed prestressed components include prestressed prestressed tendons and tensioning ends. The prestressed prestressed tendons are located in the built-in pipes of the first and second track beams. At any cross-section of the first and second track beams, the prestressed prestressed tendons are located below the neutral axis of the cross-section along the transverse direction of the bridge. The tensioning end is the end of the prestressed prestressed tendon. The tensioning end is located at the first structural joint and extends out of the end face of the first or second track beam during the prefabrication of the track beam. After the rigid connection structure at the running wheel and guide wheel is constructed, the prestressed prestressed tendons are tensioned and anchored through the tensioning end. The bridge piers are divided into continuous piers and segmented piers. The simply supported track beam bridge consists of multiple track beam segments, with adjacent track beams marked as the first track beam and the second track beam, respectively. The top surface of the track beam is for the running wheels of straddle-type monorail vehicles, while the sides of the track beam are for the guide wheels and stabilizing wheels, with the stabilizing wheels located vertically below the guide wheels. The first structural joint is a rigid connection structure located between two spans of track beams, with the running wheels and guide wheels located on its upper part. Below the first structural joint is a continuous pier. The second structural joint is the lower part of the rigid connection structure after the later pouring of concrete. The gap formed between the first and second track beams; the third structural joint is the gap between two adjacent spans of track beams at both ends of the simply supported track beam bridge, and there is no rigid connection structure above the third structural joint for the running wheels and guide wheels, and the third structural joint is a connecting pier below the third structural joint; the rigid connection structure for the running wheels and guide wheels will be constructed on site after the track beams at both ends are erected, and the top and side surfaces of the rigid connection structure are flush with the top and side surfaces of the track beams at both ends, respectively, and provide a driving surface and support for the running wheels, guide wheels and stabilizing wheels to pass through the third structural joint.

[0010] The technical principles and effects of the above invention are as follows: (1) The rigid connection structure at the running wheel and guide wheel can make the vertical area near the running surface between the first track beam and the second track beam continuous while the other vertical areas are disconnected, forming a stress state between a simply supported beam and a continuous beam, thus combining the advantages of both simply supported beam systems and continuous beam systems; (2) The rigid connection structure at the running wheel and guide wheel can effectively reduce the beam end rotation angle and warping effect of simply supported beams, realize a smooth transition between two spans of track beams, and avoid the phenomenon of vehicle jumping at this point, thereby solving the disadvantage that the span of simply supported beam systems cannot be made large, achieving the same pier density and landscape as continuous beam and continuous rigid frame systems, and also reducing beam joints to improve driving comfort and reduce (3) The rigid connection structure at the running wheel and guide wheel is mainly responsible for bearing the vertical loads such as train live load and transmitting the horizontal loads such as overall temperature rise and fall, traction force and braking force. At the same time, after connecting the track beams at both ends into a whole, the lateral bending stiffness of the whole bridge is greatly improved, and the seismic, torsional and anti-tilting performance of the whole bridge is strengthened; (4) The first structural joint is set so that there is enough space for tensioning and anchoring of the prestressed components. At the same time, it also ensures that there is enough operating space for personnel to construct the rigid connection structure at the running wheel and guide wheel, and reduces the total length of the track beam and the calculated span, and significantly saves the amount of concrete and steel used in the track beam; (5) According to the calculation and analysis, when H4≤max(H1, When H2) / 4, the negative bending moment effect transmitted to the first structural joint by the adjacent track beams under the vertical loads such as train live load is significantly reduced compared to the continuous beam system, and the vertical stress of the adjacent track beams is close to that of a simply supported beam; (6) Although the above negative bending moment effect is small, the small H4 of the rigid connection structure at the running wheel and guide wheel results in a small cross-sectional bending stiffness. Therefore, the tensile stress generated by the negative bending moment effect at its upper edge is still large, especially at the contact interface with the track beams at both ends, which is more prone to durability and fatigue problems. The above durability and fatigue problems will be further aggravated under the wheel impact of straddle-type monorail trains. Therefore, sufficient preload needs to be applied to the structure at this location to control the influence of tensile stress in the negative bending moment zone. After the track beams at both ends are erected and the running wheel is installed, After the rigid connection structure at the guide wheel, the tensioning and anchoring of the prestressed components can cause the adjacent track beams to arch upwards, thereby indirectly squeezing the rigid connection structure at the running wheel and guide wheel so that it has a certain pre-pressure in the completed bridge state, and controls the tensile stress in its operation state within the range of the material's tensile strength, so that it is not easy to crack and affect the vertical alignment of the track beam and the smoothness of the train at the continuous pier; (7) the prestressed strand is part of the load-bearing system of the track beam in the operation stage. It can be mainly used to resist the positive bending moment generated by the vertical action of the train live load, while also resisting the negative bending moment effect at the continuous pier. It can be pre-embedded in the track beam during prefabrication. Its on-site tensioning does not increase the total tensioning workload, and basically does not increase the total material usage of the prestressed strand;(8) Because the beam width B of the straddle-type monorail track beam is ≤100cm, the beam width is very narrow, allowing workers to complete the construction of the rigid connection structure and the tensioning and anchoring of all prestressed components from the side of the track beam at the first structural joint.

[0011] In a preferred embodiment of the present invention, the above-mentioned rigid connection structure is a cast-in-place reinforced concrete structure, including pre-embedded steel bars, connecting steel bars and post-cast concrete blocks. Pre-embedded steel bars are prefabricated at the opposite ends of the first track beam and the second track beam. The pre-embedded steel bars at the opposite ends are tied and fixed by connecting steel bars. Along the longitudinal direction of the bridge, the width of the rigid connection portion between the post-cast concrete block and the first track beam and the second track beam at both ends is greater than the width of the non-rigid connection portion. The bottom surface of the post-cast concrete block is lower than or equal to the lower edge of the running surface of the stabilizing wheel of the straddle-type monorail vehicle.

