A construction method for closing double-column piers with small rigidity in the side span of a continuous beam without counterweight

Abstract

This application discloses a construction method for the closure of a continuous beam with a small stiffness double-column pier without counterweight. During the pier construction, through holes are pre-drilled in the perimeter of the two pier columns. Steel bars are then inserted through these holes, and several hangers are vertically inserted into the pre-embedded holes of the cast-in-place box girder. These hangers are distributed laterally at intervals and horizontally suspended from the lower ends of the hangers onto a distribution beam. The upper surface of the transverse distribution beam is flush with the upper side of the steel bars. A longitudinal distribution beam is erected on the steel bars and the transverse distribution beam. Several transversely arranged Bailey beams are erected above the longitudinal distribution beams, and several longitudinally arranged load-bearing beams are set above the Bailey beams. The load-bearing beams, Bailey beams, and distribution beams together form a support and suspension construction platform. Formwork is then erected on the construction platform, reinforcing bars are tied on the platform, and concrete is poured to complete the closure of the continuous beam. This method helps reduce the problems of uneven pressure during pier-side support construction and repeated counterweight loading.

Description

Technical Field

[0001] This application relates to the technical field of continuous beam construction, and in particular to a construction method for closing a continuous beam with small stiffness double column piers on the side span without counterweight. Background Technology

[0002] In bridge construction, piers are used as the main load-bearing points for bridge span construction. Piers closer to the riverbank are called side piers, and the section extending from the riverbank towards the side piers is the straight section. Side piers are low-stiffness double-column piers. During the construction of the straight section of the side span of a continuous beam, the traditional pier-side bracket method (clamp method) is often used. This method involves dividing each set of steel clamps into two semi-circular structures. During installation, the elevation position of the clamps on the pier body is determined according to the bottom elevation of the cap beam. Then, the two semi-circular clamps are fixed to the pier body with high-strength bolts. Steel clamps with welded brackets are then fixed to the pier body. I-beams or Bailey beams are erected on the brackets as load-bearing structures to support the loads generated during the construction of the straight section on the side pier.

[0003] This method will cause eccentric pressure on the low-rigidity side piers, so brackets need to be installed symmetrically on both sides of the side piers for counterweight loading. The construction process consumes a lot of manpower, material resources and time, and there are problems of eccentric pressure during the construction of brackets next to the piers and repeated loading. Therefore, there is still room for improvement. Summary of the Invention

[0004] To reduce the problems of uneven pressure during the construction of the pier-side bracket and repeated counterweight loading, this application provides a construction method for the unweighted closure of small-stiffness double-column piers in the side span of a continuous beam.

[0005] The construction method for closure of a continuous beam with low stiffness and double column piers without counterweight provided in this application adopts the following technical solution:

[0006] A construction method for closing a continuous beam with low stiffness and double column piers without counterweight at the side span includes the following steps:

[0007] S1: Construction of the side support system for the pier: During the construction of the side pier, through holes are reserved in the perimeter of the two pier columns respectively. The through holes are set horizontally, and then steel bars are inserted through the reserved holes.

[0008] S2: Construction of the side suspension system for cantilever beams: Several suspension rods are vertically inserted into the pre-embedded holes of the cast-in-place box girder that has already been poured, and the suspension rods are distributed horizontally at intervals;

[0009] S3: Construction of transverse and longitudinal distribution beams of bracket system: The transverse distribution beam is horizontally suspended from the lower end of several hangers. The upper surface of the transverse distribution beam is flush with the upper side of the steel bar. The longitudinal distribution beam is erected on the steel bar and the transverse distribution beam. The length direction of the longitudinal distribution beam is consistent with the length direction of the bridge body.

[0010] S4: Bailey beam erection: Several transversely arranged Bailey beams are erected above several longitudinal distribution beams, with the Bailey beams distributed longitudinally.

