A construction method using combined formwork for closing section of continuous beam side span

Abstract

The present application discloses a construction method for a side span closing section of a continuous beam using a combined formwork, wherein the construction of a cantilever beam and a side span cast-in-place beam is completed separately, and the cantilever beam and the side span cast-in-place beam are connected by installing an outer guide beam, and the hanging basket of the cantilever beam and the outer formwork of the side span cast-in-place beam are both slidably connected to the outer guide beam; then the outer formwork of the side span cast-in-place beam is transversely moved to the construction position of the side span closing section, and the outer formwork is adjusted so that the outer formwork fits the concrete side wall of the end of the cantilever beam; the original support rods at the bottom of the cantilever beam and the cast-in-place beam are retained as support points for the casting construction of the side span closing section, and the bottom formwork is laid on the original support rods at the bottom of the cantilever beam and the cast-in-place beam, and the bottom formwork and the outer formwork are assembled to form a casting cavity for the side span closing section; concrete is poured in the casting cavity of the side span closing section, and the side span closing section is formed between the side span cast-in-place beam and the cantilever beam. The present application has the effect of improving the construction quality of the side span closing section.

Description

Technical Field

[0001] The present application relates to the field of continuous beam closing construction, and in particular to a construction method for a continuous beam side span closing section using a combined formwork. Background Art

[0002] The construction of the continuous beam closing section is an important part of the continuous beam system conversion. The order of closing construction is first the side span → then the middle span → forming a continuous beam system. The side span closing construction refers to the closing construction between the side span cast-in-place beam and the cantilever beam. The side span cast-in-place beam is cast on the side span pier, while the cantilever beam is a bridge section formed by gradually casting the adjacent piers toward the side span pier by moving the hanging blue. The side span closing is completed near the side span pier.

[0003] In the related art, when the side span closing construction is carried out, the side span closing section is set between the cantilever beam and the cast-in-place beam support. It is necessary to remove the support rods under the bottom plate of the cast-in-place beam end to leave a position for the hanging basket formwork moved over by the cantilever beam. Then the cantilever beam hanging basket is moved to the end of the cast-in-place section so that the hanging basket sling is as close to the end of the cast-in-place beam section as possible. Then, the space between the hanging basket formwork and the outer wall of the cast-in-place beam is closed to form a casting cavity for the closing section. The closing construction of the cantilever beam and the side span cast-in-place beam is completed by pouring in the hanging basket formwork.

[0004] With respect to the above-mentioned related technologies, the applicant believes that the following defects exist: At present, when casting the side span closing section, the weight at the end of the cantilever beam away from the closing section of the side span needs to be increased. Since the cantilever beam is the main load-bearing part, when casting the side span closing section at the end of the cantilever beam, it poses a great challenge to the stability of the support rod at the end of the cantilever beam, which can easily affect the construction quality of the side span closing section. Therefore, there is still room for improvement. Summary of the invention

[0005] In order to improve the construction quality of the side span closing section, the present application provides a construction method of the side span closing section of a continuous beam using a combined formwork.

[0006] The present application provides a construction method for a continuous beam side span closing section using a combined formwork, which adopts the following technical solution:

[0007] A construction method for a continuous beam side span closing section using a combined formwork comprises the following steps:

[0008] S1: Complete the construction of cantilever beam and side span cast-in-place beam respectively, use outer guide beam to install and connect cantilever beam and side span cast-in-place beam, the hanging basket of cantilever beam and the outer side formwork of side span cast-in-place beam are slidably connected to the outer guide beam;

[0009] S2: Move the outer formwork of the side span cast-in-place beam horizontally to the construction position of the side span closing section, and adjust the outer formwork so that the outer formwork fits the concrete side wall of the cantilever beam end;

[0010] S3: The original support rods at the bottom of the cantilever beam and the cast-in-place beam are retained as the support points for the casting construction of the side span closure section. The bottom formwork is laid on the original support rods at the bottom of the cantilever beam and the cast-in-place beam. The bottom formwork and the outer formwork are combined to form the casting cavity of the side span closure section.

[0011] S4: Concrete is poured into the pouring cavity of the side span closing section, and the side span closing section is formed between the side span cast-in-place beam and the cantilever beam.

