A construction method for pouring and closing a whole rigid frame bridge support
By optimizing the construction sequence and support design, and combining built-in rigid frame and micro-expansion self-compacting concrete, the problems of high construction difficulty and high safety risk of integral rigid frame bridge piers were solved, achieving efficient and low-cost construction results.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CHINA RAILWAY 12TH BUREAU GRP CO LTD
- Filing Date
- 2025-06-26
- Publication Date
- 2026-07-31
AI Technical Summary
The piers of integral rigid frame bridges have diverse forms and complex support systems. The construction of the upper piers and closure sections is difficult, with high safety risks, difficult quality control, and uncontrollable construction period and cost.
The method of casting an integral rigid frame bridge support was adopted, including building a construction support system, installing formwork and pouring concrete. An internal rigid frame and micro-expansion self-compacting concrete were used, and the construction sequence and support design were optimized to ensure the quality and safety of the closure section.
It improved construction efficiency, reduced costs and safety risks, ensured the quality and aesthetics of the closure section, shortened the construction period, and reduced equipment and labor input.
Smart Images
Figure CN120465383B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of continuous rigid frame bridge construction technology, specifically relating to a method for casting an integral rigid frame bridge support and pier closure. Background Technology
[0002] With the rapid development of high-speed railway construction technology in my country, bridge structures have made significant progress in improving safety, durability, and span. In recent years, breakthroughs have been made in research on lightweighting and cost reduction. A new type of slender, thin, and unsupported lightweight rigid frame continuous beam has emerged in high-speed railway engineering. The piers are V-shaped round-ended piers and double-cylinder piers, with smaller and thinner diameters than traditional railway bridge piers. The main beam is a double-web prestressed reinforced concrete beam. Compared with traditional rigid frame continuous beams, it has higher pier height, lighter large-span structure, more continuous spans, and more diverse applicable conditions. The construction process also differs from traditional bridges. This type of beam pours the piers in three stages: first, the lower pier body is poured, and then the 6m high upper pier body is poured simultaneously with the beam body. A 2m closure section is reserved between the upper and lower piers to be poured after the beam body has creeped. From a construction perspective, the piers are diverse in form, the support system is complex, and the construction of the upper piers and closure sections is difficult, posing high safety risks, making quality control challenging, and the construction period and costs uncontrollable. Specific challenges include:
[0003] (1) The beam support system is complex: the V-shaped pier is sloping, thin and tall; after the support at the bottom of the upper pier is removed, the support around the pier is difficult to support the load of the upper pier and the beam; the side pier is close to the abutment and there is no space for support installation around the pier; it involves cross-road construction; the beam is stopped for 60 days, the support occupies a long time and the cost is high.
[0004] (2) The upper pier body is poured synchronously with the beam, the unit area load is large, the slenderness ratio of the support is large, and the requirements for the support are high; the pier body diameter is small, the space at the bottom of the pier is small, the spacing of the main reinforcement is small, and the bottom formwork and side formwork support are difficult to erect; the reinforcement and prestressing pipes are dense, making it difficult to pour and vibrate the upper pier body concrete; the beam body is affected by tension, creep and temperature, and the beam length varies greatly, so the pre-eccentricity of the pier body needs to be set accurately.
[0005] (3) The deformation of the beam generates a large shear force on the closure section, and reliable and aesthetically pleasing measures are required to resist the shear force; the installation of the formwork and concrete pouring of the closure section of the pier body are difficult, and the misalignment of the joints and the void on the top surface are difficult to control; in order to ensure the precise alignment of the upper and lower pier bodies and avoid the impact of temperature difference on the quality of the closure section, the closure time, temperature and timing must be strictly controlled. Summary of the Invention
[0006] This invention addresses the problems of integral rigid frame bridges being constructed in three stages, which involve complex support systems, high construction difficulty and safety risks in the upper piers and closure sections due to the diverse forms of the piers, and uncontrollable construction period and costs.