[0011] S5: Construction of load-bearing beams and formwork: Several longitudinally arranged load-bearing beams are set above the Bailey beams. The load-bearing beams, the Bailey beams and the distribution beams together form a construction platform with support and hoisting. Then, the formwork is built on the construction platform.

[0012] S6: Unweighted closure construction: Reinforcing bars are tied on the construction platform, then concrete is poured, and the continuous beam closure construction is completed.

[0013] By adopting the above technical solution, combining the scaffolding method and the suspension method, and using horizontally inserted steel bars at the piers as the main load-bearing points, the load is partially distributed by the completed bridge sections. Specifically, suspension rods are installed at the already poured cast-in-place box girders, and transverse distribution beams are suspended at the lower ends of the suspension rods. A construction platform is built between the steel bars and the transverse distribution beams to facilitate the closure of the continuous beams. The load generated during construction is transferred to the piers and the already poured cast-in-place box girders through the construction platform, thereby reducing the problem of uneven pressure during pier-side scaffolding construction. Furthermore, it eliminates the need for repeated counterweight loading, which helps to accelerate the construction progress and reduces a large amount of steel and concrete. Compared with traditional hanging basket construction, by using the combination of the scaffolding method and the suspension method, the pier steel bars distribute the load borne by the suspension rods, reducing construction safety risks.

[0014] Preferably, both ends of the steel bar protrude from the outer periphery of the pier column, and the two longitudinal distribution beams are respectively mounted on the two ends of the steel bar protruding from the outer periphery of the pier column.

[0015] By adopting the above technical solution, when the load generated during the closure construction is transmitted to the pier through the construction platform, the two ends of the steel bar are in equilibrium, which helps to improve the stability of the construction platform.

[0016] Preferably, the longitudinal distribution beams located on both sides of the pier abut against the outer peripheral wall of the pier.

[0017] By adopting the above technical solution, the longitudinal distribution beam is made to be close to the pier column, so that the load generated during construction is more concentrated on the pier column, which is conducive to improving the stability of the construction platform.

[0018] Preferably, the two piers are provided with support seats at their upper ends, the outer walls of the support seats protrude from the outer circumference of the piers, and the longitudinal distribution beam is disposed in the gap between the lower surface of the support seat and the upper side of the steel bar.

[0019] By adopting the above technical solution, the support seat plays a limiting role in the longitudinal distribution beam, which helps to improve the stability of the construction platform.

[0020] Preferably, the support is located in the gap between the longitudinal distribution beam and the load-bearing beam.

[0021] By adopting the above technical solution, when the load-bearing beam is under stress, the support seat provides support for the load-bearing beam, which helps to improve the stability of the construction platform.

[0022] Preferably, both the longitudinal distribution beam and the transverse distribution beam are I-beams, and several stiffening plates are provided on both sides of the I-beams, with the stiffening plates distributed along the length of the I-beams.

[0023] By adopting the above technical solutions, the overall strength of the construction platform can be improved.

[0024] Preferably, an adjusting block is provided under the Bailey beam, and the adjusting block is used to adjust the elevation of the bottom formwork.

[0025] By adopting the above technical solution, the elevation of the bottom formwork can be adjusted by adjusting the height of the adjusting block, thereby improving the applicability of the construction platform. Attached Figure Description

[0026] Figure 1 This is an elevation layout diagram of the construction platform in a construction method for closing a continuous beam with small stiffness double column piers without counterweight, according to an embodiment of this application.

[0027] Figure 2 yes Figure 1 Diagram showing the direction of AA in the middle.

[0028] Figure 3 yes Figure 1 Diagram showing the direction of BB in the middle.

[0029] Figure 4 This is a plan view of the construction platform in a construction method for closing a continuous beam with small stiffness double column piers without counterweight in an embodiment of this application.

