Analysis Of Partial Crack In The Bottom Slab Of Continuous Box Girder

Continuous rigid frame,which combines the advantages of continuous beam bridge and T-shape rigid frame,becomes the preferred long-span bridge now.But the continuous rigid frame started late,the theory has not been perfect yet,and the quality of construction is not high,overloading vehicle and terribe conservation arised during the operation,resulting in a variety of quality problems of continuous rigid frame box girder.At the same time,partial crack in box girder bottom slab is extremely common,which endangers the life and safety of the structure,so I use software to make a detailed analysis of the variation of stress according to radial force of steel strand,and carry out the following studies in respect of a partial bottom slab crack.1)Through the interpretation of the relevant literature of domestic and foreign experts,I grasp the research status of the bottom slab crack problem,on the basis of design information and practical issues of box girder I master,make a deep analysis of partial-crack reasons.2)Theoretical research of box-girder crack introduced the concept of radial force.I discuss the impact of radial force on the structure,from the perspective of the analysis of the situation of design and construction.Respectively considering the impacts of radial force,I make a comprehensive analysis of the steel-strand radial force variation caused by various factors,discussing potential crack zone.3)In a bridge case,for the problems arising in construction,I use analysis software to establish a solid model,making a detailed comparison of the design and practical case on various factors.And I respectively discuss the impact of structural stress in each single factor model,which help to find the main reason of bottom slab crack,providing the basis for guiding for the prospective design and construction.4)For the bridge accident,I finish the finite element analysis from the perspective of design optimization to consider the effect of various parameters on the structural stresses,to avoid partial-crack accident from the design level,at the same time use the model to analyze the impact of setting the crossbeam on Closuresegment and gives some preventive measures.