Research On The Reinforcement Scheme Of Sai Qi Bridge

With the rapid development of China’s economic construction and the continuous efforts of project builders,the domestic transportation infrastructure has developed rapidly and many highway bridges have been built.However,some of the bridges were built earlier because of the earlier construction load grades,resulting in insufficient bearing capacity,insufficient bridge width,and aging of concrete.It would be neither scientific nor economical if it was completely rebuilt and rebuilt.The reinforcement and reconstruction of the old bridge can solve this problem just right,and it can also save construction funds and control the cost of construction.This paper takes the Saiqi Bridge as the engineering background,combines the theory with the finite element analysis,combined with the results of the bridge operation status test,compares and analyzes the different reinforcement methods,and analyzes the causes of the cracking of the box girder floor and the reinforcement.Factors affecting the effects were analyzed in detail.The main work of this paper is as follows:(1)First of all,this paper expounds the basic theory of increasing section method,pasting steel plate method,pasting carbon fiber cloth method and prestressed carbon fiber board method,and summarizing the applicability of these four reinforcement methods.(2)Based on the inspection results of the operation status of Saiqi Bridge,the overall model of Saiqi Bridge was established by using the bridge structure finite element analysis software Midas Civil.Through the calculation of the overall structure,the internal force and stress distribution law of Saiqi Bridge in the completed state are obtained,which lays the foundation for the analysis of local reinforcement.(3)Combined with the results of the Midas Civil overall analysis,the general finite element software ANSYS was used to perform solid modeling calculations on the mid-span of the main span of the bridge,and the three-dimensional force state of the box girder bottom plate was analyzed.Control stress of cracking;by controlling the factors affectingthe lateral force of the box girder bottom plate,a parametric analysis of the lateral force of the box girder bottom plate is carried out,and the effect of each parameter on the force of the bottom plate is obtained.The results show that factors such as the thickness of the bottom plate,the curve effect of the beam bottom,the loss of prestress and the radial force generated by the prestress have a non-negligible influence on the transverse force of the bottom plate concrete;the temperature effect and the shrinkage of the concrete are very important in the completion of the bridge There is no significant change in the reduction of transverse tensile stress over a long period of time.(4)Comparative analysis of the effect of three reinforcement methods of prestressed carbon fiber board reinforcement technology,pasted steel plate and pasted carbon fiber cloth on the bottom plate.Then,the effects of parameters such as the size of prestress,layout spacing,and bonding factors on the prestressed carbon fiber reinforced bottom plate are explored,and some reference data required for the design and construction of prestressed carbon fiber reinforcement are obtained to provide experience and reference for similar engineering practices.