[0007] This invention provides the following technical solution: a method for casting and merging an integral rigid frame bridge support, comprising the following steps:
[0008] S1: After the construction of the main pier in the middle, the lower piers of the side piers on both sides, and the abutments below the bottom of the beam of the integral rigid frame bridge is completed, the beam construction support in the main pier area, the beam construction support in the side pier area, and the upper pier body construction support in the side pier are built; the beam construction support in the main pier area and the beam construction support in the side pier area are connected to form the beam construction support system.
[0009] S2: Install beam formwork on top of the beam construction support system, and install upper pier formwork on the upper pier body construction support of the side pier.
[0010] S3: After the concrete pouring of the upper pier body and beam body of the side pier is completed and reaches the design strength, the prestressed tendons are tensioned and the pipes are grouted; the construction support of part of the beam body in the side pier area is removed to provide construction space for the side pier closure section; the construction support of the upper pier body of the side pier is removed.
[0011] S4: Install an internal rigid frame between the lower and upper pier bodies of the side pier to lock the upper and lower pier bodies together;
[0012] S5: Perform micro-expansion self-compacting concrete grouting on the closure section of the side pier between the lower and upper pier bodies;
[0013] S6: After the closure section of the side pier reaches the design strength, all supports are removed, and the construction is completed.
[0014] Further, in step S1: the clamps and brackets are welded and assembled into a whole, and the clamps are tightened on the top of the main pier by tightening bolts. A total of 4 sets of clamps and brackets are installed on the same group of main piers; the I-beam longitudinal beams and I-beam transverse beams are installed with the brackets as fulcrums to form the beam construction support for the main pier area.
[0015] Further, in step S1: the side pier is far from the abutment, and lifting steel pipe columns and surrounding disc-lock full-span scaffolding are installed on both sides of the lower part of the side pier body. The net distance between the side pier and the lifting steel pipe columns is not less than 1m. Then, sand boxes, transverse double I-beams and longitudinal I-beams are installed in sequence on the top of the lifting steel pipe columns. Together with the disc-lock full-span scaffolding, they form the beam construction support in the side pier area. The sand boxes are used to adjust the elevation of the transverse double I-beams.
[0016] Further, in step S1: the side pier is close to the abutment, and a supporting steel pipe column and a surrounding disc-lock full-span scaffold are installed on the side of the side pier facing away from the abutment. The net distance between the side pier and the supporting steel pipe column is not less than 1m. Then, sand boxes and transverse double-splitting I-beams are installed in sequence on the top of the supporting steel pipe column. The cantilevered I-beam is fixed on the top of the abutment with anchoring steel bars. The other end of the cantilevered I-beam rests on the transverse double-splitting I-beam. The cantilevered I-beam and the disc-lock full-span scaffold together constitute the beam construction support in the side pier area.
[0017] Further, in step S1: a reserved hole and a pre-embedded connecting steel plate are set at the top of the lower pier body of the side pier; a small steel pipe column is installed in the reserved hole, and an adjustable screw base, an adjustable screw with a top support, an I-beam pad beam, a double-layer square timber platform, and a steel grid are installed from bottom to top on the top of the small steel pipe column to form the construction support for the upper pier body of the side pier; the adjustable screw with a top support is inserted into the adjustable screw base.
[0018] Further, in step S2: the upper pier formwork of the side pier includes a bottom inner ring formwork, a bottom outer ring formwork, and an upper pier outer formwork; the bottom inner ring formwork is divided into two semi-circular formworks and one rectangular formwork, and the bottom outer ring formwork is divided into two semi-circular formworks and two upper strip formworks; after the bottom inner ring formwork and the bottom outer ring formwork are installed on the steel grid, the main reinforcement of the pier body is installed between the bottom inner ring formwork and the bottom outer ring formwork; the gaps between the main reinforcement of the pier body are sealed and smoothed with a steel gap mortar sealing layer; then the upper pier outer formwork is installed on the bottom inner ring formwork and the bottom outer ring formwork.