[0012] The technical principle and effect of the above invention are as follows: by setting pre-embedded steel bars and connecting steel bars in the post-cast concrete block, the connection strength between the rigid connection structure and the track beams at both ends is enhanced. Since the post-cast concrete block is still subjected to a certain tensile force, the rigid connection part ensures the stress requirements, and the non-rigid connection part facilitates the support of the guide wheel.

[0013] In a preferred embodiment of the present invention, the upper part of the post-cast concrete block is rigidly connected to the first track beam and the second track beam at both ends, and a second structural joint is provided between the lower middle part of the post-cast concrete block and the first track beam and the second track beam at both ends.

[0014] The technical principle and effect of the above invention are as follows: The structure of the above-mentioned post-cast concrete block ensures that the post-cast concrete block has both a rigid connection area and a disconnected area with the first track beam and the second track beam at both ends. Since the first track beam will rotate after the beam end undergoes corner deformation, it will cause the post-cast concrete block to rotate, which may cause the lower end of the post-cast concrete block to press against the end face of the second track beam or collide with it. Setting the second structural joint can avoid this situation.

[0015] In a preferred embodiment of the present invention, the lower edge of the contact surface of the post-cast concrete block and the rigid connection portion of the track beams at both ends is lower than or equal to the lower edge of the guide wheel running surface of the straddle-type monorail vehicle.

[0016] The technical principle and effect of the above invention are as follows: the above structure can ensure a smooth transition of the guide wheel of the straddle-type monorail vehicle at the beam joint.

[0017] In a preferred embodiment of the present invention, the above-mentioned simply supported track beam bridge has an elastic partition plate pre-embedded before the second structural joint is constructed. The elastic partition plate is located in the second structural joint and is removed after the initial setting of the cast-in-place concrete of the post-cast concrete block.

[0018] The technical principle and effect of the above invention are as follows: the elastic partition plate can prevent the post-cast concrete block in the area from being directly connected to the track beam, and after it is removed, a second structural joint is formed.

[0019] In a preferred embodiment of the present invention, the minimum longitudinal dimension F4 of the second structural joint is greater than or equal to y1*sin[max(β1, β2)], where y1 is the vertical distance from the upper edge of the beam end to the neutral axis of the support section, and β1 and β2 are the axial rotation angles of the beam segments outside the support centerline generated by the first and second track beams under the most unfavorable combination of vertical loads according to the plane section assumption and the current bridge code.

[0020] The technical principle and effect of the above invention are as follows: When the minimum longitudinal dimension of the second structural joint satisfies F4≥y1*sin[max(β1, β2)], it can be guaranteed that the horizontal displacement of the lower end of the post-cast concrete block after rotation is less than F4. The specific derivation is as follows (in conjunction with...). Figure 7 Analysis diagram of horizontal compression value at the upper edge of the beam end after deflection of the track beam: Because the beam segment from the support centerline to the first structural joint (i.e., the beam segment outside the support centerline) has basically no normal stress on its cross-section under the vertical live load of the train, that is, there is basically no horizontal compressive deformation within this beam segment. Therefore, the horizontal compression value Δ at the upper edge of the beam end is small. x1 ≈Horizontal compression value at the upper edge of the support section △ x2 According to the principle of small angle approximation, the horizontal compression value Δ at the upper edge of the support section can be determined. x2 ≈y1*tanθ≈y1*sinθ, where θ is the rotation angle of the support section. Considering the large vertical bending stiffness of the beam segment outside the support centerline, the neutral axis of this beam segment can be considered to rotate upwards along a circular arc trajectory around the neutral axis at the support section. According to the plane section assumption and the similarity relationship of triangles, θ = the rotation angle β of the neutral axis of the beam segment outside the support centerline. Combining the above formulas, it can be proved that F4 ≥ △ x1 ≈y1*sin[max(β1, β2)].

[0021] In a preferred embodiment of the present invention, the tension F of the prestressed tendons on the first or second track beam satisfies: |σ F + |≤|σ G - |-|σ p + |,σ F + σ is the maximum of the tensile stresses at the upper edge of the mid-span section and the upper edge of the 1 / 4-span section of the track beam generated by the tension force F of the prestressed tendons. G - Let σ be the minimum of the compressive stress at the upper edge of the mid-span section and the compressive stress at the upper edge of the 1 / 4-span section caused by the self-weight G of the track beam. p+ The maximum value of the tensile stress at the upper edge of the mid-span section and the tensile stress at the upper edge of the 1 / 4-span section of the track beam generated by the precast prestressed tendons.

[0022] The technical principle and effect of the above invention are as follows: When designing the tension force of the prestressed component, it should be ensured that the upper edge of the track beam does not generate tensile stress in the completed bridge state, and the design can be simplified according to the above formula.

[0023] In a preferred embodiment of the present invention, both ends of the same prestressed strand are tensioning ends, and the tensioning ends are located above the continuous pier; or the two ends of the same prestressed strand are a tensioning end and an anchoring end, respectively, and the anchoring end is located above the connecting pier. The anchoring end is anchored in the first track beam or the second track beam by an anchoring device during prefabrication.

[0024] The technical principle and effect of the above invention are as follows: a tensioning end is provided at the continuous pier, and an anchoring end is provided on the branch pier, which facilitates the tensioning and anchoring of the prestressed tendons. The third structural joint is located on the branch pier, where an expansion joint device is generally provided. Therefore, the longitudinal dimension of this structural joint is generally no more than 16cm, and tensioning operations cannot be carried out after the beam is erected. Therefore, the end of the prestressed tendon component near the branch pier is designed as the anchoring end, and it is anchored to the track beam through the anchoring device during the prefabrication of the track beam.