[0030] Explanation of reference numerals in the attached drawings: 1. Pier; 2. Support base; 3. Steel bar; 4. Transverse distribution beam; 5. Longitudinal distribution beam; 6. Hanger; 7. Load-bearing beam; 8. Cast-in-place box girder; 9. Bailey beam; 10. Adjustment block. Detailed Implementation

[0031] The following is in conjunction with the appendix Figure 1-4 This application will be described in further detail.

[0032] This application discloses a construction method for the unweighted closure of a continuous beam with low stiffness double-column piers at its side span. (Refer to...) Figure 1 and Figure 2 A construction method for closure of a continuous beam with small stiffness double-column piers without counterweight includes the following steps:

[0033] S1: Construction of the side support system of pier 1: During the construction of the side pier, through holes are reserved in the perimeter of the two pier 1 respectively. The through holes are set horizontally. Then, steel rods 3 are inserted through the reserved holes. The through rods are made of high-strength manganese steel.

[0034] S2: Construction of the cantilever beam side suspension system: Refer to... Figure 3 and Figure 4 Several hangers 6 are vertically inserted into the pre-embedded holes of the cast-in-place box girder 810# block, which has already been poured. The hangers 6 are made of high-strength threaded steel. There are four sets of hangers 6, and the four hangers 6 are distributed horizontally at intervals.

[0035] S3: Construction of the transverse and longitudinal distribution beams of the bracket system: The transverse distribution beam 4 is horizontally suspended from the lower end of the four hangers 6 to form a side suspension system. The upper surface of the transverse distribution beam 4 is flush with the upper side of the steel bar 3. The longitudinal distribution beam 5 is erected on the steel bar 3 and the transverse distribution beam 4. The length direction of the longitudinal distribution beam 5 is consistent with the length direction of the bridge body.

[0036] Specifically, both ends of the steel bar 3 protrude from the outer periphery of the pier column 1. Two longitudinal distribution beams 5 are respectively erected at the two ends of the steel bar 3 protruding from the outer periphery of the pier column 1. The longitudinal distribution beams 5 located on both sides of the pier column 1 abut against the outer periphery of the pier column 1, so that the two ends of the steel bar 3 are balanced by force, which is beneficial to improving the stability of the construction platform.

[0037] S4: Bailey Beam 9 Erection: To facilitate demolding and adjustment of the bottom formwork elevation, sand boxes are selected for adjustment blocks 10. 30 sets of sand boxes are provided. The position of each set of sand boxes is adjusted according to the placement position of Bailey Beam 9. Bailey Beam 9 is assembled on the bridge deck using a tower crane. After assembly, it is directly hoisted and placed on the corresponding adjustment blocks using a tower crane, so that several Bailey Beam 9 are laterally set on the sand boxes above the longitudinal distribution beam 5, and several Bailey Beam 9 are longitudinally distributed.

[0038] S5: Construction of Load-Bearing Beam 7 and Formwork: Several longitudinally arranged load-bearing beams 7 are set above Bailey beam 9. The load-bearing beams 7, the Bailey beams, and the distribution beams together form a construction platform with a combination of support and hoisting. Then, the formwork is erected on the construction platform. That is, the back ribs supporting the bottom formwork are placed transversely on the load-bearing beams 7 at 30cm intervals. The back ribs are constructed using 10cm×10cm square timber. For the installation of the bottom formwork of the two side flange plates, steel pipe supports are directly erected on the I25b load-bearing beams 7.

[0039] Among them, the upper ends of the two piers 1 are jointly provided with support seats 2. The outer wall of the support seat 2 protrudes from the outer circumference of the pier 1. The longitudinal distribution beam 5 is set in the gap between the lower surface of the support seat 2 and the upper side of the steel bar 3. The support seat 2 plays a limiting role for the longitudinal distribution beam 5, which helps to improve the stability of the construction platform.

[0040] In addition, the support seat 2 is located in the gap between the longitudinal distribution beam 5 and the load-bearing beam 7. When the load-bearing beam is under stress, the support seat 2 provides support for the load-bearing beam 7, which helps to improve the stability of the construction platform.