[0019] Furthermore, in step S3: after the prestressed tendons are tensioned and the ducts are grouted, the disc-type full-span scaffolding adjacent to the side pier is removed to provide construction space for the closure section.
[0020] Further, in step S5: grouting pipes are installed at intervals at the bottom of the upper pier body of the side pier, and then the closure section template is installed on the upper and lower pier bodies using the construction work space of the closure section, tightly clamped to the upper and lower pier bodies without gaps. After installation, the closure section template injection port and closure section template discharge port are opened.
[0021] An elevated hopper is installed on the grouting port of the closure section formwork to increase the pressure of the micro-expansion self-compacting concrete, and then the micro-expansion self-compacting concrete is poured. When the grout discharge port of the closure section formwork has drained the laitance and normal micro-expansion self-compacting concrete is discharged, high-strength micro-expansion grouting material is injected. The grout is injected through the grouting pipe into the cavity and joint between the bottom of the upper pier and the poured micro-expansion self-compacting concrete. When grout is discharged from the grout discharge port of the closure section formwork, the grouting pipe is pulled in the opposite direction of grouting, 10cm each time, until it is pulled out. After grouting is completed, the grouting port and the grout discharge port of the closure section formwork are closed. After curing for 1 day, the closure section formwork is removed and the closure section is wrapped with a film for curing.
[0022] Compared with the prior art, the advantages of the present invention are:
[0023] Regarding quality:
[0024] The use of fully enclosed pier closure section formwork and micro-expansion self-compacting concrete ensured the compactness of the closure section concrete, resulting in a smooth connection with the upper and lower pier sections without misalignment and an aesthetically pleasing appearance. After the concrete pouring was completed, grouting was performed with the formwork in place to supplement the grouting at the contact surface between the top of the closure section and the bottom of the upper pier section, further improving the tightness of the joint.
[0025] To ensure the quality of the upper pier, which is 8m high from the bottom to the beam surface and has dense prestressed ducts and reinforcing bars, resulting in a large drop in concrete pouring height, concrete pouring pipes and vibration channels were pre-installed during the installation of the upper pier and beam reinforcement. These channels traverse the dense prestressed ducts and reinforcing bars, allowing concrete and vibrators to reach directly to the bottom of the upper pier, keeping the drop within 2m and ensuring the quality of concrete pouring.
[0026] To ensure the accuracy of the closure of the upper and lower piers, a rigid frame with strong shear resistance was designed and manufactured. Based on the estimated temperature when the piers are closed according to the construction period, the pre-deflection of the side piers was calculated. The pre-deflection was set during the formwork installation, and the rigid frame was locked within the estimated temperature period to ensure that the center lines of the upper and lower piers are coaxial when they are closed.
[0027] In terms of efficacy:
[0028] The construction cycle of the pier body was shortened: by optimizing the construction sequence of the upper and lower pier bodies, the construction difficulty of the lower pier body was reduced and the construction efficiency was improved, saving 30 days of construction time for each beam section;
[0029] The construction cycle of the closure section was shortened: by using the closure section casting formwork with grouting and drainage outlets and specially designed self-compacting concrete, the construction speed of the closure section was improved, the concrete pouring time was shortened, and thus the input of equipment and labor was reduced.
[0030] Cost aspect:
[0031] Reduced material costs: The support system is specifically designed based on the working conditions and stress characteristics, avoiding waste of support materials. During the 60-day beam suspension period, the weight of the beam is transferred to the steel pipe column supports around the piers. Through modeling and calculation, the disc-lock supports in the flange plates, mid-span, and central pier areas can be removed, reducing the occupation time of supports and formwork, improving material turnover rate, and reducing the cost of supports and formwork.