[0025] A construction method for a simply supported track beam bridge with a continuous running surface, comprising the following steps:

[0026] S1. A simply supported track beam bridge is erected on different piers. The track beam includes a first track beam and a second track beam arranged adjacent to each other. The first track beam and the second track beam are respectively precast with precast prestressed tendons in the direction of the bridge. A third structural joint is formed between the track beams on the connecting piers and a first structural joint is formed between the track beams on the continuous piers. At the first structural joint, the pre-embedded steel bars of the first track beam and the second track beam are positioned opposite each other. At the same time, the precast prestressed tendons extend from both ends of the track beam and are tensioned and anchored at both ends of the track beam. The tensioning end of the prestressed tendon extends out of the end of the track beam.

[0027] S2. The pre-embedded steel bars with opposite positions are tied and fixed by connecting steel bars. Elastic partition plates are set at the joint ends of the first track beam and the second track beam respectively to support the formwork of the rigid connection structure. Then concrete is poured to form post-cast concrete blocks. After the cast-in-place concrete of the post-cast concrete blocks has initially set, the elastic partition plates are removed.

[0028] S3. Tensioning is performed at the tensioning end of the prestressed tendon, and the tensioning end is anchored. Finally, grouting is performed inside the duct where the prestressed tendon is located to fix it.

[0029] The technical principles and effects of the above invention are as follows: (1) The construction method of the present invention is specifically designed for the narrow and high cross-section track beams unique to straddle-type monorail transit. The on-site steel reinforcement connection, concrete casting and prestressed tendon tensioning and anchoring operations can be conveniently completed from the operating space on both sides or top of the track beam; (2) Compared with continuous beams and continuous rigid frame systems, the construction method of the present invention eliminates the two time-consuming procedures of tensioning the negative moment tendons at the pier top and the large and dense steel reinforcement connection operations in the limited space at the wet joint at the pier top. The prestressed tendons are part of the load-bearing system during the operation of the track beam. They can be pre-embedded in the track beam during prefabrication. The on-site tensioning does not increase the total tensioning workload. It can be seen that the present invention significantly reduces the overall construction difficulty, saves construction measures costs and shortens the construction period.

[0030] Compared with existing simply supported beam systems, continuous beam systems, and continuous rigid frame systems, the beneficial effects of the simply supported track beam bridge in this invention, addressing the long-standing shortcomings described in the background art, are summarized as follows:

[0031] I. Improved Mechanical Performance: This invention connects two track beams into a whole through a rigid connection structure at the running wheels and guide wheels, significantly improving the lateral bending stiffness of the entire bridge and enhancing its seismic, torsional, and anti-tilting performance. Furthermore, the ingenious application of prestressed components allows the adjacent track beams to arch and compress the rigid connection structure at the running wheels and guide wheels, ensuring that this structure and its contact interface with the track beams at both ends have a certain pre-stress in the completed bridge state. This ensures its durability and fatigue resistance. It is evident that the prestressed components cleverly achieve both resistance to positive bending moments at mid-span and negative bending moments at supports. Therefore, the mechanical performance of this invention is significantly better than that of the existing simply supported beam system.

[0032] II. Improved driving comfort: This invention achieves a smooth transition between two spans of track beams through the combined use of rigid connection structures at the running wheels and guide wheels and prestressed components. This significantly reduces the number of expensive, specially designed expansion joint devices at the running wheels, stabilizing wheels, and guide wheels, avoids the bouncing effect at expansion joints, and reduces tire wear. Therefore, the driving comfort of this invention is significantly better than that of the existing simply supported beam system.

[0033] III. Enhanced Bridge Aesthetics: This invention effectively reduces the beam end rotation angle and warping effect of the track beam through the rigid connection structure at the running wheels and guide wheels and the prestressed components. This eliminates the limitation on the span of simply supported track beams caused by beam end rotation angle and ride comfort, allowing for the same pier density and under-bridge permeability as existing continuous beam systems. Therefore, the bridge aesthetics of this invention are significantly better than those of existing simply supported beam systems.

[0034] IV. Superior Economic Benefits: This invention reduces the total length and calculated span of the track beam, significantly saves on the amount of concrete and steel used in the track beam, and reduces the direct construction costs of the bridge. Compared with simply supported beam systems, it also significantly reduces the use of expensive special expansion joint devices, maintenance and repair work, and saves indirect operation and maintenance costs. Compared with continuous beam and continuous rigid frame systems, it also avoids the tensioning of negative moment bundles, thereby significantly reducing the accuracy requirements for alignment control and saving construction measures costs. Therefore, the economic benefits of this invention are significantly better than those of existing simply supported beam systems, continuous beam systems, and continuous rigid frame systems.

[0035] The construction method of the present invention also has the following beneficial effects:

[0036] I. Faster Construction Speed: The construction method of the simply supported track beam bridge of this invention eliminates two time-consuming processes: tensioning the negative moment tendons and connecting a large number of dense steel bars in the limited space at the wet joint at the pier top. Since the prestressed tendons are part of the load-bearing system during the operation of the track beam, they can be pre-embedded in the track beam during prefabrication. Their on-site tensioning does not increase the total tensioning workload, thus significantly reducing the overall construction difficulty and saving construction time. Therefore, it has a faster construction speed compared with the existing continuous beam system and continuous rigid frame system.

[0037] II. Superior Social and Environmental Benefits: The construction method of the simply supported track beam bridge of this invention shortens the construction period, thereby reducing the interference with existing traffic and nearby residents under the bridge. It is more suitable for the construction environment and requirements of urban rail transit bridges such as straddle-type monorails. Therefore, compared with the existing continuous beam system and continuous rigid frame system, it has superior social and environmental benefits.

