A cast-in-place skybridge pile and column integrated pouring reverse construction process
By using the in-situ cast-in-place pile and column integrated reverse construction technique, the problems of high construction difficulty and high safety risks in complex terrain caused by traditional construction methods have been solved. This has achieved uninterrupted road access, improved overall structure, reduced safety risks, and shortened construction period.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- 陕西兴通监理咨询有限公司
- Filing Date
- 2026-04-15
- Publication Date
- 2026-06-09
AI Technical Summary
Traditional methods of constructing overpasses present challenges such as high construction difficulty, high safety risks, long construction periods, and high costs in complex terrains with deep cuts, steep slopes, and well-developed gullies. Furthermore, they can disrupt the main roads for villagers' travel, leading to social conflicts.
The construction process of cast-in-place bridge piles and columns is carried out in reverse, including road maintenance, integrated pile and column grouting, bridge abutment cap beams, box girder ground formwork casting, ancillary structure construction, earthwork excavation and pier decoration. Through the reverse process of 'maintaining traffic first, then structure, and then excavation', a seamless integral structure is formed, avoiding the risks of high-scaffold construction.
This approach ensured uninterrupted road access during construction, reduced social conflicts, improved structural integrity and load-bearing capacity, reduced construction safety risks, shortened the construction period, and lowered costs.
Smart Images
Figure CN122169436A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the technical field of pedestrian bridge construction, and in particular to a reverse construction process for the integrated casting of piles and columns for cast-in-place pedestrian bridges. Background Technology
[0002] With the continuous acceleration of urbanization, urban traffic construction is becoming increasingly busy. As an important traffic facility, overpasses bear a large number of pedestrian and non-motorized traffic flows.
[0003] There are generally three traditional methods for constructing overpasses. The first is conventional precast beam hoisting, where the main roadbed is excavated first, the substructure is constructed sequentially, a detour is built, and then the precast beams are hoisted using a crane / bridge erecting machine. The disadvantages are that it requires blocking village roads, the detour is difficult to construct, social conflicts are prominent, the beam hoisting distance is nearly 40m, the beam body is heavy, the safety risks are extremely high, and the process is complicated, the construction period is long, and the cost is high. The second method is full-span scaffolding cast-in-place, where the substructure is completed after the roadbed is excavated, and then a full-span scaffolding is erected. The first method is on-site cast-in-place box girder construction. The disadvantages are that the high supports are erected on the slope, the geological conditions are poor, and landslides and support instability are prone to occur, which can block village roads and interfere with the main line. The construction period is long, and the support investment is large, resulting in high costs and difficulty in quality control. The second method is jacking construction, where the precast beams are placed behind the abutments and jacked up to the design position section by section through a hydraulic system. The disadvantages are that the precast platform needs to be leveled, it is not suitable for undulating terrain and small box girder structures, temporary works and equipment investment are large, the cost is high, the beam stress is complex, and the controllability of the construction period is poor.
[0004] The three traditional construction methods all require the excavation of the main roadbed or the construction of large temporary facilities in advance, which inevitably blocks the only main road for villagers to travel, necessitating the construction of detour roads, which can lead to social conflicts. Moreover, the construction of detour roads is difficult and costly. Conventional precast beam hoisting has safety hazards due to long-distance hoisting, full-span scaffolding cast-in-place construction has the risk of high scaffolding and slope collapse, and jacking construction has the risk of beam displacement and instability of temporary facilities. None of these methods are suitable for complex terrain features such as steep slopes and well-developed gullies, which greatly increases the construction difficulty and makes it difficult to guarantee construction quality and progress. Summary of the Invention
[0005] In order to improve the problem that traditional construction methods cannot be adapted to the complex terrain features of deep road cuts, steep slopes, and gully development, this application provides a reverse construction process for cast-in-place bridge piles and columns.
