Analysis Of The Influence Factors Of Long-term Rigidity Of Beam By External Prestressing

The technology of external prestressing reinforcement has the advantages of lightweight and high strength?explicit force?the light self weight?convenient operation and so on,Widely used in building structure reinforcement.Therefore, the research on the application of external prestressing reinforcement technology is more and more.But most of the studies only consider the effects of short-term effects,the research on the effect of the long-term effect of the strengthening beam is not much.So, it is necessary to have a comprehensive analysis of the effects of long-term effects of external prestressing beam,to provide theoretical support for external prestressing reinforcement technology.This paper focus on the research for the factors affecting the long-term stiffness of external prestressing beam,the influence of factors of constraint of the old beam?the number of steering block?the type of prestressing tendon, and the magnitude of pre-stress putting on the long-term stiffness of the strengthened beam are considered,at the same time,with the analysis of the difference of inertia moment and the contribution rate of the prestressing tendon, the formula for calculating the long-term stiffness of the strengthened beam is given;Based on the assumptions,force-summing analysis is done on the strengthened beams under long-term load,the calculation formula for the long-term deflection of the strengthened beams is derived;the engineering as an example to verify;Combination of finite element method to conduct finite element analysis about the influencing factors.Through the finite element analysis of 7 reinforcement beam model, the effects of the above factors are considered, and the following conclusions are obtained:The constraint conditions of the original beam have a great influence on the long-term rigidity,the better reinforcement can achieve by strengthening support restraint; Like the type of prestressing tendon?the number of steering block?the magnitude of pre-stress putting etc,They effect of the long term rigidity of the beam is different.The layout form of prestressed tendons is the most prominent,The placement of the steering block and the number have a great influence on the long-term deformation of the reinforced beam.Combing with practice, the influence of external prestressed reinforcement on the long-term stiffness of beams is obtained by using theoretical knowledge and finite element analysis,in order to provide reference for the future research, and to provide the theoretical basis for the practical application of engineering.