[0038] In summary, this invention is a new type of simply supported track beam bridge and its construction method that is safer, more economical, more applicable, and more aesthetically pleasing than existing technologies. It can be widely used in various small and medium span straddle-type monorail bridge structures. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of the straddle-type monorail vehicle of the present invention and its positional relationship with the track beam;

[0040] Figure 2 This is a schematic diagram of the simply supported track beam bridge of the present invention;

[0041] Figure 3 This is an elevation view of the simply supported track beam bridge according to Embodiment 1 of the present invention;

[0042] Figure 4 This is an elevation view of the simply supported track beam bridge according to Embodiment 2 of the present invention;

[0043] Figure 5 For the present invention Figure 4AA section view in the middle;

[0044] Figure 6 For the present invention Figure 4 BB section view in the middle;

[0045] Figure 7 This is an analysis diagram of the horizontal compression value of the upper edge of the track beam after deflection according to the present invention.

[0046] Figure 8 This is a schematic diagram illustrating the construction process of a simply supported track beam bridge with a continuous running surface according to the present invention.

[0047] The markings in the diagram are: 1-First track beam, 121-Support, 122-Precast prestressed tendon, 2-Second track beam, 3-Track beam, 31-Continuous pier, 32-Branch pier, 33-First structural joint, 34-Third structural joint, 4-Rigid connection structure, 41-Embedded steel bar, 42-Connecting steel bar, 43-Post-cast concrete block, 431-Second structural joint, 432-Elastic partition plate, 5-Prestressed component, 51-Prestressed tendon, 52-Tensioning end, 53-Anchoring end, 61-Vehicle, 62-Running wheel, 63-Guide wheel, 64-Stabilizing wheel. Detailed Implementation

[0048] 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.

[0049] Example 1

[0050] Please refer to Figure 1 and Figure 2This embodiment provides a simply supported track beam bridge with a continuous running surface. The simply supported track beam bridge has n spans of track beam 3 and n+1 piers, where n is an integer ≥ 2. The n+1 piers include n-1 continuous piers 31 and 2 connecting piers 32. In this embodiment, n=3. The connecting piers 32 are located at both ends of the simply supported track beam 3, and the continuous piers 31 are arranged between the two connecting piers 32. Both the continuous piers 31 and the connecting piers 32 are provided with two supports 121. Adjacent track beams 3 are joined and erected on the connecting piers 32, and the track beams 3 are supported by the supports 121. Adjacent track beams 3 are marked as the first track beam 1 and the second track beam 2, respectively. The simply supported track beam bridge also includes a rigid connection structure 4 at the running wheel 62 and the guide wheel 63. The joint ends of the first track beam 1 and the second track beam 2 are connected and fixed by the rigid connection structure 4. The rigid connection structure 4 can just align with the track. The track vehicle 61 is supported by its running wheels 62 and guide wheels 63. The first track beam 1 and the second track beam 2 are also equipped with precast prestressed tendons 122 and prestressed components 5. The two track beams 3 are connected as a whole by a rigid connection structure 4, significantly improving the lateral bending stiffness of the entire bridge and enhancing its seismic, torsional, and anti-tilting performance. Simultaneously, it reduces the total length and calculated span of the track beams 3, significantly saving on concrete and steel usage and reducing direct bridge construction costs. Compared to simply supported beam systems, it also significantly reduces the use of expensive special expansion joint devices, maintenance, and repair work, saving indirect operation and maintenance costs. Compared to continuous beam and continuous rigid frame systems, it avoids the tensioning of negative moment tendons, thus significantly reducing the accuracy requirements for alignment control and saving on construction costs. Its economic benefits are significantly superior to existing simply supported beam, continuous beam, and continuous rigid frame systems. By using the rigid connection structure 4 at the running wheel 62 and guide wheel 63 and the prestressed components, a smooth transition between the two spans of the track beam 3 is achieved. This significantly reduces the number of expensive special expansion joint devices at the running wheel 62, stabilizing wheel 64 and guide wheel 63, avoids the bouncing effect at the expansion joint, and reduces tire wear. It also effectively reduces the beam end angle and warping effect of the track beam 3, so that the simply supported track beam 3 is no longer limited by the beam end angle and the problem of not being able to increase the span due to the smoothness of the ride. It can achieve the same pier density and under-bridge permeability as the existing continuous beam system.

[0051] Please refer to Figure 3In this embodiment, both the first track beam 1 and the second track beam 2 are precast concrete structures. During precasting, precast prestressed tendons 122 are pre-embedded and anchored in the first track beam 1 and the second track beam 2 respectively. In the same track beam 3, there are two precast prestressed tendons 122. The two prestressed tendons are placed in corrugated pipes. The corrugated pipes are curved downwards in an arc shape in the track beam 3. The arc design is determined according to the construction needs. The ends of the two prestressed tendons are anchored at the upper and middle positions at both ends of the track beam 3 respectively. The middle part of the two prestressed tendons is located below the transverse central axis of the track beam 3. In this embodiment, the beam width B of the first track beam 1 and the second track beam 2 is ≤100cm. Because the beam width B of the straddle-type monorail track beam 3 is also ≤100cm, the beam width is very narrow, allowing workers to complete the tensioning and anchoring operations of all prestressed components 5 from the side of the track beam 3 at the first structural joint 33. The gap between the connecting ends of the first track beam 1 and the second track beam 2 is the first structural joint 33. Below the first structural joint 33 is a continuous pier 31. The longitudinal dimension F1 of the first structural joint 33 is ≥30cm. The first structural joint 33 is thus established. This provides sufficient space for tensioning and anchoring of the prestressed components, while also ensuring sufficient space for personnel to construct the rigid connection structure 4 at the traveling wheels 62 and guide wheels 63. It also reduces the total length and calculated span of the track beam 3, significantly saving on concrete and steel usage. The third structural joint 34 is the gap between two adjacent spans of the simply supported track beam 3 at both ends of the bridge. There is no rigid connection structure 4 at the traveling wheels 62 and guide wheels 63 above the third structural joint 34, and a connecting pier 32 is located below it. A rigid connection structure 4 is installed in the upper middle part of the first structural joint 33. The rigid connection structure 4 is rigidly connected to the first track beam 1 and the second track beam 2 respectively. The rigid connection structure 4 is a reinforced concrete structure, with the reinforcing steel located within the first track beam 1 and the second track beam 2. Both ends of the rigid connection structure 4 have connection surfaces with the first track beam 1 and the second track beam 2 respectively. The maximum vertical dimension H4 of the connection surface satisfies:

[0052] H4≤max(H1, H2) / 4

[0053] Where H1 is the maximum beam height of the first track beam 1, and H2 is the maximum beam height of the second track beam 2.

