Large-span prestressed bent cap of gate-type pier over-crossing existing line of road and construction method of large-span prestressed bent cap

Abstract

The invention provides an overpass road existing line gate-type pier large-span prestress bent cap and a construction method, and the construction method comprises the following steps: after the construction of a lower structure of the bent cap is completed by utilizing an original terrain condition on site, protecting the exterior of a pier column, then carrying out soil body backfilling and compaction leveling construction, and playing a supporting role by utilizing the backfilling soil body; compared with traditional steel bar supporting construction, operation is easy and convenient, construction safety is high, the construction period is effectively shortened, and the overall construction quality of the bent cap is well guaranteed; the inclined steel pipe stand columns are arranged on the side face of the cover beam to support the prestress operation platform, the I-shaped steel sliding rails and the cross beams are installed above the inclined steel pipe stand columns, the operation space and convenience of workers are increased, a tensioning jack can be conveniently suspended by means of the cross beams, the position of the jack can be flexibly adjusted at high altitude, and field tensioning operation is facilitated.

Description

Technical Field

[0001] The invention relates to the field of bridge construction, and in particular to a large-span prestressed cap beam of a portal pier across an existing road and a construction method. Background Art

[0002] In order to meet the growing traffic demand, the field of bridge engineering is facing more and more challenges, and more large-span, high-strength bridges need to be built. In bridge construction, it is often necessary to cross obstacles such as rivers and existing lines. The large-span prestressed cap beam of the portal pier has become an effective means to solve such problems due to its strong spanning capacity, so it has been widely used in engineering. However, under the influence of factors such as limited site and complex construction environment, the traditional large-span prestressed cap beam construction process has the disadvantages of long construction period, high construction risk, and great impact on the surrounding environment, which can no longer meet the current goal of high-quality construction. Therefore, it is of great significance to study the large-span prestressed cap beam of the portal pier that crosses the existing line of the road and the construction method. Summary of the invention

[0003] The object of the present invention is to provide a large-span prestressed cap beam and a construction method for a portal pier across an existing road that solves the above-mentioned technical problems.

[0004] In order to solve the above technical problems, the present invention provides a construction method for a large-span prestressed cap beam of a portal pier across an existing road, comprising the following steps:

[0005] S1. For cap beams with piers shorter than the standard height, after completing the construction of the lower pile foundation, abutment and pier structure of the bridge, use protective film to wrap around the pier, then backfill the soil according to the elevation of the bottom of the cap beam, pour a concrete cushion layer on top of the backfill soil for leveling, then lay the cap beam formwork, hoist the steel frame, and pour concrete. After the cap beam construction is completed, the lower backfill soil is reversed and sloped, and finally the protective film wrapped around the pier is removed;

[0006] S2. When the pier body is higher than the standard height, it is necessary to use brackets to support the construction. The expanded foundation is prefabricated in advance, and the steel pipe column base is installed on the upper part of the expanded foundation. The steel pipe column base is connected to the expanded foundation through anchor bars, and the steel pipe column segments are installed on the expanded foundation;

[0007] S3. During the assembly of the cap beam reinforcement skeleton, the corrugated pipe and the steel strand in the cap beam are pre-installed together, so that the steel strand is inserted into the corrugated pipe after the corrugated pipe is installed to the designated position, and the exposed part of the steel strand end is wrapped with plastic film for protection. After the assembly is completed, the entire cap beam reinforcement skeleton is hoisted to the designated position for subsequent construction;

[0008] S4. Before the prestressing construction of the cap beam, first install the steel pipe columns on the side of the cap beam and above the pedestal, then install the prestressed working platform on the steel pipe columns, set up vertical supports above the prestressed working platform for installing I-beam slide rails, and insert the ends of the I-beam slide rails into the reserved holes on the top of the cap beam side; when the prestressed tensioning construction requires adjusting the position of the equipment, place the crossbeam between the limit blocks of the I-beam slide rails, and use a hand winch to move and adjust the tensioning equipment through the crossbeam.

[0009] The beneficial effects of the present invention are:

[0010] (1) The backfill soil is used to support the construction. Compared with the traditional steel rod support construction, the operation is simple and the construction safety is high, which effectively saves the construction period and ensures the overall construction quality of the cap beam.

