Design method of unbonded prestress and steel plate-concrete composite reinforcement of T-beam

Abstract

The invention discloses an unbounded prestress and steel plate-concrete combined reinforcing design method of a T-type beam. The method comprises the steps that first, a combined reinforcing structure is determined, specifically, the unbounded prestress and steel plate-concrete combined reinforcing structure of the reinforced T-type beam is determined and comprises a steel jacket box composed of a bottom steel board, two longitudinal side steel boards and two end portion sealing steel boards, and a plurality of unbounded prestress steel bars are arranged inside the steel jacket box; second, the structure parameters of the T-type beam are determined before reinforcement; and third, the structure parameters of the combined reinforcing structure are determined, specifically, the parameters are initialized, the maximum theory thickness of reinforcing steel boards is calculated, the thickness of the reinforcing steel boards and the thickness of concrete are determined, and the height of the longitudinal side steel boards and the width of the bottom steel board are determined. The method is simple in step, reasonable in design, convenient to implement, good in use effect, and capable of determining the structure parameters of the bridge combined reinforcing structure easily, conveniently and rapidly, and the designed bridge combined reinforcing structure is economical, practical and good in reinforcing effect.

Description

Technical field [0001] The invention belongs to the technical field of bridge reinforcement, and particularly relates to a T-shaped beam unbonded prestress and steel plate-concrete combined reinforcement design method. Background technique [0002] According to a survey in 2007, there are more than 570,000 bridges in my country, of which more than 98,600 are dangerous bridges, accounting for about 17%. There are also a large number of highway bridges each year due to low design grades, increasing traffic volume, or various factors. A variety of diseases and disaster damage have occurred, resulting in a decrease in carrying capacity and unable to meet the needs of transportation. The repair and reinforcement of these bridge structures is imminent. Therefore, bridge repair, reinforcement and reconstruction technology research has become an important direction for the development of bridge technology. At present, the reinforcement of bridge superstructure mainly adopts methods such ...

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Problems solved by technology

Although the above-mentioned external prestressed concrete reinforcement method can play the role of prestressed reinforcement to a certain extent, it has the following disadvantages: First, it is necessary to add a layer of concrete with a thickness of about 20cm to 50cm on the side or bottom of the beam. , the self-weight of the bridge increases greatly, and the appearance is irregular, which affects the appearance; second, the prestressed tendons are exposed in the air, and measures need to be taken regularly to prevent the prestressed tendons from rusting, maintenance is difficult, and the maintenance cost is high; third, the newly added The dynamic performance of prestressed tendons is poor, and shock absorbers need to be installed to reduce the resonance effect of prestressed tendons and structures; The steering block is used to realize the stress concentration at the steering block and the anchor block; once the steering block is loosened or slipped, it will cause a huge loss of prestress or even failure of the prestress; fifth, the contribution to the stiffness of the original structure is very limited

However, when using prestressed reinforcement and steel plate-concrete composite reinforcement methods to strengthen bridges, the structural design of the composite reinforcement structure is very important. Whether the reinforcement structure design is reasonable or not directly affects the reinforcement cost and reinforcement effect of the bridge. Not only the input cost is high, but the economy is poor. And it leads to unreasonable stress and poor mechanical properties of the reinforced bridge

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