[0054] When H4≤max(H1, H2) / 4, the negative bending moment effect transmitted to the first structural joint 33 by the adjacent track beam 3 under the action of vertical loads such as train live load is significantly reduced compared with the continuous beam system, and the vertical force of the adjacent track beam 3 is close to that of a simply supported beam. The rigid connection structure 4 at the running wheel 62 and the guide wheel 63 will be constructed on site after the track beams 3 at both ends are erected. The top surface of the rigid connection structure 4 is flush with the top of the first track beam 1 and the second track beam 2. The top surface of the track beam 3 and the top surface of the rigid connection structure 4 are used for the running wheel 62 of the straddle-type monorail vehicle 61 to travel. The side of the rigid connection structure 4 is flush with the side of the first track beam 1 and the second track beam 2. The side of the track beam 3 and the side of the rigid connection structure 4 are used for the guide wheel 63 and the stabilizing wheel 64 to travel. The stabilizing wheel 64 is located below the guide wheel 63 in the vertical direction. The position of the rigid connection structure 4 is just right so that its side can serve as the running surface to support the stabilizing wheel 64. The rigid connection structure 4 at the running wheels 62 and guide wheels 63 ensures that only the vertical region near the running surface between the first track beam 1 and the second track beam 2 is continuous, while other vertical regions are discontinuous, forming a stress state between a simply supported beam and a continuous beam. This combines the advantages of both systems. The rigid connection structure 4 at the running wheels 62 and guide wheels 63 effectively reduces the beam end rotation angle and warping effect of the simply supported beam, achieving a smooth transition between the two spans of track beam 3 and preventing vehicle bouncing at this point. This solves the problem of span... Despite the limitation of not being able to make the bridge too large, it can achieve the same pier density and aesthetics as continuous beam and continuous rigid frame systems. It also achieves the effects of reducing expansion joint devices to improve driving comfort, reduce tire wear, and reduce maintenance workload. The rigid connection structure 4 at the running wheel 62 and guide wheel 63 is mainly responsible for bearing vertical loads such as train live loads and transmitting horizontal loads such as overall temperature rise and fall, traction force and braking force. At the same time, after connecting the track beams 3 at both ends of the bridge into a whole, the lateral bending stiffness of the entire bridge is greatly improved, and the seismic, torsional and anti-tilting performance of the entire bridge is enhanced.

[0055] In this embodiment, prestressed prestressing components 5, connected to both ends of each track beam 3, are pre-installed along the longitudinal direction within the first track beam 1 and the second track beam 2. Each prestressed prestressing component 5 includes a prestressed prestressing strand 51, a tensioning end 52, and an embedded conduit within the first track beam 1 and the second track beam 2. The embedded conduit is a corrugated pipe. The prestressed prestressing strand 51 is located within the embedded conduit of the first track beam 1 and the second track beam 2. At any cross-section of the first track beam 1 and the second track beam 2, the prestressed prestressing strand 51 is located below the neutral axis of the cross-section along the transverse direction. That is, the track beam 3 is divided into upper and lower parts by a horizontal cross-section along the longitudinal direction. The prestressed prestressing strand 51 is always located in the lower part of the track beam 3. The tensioning end 52 is the end of the prestressed prestressing strand 51, located at the first structural joint 33 and tensioned. End 52 extends from the end face of the first track beam 1 or the second track beam 2 during the prefabrication of track beam 3. The other end opposite to tensioning end 52 can also be tensioning end 52, or pre-anchored in the first track beam 1 or the second track beam 2. After the rigid connection structure 4 at the running wheel 62 and guide wheel 63 is constructed, the tensioning and anchoring of the prestressed tendons 51 are carried out through tensioning end 52. The tensioning adopts the existing traction device, and the anchoring adopts the existing anchoring device. The prestressed tendons 51 are part of the load-bearing system of track beam 3 during the operation phase. They can be mainly used to resist the positive bending moment generated by the vertical action of train live load, while also resisting the negative bending moment effect at the continuous pier 31. They can be pre-embedded in track beam 3 during prefabrication. Their on-site tensioning does not increase the total tensioning workload, nor does it increase the total material consumption of the prestressed tendons. By cleverly applying the prestressed components, the rigid connection structure 4 at the upper arch of the adjacent track beam 3 and the running wheel 62 and guide wheel 63 can be rigidly squeezed, so that the structure and the contact interface with the track beams 3 at both ends have a certain pre-stress in the bridge state, thereby ensuring its durability and fatigue resistance. Therefore, the mechanical properties of the present invention are significantly better than those of the simply supported beam system of the prior art. Although the negative bending moment effect is relatively small, the small H4 of the rigid connection structure 4 at the running wheel 62 and guide wheel 63 results in a small cross-sectional bending stiffness. Therefore, the tensile stress generated by the negative bending moment effect at its upper edge is still relatively large, especially at the contact interface with the track beams 3 at both ends, which is more prone to durability and fatigue problems. These durability and fatigue problems will be further aggravated under the wheel impact of straddle-type monorail trains. Therefore, sufficient preload needs to be applied to the structure to control the influence of tensile stress in the negative bending moment zone. After the track beams 3 at both ends are erected and the rigid connection structure 4 at the running wheel 62 and guide wheel 63 is completed, the tensioning and anchoring of the prestressed components can cause the adjacent track beams 3 to arch upwards, thereby squeezing the rigid connection structure 4 at the running wheel 62 and guide wheel 63 to have a certain preload in the completed bridge state, and controlling the tensile stress in the operating state within the tensile strength range of the material, making it less likely to crack and affect the vertical alignment of the track beam 3 and the ride smoothness at the continuous pier 31.

