Mechanical Analysis And Evaluation Of Prestressed Concrete T-beam With Web Cracking

Prestressed concrete T-beam bridges have been widely used in the construction of medium and small span bridges due to their advantages of simple and convenient construction and good mechanical performance.However,with the passage of time,prestressed concrete T-beam bridges will produce different degrees of cracks in use,especially vertical cracks in the web.However,the impact of such cracks on the structural bearing capacity is still unclear.In this paper,the characteristics of existing cracks in real bridges are summarized and statistically analyzed.Using a total strain crack model and nonlinear finite element analysis,the impact of web cracking on the bearing capacity of prestressed concrete T-beams is studied.The method of qualitative and quantitative evaluation of the working performance of prestressed concrete T-beams based on the vertical crack status of the web is improved,providing a reference for the maintenance and reinforcement of similar bridges in the future.The main research contents are as follows:(1)Based on the inspection results of the actual T-beam bridge and relevant documents,the characteristics and laws of existing crack diseases are analyzed,and the parameters studied in this paper,such as crack location,crack number,crack width,and crack height,are determined.(2)Based on the total strain crack model,a nonlinear finite element model of a simply supported prestressed concrete T-beam is established and verified;On this basis,using the crack location,crack number,crack width,crack height,and effective prestress as the research parameters,the variation rules of the deflection,concrete stress,prestressed tendon stress,and structural stiffness of the cracked webs of prestressed concrete T-beams with increasing load are analyzed.(3)The existing evaluation methods for the impact of cracks on the bearing capacity of bridges are analyzed.Based on the results of nonlinear finite element analysis for vertical cracks in the webs of T-beams,the qualitative and quantitative evaluation method for the working performance of prestressed concrete T-beams with vertical web cracks is improved,providing a reference for the maintenance and reinforcement of similar bridges in the future.