The Optimizational Design Of The External Prestressed Technique In Continuous Beam Bridge Reinforcement

As time goes by and economy develops, more and more bridges cannot meet the increasing demand of traffic, in consideration of the social benefit and the economic benefits, bridge reinforcement has already been a hot issue in engineering, and, the technology of external pre-stressing will be an efficient and important method for bridge reinforcing, therefore, making a research of external pre-stressing has a prodigious actual meaning.This article conducts the deep research to vitro pre-stressed reinforcement law. This article in analytical study domestic and foreign experimental study material, design standard as well as in related literature foundation, has a system research in optimizational designing of external pre-stressing, and, go a step further, putting the research finding apply to broad bridge, meanwhile, programming because of this principle; do a research about the drift between the external pre-stressing cables with the turning block and draw up a procedure which can computing the cables’stress with the affect of the drift; make a study about the extreme stress of the external pre-stressing cables. Has the following research work specifically:(1) elaborated the domestic and foreign bridge present situation, has expounded carries on the bridge reinforcement aspect research work’ necessity and the pressing.(2) this article made the careful analysis to the bridge reinforcement mechanism, introduced the method for computing the loss of pre-stresses, did a research about force analysis at the turning block.(3) performed mathematical calculations how to optimizational design the external pre-stressing, and, go a step further, put the research finding apply to broad bridge, meanwhile, programming because of this mechanism.(4) did a research about the drift between the external pr-estressing cables with the turning block and drew up a procedure which can computing the cables’stress with the affect of drift.(5) made a study about the extreme stress of the external pre-stressing cables, introduced the computing method now used, analysed the influence to the extreme stress making use of large-scale finite element software-MIDAS when the beam with different quantity of pulling steel, different quantity of pressing steel, different quantity of pre-stressing steel, different effective height and different pressing methods.(6) used the method that this article introduced to carry on the calculation for in vitro pre-stressed reinforcement bridge. According from the result of checked calculation, reinforce computational method of vitro pre-stressed recommended by this article is more ideal reflect that the beam’s stress situation after has used in vitro pre-stressed reinforcement.