[0041] S6: Unweighted closure construction: Tie steel bars on the construction platform, then pour concrete, and complete the closure construction of continuous beam block #12.

[0042] By combining the support method and the suspension method, steel bar 3 serves as the main load-bearing point, and the completed continuous beam shares part of the load. Specifically, suspension rod 6 is set at the cast-in-place box girder 8 that has been poured, and a transverse distribution beam 4 is suspended at the lower end of the suspension rod 6. A construction platform is built between steel bar 3 and transverse distribution beam 4 so that the continuous beam can be closed on the construction platform. The load generated during construction is transferred to the pier column 1 and the cast-in-place box girder 8 through the construction platform, thereby reducing the problem of eccentric pressure during the construction of the pier-side support and eliminating the need for repeated stacking of counterweights, which helps to speed up the construction progress and reduces a large amount of steel and concrete.

[0043] 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 construction method for the unweighted closure of a continuous beam with low stiffness double-column piers at the side span, characterized in that: Includes the following steps: S1: Construction of the side support system of the pier (1): During the construction of the side pier, through holes are reserved in the perimeter of the two piers (1), and the through holes are set horizontally. Then, steel rods (3) are inserted through the reserved holes. S2: Construction of the cantilever beam side suspension system: Several hangers (6) are vertically inserted into the pre-embedded holes of the cast-in-place box beam (8) that has been poured and formed, and the hangers (6) are distributed horizontally at intervals; S3: Construction of the transverse and longitudinal distribution beams of the bracket system: The transverse distribution beam (4) is horizontally suspended at the lower end of several hangers (6). The upper surface of the transverse distribution beam (4) is flush with the upper side of the steel bar (3). The longitudinal distribution beam (5) is erected on the steel bar (3) and the transverse distribution beam (4). The length direction of the longitudinal distribution beam (5) is consistent with the length direction of the bridge body. S4: Bailey beam (9) erection: Several transversely arranged Bailey beams (9) are erected above several longitudinal distribution beams (5), and the several Bailey beams (9) are longitudinally distributed; S5: Construction of load-bearing beams (7) and formwork: Several longitudinally arranged load-bearing beams (7) are set above Bailey beams (9). The load-bearing beams (7), Bailey beams (9) and distribution beams together form a construction platform with support and hoisting. Then, formwork is built on the construction platform. S6: Unweighted closure construction: Reinforcing bars are tied on the construction platform, then concrete is poured, and the continuous beam closure construction is completed. The two piers (1) are provided with support seats (2) at their upper ends. The outer wall of the support seat (2) protrudes from the outer circumference of the pier (1). The longitudinal distribution beam (5) is located in the gap between the lower surface of the support seat (2) and the upper side of the steel bar (3). The support base (2) is located in the gap between the longitudinal distribution beam (5) and the load-bearing beam (7); Both ends of the steel bar (3) protrude from the outer periphery of the pier (1), and the two longitudinal distribution beams (5) are respectively erected at the two ends of the steel bar (3) protruding from the outer periphery of the pier (1).

2. The construction method for the unweighted closure of a continuous beam with small stiffness double-column piers at the side span, as described in claim 1, is characterized in that: The longitudinal distribution beams (5) located on both sides of the pier (1) abut against the outer peripheral wall of the pier (1).

3. The construction method for the unweighted closure of a continuous beam with small stiffness double-column piers at the side span, as described in claim 1, is characterized in that: Both the longitudinal distribution beam (5) and the transverse distribution beam (4) are I-beams, and several stiffening plates are provided on both sides of the I-beams, with the stiffening plates distributed along the length of the I-beams.

4. The construction method for the unweighted closure of a continuous beam with small stiffness double-column piers at the side span, as described in claim 1, is characterized in that: An adjusting block is provided under the Bailey beam (9) for adjusting the elevation of the bottom formwork.

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