[0056] Example 2

[0057] Please refer to Figure 4 This embodiment provides a simply supported track beam bridge with a continuous running surface. The simply supported track beam bridge 3 is the same as in Embodiment 1, and the precast prestressed tendons 122, prestressed components 5, and rigid connection structure 4 used are largely the same as in Embodiment 1. The difference is that in this embodiment, the above structure specifically includes the following:

[0058] Please refer to Figure 5 and Figure 6 In this embodiment, the rigid connection structure 4 includes embedded steel bars 41, connecting steel bars 42, and post-cast concrete blocks 43. The opposite ends of the first track beam 1 and the second track beam 2 are prefabricated with embedded steel bars 41. There are multiple sets of embedded steel bars 41, and in this embodiment there are 4 sets. The embedded steel bars 41 are U-shaped. The U-shaped embedded steel bars 41 are vertically arranged and their open ends are prefabricated at the opposite ends of the first track beam 1 and the second track beam 2. They are formed when the first track beam 1 and the second track beam 2 are manufactured. The embedded steel bars 41 at the opposite ends are tied and fixed by connecting steel bars 42. The connecting steel bars 42 are ring-shaped. The connecting steel bars 42 are staggered from the two embedded steel bars 41 in each set, and the opposite sides of the connecting steel bars 42 are tied to the two embedded steel bars 41 in each set by steel bars. The upper part of the post-cast concrete block 43 is rigidly connected to the first track beam 1 and the second track beam 2 at both ends. The middle and lower part of the post-cast concrete block 43 is provided with a second structural joint 431 between it and the first track beam 1 and the second track beam 2 at both ends. The second structural joint 431 is the gap formed between the middle and lower part of the rigid connection structure 4 after the concrete is poured later and the first track beam 1 and the second track beam 2. The bottom surface of the post-cast concrete block 43 is lower than or equal to the lower edge of the running surface of the stabilizing wheel 64 of the straddle-type monorail vehicle 61. Before constructing the second structural joint 431, an elastic partition plate 432 is pre-embedded. The elastic partition plate 432 is located at the second structural joint 431, with a reserved space above it for the rigid connection portion of the rigid connection structure 4. The elastic partition plate 432 is removed after the initial setting of the cast-in-place concrete of the post-cast concrete block 43. The lower edge of the contact surface between the post-cast concrete block 43 and the rigid connection portion of the track beams 3 at both ends, i.e., the top edge of the elastic partition plate 432, is lower than or equal to the lower edge of the running surface of the guide wheel 63 of the straddle-type monorail vehicle 61. This ensures a smooth transition of the guide wheel 63 of the straddle-type monorail vehicle 61 at the beam joint. The elastic partition plate 432 prevents the post-cast concrete block 43 in its area from being directly connected to the track beam 3. After removal, the second structural joint 431 is formed. Thus, along the longitudinal direction of the bridge, the width of the rigid connection portion between the post-cast concrete block 43 and the first track beam 1 and the second track beam 2 at both ends is greater than the width of the non-rigid connection portion. Please refer to... Figure 7This structure ensures that the post-cast concrete block 43 has both a rigid connection area with the first track beam 1 and the second track beam 2 at both ends, as well as a disconnected area. Since the first track beam 1 will rotate after the beam end undergoes corner deformation, the post-cast concrete block 43 will still be subjected to a certain tensile force, which may cause the lower end of the post-cast concrete block 43 to press against the end face of the second track beam 2 or collide with it. The second structural joint 431 can avoid this situation. The rigid connection part ensures the stress requirements, and the non-rigid connection part facilitates the support of the guide wheel 63.

[0059] In this embodiment, the minimum longitudinal dimension F4 of the second structural joint 431 satisfies:

[0060] F4≥y1*sin[max(β1, β2)]

[0061] Where y1 is the vertical distance from the upper edge of the beam end to the neutral axis of the support 121 section, and β1 and β2 are the axial rotation angles of the neutral axis of the beam segments outside the centerline of support 121 generated by the first and second track beams 2 under the most unfavorable combination of vertical loads according to the plane section assumption and current bridge specifications; when the minimum longitudinal dimension of the second structural joint 431 satisfies F4≥y1*sin[max(β1,β2)], it can be guaranteed that the horizontal displacement of the lower end of the post-cast concrete block 43 after rotation is less than F4. The specific derivation is as follows (combined with Figure 7 Analysis diagram of horizontal compression value at the upper edge of the beam end after deflection of track beam 3: Because the beam segment within the range from the center line of support 121 to the first structural joint 33 (i.e., the beam segment outside the center line of support 121) under the vertical live load of the train has basically no normal stress on its cross section, that is, there is basically no horizontal compressive deformation within this beam segment range. Therefore, the horizontal compression value Δ at the upper edge of the beam end is small. x1 ≈Horizontal compression value of the upper edge of section 121 of support △ x2 According to the principle of small angle approximation, the horizontal compression value of the upper edge of the support 121 section is Δ. x2 :

[0062] △ x2 ≈y1*tanθ≈y1*sinθ

[0063] Where θ is the rotation angle of the section at support 121. Considering the large vertical bending stiffness of the beam segment outside the centerline of support 121, the neutral axis plane of this beam segment can be considered to rotate upwards about the neutral axis at the section at support 121 along a circular arc trajectory. According to the plane section assumption and the similarity relationship of triangles, θ = the rotation angle β of the neutral axis plane of the beam segment outside the centerline of support 121. Combining the above formulas, the minimum longitudinal dimension F4 can be proved:

[0064] F4≥△ x1 ≈y1*sin[max(β1, β2)]