[0006] This application provides a reverse construction process for the integrated casting of piles and columns for a cast-in-place pedestrian bridge, employing the following technical solution: A reverse construction technique for integral casting of piles and columns for a cast-in-place pedestrian bridge includes the following steps: S1. Road Traffic Flow: The existing roads connected by the overpass will be widened and isolation zones will be set up to ensure normal traffic flow during construction. S2. Pile and column integrated grouting: The pile foundation and the pier column are formed in one go by rotary drilling, and the steel cage of the pile foundation and the pier column are lowered as a whole. The underwater grouting method is used to continuously grout the pile foundation and the pier column in one go, so that the pile foundation and the pier column form an integral structure without construction joints. S3. Abutment and cap beam construction: Cap beam construction is carried out on top of the integrated pile and column structure; S4. Box girder ground formwork method for cast-in-place construction: After the cap beam is constructed, the foundation at the bridge span location is treated, a concrete cushion layer is poured to form a ground formwork, and the box girder is cast in place on the ground formwork; S5. Construction of ancillary structures: Complete the bridge deck paving and ancillary facility construction; S6. Earthwork excavation and pier finishing: After the box girder reaches the design strength, earthwork is excavated in layers from top to bottom, and the exposed piers are cleaned, reinforced, wire mesh is installed, and the finishing concrete is poured at the same time. S7. Tie Beam Construction: After the earthwork is excavated to the design elevation of the tie beam, the tie beam is constructed and a reliable connection is formed between the tie beam and the pier column.
[0007] By adopting the above-mentioned technical solutions and employing a reverse construction process of "first ensuring access, then constructing the structure, and finally excavating," the traditional forward construction logic has been overturned. This ensures that the original roads are not interrupted during construction and that no detours need to be built, significantly reducing social conflicts. The integrated grouting of piles and columns creates a seamless overall structure between the pile foundation and the pier, improving the structural integrity and load-bearing capacity. The use of the ground formwork method for cast-in-place box girders eliminates the need for full-span scaffolding, avoiding the safety risks associated with high-scaffolding construction. The simultaneous layered excavation of earthwork and pier finishing avoids high-altitude scaffolding work, significantly reducing construction safety risks.
[0008] Preferably, in step S2, the borehole diameter for integrated pile-column grouting is controlled according to the pile foundation design diameter. During the drilling process, the verticality is checked every 5 meters of drilling depth. A plumb line and a drilling rig verticality meter are used for dual control to ensure that the verticality of the pile-column meets the requirements.
[0009] By adopting the above technical solution, during the integrated grouting of piles and columns, the verticality is checked every 5 meters of drilling depth. Combined with the dual control method of plumb line and drilling rig verticality instrument, the verticality of the borehole can be monitored in real time to ensure that the verticality of the piles and columns meets the specifications and design requirements, avoid structural stress defects caused by verticality deviation, and ensure the construction quality of piles and columns.
[0010] Preferably, in step S2, the pile foundation concrete and the pier column concrete are poured in one go using concrete of the same strength grade.
[0011] By adopting the above technical solution, the pile foundation concrete and the pier column concrete are poured in one go using the same strength grade of concrete, which avoids construction cold joints caused by alternating pouring of concrete of different strength grades, simplifies the concrete mixing process, and at the same time ensures the integrity and structural strength of the pile-column connection and improves construction efficiency.
[0012] Preferably, in step S2, after the integrated grouting of the pile and column is completed, a continuous acoustic logging tube is installed in the pile and column reinforcement cage, and ultrasonic testing of the pile and column is carried out after the design age is reached.
[0013] By adopting the above technical solution, and by installing a continuous sonic logging tube in the pile column reinforcement cage, and conducting ultrasonic testing on the pile column after it reaches the design age, the overall density and continuity of the pile column concrete can be comprehensively tested, potential defects can be detected in time, and the internal quality of the integrated pile column structure can be ensured to meet the design requirements.
[0014] Preferably, in S4, the box girder ground formwork method for cast-in-place construction specifically includes: mechanically excavating the earth to 22cm below the bottom of the beam, conducting a bearing capacity test on the foundation, and after the bearing capacity meets the requirements, pouring a concrete cushion layer with a thickness of not less than 20cm, and then laying the bottom formwork on the cushion layer for box girder casting.
[0015] By adopting the above technical solution, in the cast-in-place construction of box girder using the ground formwork method, the process is controlled by mechanically excavating to 22cm below the bottom of the beam, testing the bearing capacity, and pouring a concrete cushion layer of not less than 20cm. The original soil that has not been excavated is used as a natural foundation, eliminating the need to erect a full-span scaffold. This not only ensures the bearing capacity and stability of the ground formwork but also significantly reduces the cost of scaffold erection and the risk of slope collapse.