[0032] Reduced equipment and labor costs: The targeted design of the support system, the optimization of the construction sequence of the upper and lower piers, and the application of closure section tooling and self-compacting concrete reduced construction difficulty and shortened construction time, further reducing the input of equipment, manpower, and materials, thus lowering construction costs. The bottom support of the upper pier and the rigid frame and formwork structure of the closure section are simple, quick to install, and have lower material and labor costs.
[0033] Regarding security:
[0034] Construction safety was ensured: a diverse and safe support system was designed and used to address the structural characteristics. In particular, the corbel bracket of the central pier solved the problem of the difficulty in erecting the support on the sloping surface of the central pier; steel pipe column supports were added around the side piers to bear the huge load of the upper pier and beam during the beam stop, ensuring the safety of the disc buckle frame around the pier; small steel pipe supports and steel grids on the upper pier body ensured the safety of the upper pier support.
[0035] Environmental aspects:
[0036] The materials used are more conventional, have a high recycling rate, and consume fewer resources. This shortens the time required for each process, reduces the number of machines used, and decreases energy consumption such as fuel and electricity. It also reduces pollutant emissions and noise release time, significantly reducing energy consumption and environmental pollution. Attached Figure Description
[0037] Figure 1 This is a construction sequence diagram for an integral rigid frame bridge.
[0038] Figure 2 This is a schematic diagram of a monolithic rigid frame bridge;
[0039] Figure 3 A schematic diagram of the beam construction support system for the main pier area;
[0040] Figure 4 A schematic diagram of the beam construction support system in the area of the side pier (away from the abutment);
[0041] Figure 5 A schematic diagram of the beam construction support system in the area near the abutment (adjacent to the bridge abutment);
[0042] Figure 6 This is a schematic diagram of the construction support for the upper part of the side pier.
[0043] Figure 7 This is a schematic diagram of a steel reinforcement grid.
[0044] Figure 8 This is a schematic diagram of the bottom inner ring template and the bottom outer ring template;
[0045] Figure 9 This is a schematic diagram of the grouting process for the closure section.
[0046] In the diagram: 1-Main pier; 2-Lower pier body; 3-Closing section; 4-Upper pier body; 5-Beam body; 6-Clamping hoop; 7-Corner; 8-I-beam longitudinal beam; 9-I-beam transverse beam; 10-Combined distribution beam of square timber and I-beam; 11-Steel pipe column for support; 12-Disc-type full-span scaffolding. 15-Sand box; 16-Transverse double-section I-beam; 17-Longitudinal I-beam; 18-Bridge abutment; 19-Anchoring reinforcement; 20-Cantilever I-beam; 21-Small steel pipe column; 22-Adjustable screw rod base; 23-Adjustable screw rod with top support; 24-I-beam pad beam; 25-Double-layer square timber platform; 26-Reinforcing steel grid; 27-Pier main reinforcement; 28-Upper pier formwork; 28.1-Semi-circular formwork; 28.2-Rectangular formwork; 28.3-Semi-circular formwork; 28.4-Upper strip formwork; 29-Built-in stiffening frame; 30-Grouting pipe; 31-Closing section formwork; 32-Closing section formwork grouting port; 33-Closing section formwork grout discharge port; 34-Elevated hopper. Detailed Implementation
[0047] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0048] like Figure 1 , Figure 2 As shown: A construction method for casting the support frame and closing the pier of an integral rigid frame bridge includes the following steps:
[0049] S1: After the construction of the main pier 1 in the middle of the integral rigid frame bridge, the lower pier body 2 of the side piers on both sides, and the abutment 18 below the bottom of the beam is completed, the beam construction support in the main pier area, the beam construction support in the side pier area, and the upper pier body construction support in the side pier are built; the beam construction support in the main pier area and the beam construction support in the side pier area are connected to form the beam construction support system.
[0050] S2: Install beam formwork on top of the beam construction support system, and install upper pier formwork 28 on the upper pier body construction support of the side pier.