[0012] By adopting the above technical scheme, the cantilever beam and the side span cast-in-place beam are connected by an outer guide beam, and the outer formwork of the hanging basket and the side span cast-in-place beam share the outer guide beam as a slide rail, so that the outer formwork of the side span cast-in-place beam can be slid to the construction position of the side span closing section without moving the hanging basket at the cantilever beam, and the outer formwork can be conveniently spliced ​​with the concrete on both sides of the cantilever beam. At the same time, the original support rods at the bottom of the cantilever beam and the cast-in-place beam are used as supporting components to build the bottom formwork, so that during the casting construction of the side span closing section, the cantilever beam and the cast-in-place beam jointly bear the load generated by the construction of the side span closing section, reducing the instability of the support rods, which is beneficial to improving the construction stability of the side span closing section and improving the construction quality of the side span closing section.

[0013] Preferably, when the cantilever beam and the side span cast-in-place beam are connected by the outer guide beam in S1, the counter-pressure beam is first anchored on the upper end surface of the side span cast-in-place beam, and the counter-pressure beam and the outer guide beam are connected by an anchor.

[0014] By adopting the above technical solution, the load generated by the construction of the side span closing section is transferred to the cast-in-place beam of the side span through the counter-pressure beam, and then transferred to the side span pier. The counter-pressure beam provides a connection point for fixing the outer guide beam, which is convenient for fixing the outer guide beam and is beneficial to improving the stability of the outer guide beam.

[0015] Preferably, when casting the side span cast-in-place beam in S1, anchors are pre-embedded on the upper end surface of the side span cast-in-place beam, and the counter-pressure beam is anchored on the upper end surface of the side span cast-in-place beam through the anchors.

[0016] By adopting the above technical scheme, anchors are embedded in advance on the upper end surface of the side span cast-in-place beam when casting the side span cast-in-place beam, so as to provide a connection point for the back-pressure beam on the upper end surface of the side span cast-in-place beam, so as to install and fix the back-pressure beam and improve the stability of the back-pressure beam on the side span cast-in-place beam.

[0017] Preferably, when the side span cast-in-place beam is cast in S1, the side span cast-in-place beam is cantilevered out of the side span pier toward one end of the cantilever beam.

[0018] By adopting the above technical solution, the cast-in-place beam of the side span can be brought closer to the cantilever beam, which can reduce the length of the cantilever beam and the bending moment of the cantilever beam, thereby improving the stability of the construction of the side span closing section.

[0019] Preferably, when the S1 side span cast-in-place beam is pre-embedded with an anchor, the anchor is anchored at one end of the side span cast-in-place beam away from the side span cantilever beam, and the anchor is located above the side span pier.

[0020] By adopting the above technical solution, the load generated by the construction of the side span closing section is transmitted to the rear end of the side span cast-in-place beam through the outer guide beam, and acts vertically on the side span pier through the side span cast-in-place beam, which is beneficial to the stability of the construction of the side span closing end.

[0021] Preferably, when the cantilever beam is cast in S1, load-bearing hangers are anchored at the flange plates on both sides of the cantilever beam, and the load-bearing hangers are used to fix the outer guide beam.

[0022] By adopting the above technical scheme, the outer guide beam is fixed under the flange plate of the cantilever beam by means of a load-bearing hanger, instead of being directly fixed on the side wall of the cantilever beam. While fixing the outer guide beam, a gap can be created between the outer guide beam and the side wall of the cantilever beam so that the hanging basket formwork and the outer side formwork of the side span cast-in-place beam can be moved between the outer guide beam and the side wall of the cantilever beam, providing sufficient space for the outer side formwork to be adjusted so that the outer side formwork can fit the concrete on the side of the cantilever beam, which is beneficial to improving the construction quality of the closed section of the side span.

[0023] Preferably, in the S1 cantilever beam casting step, the hanging basket is slidably connected to the outer guide beam, and the outer guide beam is used as a sliding guide rail for the hanging basket; when the S1 outer guide beam is used to install and connect the cantilever beam and the side span cast-in-place beam, the fixed relationship between the load-bearing hanger and the outer guide beam is first released, and then the outer guide beam is moved toward the side span cast-in-place beam, one end of the outer guide beam is anchored to the side span cast-in-place beam, and the other end of the outer guide beam is fixed to the load-bearing hanger, and the outer guide beam is used as a common sliding guide rail for the hanging basket and the outer side formwork of the cast-in-place beam.