[0065] In this embodiment, the tension F of the prestressed tendon 51 on the first track beam 1 or the second track beam 2 satisfies:

[0066] |σ F + |≤|σ G - |-|σ p + |

[0067] Where, σ F + σ is the maximum value of the tensile stress at the upper edge of the mid-span section and the upper edge of the 1 / 4-span section of the track beam generated by the tension force F of the prestressed tendon 51. G - Let σ be the minimum of the compressive stress at the upper edge of the mid-span section and the compressive stress at the upper edge of the 1 / 4-span section of track beam 3 caused by the self-weight G of track beam 3. p + The maximum value of the tensile stress at the upper edge of the mid-span section and the upper edge of the 1 / 4-span section of the track beam 3 generated by the prestressed prestressed tendon 122 is given. When designing the tension force of the prestressed component 5, it should be ensured that the upper edge of the track beam 3 does not generate tensile stress in the completed bridge state. The design can be simplified according to the above formula.

[0068] The tensioning end 52 and anchoring end 53 of the prestressed concrete assembly 5 are configured as follows: The prestressed concrete assembly 5, located between the two continuous piers 31 of the simply supported track beam 3 bridge, includes a prestressed concrete tendon 51 and two tensioning ends 52. Both ends of the same prestressed concrete tendon 51 are tensioning ends 52, located above the continuous piers 31. The prestressed concrete tendon is tensioned from both ends through the tensioning ends 52. After tensioning, the existing anchoring device is used. Anchoring is performed on the track beam 3 located between the connecting pier 32 and the adjacent continuous pier 31. The prestressed component 5 includes an anchoring end 53, a prestressed tendon 51, and a tensioning end 52. That is, the two ends of the same prestressed tendon 51 are the tensioning end 52 and the anchoring end 53, respectively. The anchoring end 53 is located above the connecting pier 32. The anchoring end 53 is fixed at one end in the first track beam 1 or the second track beam 2 during prefabrication. After tensioning, it is anchored using the existing anchoring device. By setting a tensioning end 52 at the continuous pier 31 and an anchoring end 53 on the branch pier 32, it is convenient to tension and anchor the prestressed tendons 51. The third structural joint 34 is located on the branch pier 32. An expansion joint device is generally provided at this location. Therefore, the longitudinal dimension of this structural joint generally does not exceed 16cm, otherwise tensioning operations cannot be carried out. Therefore, the end of the prestressed component 5 closest to the branch pier 32 is designed as the anchoring end 53, which is anchored to the track beam 3 by the anchoring device during the prefabrication of the track beam 3.

[0069] Example 3

[0070] Please refer to Figure 8 This embodiment provides a construction method for a simply supported track beam bridge with a continuous running surface. The construction method adopts the simply supported track beam bridge with a continuous running surface as described in Embodiment 1 or 2, and includes the following steps:

[0071] S1. Along the arrangement direction of the bridge piers, simply supported track beams 3 are erected on different bridge piers. The track beams 3 include a first track beam 1 and a second track beam 2 arranged adjacent to each other. The first track beam 1 and the second track beam 2 are respectively precast with prestressed tendons 122 along the bridge direction. A third structural joint 34 is formed between the track beams 3 on the connecting piers 32, and a first structural joint 33 is formed between the track beams 3 on the continuous piers 31. At the first structural joint 33, the pre-embedded steel of the first track beam 1 and the second track beam 2 is... The reinforcement 41 is positioned opposite each other, and the precast prestressed tendons 122 extend from both ends of the track beam 3 and are tensioned and anchored at both ends of the track beam 3. The tensioning end 52 of the prestressed tendon 51 extends out of the end of the track beam 3 and is anchored at the continuous pier 31. The prestressed tendon 51 between the connecting pier 32 and the adjacent continuous pier 31 has one end pre-anchored in the track beam 3, so only the tensioning end 52 of the prestressed tendon 51 above the continuous pier 31 needs to be anchored.

[0072] S2. The pre-embedded steel bars 41 with opposite positions are tied and fixed by connecting steel bars 42. The tying is done by tightening iron wire. Elastic partition plates 432 are set at the joint ends of the first track beam 1 and the second track beam 2 respectively. The vertical dimension H4 of the connection surface is reserved above the elastic partition plate 432. The formwork of the rigid connection structure 4 is supported by the first structural joint 33. Then concrete is poured and cured to form a post-cast concrete block 43. After the cast-in-place concrete of the post-cast concrete block has initially set, the elastic partition plate 432 is removed and the formwork is dismantled.

[0073] S3. Tensioning is performed at the tensioning end 52 of the prestressed tendon 51. After the tensioning force reaches the design value, the tensioning end 52 is fixed by the anchoring device. Finally, grouting is performed in the duct where the prestressed tendon 51 is located to fix it. After the docking construction of an adjacent track beam 3 is completed, the docking construction continues in the direction of the bridge until the entire simply supported track beam 3 bridge is completed.

[0074] The construction method of this embodiment is specifically designed for the narrow-section track beam 3 unique to straddle-type monorail transit. The on-site reinforcement connection, concrete casting, and prestressed tendon tensioning and anchoring operations can be conveniently completed from the operating space on both sides or top of the track beam 3. Compared with continuous beams and continuous rigid frame systems, it eliminates two time-consuming processes: tensioning the negative moment tendons at the pier top and the extensive and dense reinforcement connection work in the limited space at the wet joint at the pier top. Furthermore, the prestressed tendons 51 are part of the load-bearing system of the track beam 3 during the operation phase. They can be pre-embedded in the track beam 3 during prefabrication, and their on-site tensioning does not increase the total tensioning workload. It can be seen that this invention significantly reduces the overall construction difficulty, saves construction costs, and shortens the construction period.