[0051] S3: After the concrete pouring of the upper pier body 4 and beam body 5 of the side pier is completed and reaches the design strength, the prestressed tendons are tensioned and the pipes are grouted; the construction support of part of the beam body in the side pier area is removed to provide construction space for the side pier closure section 3; the construction support of the upper pier body of the side pier is removed.
[0052] S4: Install an internal stiffening frame 29 between the lower pier body 2 and the upper pier body 4 of the side pier to lock the upper and lower pier bodies together; prevent the beam body 5 from expanding and contracting due to temperature changes, which in turn causes the upper pier body 4, which is together with the beam body 5, to shift and damage the concrete of the closure section 3.
[0053] S5: Perform micro-expansion self-compacting concrete grouting on the pier closure section 3 between the lower pier body 2 and the upper pier body 4 of the pier.
[0054] S6: After the closing section 3 of the side pier reaches the design strength, all supports are removed, and the construction is completed.
[0055] like Figure 3 As shown: In step S1: Taking advantage of the fact that the elevation of the main pier 1 is a sloping surface and the plane is a rounded shape, a clamp of matching size is designed and manufactured to hug the main pier 1; the clamp 6 and the corbel 7 are welded and assembled into a whole, and the clamp 6 is tightened to the top of the main pier 1 by tightening bolts on the corbel 7. A total of 4 sets of clamps 6 and corbel 7 are installed on the same group of main piers 1; the I-beam longitudinal beams 8 and I-beam transverse beams 9 are installed with the corbel 7 as the fulcrum to form the beam construction support for the main pier area.
[0056] like Figure 4 As shown: In step S1: The side pier is far away from the abutment 18. On both sides of the lower part of the side pier body 2, the supporting steel pipe columns 11 and the surrounding disc-type full-span scaffolding 12 are installed. The net distance between the side pier and the supporting steel pipe columns 11 is not less than 1m. Then, sand boxes 15, transverse double I-beams 16 and longitudinal I-beams 17 are installed in sequence on the top of the supporting steel pipe columns 11. Together with the disc-type full-span scaffolding 12, they form the beam construction support in the side pier area. The sand boxes 15 are used to adjust the elevation of the transverse double I-beams 16.
[0057] The supporting steel pipe column 11 is a spiral steel pipe column with a diameter of 428mm. A steel plate is pre-embedded on the bearing platform, and the supporting steel pipe column 11 is welded to the pre-embedded steel plate.
[0058] like Figure 5 As shown: In step S1: The side pier is adjacent to the abutment 18. On the side of the side pier facing away from the abutment 18, the supporting steel pipe column 11 and the surrounding disc-lock full-span scaffold 12 are installed. The net distance between the side pier and the supporting steel pipe column 11 is not less than 1m. Then, sand box 15 and transverse double I-beam 16 are installed on the top of the supporting steel pipe column 11 in sequence. The top of the abutment 18 is fixed with anchor steel bar 19 to the cantilever I-beam 20. The other end of the cantilever I-beam 20 rests on the transverse double I-beam 16. Due to space limitations, the end of the beam 5 cannot be supported by the disc-lock full-span scaffold 12. The cantilever I-beam 20 is used for support. The cantilever I-beam 20 and the disc-lock full-span scaffold 12 together constitute the beam construction scaffold in the side pier area.
[0059] After the construction support system of beam 5 is erected, a combination distribution beam 10 of square timber and I-beams is installed on the top of the support to lay the bottom formwork of beam 5.
[0060] like Figure 6 , Figure 7 As shown: In step S1: the lower pier body 2 of the middle pier 1 and the side piers of the rigid frame bridge are constructed using conventional methods; pre-reserved holes and pre-embedded connecting steel plates are set at the top of the lower pier body 2 of the side pier; small steel pipe columns 21 are installed in the pre-reserved holes, and adjustable threaded rod bases 22, adjustable threaded rods 23 with top supports, I-beam pad beams 24, double-layer square timber platforms 25, and steel reinforcement grids 26 are installed from bottom to top on the top of the small steel pipe columns 21 to form the construction support for the upper pier body of the side pier; the adjustable threaded rods 23 with top supports are inserted into the adjustable threaded rod bases 22. The steel reinforcement grids 26 are formed by alternating arrangements of 32mm diameter steel bars and 16mm diameter steel bars, and the main reinforcement bars 27 of the pier body can pass through the gaps in the steel reinforcement grids 26.