[0024] By adopting the above technical solution, the outer guide beam is moved and a group of outer guide beams are used to complete the construction of the cantilever beam and the side span closing section, thereby improving the utilization rate of the outer guide beam and facilitating the splicing of the outer formwork of the side span cast-in-place beam and the hanging basket formwork.

[0025] Preferably, before the outer formwork of the side span cast-in-place beam is laterally moved to the construction position of the side span closing section in S2, the slings on the outer side of the hanging basket are first removed to eliminate obstacles in the moving path of the outer formwork.

[0026] By adopting the above technical solution, obstacles in the moving path of the outer formwork can be eliminated, making it easier to move the outer formwork to the construction position of the side span closure section.

[0027] In summary, the present application includes at least one of the following beneficial technical effects:

[0028] 1. The cantilever beam and the side span cast-in-place beam are connected by the outer guide beam. At the same time, the outer formwork of the hanging basket and the side span cast-in-place beam uses the outer guide beam as a slide rail, and the outer formwork of the side span cast-in-place beam is slid to the construction position of the side span closing section. The outer formwork is spliced ​​with the concrete on both sides of the cantilever beam. At the same time, the cantilever beam and the original support rods at the bottom of the cast-in-place beam are used as supporting components to build the bottom formwork. In this way, during the pouring construction of the side span closing section, the cantilever beam and the cast-in-place beam jointly bear the load generated by the construction of the side span closing section, reducing the instability of the support rods, which is conducive to improving the construction stability of the side span closing section and improving the construction quality of the side span closing section;

[0029] 2. By anchoring the counter-pressure beam on the upper end face of the cast-in-place beam of the side span, the counter-pressure beam transfers the load generated by the construction of the side span closure section to the cast-in-place beam of the side span, and then transfers it to the side span pier. The counter-pressure beam provides a connection point for fixing the outer guide beam, which is convenient for fixing the outer guide beam and is beneficial to improving the stability of the outer guide beam. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of the state of casting the last section of the cantilever beam and the cast-in-place beam of the side span in a construction method of a continuous beam side span closing section using a combined formwork in an embodiment of the present application.

[0031] Figure 2 It is a schematic diagram of the state when the outer guide beam is connected to the cantilever beam and the side span cast-in-place beam in a construction method of a continuous beam side span closing section using a combined formwork in an embodiment of the present application.

[0032] Figure 3 It is a schematic diagram of the state when the outer side formwork is moved to the construction position of the side span closing section in a construction method of a continuous beam side span closing section using a combined formwork in an embodiment of the present application.

[0033] Figure 4 It is a schematic diagram of the state of casting construction of the side span closing section after the remaining support rods except the bottom of the cantilever beam are removed from the hanging basket in a construction method of the side span closing section of a continuous beam using a combined formwork in an embodiment of the present application.

[0034] Explanation of the reference numerals in the accompanying drawings: 1. Cantilever beam; 2. Side span cast-in-place beam; 21. Anchor; 3. Side span pier; 4. Hanging basket; 5. Construction position of the side span closing section; 6. Outer guide beam; 7. Outer formwork; 8. Load-bearing hanger; 9. Support rod; 10. Counter-pressure beam. DETAILED DESCRIPTION

[0035] The following is combined with Figure 1-4 This application is described in further detail.

[0036] The present application embodiment discloses a construction method of a continuous beam side span closing section using a combined formwork, comprising the following steps:

[0037] S1: Reference Figure 1 and Figure 2 , respectively completing the construction of the cantilever beam 1 and the side span cast-in-place beam 2. The cantilever beam 1 of the present application adopts a box beam with a uniform cross section, and a hanging basket 4 is used for the casting construction of the cantilever beam 1. The hanging basket 4 is a load-bearing frame that can slide or roll along the top of the beam, and is anchored and suspended on the constructed cantilever beam 1. The formwork, steel bars, and prestressed pipes of the next beam section can be installed on the hanging basket 4, and concrete pouring, prestressing, grouting and other operations can be carried out. After completing the cycle of one segment, the hanging basket 4 moves forward and is fixed to carry out the hanging pouring of the next segment of the cantilever beam 1, and the cycle is repeated until the cantilever pouring is completed.