[0011] (2) The prefabricated expanded foundation is prefabricated in the factory. When the support system is constructed, the prefabricated expanded foundation is placed on the existing road and firmly connected to the steel pipe column segment through bolts, making the support system construction more convenient and improving the turnover utilization rate of the expanded foundation;

[0012] (3) When assembling the steel bar skeleton of the cap beam, high-strength corrugated pipes are installed at designated locations and steel strands are inserted. After installation, the whole is hoisted, which reduces the risk of high-altitude operations in the later stage, improves construction efficiency, and reduces the impact on the existing lines below.

[0013] (4) By arranging inclined steel pipe columns on the side of the cap beam to support the prestressed working platform and installing I-beam slide rails and crossbeams on top, the operating space and convenience of workers are increased. With the help of the crossbeam, the tensioning jack can be conveniently suspended, so that the position of the jack can be adjusted more flexibly at high altitudes, which is convenient for on-site tensioning operations. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 Schematic diagram of soil-raising construction technology for low pier side cap beam

[0015] Figure 2 Schematic diagram of prefabricated enlarged foundation structure

[0016] Figure 3 Prefabricated enlarged foundation main view

[0017] Figure 4 Schematic diagram of prefabrication and assembly technology of steel strands passing through steel cage first

[0018] Figure 5 Schematic diagram of optimization technology for cap beam prestressed working platform

[0019] Figure 6 Top view of steel pipe column hoop pier structure

[0020] Figure 7Side view of prestressed working platform

[0021] Explanation of the accompanying numbers: 1-cap beam, 2-backfill soil, 3-slope, 4-protective membrane, 5-pier, 6-cap, 7-pile foundation, 8-expanded foundation, 9-lower flange steel plate, 10-stiffening ribs, 11-steel pipe, 12-bolt hole, 13-anchor bar, 14-upper flange steel plate, 15-steel pipe column, 16-steel clamp, 17-anchor pad, 18-anchor bolt, 19-longitudinal frame, 20-platform bottom steel plate, 21-guardrail, 22-reserved hole, 23-cross beam, 24-limit block, 25-I-beam slide rail, 26-vertical support, 27-transverse frame, 28-cap beam reinforcement frame, 29-corrugated pipe, 30-steel strand. DETAILED DESCRIPTION

[0022] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present invention.

[0023] Those skilled in the art should understand that, in the disclosure of the present invention, the orientation or position relationship indicated by the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc. are based on the orientation or position relationship shown in the drawings, which are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, the above terms should not be understood as limiting the present invention.

[0024] It is to be understood that the term "one" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element may be one, while in another embodiment, the number of the element may be multiple, and the term "one" should not be understood as a limitation on the quantity.

[0025] like Figure 1-Figure 7 The present invention provides a large-span prestressed cap beam for a portal pier across an existing road and a construction method thereof, comprising the following steps:

[0026] S1, such as Figure 1As shown, for the cap beam 1 whose pier body is shorter than the standard height, after the construction of the lower pile foundation 7, the pedestal 6 and the pier 5 structure of the bridge is completed on site, the protective film 4 is used to wrap the pier 5 to prevent subsequent construction damage, and then the backfill soil 2 is constructed according to the elevation of the bottom position of the cap beam 1. After the backfill soil 2 is compacted, a concrete cushion layer is poured on top of it to level it to play a supporting role. Then, the cap beam 1 formwork is laid, the steel frame is hoisted, and concrete is poured. After the construction of the cap beam 1 is completed, the lower backfill soil 2 is reverse-excavated and the slope 3 is constructed. Finally, the protective film 4 wrapped around the pier 5 is removed, and the surface of the pier 5 and the cap beam 1 are cleaned and decorated.

[0027] When the protective film 4 is used to wrap the periphery of the pier column 5, the protective film 4 is made of plastic film + waterproof geotextile, and at least two layers of the plastic film are arranged.

[0028] The standard height of the pier body is obtained through specific on-site measurements and overall structural dimension evaluation.

[0029] S2. When the pier body is higher than the standard height, a bracket is required to support the construction. The expanded foundation 8 is prefabricated in the factory in advance, and a steel pipe column base is installed on the upper part of the expanded foundation 8. The steel pipe column base is fixedly connected to the expanded foundation 8 through anchor bars 13. After the production is completed, the expanded foundation 8 is transported to the site and placed on the existing road. After the placement is completed, the steel pipe column segments to be assembled on site are installed on the expanded foundation 8. After the steel pipe column segments are hoisted to the corresponding positions, bolts are used to pass through the bolt holes 12 on the steel pipe column segments and the upper flange steel plate 14 for a firm connection. After the construction is completed, the on-site support frame can be quickly disassembled and transported, and the expanded foundation 8 can be transported to the next construction location, thereby improving the material turnover.

