Numerical Study Of The Bridge Crack Analysis And Control Of Prestressed Concrete Box

In recent years, with the rapid development of transport,China’s bridge construction levels have a new level.Prestressed concrete box girder bridge due to flexural,torsional stiffness,construction convenient,low cost and other advantages and very competitive,bridge type in recent years in terms of size or span have made a major breakthrough,but with the problem arising more and more,where the cracking problem has been built or under construction projects are more common.Cracking problem will affect the quality and safety of the subsequent construction,making the structure and lay hidden defects,it built a bridge not only affect the appearance of cracks in the structure,while the safety and durability of the structure constitutes a greater threat to construction in progress Therefore it is necessary to carry out concrete box girder cracking systematic study to explore the fundamental reason to produce this disease.in this paper,Guangyuan Eguchi Jialing River Bridge on the background and combining the actual situation,the impact of factors on prestressed concrete box girder bridge cracks in a study,the specific content of the work are summarized as follows:①through access to a large number of cracking of prestressed concrete box girder bridge of related books and literatures, have a certain awareness of such issues, and through the summary and analysis, the causes of cracks, the distribution characteristics and mechanical characteristics, in order to guide the subsequent work to better carry out.②by means of the finite element analysis, combined with the standard of our country and obtains the influence law of vertical temperature gradient force on the bridge, and the comparative analysis of the most unfavorable effect of temperature gradient and the live load effect, the temperature gradient of the bridge by the force of impact; at the same time, select the other two foreign specifications, calculation and analysis found that temperature gradient effect of three kinds of norms: the difference between the larger, so the climate or engineering background of special circumstances, to deal with the temperature field observation, more accurate temperature effect.③studied by calculation and analysis, the top bottom longitudinal prestress loss of the whole bridge longitudinal stress, obtained the most unfavorable influence range, provide a useful reference for engineering design.④using the ANSYS finite element analysis simulation of the actual location of cracks in box girder, and through the calculation and analysis of longitudinal prestressed reinforcement: in normal working condition, the vertical prestress loss is too large and the size of the web design is a major cause of cracks in the box girder webs.⑤the causes of crack, distribution, influencing factors and other aspects of analysis and research, from the longitudinal, vertical prestress improvement, reasonable reinforcement, beam size, temperature effect analysis, construction technology and other aspects of the box girder crack control measures, and for different crack repair measures put forward corresponding.