[0016] Preferably, in S6, the height of each layer of earthwork excavation is 2m, the concrete for the pier column cover is C40 concrete with the same strength grade as the pier column, and it is cast using 1.8m fixed steel formwork.
[0017] By adopting the above technical solution, the earthwork was excavated in layers of 2m each from top to bottom, and simultaneously, 1.8m fixed steel formwork was used to support the pouring of C40 facing concrete of the same strength grade as the pier column. This achieved a continuous operation of excavation and decoration, avoiding the safety hazards of later high-altitude scaffolding erected from the bottom for decoration work, shortening the construction period, and ensuring the appearance quality of the pier column.
[0018] Preferably, in S6, the requirements for rebar installation in the pier column decoration are as follows: 4 HRB400φ16 steel bars per square meter, with an installation depth of 25cm, and a double layer of φ10 steel mesh with a mesh spacing of 20cm.
[0019] By adopting the above technical solution, the rebar installation for the pier column decoration uses 4 HRB400φ16 steel bars per square meter with an installation depth of 25cm, and a double layer of φ10 steel mesh with a mesh spacing of 20cm is hung. The rebar installation and mesh hanging parameters have been verified by engineering projects, which can ensure the reliable anchoring of the cover layer and the pier column body, prevent the cover layer from cracking or falling off, and ensure the long-term stability of the pier column decoration structure.
[0020] Preferably, in S7, the construction of the tie beam includes: inserting Φ22 steel bars of the same specification as the main reinforcement of the tie beam into the inner side of the pier column, with an insertion depth of not less than 45cm and a pull-out force of not less than 150kN; the outermost main reinforcement of the tie beam is arranged in a ring to wrap around the cylindrical pier, with a longitudinal spacing of 10cm.
[0021] By adopting the above technical solution, during the construction of the tie beam, Φ22 steel bars are inserted into the inner side of the pier column, with an insertion depth of not less than 45cm and a pull-out force of not less than 150kN. The outermost main reinforcement of the tie beam is wrapped around the pier column in a ring with a longitudinal spacing of 10cm. This structural measure can ensure reliable force transmission between the tie beam and the pier column, enhance the tensile strength of the structure, and effectively resist the horizontal thrust generated during the later earthwork excavation and operation.
[0022] Preferably, in step S7, the inserted reinforcing bars and the horizontal reinforcing bars of the tie beam are welded on both sides, and the weld length is not less than 5d; when the connection surface between the column and the tie beam is roughened, the concrete of the pier column penetrates 2cm into the concrete of the tie beam.
[0023] By adopting the above technical solution, the reinforcing bars and the horizontal bars of the tie beam are welded on both sides with a weld length of not less than 5d. The connection surface between the column and the tie beam is roughened and the concrete of the pier column is ensured to penetrate 2cm into the concrete of the tie beam. This connection structure can ensure a reliable rigid connection between the tie beam and the pier column, avoid shear failure caused by improper treatment of the connection surface, and ensure structural safety.
[0024] Preferably, in step S7, the construction of the tie beam further includes: first constructing the foundation layer, then binding the reinforcing bars, and finally setting up the formwork and pouring concrete; the main reinforcing bars of the tie beam are arranged in a ring with a longitudinal spacing of 10cm, wrapping around the cylindrical pier.
[0025] By adopting the above technical solution, the tie beam construction first constructs the foundation layer, then ties the reinforcing bars, and finally sets up the formwork and pours the concrete. The main reinforcement of the tie beam is arranged in a ring with a longitudinal spacing of 10cm around the cylindrical pier. This construction process ensures the flatness and bearing capacity of the bottom formwork of the tie beam. The ring-arranged main reinforcement effectively enhances the circumferential constraint force of the tie beam on the pier column, thereby improving the overall seismic performance and deformation resistance of the structure.
