CN103866698A - Symmetrical suspension splicing bridge support seat end pseudo-suspension splicing construction method - Google Patents

Abstract

The invention provides a symmetrical suspension splicing bridge support seat end pseudo-suspension splicing construction method. The method aims at a convex support seat end construction pseudo-suspension splicing structure. Two support seat section end beams are subjected to opposite pulling and prestress by temporary prestress beams and temporary prestress rebars, so the certain number of section beams arranged at two sides and corresponding to respective suspension splicing structures are born. As the temporary prestress structures are adopted to transmit the internal forces such as bending moment and pressure in the cantilever splicing to a cover beam, the possibility of the support seat end cantilever construction is realized; after the pseudo-suspension splicing structure is constructed, common suspension beams can be sequentially spliced according to the cantilever splicing method, the effect of a support method is reduced without the support turnover time and the influence on the lower transportation is reduced.

Description

Construction Method of False Cantilever at the Bearing End of Symmetrical Suspended Bridge

technical field

The invention relates to the technical field of bridge construction, in particular to a pseudo-cantilever construction method at the bearing end of a symmetrical cantilevered bridge.

Background technique

Bridge segment prefabrication construction has the advantages of less site occupation, fast construction speed, high precision, easy quality control, and reduced on-site adjustment time. Especially in crowded urban areas, its component and factory characteristics are best reflected. Segmental beams can be assembled in the way of whole hole assembly and symmetrical cantilever assembly. Among them, symmetrical cantilever assembly is a better method of segmental assembly due to the small number of segments lifted each time and the bridge erecting machine is relatively simple. kind.

For multi-connected bridges, the support cannot bear force before the bridge is completed, especially for the convex support end (as shown in Figure 1), there is no consolidation condition at the support end when performing symmetrical suspension, and the support method is generally used First assemble the half-span bridge. However, this method occupies a large area, has a great impact on the lower traffic, and has a high risk of high altitude and time-consuming construction. For this reason, the present invention adopts a kind of false overhang construction method for this convex support.

Contents of the invention

The invention provides a pseudo-cantilever construction method at the support end of a symmetrical cantilever bridge, which constructs a false cantilever structure for the convex support end, so that the general segmental beams can be assembled sequentially according to the cantilever assembly method, reducing the need for support methods. impact, and no support turnaround time, reducing the impact of construction on lower traffic.

A false cantilever construction method for a symmetrical cantilevered bridge bearing end, comprising the following steps:

Step 1. Hoist the two support segment beams to the cover beam with convex support end, install the cover beam with convex support end on the pier column, and install the cover beam and support segment with convex support end Temporary supports are installed between beams;

Step 2. Install the top gasket and the bottom gasket between the support segment beam and the upper and lower sides of the cover beam with convex support end respectively;

Step 3. Install temporary prestressed beams on the top of the cover beam with convex support end and the segmental beam of the support, install temporary prestressed steel bars at the bottom, and carry out tensioning, and connect the segmental beam of the support and the segmental beam with convex support The cover beams at the end are consolidated together, and a false cantilever is formed by temporary prestressed beams, temporary prestressed steel bars, top gaskets and bottom gaskets;

Step 4, the ordinary segmental beam is constructed on the false cantilever according to the general cantilever assembly method, and the first ordinary segmental beam is fixed by tensioning the permanent prestressed beam of the segmental beam roof;

Step 5, after removing the temporary prestressed steel bars of the base plate, install and tension the segmental beam roof bundles in turn for other common segmental beams (4);

Step 6. After all the cantilever segments are erected and closed, the temporary prestressed beams on the roof of the segmental beams are cut off one by one;

Step 7. Remove the top gasket, bottom gasket and temporary support, install the permanent support, and complete the system conversion.

In the pseudo-cantilever construction method at the support end of the symmetrical cantilevered bridge as described above, the removal of the temporary prestressed reinforcement of the bottom plate is carried out after the false cantilever is formed in step 3 or after the first ordinary segmental beam is assembled.