[0030] like Figure 2 , Figure 3 As shown, before the construction of the on-site support system, the expanded foundation 8 is prefabricated in the factory in advance to meet the needs of rapid turnover during construction. The position of the embedded parts of the expanded foundation 8 needs to be checked several times during the production process to ensure the quality of the components. When the expanded foundation 8 is produced, a steel pipe column base is preinstalled on the upper part. The steel pipe column base includes a lower flange steel plate 9 and an upper flange steel plate 14. The anchor ribs 13 anchor the lower flange steel plate 9 to the expanded foundation 8. A steel pipe 11 is arranged between the lower flange steel plate 9 and the upper flange steel plate 14. Stiffening ribs 10 are arranged between the steel pipe 11 and the lower flange steel plate 9 and between the steel pipe 11 and the upper flange steel plate 14. When transported to the site for installation, the expanded foundation 8 is placed in the designated position, and then the bottom of the steel pipe column segment to be assembled is aligned with the upper flange steel plate 14, and bolts are used to secure the connection through the reserved bolt holes 12.

[0031] S3. The on-site working space is limited, so the cap beam reinforcement skeleton 28 is selected to be assembled near the construction site. When assembling the cap beam reinforcement skeleton 28, the corrugated pipe 29 and the steel strand 30 in the cap beam 1 are pre-installed together. The corrugated pipe 29 is made of high-strength material to enhance its rigidity to avoid construction losses affecting the quality. After the corrugated pipe 29 is installed to the designated position, the steel strand 30 is inserted into the corrugated pipe 29, and the exposed part of the end of the steel strand 30 is wrapped with plastic film for protection. After the assembly is completed, the overall cap beam reinforcement skeleton 28 is hoisted to the designated position for subsequent construction.

[0032] like Figure 4 As shown, due to the influence of the surrounding existing lines, the construction site is limited. First, the processed steel bar semi-finished products are assembled into an integral cap beam steel bar skeleton 28 near the construction site. During the assembly of the cap beam steel bar skeleton 28, frequent measurements are required to ensure the assembly accuracy. After the assembly is completed, protection is strengthened to avoid damage.

[0033] S4. Before the prestressing construction of the cap beam 1, first install the steel pipe column 15 on the side of the cap beam 1 and above the pedestal 6, use the anchor bolt 18 to temporarily fix the anchor plate 17 at the bottom of the steel pipe column 15 to the pedestal 6, then weld two steel clamps 16 on the side of the steel pipe column 15 to establish a stable horizontal connection with the pier 5, then install the prestressed working platform, set a vertical support 26 above the prestressed working platform for the installation of the I-beam slide rail 25, and insert the end of the I-beam slide rail 25 into the reserved hole 22 at the top of the cap beam 1 side, finally lay the platform bottom steel plate 20 above the prestressed working platform, and install the construction guardrail 21 around the prestressed working platform. When the prestressed tensioning construction needs to adjust the equipment position, place the cross beam 23 between the limit blocks 24 of the I-beam slide rail 25, and use the hand winch to move and adjust the tensioning equipment within a small range with the help of the cross beam 23. Compared with large-scale lifting machinery, the position adjustment of the tensioning equipment is more flexible.

[0034] like Figure 5 to Figure 7 As shown, the prestressed working platform is optimally arranged above the pedestal 6 and on the side of the cap beam 1, and the length of the prestressed working platform of the cap beam 1 is maintained at about 2m; the prestressed working platform is supported above the pedestal 6 by steel pipe columns 15 below; the prestressed working platform includes a longitudinal frame 19 and a transverse frame 27 welded to the top of the steel pipe columns 15, and a vertical support 26 is arranged under the I-beam slide rail 25 and erected on the longitudinal frame 19.

[0035] The present invention is not limited to the above-mentioned optimal implementation mode. Anyone can derive other various forms of products under the inspiration of the present invention. However, no matter what changes are made in the shape or structure, all technical solutions that are the same or similar to those of the present application fall within the protection scope of the present invention.