[0026] In summary, this application includes at least one of the following beneficial technical effects: By adopting a reverse construction process of "first ensuring access, then structuring, and finally excavation," the traditional forward construction logic was overturned. This ensured that the original roads were not interrupted during construction and that no detours needed to be built, significantly reducing social conflicts. The integrated grouting of piles and columns created a seamless integral structure between the pile foundation and the pier, improving the overall integrity and load-bearing capacity of the structure. The cast-in-place box girder using the ground formwork method eliminated the need for full-span scaffolding, avoiding the safety risks associated with high-scaffolding construction. The simultaneous layered excavation of earthwork and pier finishing avoided high-altitude scaffolding operations, significantly reducing construction safety risks. During the integrated grouting of piles and columns, the verticality is checked every 5 meters of drilling depth. Combined with the dual control method of plumb line and drilling rig verticality instrument, the verticality of the borehole can be monitored in real time to ensure that the verticality of the piles and columns meets the specifications and design requirements, avoid structural stress defects caused by verticality deviation, and ensure the construction quality of piles and columns. The pile foundation concrete and pier column concrete are poured in one go using the same strength grade of concrete, which avoids construction cold joints caused by alternating pouring of concrete of different strength grades, simplifies the concrete mixing process, ensures the integrity and structural strength of the pile-column connection, and improves construction efficiency. Attached Figure Description
[0027] Figure 1 This is a flowchart of the reverse construction process for the integrated casting of piles and columns for a cast-in-place overpass, according to an embodiment of this application. Detailed Implementation
[0028] The following is in conjunction with the appendix Figure 1 This application will be described in further detail.
[0029] This application discloses a reverse construction process for the integrated casting of piles and columns for cast-in-place pedestrian bridges. (Refer to...) Figure 1 The construction process of cast-in-place overpass piles and columns in a reverse manner includes the following steps: S1. Road Accessibility: The original road connected by the overpass is located on one side of the mountain. Before the overpass is built, the earthwork of the road cut will be excavated to the original road surface elevation. Then, the side of the original road closest to the mountain will be widened to ensure normal passage. Finally, standardized railings will be used to isolate the construction area from the access road and warning signs will be set up to ensure that the original village road is not interrupted during the construction period and that no detour access road needs to be built.
[0030] S2. Integrated Pile-Column Grouting: Includes the following steps: I. Drilling: A rotary drilling rig is used to form the hole in one pass. The hole diameter is controlled according to the pile foundation design diameter of 1.6m, and the cross-section of the pile diameter and column diameter is changed in one pass. During the drilling process, the verticality is checked every 5 meters of drilling depth. The verticality check is controlled by both a plumb line and a verticality gauge of the drilling rig to ensure that the verticality of the pile and column meets the specifications and design requirements. The drilling rig is installed at a position of 1.4m above the column top to ensure the length of the reinforcing steel for the cap beam after the concrete at the top of the column is removed.
[0031] 2. Reinforcing cage installation: The pile column reinforcing cage is hoisted into the hole as a whole in sections. Mechanical connection is used between the pile column sections. At the pile-column cross-section change position, single-sided lap welding is used, and the welding length is not less than 10d.
[0032] III. Concrete Pouring: The design grade of the pile foundation concrete is C30, and the design grade of the pier column concrete is C40. To ensure the pouring quality and continuous pouring requirements, both piles and columns will be poured with C40 concrete in one continuous pour. The underwater concrete pouring process will be adopted to ensure continuous concrete pouring. The concrete will be poured to 100cm above the design elevation of the column top to ensure that the concrete at the top of the column is dense.
[0033] IV. Testing: Install a continuous sonic logging tube in the pile reinforcement cage, and conduct ultrasonic testing on the pile after it reaches the design age to ensure the overall compactness of the concrete.
[0034] S3. Construction of bridge abutments and cap beams: The double ring cutting method is used to break the concrete at the top of the column and clean the floating slag on the top of the column. The traditional ground formwork method is used to construct the bridge abutments and cap beams: a 10cm thick C20 concrete cushion layer is laid, and then the steel bars are tied, the formwork is erected, and the concrete is poured.
[0035] S4. Cast-in-place construction of box girders using the ground formwork method: This includes the following steps: I. Foundation Treatment: After the abutments and cap beams are constructed and reach the design strength, the soil is mechanically excavated to 22cm below the bottom of the beams, followed by manual excavation in conjunction with machinery. Before pouring the foundation surface layer, a penetrometer is used to test the foundation bearing capacity, which is not less than 120kPa.
[0036] II. Subbase construction: After the bearing capacity meets the requirements, pour a 20cm thick C25 concrete subbase to form a natural ground mold.
[0037] 3. Laying the bottom formwork: Lay the bottom formwork on the subbase. The bottom formwork is made of 18mm thick bamboo plywood.