In the pseudo-cantilever construction method at the support end of the symmetrical cantilevered bridge as described above, the top gasket and the bottom gasket are (300-500mm)*(800-1300mm) concrete blocks.

In the pseudo-cantilever construction method at the support end of the symmetrical cantilevered bridge mentioned above, the temporary prestressed reinforcement adopts Φ32mm and above steel bars, at least one on each side.

The present invention pulls and applies prestress to two support segmental beams through the temporary prestressing bundle and the temporary prestressing steel bar, so as to bear the number of segmental beams on both sides respectively and corresponding to the symmetrical cantilever. Due to the adoption of the temporary prestressed structure to transmit the internal forces such as the bending moment and pressure of the cantilever assembly to the cover beam, the possibility of cantilever construction at the support end is realized; after the false cantilever structure is constructed, the general segmental beam can be assembled according to the cantilever method Sequential assembly reduces the impact of the bracket method, and there is no bracket turnaround time, which reduces the impact on the lower traffic.

Description of drawings

Fig. 1 is a schematic structural view of a bridge with a convex bearing end;

Fig. 2 is a schematic diagram of construction step 1 of the pseudo-cantilever construction method at the bearing end of a symmetrical cantilevered bridge of the present invention;

Fig. 3 is a schematic diagram of construction step 2 of the pseudo-cantilever construction method at the bearing end of a symmetrical cantilevered bridge of the present invention;

Fig. 4 is a schematic diagram of construction step 3 of the pseudo-cantilever construction method at the bearing end of a symmetrical cantilevered bridge of the present invention;

Fig. 5 is a schematic diagram of construction step 4 of the pseudo-cantilever construction method at the bearing end of a symmetrical cantilevered bridge of the present invention;

Fig. 6 is a sectional view of the false cantilever constructed in the construction method of the present invention.

In the figure: 1—pier column, 2—cap beam with convex support end, 3—support segmental beam, 4—ordinary segmental beam, 5—temporary support, 6—top gasket, 7—bottom pad Sheet, 8—temporary prestressed beam, 9—temporary prestressed reinforcement.

Detailed ways

The technical solutions in the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the present invention.

Please refer to Fig. 2-5, the pseudo-cantilever construction method of the bearing end of the symmetrical cantilevered bridge of the present invention includes the following steps:

Step 1. Use a crane, bridge erecting machine or other equipment to hoist the two support segment beams 3 onto the cover beam 2 with a convex support end, and the cover beam 2 with a convex support end is installed on the pier column 1 superior. A temporary support 5 is installed between the cover beam 2 with a convex support end and the support segment beam 3 to bear the vertical force and adjust the position of the support segment beam 3 and the ordinary segment beam 4 (as shown in Figure 2 shown).

Step 2: Install the top gasket 6 and the bottom gasket 7 (as shown in Figure 3) between the support segment beam 3 and the upper and lower sides of the cover beam 2 with convex support ends, respectively, to transmit the bending moment And adjust the alignment of the support segmental beam 3 and the ordinary segmental beam 4 .

Step 3: Install temporary prestressed beams 8 on the top of the cover beam 2 with the convex support end and the support segment beam 3, install temporary prestressed steel bars 9 at the bottom, and stretch them, and connect the support segment beam 3 and the support segment beam 3 The cover beam 2 with convex support end is consolidated together, and a false cantilever is formed by temporary prestressed beam 8, temporary prestressed steel bar 9, top spacer 6 and bottom spacer 7, so that all section forces are transmitted through the false cantilever (As shown in Figure 4).

Temporary prestressed beams 8 can be adjusted according to the weight of the cantilever section, generally there are at least 7 holes on one side, and each hole has at least 5 beams.

Temporary prestressed steel bars 9 provide sufficient preload to ensure that there is no tension in the lower part. Generally, at least Φ32mm and above steel bars are used, with at least one on each side.