[0061] Small steel pipe columns 21, adjustable threaded rod bases 22, adjustable threaded rods with top supports 23, I-beam pad beams 24, double-layer square timber platforms 25, and steel bar grids 26 are erected in the narrow pier closure section to support the upper pier and the loads of the simultaneously poured beam concrete, formwork, steel bars, etc.; the steel bar grids 26 can pass through the steel bars of the closure section with small spacing to support the outer formwork of the upper pier.
[0062] When installing the upper pier reinforcement and beam formwork, reinforcement, and steel strands, the direction of the pre-bent joint of the main reinforcement of the upper pier 4 should be consistent with the direction of the pre-reserved main reinforcement joint of the lower pier 2 to ensure that the reinforcement joints of the upper and lower piers are accurately aligned on the closing section 3 after the beam 5 is tensioned; during the reinforcement installation process, concrete pouring and vibration channels are installed, and then concrete is poured through the dense pier reinforcement and beam prestressed ducts to ensure the concrete pouring drop and vibration quality.
[0063] like Figure 8 As shown: In step S2: the upper pier formwork 28 of the side pier includes a bottom inner ring formwork, a bottom outer ring formwork, and an upper pier outer formwork; to facilitate the installation of the bottom formwork on the inner and outer rings of the main reinforcement 27 of the pier body, and to adapt to the suspended casting of the upper pier body 4, a bottom sealing design is required; the bottom inner ring formwork is divided into two semi-circular formworks 28.1 and one rectangular formwork 28.2, and the bottom outer ring formwork is divided into two semi-circular formworks 28.3 and two upper strip formworks 28.4; after the bottom inner ring formwork and the bottom outer ring formwork are installed on the steel grid 26, the main reinforcement 27 of the pier body is installed between the bottom inner ring formwork and the bottom outer ring formwork; the gap between the main reinforcement 27 of the pier body is sealed and smoothed with a steel gap mortar sealing layer to prevent concrete leakage; then the upper pier outer formwork is installed on the bottom inner ring formwork and the bottom outer ring formwork.
[0064] In step S3: After the prestressed tendons are tensioned and the ducts are grouted, the disc-type full-span scaffold 12 adjacent to the side pier is removed to provide construction space for the closure section 3; specifically, the disc-type full-span scaffold 12 between the side pier and the supporting steel pipe column 11 is removed; and the disc-type full-span scaffold 12 at the main pier 1 is removed; thereby improving the scaffold turnover rate and reducing scaffold investment.
[0065] Remove the upper pier construction scaffold at the bottom of the upper pier 4, install a chain hoist on the top of the supporting steel pipe column 11 next to the side pier, and use the chain hoist to remove the upper pier formwork.
[0066] like Figure 9 As shown: In step S5: First, roughen the top surface of the lower pier 2 and the bottom surface of the upper pier 4; install grouting pipes 30 at intervals at the bottom of the upper pier 4 of the side pier, with a spacing of 40cm between the grouting pipes 30; then weld the reserved steel bars of the upper and lower piers; install the distributed steel bars of the pier closure section; then use the construction work space of the closure section 3 to install the closure section template 31 on the upper and lower piers, tightly clamp it with the upper and lower piers without gaps, and ensure that there is no leakage of grout during concrete pouring; after installation, open the closure section template pouring port 32 and the closure section template grout discharge port 33 on the closure section template 31.