[0038] In order to improve the movement stability of the hanging basket 4, the load-bearing hanger 8 is anchored at the flange plates on both sides of the cantilever beam 1. The load-bearing hanger 8 is used to fix the outer guide beam 6. The hanging basket 4 is slidably connected to the inner side of the outer guide beam 6. The outer guide beam 6 extends along the construction direction of the cantilever beam 1. After the construction of each section of the cantilever beam 1 is completed, the fixation of the outer guide beam 6 is released and the outer guide beam 6 is moved forward to the construction position of the next section of the cantilever beam 1. The outer guide beam 6 moves into place before the hanging basket 4. The outer guide beam 6 is used as a sliding guide rail for the hanging basket 4, so that the hanging basket 4 can stably move to the construction position of the next section of the cantilever beam 1.

[0039] When the cantilever beam 1 is cast, the side span cast-in-place beam 2 on the side span pier 3 is also constructed at the same time, and the side span cast-in-place beam 2 is constructed by using an external energy support rod 9 to support the formwork. The support rod 9 at the bottom of the side span cast-in-place beam 2 is cantilevered out of the side span pier 3 in the direction of the cantilever beam 1, so that the cast-in-place side span beam 2 is also cantilevered out of the side span pier 3 at one end facing the cantilever beam 1.

[0040] When casting the side span cast-in-place beam 2, an anchor 21 is pre-embedded in advance on the upper end surface of the side span cast-in-place beam 2. The anchor 21 is made of finely rolled threaded steel and is used to anchor the counter-pressure beam 10. By pre-embedding the anchor 21 at one end of the side span cast-in-place beam 2 away from the side span cantilever beam, and the anchor 21 is located above the side span pier 3, the counter-pressure beam 10 is anchored at the rear end of the side span cast-in-place beam 2.

[0041] Before the construction of the side span closing section is carried out, the outer guide beam 6 is first installed and connected between the cantilever beam 1 and the side span cast-in-place beam 2. Specifically, the fixed relationship between the load-bearing hanger 8 and the outer guide beam 6 is first released, and then the outer guide beam 6 is moved toward the side span cast-in-place beam 2, and one end of the outer guide beam 6 is anchored to the back pressure beam 10 on the upper end surface of the side span cast-in-place beam 2 with the anchor 21. The anchor 21 is made of fine-rolled threaded steel. Then the other end of the outer guide beam 6 is fixed to the load-bearing hanger 8, and at the same time, the outer formwork 7 of the side span beam is slidably connected to the inner side of the outer guide beam 6. At this time, the outer guide beam 6 is used as a common sliding guide rail for the hanging basket 4 and the outer formwork 7 of the cast-in-place beam, which is convenient for the subsequent movement of the outer formwork 7 to the side span closing construction position.

[0042] S2: Reference Figure 3 and Figure 4 When preparing for the construction of the side span closing section, first remove the slings on the outside of the hanging basket 2 to remove obstacles in the moving path of the outer template 7. Then, using the guiding function of the outer guide beam 6, move the outer template 7 of the side span cast-in-place beam 2 horizontally to the construction position 5 of the side span closing section, and then adjust the outer template 7 so that the outer template 7 fits the concrete side wall of the end of the cantilever beam 1, and combine the outer template 7 with the hanging basket 4 template of the cantilever beam 1 to form a combined template for the casting construction of the side span closing section.

[0043] S3: retain the cantilever beam 1 and the original support rod 9 at the bottom of the cast-in-place beam as the support point for the casting construction of the side span closing section, lay the bottom formwork on the cantilever beam 1 and the original support rod 9 at the bottom of the cast-in-place beam, and the bottom formwork and the outer formwork 7 are assembled to form the casting cavity of the side span closing section.

