Prestressed concrete variable-cross-section box girder bridge with internal tilted-leg rigid frame and construction method of prestressed concrete variable-cross-section box girder bridge

Abstract

The invention discloses a prestressed concrete variable-cross-section box girder bridge with an internal tilted-leg rigid frame. The prestressed concrete variable-cross-section box girder bridge with the internal tilted-leg rigid frame comprises a bottom plate and web plates which form a box girder, a tilted-leg rigid frame structure is arranged in a variable-cross-section box girder bridge box and comprises an internal longitudinal beam and an internal tilted leg, the internal longitudinal beam tilts upwards or is bent along the longitudinal direction of the box girder from the midspan to a pier direction, the internal longitudinal beam and the bottom plate are integrated in a segment from the midspan to the 3L / 8 section, the rest portions are separated from one another, a midspan positive-bending-moment bottom plate cable is bent along the internal longitudinal beam, jagged blocks are arranged at bottom plate cable tensioning and anchoring positions of the internal longitudinal beam, the bottom plate cable tensioning and anchoring ends are bent in the box from the jagged block positions, and the bottom plate cable is symmetrically tensioned and anchored on the jagged blocks by the two tensioning and anchoring ends. Down-warping deformation of a girder caused by second-phase dead load is eliminated or reduced by the aid of upward radial force of the bottom plate cable, and the box girder is reasonable in structural bearing. The invention further provides a construction method of the prestressed concrete variable-cross-section box girder bridge with the internal tilted-leg rigid frame.

Description

technical field [0001] The invention relates to the technical field of civil engineering bridges, more specifically, to a prestressed concrete variable-section box girder bridge with built-in oblique-leg rigid frame and a construction method thereof. Background technique [0002] Long-span prestressed concrete variable-section box-girder bridges are widely used bridge types at present, and continuous beams and continuous rigid-frame bridges are the most common, and they are often constructed by hanging basket cantilever casting method. figure 1 It is a facade layout diagram of a long-span prestressed concrete variable cross-section box girder bridge in the prior art. It is a continuous rigid frame bridge. The façade of the lower edge of the main girder is in the shape of a flat arch, and the bridge is constructed using the segmented hanging basket cantilever cast-in-place process. It includes the mid-span closing section 08, the side-span closing section 09, the pier top se...

AI Technical Summary

Problems solved by technology

[0009] (3) It cannot provide an upward component force, and cannot balance the second-phase dead load and the downward force of the lane load

[0010] (4) No control method is provided to eliminate or reduce the deflection deformation of the main girder caused by the second-stage dead load, and the deformation is not easy to control after the main span is closed

[0011] (5) On a bridge with a two-way longitudinal slope in the main span, the downward radial force of the floor cable 05, the first-phase and second-phase dead load, and the driveway load are all downward, which intensifies the concrete shrinkage and creep effect, resulting in certain continuous downward

[0012] (6) The built-in slanted leg 042 and the box girder floor 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 beam height H of the fulcrum, and the built-in longitudinal beam 041 and built-in The distance between the inclined legs 042 is too large, exceeding 5 to 6 meters, and the stability of the web 02 and the torsional capacity of the box girder are not good

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