[0038] IV. Box Girder Casting: The box girder concrete casting is completed in two stages. The first stage involves casting the bottom slab and web, and the second stage involves casting the top slab. The concrete volume is calculated in advance and a truck-mounted pump is used for continuous casting.
[0039] V. Curing: After the concrete has set, immediately cover it with geotextile and water it for curing. Water it daily to keep the concrete surface moist. The curing time is generally 7 days.
[0040] VI. Prestressing Tensioning: The steel strands can only be tensioned when the concrete strength reaches 90% of the design strength and the curing period is not less than 7 days. Before tensioning, the end formwork, inner formwork, and outer formwork must be removed. The tensioning sequence of the prestressed steel strands in the box girder is as follows: tension the web steel strands first, and finally tension the top slab steel strands. When tensioning the steel strands, it is necessary to ensure symmetrical tensioning at both ends. Tensioning adopts dual control, with stress control as the main method and elongation as the check.
[0041] 7. Grouting: After the prestressed steel strands are tensioned, vacuum grouting should be carried out in a timely manner. The strength of the grouting material should not be less than 50MPa, and pre-made grouting material should be used.
[0042] S5. Construction of ancillary structures: The bridge deck paving shall be carried out in accordance with the conventional process of roughening and cleaning the bridge deck → laying steel bars → laying reinforcing steel bars → pouring concrete → vibrating with a vibrator → leveling the vibrating beam → precise manual leveling → curing with geotextile.
[0043] S6. Earthwork excavation and pier finishing: After the box girder reaches the design strength, excavate in layers from the top of the column along the outside of the column. Excavate in layers of 2m each, and finish each layer. Avoid damaging the column during excavation. Ensure that the road cut slope meets the design requirements during the excavation process.
[0044] The pier finishing and earthwork excavation were carried out simultaneously: the soil surface of the cylindrical pier was manually cleaned and roughened until the coarse aggregate was exposed; four HRB400 φ16 steel bars were installed per square meter, with an insertion depth of 25cm; a double layer of φ10 steel mesh was installed, with a mesh spacing of 20cm; the finishing concrete was poured in layers using C40 concrete of the same grade, and 1.8m standardized steel formwork was used. The finishing concrete was constructed from top to bottom, with each layer of soil excavated 2m in time to avoid the need for scaffolding to be erected from the bottom later.
[0045] S7. Tie Beam Construction: Excavation proceeds from top to bottom to 12cm below the bottom elevation of the tie beam. A foundation layer is constructed first, followed by reinforcement binding, formwork erection, and concrete pouring. To ensure the tie beam better meets tensile requirements, the outermost main reinforcement bars are arranged in a ring around the cylindrical pier, with a longitudinal spacing of 10cm. Φ22 steel bars of the same specification as the tie beam's main reinforcement bars are inserted into the inner side of the column, with an insertion depth of not less than 45cm. The pull-out force of the inserted steel bars should not be less than 150kN. Holes are drilled using a Φ26 drill bit, and the inserted steel bars are welded to the horizontal reinforcement bars of the tie beam on both sides, with a weld length of not less than 5d. When roughening the connection surface between the column and the tie beam, the pier concrete should penetrate 2cm into the tie beam concrete to ensure connection quality.
[0046] The implementation principle of the cast-in-place overpass pile and column integrated casting reverse construction process in this application embodiment is as follows: By adopting the reverse construction process of "first ensuring traffic, then constructing the structure, and finally excavating", the traditional forward construction logic is subverted, realizing that the original road is not interrupted during construction and there is no need to build detours, which greatly reduces social conflicts; by using integrated pile and column casting, the pile foundation and pier column form an integral structure without construction joints, which improves the structural integrity and bearing capacity; by using the ground formwork method to cast the box girder, there is no need to erect full-span scaffolding, which avoids the safety risks of high-scaffolding construction; by carrying out the earthwork layered excavation and pier column decoration simultaneously, high-altitude scaffolding work is avoided, which significantly reduces the construction safety risks.
[0047] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.