[0044] S4: When constructing the side span closing section, steel bars are tied in the casting cavity of the side span closing section, and then concrete is poured in the casting cavity of the side span closing section. During the pouring of concrete, it is necessary to counterweight the upper end surfaces of both ends of the cantilever beam 1 to maintain the stability of the side span closing section during the pouring construction. Finally, the side span closing section is formed between the side span cast-in-place beam 2 and the cantilever beam 1. After the pouring is completed, the redundant support rods 9 and the template are removed.

[0045] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A construction method using a combined formwork for the closing section of a continuous beam side span, characterized in that: The following steps are involved: S1: The cantilever beam (1) and the side span cast-in-place beam (2) are constructed respectively, and the cantilever beam (1) and the side span cast-in-place beam (2) are installed and connected by an outer guide beam (6), and the hanging basket (4) of the cantilever beam (1) and the outer side formwork (7) of the side span cast-in-place beam (2) are both slidably connected to the outer guide beam (6); S2: The outer formwork (7) of the side span cast-in-place beam (2) is moved horizontally to the construction position (5) of the side span closing section, and the outer formwork (7) is adjusted so that the outer formwork (7) is in contact with the concrete side wall of the end of the cantilever beam (1); S3: retain the cantilever beam (1) and the original support rod (9) at the bottom of the cast-in-place beam as the support point for the casting construction of the side span closing section, lay the bottom formwork on the cantilever beam (1) and the original support rod (9) at the bottom of the cast-in-place beam, and splice the bottom formwork and the outer formwork (7) to form the casting cavity of the side span closing section; S4: pouring concrete in the pouring cavity of the side span closing section, so that the side span closing section is formed between the side span cast-in-place beam (2) and the cantilever beam (1); When the cantilever beam (1) and the side span cast-in-place beam (2) are connected by the outer guide beam (6) in S1, the back pressure beam (10) is first anchored on the upper end surface of the side span cast-in-place beam (2), and the back pressure beam (10) and the outer guide beam (6) are connected by an anchor (21); When the side span cast-in-place beam (2) is cast in step S1, an anchor (21) is pre-buried on the upper end surface of the side span cast-in-place beam (2), and the counter-pressure beam (10) is anchored on the upper end surface of the side span cast-in-place beam (2) through the anchor (21); When the side span cast-in-place beam (2) is cast in S1, the side span cast-in-place beam (2) is cantilevered out of the side span pier (3) toward one end of the cantilever beam (1).

2. The construction method of a continuous beam side span closing section using a combined formwork according to claim 1, characterized in that: When the S1 side span cast-in-place beam (2) is pre-buried with an anchor (21), the anchor (21) is anchored at one end of the side span cast-in-place beam (2) away from the side span cantilever beam, and the anchor (21) is located above the side span pier (3).

3. The construction method of a continuous beam side span closing section using a combined formwork according to claim 1, characterized in that: When the cantilever beam (1) is cast in S1, load-bearing hangers (8) are anchored at the flange plates on both sides of the cantilever beam (1), and the load-bearing hangers (8) are used to fix the outer guide beam (6).

4. The construction method of the continuous beam side span closure section using a combined formwork according to claim 3, characterized in that: In the step of casting the S1 cantilever beam (1), the hanging basket (4) is slidably connected to the outer guide beam (6), and the outer guide beam (6) is used as a sliding guide rail for the hanging basket (4); when the S1 outer guide beam (6) is used to install and connect the cantilever beam (1) and the side span cast-in-place beam (2), the fixed relationship between the load-bearing hanger (8) and the outer guide beam (6) is first released, and then the outer guide beam (6) is moved toward the side span cast-in-place beam (2), one end of the outer guide beam (6) is anchored to the side span cast-in-place beam (2), and the other end of the outer guide beam (6) is fixed to the load-bearing hanger (8), and the outer guide beam (6) is used as a common sliding guide rail for the hanging basket (4) and the outer side template (7) of the cast-in-place beam.

5. The construction method of the continuous beam side span closure section using a combined formwork according to claim 1, characterized in that: Before the outer formwork (7) of the side span cast-in-place beam (2) is laterally moved to the side span closing section construction position (5) in step S2, the slings on the outer side of the hanging basket (4) are first removed to eliminate obstacles in the moving path of the outer formwork (7).

Images