| Simply-supported girder bridges are widely used in our country’s highway system because of its advantages such as simple structure and convenient construction.However,with the increase of its service time,different types of structural diseases inevitably appear,which affect the normal use of the bridge.To more accurately grasp the simply supported girder bridge seismic performance and seismic risk of these diseases,and to the provincial trunk highway of typical girder bridge in Yunnan province as the foundation,in view of the typical disease in the line,respectively from the disease of the numerical simulation,the influence of single disease of simply supported girder bridge seismic vulnerability and vulnerability to diseases earthquake sensitivity analysis discusses the three angles,the relative effects of typical diseases on the aseismic performance of simply supported girder Bridges are obtained.The main research contents are as follows:1.According to the existing information of simply supported girder Bridges on national and provincial trunk highways of Yunnan Province,the background bridge structure and typical diseases to be studied are determined,including corrosion of steel bars,erosion of pile foundation and aging of support;Based on the existing research results of disease mechanism,the numerical simulation methods of typical diseases are defined.2.Analyzing the seismic capacity of the section of the corroded pier column and the change of dynamic characteristics of the bridge after pile foundation scouring.Taking the ductility ratio of piers and displacement ductility ratio of bearings as damage indexes,the seismic vulnerability surfaces of simply supported girder Bridges with typical diseases are drawn,and the influence of typical diseases on the seismic vulnerability of simply supported girder Bridges is discussed.3.For many diseases coexist,respectively by using a first order polynomial and a second order polynomial response surface model of structural earthquake damage probability and disease parameters fitting,inspection of the function relation,identified with cross terms of second-order polynomial function for optimal polynomial response surface model,based on the optimal polynomial response surface model and partial derivatives,the relative influence of each disease on the seismic performance of the bridge is analyzed quantitatively. |
