A method for improving the mechanical performance of steel-concrete composite multi-box continuous girder bridges in the negative moment zone

Abstract

The invention discloses a method for improving stress performance of a negative bending moment zone ofa steel-concrete combined multi-box continuous beam bridge. The continuous girder bridge built by using the method comprises multiple horizontally connected separate small box beams. The upper portion of each small box beam is a concrete bridge surface plate. The lower portion is a steel box beam. The concrete bridge surface plate and the steel box beam are connected into an integral body by the shear force of the top flange of the steel box beam. Normal stress steel bars and constructional steel bars are arranged in the concrete bridge surface plates of the whole bridge. Normal horizontal and longitudinal stiffening ribs are arranged in the steel box beams. The longitudinal stress steel bars in the concrete bridge surface plates of the negative bending moment zone are intensified in density. After the steel box beams is erected, the surface plates are grouted and the preformed holes are prepared, concrete is grouted in the steel beam base plates of the negative bending moment zone through the holes, the concrete grade is identical to the concrete grade of the bridge surface plates. The method can increase the compression strength of the steel box beam base plate, improve the unfavorable stress condition that the steel box beam base plates in the negative bending moment zone is bent by pressure.

Description

technical field [0001] The invention relates to structural design measures for the negative bending moment area of ​​a steel-concrete composite separated multi-box continuous girder bridge. The method can improve the disadvantages of the tensile cracking of the upper edge concrete slab and the easy buckling of the lower edge steel box girder under compression in the negative bending moment area. In particular, it relates to a method for improving the mechanical performance in the negative bending moment area of ​​a steel-concrete composite multi-box continuous girder bridge. Background technique [0002] As an emerging bridge structure, steel-concrete composite bridges have the characteristics of light weight and high stiffness compared with concrete bridges and steel bridges. Its biggest advantage is that it can fully combine the tensile capacity of steel and the compressive capacity of concrete, so that the overall performance of the combination is better than the performa...

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Problems solved by technology

The existing common method is to add prestressed reinforcement on the bridge deck or increase the thickness of the steel box girder floor and the number of stiffeners, but the construction technology of these methods is relatively complicated, which increases the workload, prolongs the construction period, and is also unfavorable to the project cost It is mainly used in continuous girder bridges with composite structures with spans of 80m and above

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