[0067] Install an elevated hopper 34 on the grouting port 32 of the closure section formwork to increase the pressure of the micro-expansion self-compacting concrete, and then grout the micro-expansion self-compacting concrete. When the grouting port 33 of the closure section formwork drains the laitance and normal micro-expansion self-compacting concrete is discharged, start injecting high-strength micro-expansion grouting material. The grout is injected through the grouting pipe 30 into the cavity and joint between the bottom of the upper pier 4 and the grouting micro-expansion self-compacting concrete. When grout is discharged from the grouting port 33 of the closure section formwork, pull the grouting pipe 30 in the opposite direction of grouting, pulling 10cm each time until it is pulled out. After grouting is completed, close the grouting port 32 and the grouting port 33 of the closure section formwork. After curing for 1 day, remove the closure section formwork 31 and wrap the closure section 3 with a film for curing.
[0068] Grouting with formwork using a backward grouting method is a grouting technique for closed structures. Grouting pipes 30 are pre-installed at the bottom of the upper pier body 4 where grouting is required. The grouting pipes 30 are not too firmly fixed; only their vertical and horizontal positions are restricted, not their longitudinal position, ensuring they can be withdrawn. Three 10mm diameter steel wire rubber pipes are arranged in parallel, spaced 400mm apart. The pipe outlet is 0.1m from the grout outlet of the closure section formwork, and the inlet extends 1 meter beyond the grouting port. Grouting is performed after the closure section concrete is poured. The grouting fluid is a prestressed duct grouting material with micro-expansion properties, and the grouting pressure is 0.5MPa. Grouting begins from one end. After grout is discharged from the outlet, the grouting pipe is withdrawn, moving the pipe opening backward. Grouting is then repeated, with each withdrawal stroke being 0.1m. This process of withdrawing and grouting continues until the grouting pipe 30 is completely withdrawn. Finally, the closure section formwork is sealed.
[0069] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims
1. A method for construction of a monolithic rigid frame bridge support casting and pier body closure, characterized in that, Includes the following steps: S1: After the construction of the main pier (1) in the middle of the integral rigid frame bridge, the lower pier body (2) of the side piers on both sides, and the bridge abutment (18) below the beam bottom is completed, the beam construction support in the main pier area, the beam construction support in the side pier area and the upper pier body construction support in the side pier are built; the beam construction support in the main pier area and the beam construction support in the side pier area are connected to form the beam construction support system. S2: Install beam formwork on top of the beam construction support system, and install upper pier formwork on the upper pier construction support of the side pier (28). S3: After the concrete pouring of the upper pier body (4) and beam body (5) of the side pier is completed and reaches the design strength, the prestressed tendons are tensioned and the pipes are grouted; the construction support of part of the beam body in the side pier area is removed to provide the construction operation space for the closing section (3) of the side pier; the construction support of the upper pier body of the side pier is removed. S4: Install an internal stiffening frame (29) between the lower pier body (2) and the upper pier body (4) of the side pier to lock the upper and lower pier bodies together; S5: Perform micro-expansion self-compacting concrete grouting on the pier closure section (3) between the lower pier body (2) and the upper pier body (4) of the pier. S6: After the closure section (3) of the side pier reaches the design strength, all supports are removed and the construction is completed.
2. The method according to claim 1, wherein, In step S1: the clamp (6) and the corbel (7) are welded and assembled into a whole. The clamp (6) is tightened on the top of the main pier (1) by tightening bolts. A total of 4 sets of clamps (6) and corbels (7) are installed on the main pier (1) in the same group. The I-beam longitudinal beam (8) and I-beam transverse beam (9) are installed with the corbel (7) as the fulcrum to form the beam construction support of the main pier area.
3. The method according to claim 2, wherein, In step S1: the side pier is far away from the abutment (18). On both sides of the lower pier body (2) of the side pier, the supporting steel pipe column (11) and the surrounding disc-type full-span scaffold (12) are installed. The net distance between the side pier and the supporting steel pipe column (11) is not less than 1m. Then, the sand box (15), the transverse double I-beam (16) and the longitudinal I-beam (17) are installed in sequence on the top of the supporting steel pipe column (11). Together with the disc-type full-span scaffold (12), they form the beam construction scaffold in the side pier area. The sand box (15) is used to adjust the elevation of the transverse double I-beam (16).