Claims

1. A construction method for a large-span prestressed cap beam of a portal pier over an existing road, characterized in that: The following steps are involved: S1. For a cap beam (1) whose pier body is shorter than the standard height, after the construction of the lower pile foundation (7), the pedestal (6) and the pier column (5) structures of the bridge is completed in sequence, the protective film (4) is used to wrap around the pier column (5), and then the backfill soil (2) is constructed according to the elevation of the bottom position of the cap beam (1), and a concrete cushion layer is poured on the backfill soil (2) for leveling, and then the cap beam (1) formwork is laid, the steel frame is hoisted, and concrete is poured. After the construction of the cap beam (1) is completed, the lower backfill soil (2) is reversely excavated and the slope is constructed (3), and finally the protective film (4) wrapped around the pier column (5) is removed; S2. When the pier body is higher than the standard height, a support is required for construction. The expanded foundation (8) is prefabricated in advance. A steel pipe column base is installed on the upper part of the expanded foundation (8). The steel pipe column base is connected to the expanded foundation (8) through anchor bars (13), and the steel pipe column segments are installed on the expanded foundation (8); S3. During the assembly of the cap beam reinforcement skeleton (28), the corrugated pipe (29) and the steel strand (30) in the cap beam (1) are pre-installed together, so that after the corrugated pipe (29) is installed to the designated position, the steel strand (30) is inserted into the corrugated pipe (29), and the exposed end of the steel strand (30) is wrapped with a plastic film for protection. After the assembly is completed, the entire cap beam reinforcement skeleton (28) is hoisted to the designated position for subsequent construction; S4. Before the prestressing construction of the cap beam (1), first install the steel pipe column (15) on the side of the cap beam (1) and above the pedestal (6), then install the prestressed working platform on the steel pipe column (15), and set a vertical support (26) above the prestressed working platform for installing the I-beam slide rail (25). The end of the I-beam slide rail (25) is inserted into the reserved hole (22) at the top of the cap beam (1) side. When the prestressed tensioning construction requires adjustment of the equipment position, place the cross beam (23) between the limit blocks (24) of the I-beam slide rail (25), and use a hand winch to move and adjust the tensioning equipment through the cross beam (23).

2. The construction method of a large-span prestressed cap beam of a portal pier across an existing road according to claim 1 is characterized in that: In step S1, the protective film (4) is made of plastic film + waterproof geotextile, and at least (2) layers of plastic film are arranged.

3. The construction method of a large-span prestressed cap beam of a portal pier across an existing road according to claim 1 is characterized in that: In step S2, the steel pipe column base includes a lower flange steel plate (9) and an upper flange steel plate (14), and the anchoring ribs (13) anchor the lower flange steel plate (9) and the enlarged foundation (8).

4. The construction method of a large-span prestressed cap beam of a portal pier across an existing road according to claim 3 is characterized in that: In step S2, when the steel pipe column segment is installed on the enlarged foundation (8), after the steel pipe column segment is hoisted to the corresponding position, bolts are used to pass through the bolt holes (12) on the steel pipe column segment and the upper flange steel plate (14) to firmly connect them.

5. The construction method of a large-span prestressed cap beam of a portal pier across an existing road according to claim 3 is characterized in that: A steel pipe (11) is arranged between the lower flange steel plate (9) and the upper flange steel plate (14), and stiffening ribs (10) are arranged between the steel pipe (11) and the lower flange steel plate (9) and between the steel pipe (11) and the upper flange steel plate (14).

6. The construction method of a large-span prestressed cap beam of a portal pier across an existing road according to claim 1 is characterized in that: In step S4, anchor bolts (18) are used to temporarily fix the anchor plate (17) at the bottom of the steel pipe column (15) to the cap (6), and then at least two steel hoops (16) are arranged between the side of the steel pipe column (15) and the pier (5).

7. The construction method of a large-span prestressed cap beam of a portal pier across an existing road according to claim 1 is characterized in that: In step S4, a platform bottom steel plate (20) is laid above the prestressed working platform, and a construction guardrail (21) is installed around the prestressed working platform.

8. The construction method of a large-span prestressed cap beam of a portal pier across an existing road according to claim 1 is characterized in that: The prestressed working platform is supported above the pedestal (6) by steel pipe columns (15) at the bottom; the prestressed working platform comprises a longitudinal frame (19) and a transverse frame (27) arranged at the top of the steel pipe columns (15); a vertical support (26) is arranged at the bottom of the I-beam slide rail (25), and the vertical support (26) is erected on the longitudinal frame (19).

9. A large-span prestressed cap beam for a portal pier over an existing road, characterized in that: The method for constructing a large-span prestressed cap beam of a portal pier across an existing road as described in any one of claims 1 to 8 is used to obtain the prestressed cap beam.

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