Prestressed concrete variable-section box girder bridge with internal slant leg rigid frame, and construction method thereof

Abstract

The invention discloses a prestressed concrete variable-section box girder bridge with an internal slant leg rigid frame. The prestressed concrete variable-section box girder bridge with the internal slant leg rigid frame comprises a bottom slab box with box bottom slabs, box top slabs and box webs, top slabs and a pier. Middle webs and transverse partitions are disposed in a box girder. Upper bent anchor plates are arranged longitudinally along the box girder from the midspan to the pier. The slant leg rigid frame structure comprising internal longitudinal beams, internal upper slant legs and internal lower slant legs is disposed above the base slab box. The internal longitudinal beams are upwardly inclined or bent longitudinally along the box girder from the midspan to the pier. The internal longitudinal beams, the box bottom slabs and the upwardly bent anchor plates are all provided with upwardly bent bottom slab ropes. The invention further provides a construction method of the prestressed concrete variable-section box girder bridge with the internal slant leg rigid frame. The bridge and the construction method thereof have the advantages that layout of the bottom slab ropes is more reasonable, the upwardly bent bottom slab ropes provide upward radial force, and downward force generated by secondary dead load and partial vehicle load can be eliminated or reduced.

Description

technical field [0001] The invention relates to the technical field of civil engineering bridges, in particular to a prestressed concrete variable-section box girder bridge with built-in oblique-leg rigid frame and a construction method thereof. Background technique [0002] With the increasing improvement of bridge design technology, various bridges have emerged. Among them, long-span prestressed concrete variable cross-section box girder bridges are currently widely used bridge types, and continuous beams and continuous rigid frame bridges are the most common. Basket cantilever casting method construction. [0003] figure 1 It is a facade layout diagram of a long-span prestressed concrete variable-section box girder bridge in the prior art. The girder bridge shown in the figure is a continuous rigid frame bridge. Beam floor 01, the lower edge of the main beam is flat and arched, and the bridge is constructed by segmented hanging basket cantilever cast-in-place technology...

AI Technical Summary

Problems solved by technology

[0010] (3) In the existing technology, when the width of the long-span bridge box is greater than 8 to 10 meters, the L / 4 section to the pier fulcrum section, the pressure on the lower edge is relatively large, and the vertical stability of the bottom plate is prominent

Improve its vertical stability by thickening the bottom plate, which is ineffective and uneconomical

[0011] (4) It cannot provide upward component force, and cannot balance the second-stage dead load and the downward force of the lane load

[0012] (5) There is no control method to eliminate or reduce the deflection deformation of the main girder caused by the second-stage dead load, and the deformation of the main span is not easy to control after the main span is closed

[0013] (6) On bridges with two-way longitudinal slopes in the main span, the downward radial force of floor cable 05, the first-phase and second-phase dead loads, and the driveway loads are all downward, aggravating the shrinkage and creep effect of concrete, resulting in certain continuous downward

[0014] (7) The built-in slanted leg 042 and the box girder bottom plate 01 are arranged in parallel, the radial distance between the built-in slanted leg 042 and the bottom plate 01 is 1 / 4 to 1 / 5 of the total girder height H of the fulcrum, and the built-in longitudinal beam 041 and built-in The distance between the oblique legs 042 is too large, exceeding 5 to 6 meters, and the stability of the abdomen 02 and the torsion resistance of the box girder are not good

[0020] (10) The rigidity of the roof is relatively small, and the unbalanced force during construction and the radial force of the prestressed beam of the roof lead to longitudinal cracking of the roof

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