4. The method according to claim 2, wherein, In step S1: The side pier is close to the abutment (18). On the side of the side pier facing away from the abutment (18), the supporting steel pipe column (11) and the surrounding disc-lock full-span scaffold (12) are installed. The net distance between the side pier and the supporting steel pipe column (11) is not less than 1m. Then, the sand box (15) and the transverse double I-beam (16) are installed on the top of the supporting steel pipe column (11). The cantilever I-beam (20) is fixed on the top of the abutment (18) using anchor steel bars (19). The other end of the cantilever I-beam (20) rests on the transverse double I-beam (16). The cantilever I-beam (20) and the disc-lock full-span scaffold (12) together constitute the beam construction scaffold in the side pier area.
5. The method according to claim 3 or 4, characterized in that, In step S1: a reserved hole and a pre-embedded connecting steel plate are set at the top of the lower pier body (2) of the side pier; a small steel pipe column (21) is installed in the reserved hole, and an adjustable screw base (22), an adjustable screw with top support (23), an I-beam pad beam (24), a double-layer square timber platform (25) and a steel grid (26) are installed from bottom to top on the top of the small steel pipe column (21) to form the upper pier body construction support of the side pier; the adjustable screw with top support (23) is inserted into the adjustable screw base (22).
6. The construction method for casting and pier closure of an integral rigid frame bridge support according to claim 5, characterized in that, In step S2: the upper pier body formwork (28) of the side pier includes the bottom inner ring formwork, the bottom outer ring formwork and the upper pier body outer formwork; the bottom inner ring formwork is divided into 2 semi-circular formworks (28.1) and 1 rectangular formwork (28.2), and the bottom outer ring formwork is divided into 2 semi-circular formworks (28.3) and 2 upper strip formworks (28.4); after the bottom inner ring formwork and the bottom outer ring formwork are installed on the steel grid (26), the pier body main reinforcement (27) is installed between the bottom inner ring formwork and the bottom outer ring formwork; the gap between the pier body main reinforcement (27) is sealed and smoothed with steel gap mortar; then the upper pier body outer formwork is installed on the bottom inner ring formwork and the bottom outer ring formwork.
7. The construction method for casting and pier closure of an integral rigid frame bridge support according to claim 6, characterized in that, In step S3: After the prestressed tendons are tensioned and the ducts are grouted, the disc-type full-span scaffold (12) of the adjacent side pier is removed to provide construction space for the closure section (3).
8. The construction method for casting and pier closure of an integral rigid frame bridge support according to claim 7, characterized in that, In step S5: Grouting pipes (30) are installed at intervals at the bottom of the upper pier body (4) of the side pier. Then, the closure section template (31) is installed on the upper and lower pier bodies using the construction work space of the closure section (3). It is tightly clamped to the upper and lower pier bodies without gaps. After installation, the closure section template grouting port (32) and closure section template grout discharge port (33) on the closure section template (31) are opened. Install an elevated hopper (34) on the grouting port (32) of the closure section formwork to increase the pressure of the micro-expansion self-compacting concrete, and then grout the micro-expansion self-compacting concrete; when the grouting port (33) of the closure section formwork drains the floating slurry and normal micro-expansion self-compacting concrete is discharged, start injecting high-strength micro-expansion grouting material. The grout is injected through the grouting pipe (30) into the cavity and joint between the bottom of the upper pier body (4) and the grouting micro-expansion self-compacting concrete; when the grout is discharged from the grouting port (33) of the closure section formwork, pull the grouting pipe (30) in the opposite direction of grouting, pull 10cm each time until it is pulled out. After the grouting is completed, close the grouting port (32) and the grouting port (33) of the closure section formwork. After curing for 1 day, remove the closure section formwork (31) and use a film to wrap and cure the closure section (3).