Claims
1. A reverse construction process for integral casting of piles and columns for cast-in-place pedestrian bridges, characterized in that: Includes the following steps: S1. Road Traffic Flow: The existing roads connected by the overpass will be widened and isolation zones will be set up to ensure normal traffic flow during construction. S2. Pile and column integrated grouting: The pile foundation and the pier column are formed in one go by rotary drilling, and the steel cage of the pile foundation and the pier column are lowered as a whole. The underwater grouting method is used to continuously grout the pile foundation and the pier column in one go, so that the pile foundation and the pier column form an integral structure without construction joints. S3. Abutment and cap beam construction: Cap beam construction is carried out on top of the integrated pile and column structure; S4. Box girder ground formwork method for cast-in-place construction: After the cap beam is constructed, the foundation at the bridge span location is treated, a concrete cushion layer is poured to form a ground formwork, and the box girder is cast in place on the ground formwork; S5. Construction of ancillary structures: Complete the bridge deck paving and ancillary facility construction; S6. Earthwork excavation and pier finishing: After the box girder reaches the design strength, earthwork is excavated in layers from top to bottom, and the exposed piers are cleaned, reinforced, wire mesh is installed, and the finishing concrete is poured at the same time. S7. Tie Beam Construction: After the earthwork is excavated to the design elevation of the tie beam, the tie beam is constructed and a reliable connection is formed between the tie beam and the pier column.
2. The reverse construction method for integrated casting of piles and columns for a cast-in-place overpass as described in claim 1, characterized in that: In S2, the borehole diameter for integrated pile-column grouting is controlled according to the pile foundation design diameter. During the drilling process, the verticality is checked every 5 meters of drilling depth. A plumb line and a drilling rig verticality meter are used for dual control to ensure that the verticality of the pile-column meets the requirements.
3. The reverse construction process for integrated casting of piles and columns for a cast-in-place overpass as described in claim 1, characterized in that: In S2, the pile foundation concrete and the pier column concrete are poured in one go using the same strength grade of concrete.
4. The reverse construction method for integrated casting of piles and columns for a cast-in-place overpass as described in claim 1, characterized in that: In step S2, after the integrated grouting of the pile and column is completed, a continuous sonic logging tube is installed in the pile and column reinforcement cage, and ultrasonic testing of the pile and column is carried out after the design age is reached.
5. The reverse construction method for integrated casting of piles and columns for cast-in-place overpasses according to claim 1, characterized in that: In S4, the box girder ground formwork method for cast-in-place construction specifically includes: mechanically excavating the earth to 22cm below the bottom of the beam, testing the bearing capacity of the foundation, and after the bearing capacity meets the requirements, pouring a concrete cushion layer with a thickness of not less than 20cm, and then laying the bottom formwork on the cushion layer for box girder casting.
6. The reverse construction method for integrated casting of piles and columns for a cast-in-place overpass as described in claim 1, characterized in that: In S6, the height of each layer of earthwork excavation is 2m, the concrete for the pier column cover is C40 concrete with the same strength grade as the pier column, and it is cast using 1.8m fixed steel formwork.
7. The reverse construction method for integrated casting of piles and columns for a cast-in-place overpass as described in claim 1, characterized in that: In S6, the requirements for rebar installation in the pier column decoration are as follows: 4 HRB400φ16 steel bars per square meter, with an installation depth of 25cm, and double-layer φ10 steel mesh with a mesh spacing of 20cm.
8. The reverse construction method for integrated casting of piles and columns for a cast-in-place overpass as described in claim 1, characterized in that: In S7, the construction of the tie beam includes: inserting Φ22 steel bars of the same specification as the main reinforcement of the tie beam into the inner side of the pier column, with an insertion depth of not less than 45cm and a pull-out force of not less than 150kN; the outermost main reinforcement of the tie beam is arranged in a ring to wrap around the cylindrical pier, with a longitudinal spacing of 10cm.
9. The reverse construction method for integral casting of piles and columns for cast-in-place overpasses according to claim 1, characterized in that: In S7, the inserted reinforcing bars and the horizontal reinforcing bars of the tie beam are welded on both sides, and the weld length is not less than 5d; when the connection surface between the column and the tie beam is roughened, the concrete of the pier column penetrates 2cm into the concrete of the tie beam.
10. The reverse construction method for integrated casting of piles and columns for a cast-in-place overpass as described in claim 1, characterized in that: In S7, the construction of the tie beam also includes: first constructing the foundation layer, then binding the reinforcing bars and finally setting up the formwork and pouring concrete; the main reinforcement of the tie beam is arranged in a ring with a longitudinal spacing of 10cm, wrapping around the cylindrical pier.