[0075] 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 simply supported track beam bridge with a continuous running surface, characterized in that, The system includes a first and second track beam erected adjacent to each other on the bridge piers, and a rigid connection structure at the junction of the traveling wheels and guide wheels. Both the first and second track beams are precast concrete structures, with precast prestressed tendons embedded and anchored within each beam. The beam width B of the first and second track beams is ≤100cm. The rigid connection structure is located in the upper middle part of a first structural joint between the first and second track beams, with a longitudinal dimension F1 ≥30cm. The top surface of the rigid connection structure is flush with the tops of the first and second track beams. The rigid connection structure is rigidly connected to both the first and second track beams, and the maximum vertical dimension H4 of the connection surface satisfies: H4 ≤ max(H1, H2) / 4, where H1 is... The first track beam has a maximum height of H2, and the second track beam has a maximum height of H2. The first and second track beams each have pre-installed prestressed components connected to both ends along the longitudinal direction of the bridge. Each prestressed component includes a prestressed tendon and a tensioning end. The prestressed tendon is located within an internal conduit of the first and second track beams. At any cross-section of the first and second track beams, the prestressed tendon is positioned below the neutral axis along the transverse direction of the cross-section. The tensioning end is the end of the prestressed tendon, located at the first structural joint, and extends beyond the end face of the first or second track beam during prefabrication. After the rigid connection structure at the running wheels and guide wheels is constructed, the prestressed tendon is tensioned and anchored through the tensioning end.

2. The simply supported track beam bridge with a continuous running surface according to claim 1, characterized in that, The rigid connection structure is a cast-in-place reinforced concrete structure, including pre-embedded steel bars, connecting steel bars, and post-cast concrete blocks. Pre-embedded steel bars are prefabricated at the opposite ends of the first track beam and the second track beam. The pre-embedded steel bars at the opposite ends are tied and fixed by connecting steel bars. Along the longitudinal direction of the bridge, the width of the rigid connection part between the post-cast concrete block and the first track beam and the second track beam at both ends is greater than the width of the non-rigid connection part. The bottom surface of the post-cast concrete block is lower than or equal to the lower edge of the running surface of the stabilizing wheel of the straddle-type monorail vehicle.

3. The simply supported track beam bridge with a continuous running surface according to claim 2, characterized in that, The upper part of the post-cast concrete block is rigidly connected to the first track beam and the second track beam at both ends, and a second structural joint is provided between the lower middle part of the post-cast concrete block and the first track beam and the second track beam at both ends.

4. The simply supported track beam bridge with a continuous running surface according to claim 2, characterized in that, The lower edge of the contact surface of the post-cast concrete block and the rigid connection between it and the track beams at both ends is lower than or equal to the lower edge of the guide wheel running surface of the straddle-type monorail vehicle.

5. The simply supported track beam bridge with a continuous running surface according to claim 3, characterized in that, An elastic partition plate is pre-embedded before the second structural joint is constructed. The elastic partition plate is placed in the second structural joint and is removed after the initial setting of the cast-in-place concrete of the post-cast concrete block.

6. The simply supported track beam bridge with a continuous running surface according to claim 3, characterized in that, The minimum longitudinal dimension of the second structural joint is F4≥y1*sin[max(β1, β2)], where y1 is the vertical distance from the upper edge of the beam end to the neutral axis of the support section, and β1 and β2 are the axial rotation angles of the beam segments outside the support centerline generated by the first and second track beams under the most unfavorable combination of vertical loads according to the plane section assumption and the current bridge code.

7. The simply supported track beam bridge with a continuous running surface according to claim 1, characterized in that, The tension F exerted by the prestressed tendons on the first or second track beam satisfies: |σ F + |≤|σ G - |-|σ p + |,σ F + σ is the maximum of the tensile stresses at the upper edge of the mid-span section and the upper edge of the 1 / 4-span section of the track beam generated by the tension force F of the prestressed tendons. G - Let σ be the minimum of the compressive stress at the upper edge of the mid-span section and the compressive stress at the upper edge of the 1 / 4-span section caused by the self-weight G of the track beam. p + The maximum value of the tensile stress at the upper edge of the mid-span section and the tensile stress at the upper edge of the 1 / 4 span section of the track beam generated by the precast prestressed tendons.

8. The simply supported track beam bridge with a continuous running surface according to claim 1, characterized in that, Both ends of the same prestressed strand are tensioning ends, and the tensioning ends are located above the continuous pier; or both ends of the same prestressed strand are a tensioning end and an anchoring end, respectively, and the anchoring end is located above the connecting pier. The anchoring end is anchored to the first track beam or the second track beam by an anchoring device during prefabrication.

9. A construction method for a simply supported track beam bridge with a continuous running surface, employing the simply supported track beam bridge with a continuous running surface as described in any one of claims 1-8, characterized in that, The construction method includes the following steps: S1. A simply supported track beam bridge is erected on different piers. The track beam includes a first track beam and a second track beam arranged adjacent to each other. The first track beam and the second track beam are respectively precast with precast prestressed tendons in the direction of the bridge. A third structural joint is formed between the track beams on the connecting piers and a first structural joint is formed between the track beams on the continuous piers. At the first structural joint, the pre-embedded steel bars of the first track beam and the second track beam are positioned opposite each other. At the same time, the precast prestressed tendons extend from both ends of the track beam and are tensioned and anchored at both ends of the track beam. The tensioning end of the precast prestressed tendon extends out of the end of the track beam. S2. The pre-embedded steel bars with opposite positions are tied and fixed by connecting steel bars. Elastic partition plates are set at the joint ends of the first track beam and the second track beam respectively to support the formwork of the rigid connection structure. Then concrete is poured to form post-cast concrete blocks. After the cast-in-place concrete of the post-cast concrete blocks has initially set, the elastic partition plates are removed. S3. Tension the tensioning end of the prestressed tendon and anchor the tensioning end. Finally, grout the prestressed tendon into the duct where it is located to fix it.

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