Study On The Seismic Collapse Resistance Of Continuous Rigid Frame Bridge Based On IDA Method

In recent years, the global happened more intensity bigger earthquake, which caused serious structural damage and casualties. A large number of the lifeline project of roads, bridges, airports, happen to serious damage. These are exposed the shortcomings of the exist system of the earthquake relief of all countries. The bridge structure as lifeline engineering, which destroy not only will cause serious direct economic losses, and will brings great difficulties of relief work of lives rescue and material transportation, therefore, how to guarantee the smooth of lifeline project after earthquake is particularly important. The research of the seismic performance of bridge structures, shall ensure reducing the damage as much as possible during the quake possible, or even though destroyed but not collapse. At present, the design principle our country’s code,such as the aseismatic design idea and design methods, is relative onefold, and exist some deficiencies in multiple earthquake levels and multiple-phase seismic design, which lead the bridge structure lack of design method and basis in the collapsed design of strong earthquakes resistance. The concept of aseismatic design, which base on the Performance, will integrate into the system of continuous rigid frame bridge used IDA method in the paper. To analysis the collapse resistant capacity of bridge structure, proposed the quantitative method of performance target of continuous rigid frame bridge, and analysis the vulnerability of continuous rigid frame bridge based on the analysis result of IDA. The main contents include the following respects:(l)Analyze the characteristics of the earthquake damage and collapsed mechanism of continuous rigid frame bridge. Analyze all kinds of the destruction reasons based on the situation of the bridge structure suffered earthquake damage, and put forward the corresponding seismic measures.(2)Determined constitutive relation of concrete, constitutive relation of steel and restoring force model of plastic hinge model of continuous rigid frame bridge used MIDAS/CIVIL finite element software, which based on the whole process of the collapse and destruction of continuous rigid frame bridge, and Determined the direct integrant method of Newmark-P to analyze dynamic elastic-plastic of the whole bridge.(3)IDA method.the paper makes clear the principle of IM and DM according to the IDA method, and determined the selection principle of earthquake records. Because of the traditional IDA method exist certain deficiencies in the convergence aspect, so puts forward the improved IDA method in the paper, which use earthquake records of strong convergence and can considering cycle slip of structure as IM function. Analyze the vulnerability of structure based on the IDA method, and Put forward quantitative index of collapse resistant capacity of structure.(4)Selecting the22earthquake records to conduct the IDA analysis used different IM functions respectively, and received multiple IDA curve. Comparative analyze the difference of IDA through result data of IDA, and get the IDA curve and collapse of vulnerability curve, which is in the sense of the Probability and statistics. Combined with the result data of IDA to assess the collapse resistant capacity of continuous rigid frame bridge used the CMR method, and determined the quantitative index of structure collapsed in the different IM functions.