Simply-supported box girder bridge strengthening method with oblique cables

Abstract

The invention discloses a simply-supported box girder bridge strengthening method with oblique cables. In an implementation process, a prestressing simply-supported beam bridge, a simply-support box girder pile foundation, a steel concrete column, an integrated bent cap, a strengthen girder, a transverse prestressing pipe, a transverse prestressing steel strand, suspension steel wires, a prestressing hollow plate girder, a sidespan bent cap, a horizontal prestressing pulling rod, an original expansion joint and an inclined strut. With the strengthening method, a upward component force is generated near the 1 / 3 span by the prestressing simply-supported beam bridge to offset part of bend moment and shearing force which are generated by constant loads to achieve strengthening or improving bearing capacity of the whole prestressing simply-supported box girder; and the suspension steel wires are anchored on an anchoring device of the strengthen girder and the sidespan bent cap of the prestressing simply-supported box girder. Anti-bending and anti-shearing capacity of the simply-supported box girder bridge is improved, the strengthening method has deloading functions on the shearing force, mid-span moment and the like of a lower constant load pivot, and flatness and comfortableness of bridge deck lines are improved.

Description

technical field [0001] The invention belongs to the technical field of bridge engineering, and in particular relates to a method for reinforcing simply supported box girder bridges with inclined cables. Background technique [0002] Prestressed concrete box girder bridges are widely used in bridge engineering because of their high torsional and flexural rigidity. In the prestressed concrete box girder bridges built in the early stage, in order to avoid large hoisting weight, facilitate construction, increase spanning capacity, and save cost, especially on rivers such as canals with relatively developed river systems in Jiangsu and Zhejiang, the mid-span needs to pass 300 to 500 meters. Tons of ships, but usually only box girders with a span of about 50m are repaired in the middle span, while the side spans are spanned with economical spans, such as simply supported prestressed concrete hollow slab girder bridges with spans of 16m and 20m. However, with the development of th...

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Problems solved by technology

However, with the development of the economy, the traffic volume and traffic load continue to increase. Compared with the current road load level standard, the original load level of the bridge is about 20-40% lower. How to make full use of it from the perspective of sustainable development and Improving the load rating or bearing capacity of these bridges has become a key technical issue for bridge engineers to solve. Secondly, the web thickness of these simply supported box girder bridges was designed to be thin at that time, resulting in bridges near 1 / 4 span under overload and other effects. The web is prone to oblique cracks, which will reduce the overall mechanical performance of the bridge. In severe cases, it will cause rainwater leakage, corrosion of steel bars, and reduction of structural durability, which will eventually endanger the bearing capacity of the bridge.

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