The size of the top spacer 6 and the bottom spacer 7 can be adjusted according to the stress results. Generally, it can be made into a concrete block of (300-500mm)*(800-1300mm). The strength of the concrete should be higher than the strength of the beam body. When When the force increases, the bearing capacity can be enhanced by reinforcing the reinforcement.

Step 4: The ordinary segmental beam 4 is constructed on the false cantilever according to the general cantilever assembly method, and the first ordinary segmental beam 4 (that is, the cantilever segment) is fixed by the temporary prestressed beam 8, as shown in Figure 5 Show. The length of the ordinary segmental beam 4 is 2-3.5m, and generally there are 4-7 ordinary segmental beams 4 .

Step 5. After the false cantilever is formed in step 3 or after the assembly of the first common segmental beam 4, remove the temporary prestressed steel bar 9 of the bottom plate, install and stretch the segmental beam roof bundles in turn for other common segmental beams 4, as long as the resistance The self-weight of the bridge segment is sufficient.

Step 6: After all the cantilever sections are erected and closed, the temporary prestressed beams 8 on the top plate of the section beams are cut off one by one. At this time, the false cantilever fails, and the load is transmitted through the support section beams 3 .

Step 7. Remove the top gasket 6, the bottom gasket 7 and the temporary support 5, and install the permanent support to complete the system conversion.

The above is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto, any changes or substitutions that can be easily imagined by those skilled in the art within the technical scope disclosed in the present invention, All should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be determined by the protection scope of the claims.

Claims (4)

1. the false cantilever construction method of symmetrical cantilever bridge pad end, is characterized in that comprising the steps:

Step 1, two bearing beam sections (3) are lifted to the bent cap with convex bearing end (2), it is upper that bent cap (2) with convex bearing end is arranged on pier stud (1), between the bent cap (2) with convex bearing end and bearing beam sections (3), temporary support (5) is installed;

Step 2, at bearing beam sections (3) and the bent cap with convex bearing end (2) embodiment in which top gasket (6) and bottom gasket (7) be installed respectively between two sides up and down;

Step 3, at the top of the bent cap with convex bearing end (2) and bearing beam sections (3), interim prestressing tendon (8) is installed, interim prestressed reinforcement (9) is installed in bottom, and carry out stretch-draw, bearing beam sections (3) and the bent cap with convex bearing end (2) are consolidated, form false cantilever by interim prestressing tendon (8), interim prestressed reinforcement (9), embodiment in which top gasket (6) and bottom gasket (7);

Step 4, common beam sections (4), according to general cantilever assembling method, are constructed on described false cantilever, fix the common beam sections of first (4) by the permanent prestressing tendon of stretch-draw beam sections top board;

After the interim prestressed reinforcement (9) of step 5, dismounting base plate, other common beam sections (4) are installed and stretch-draw beam sections top board bundle successively;

Step 6, boom segments all set up after complete and closure, and the interim prestressing tendon (8) of beam sections top board cuts off one by one;

Step 7, remove embodiment in which top gasket (6), bottom gasket (7) and temporary support (5), permanent bearing is installed, complete system conversion.

2. the false cantilever construction method of symmetrical cantilever bridge pad end as claimed in claim 1, is characterized in that: the interim prestressed reinforcement (9) of described base plate is removed after step 3 forms false cantilever or the common beam sections of first (4) is carried out after assembled.

3. the false cantilever construction method of symmetrical cantilever bridge pad end as claimed in claim 1, is characterized in that: embodiment in which top gasket (6) and bottom gasket (7) are the concrete block of (300-500mm) * (800-1300mm).

4. the false cantilever construction method of symmetrical cantilever bridge pad end as claimed in claim 1, is characterized in that: interim prestressed reinforcement (9) adopts Φ 32mm and above reinforcing bar, at least one of every side.

Images