Seismic Response Of Extradossed Bridge Considered Different Damping Structural Models

In reacent days,with prestressed concrete bridge span constantly increasing,new type of bridge structure keep coming, extradossed bridge is one of them, it is a form of bridge between the prestressed concrete beam bridge and cable-stayed bridge,as such large-span bridges are newly emerging,their force of deformation under earthquake are not fully understood so studyseimic response action extradossed bridge is necessary.We know that any structure having a vibration damping system,because existing of damping,bridge structure will produce vibration energy dissipation,ithas a very important influence on the bridge structural response under earthquake,then the influence of damping on the seismic response of extradossed psgbridge is also very important.When doing response spectrum analysis,using different damping ratio,seismic response analysis of bridge structure will be different,in addition, provisions of 08 seismic design specifications,for the purposes of concrete beam bridge,damping ratio values generally,the cable-stayed bridge due tostructural somewhat flexible,damping ratio values generally 0.03, the mechanical characteristics of extradossed bridge is between beam bridge and cable-stayed bridge,when making its seismic response analysis,damping ratiovalues should be different from the traditional girder bridges and cable-stayed bridge.For extradossed bridge,when making the response spectrum analysis method to analyze the seismic response,analysis using the CQC modal combination does not guarantee the accuracy of the analysis results, Therefore, response spectrum analysis method can not completely replace the history analysis;at the same time, during the time history analysis,enter different seismic waves will have a huge impact on the results, And seismic code defines thattime history analysis results do not reflect the statistical characteristics of the structure,it is just a sample of random response,a plurality of samples to be analyzed for statistical structure, so as to get a reliable results. For these reasons, during extradossed bridge seismic response analysis, using two methods of analysis at the same time,we should analyze the results of the two methods and check each other,seismic response analysisof the final results can be obtained.In this paper, the pritical bridge engineering background is Xin bian he bridge in Su zhou, the main research is carried out the following aspects:1) Access to relevant documents and information with respect bridge seismic and summarizes theoretical knowledge in the field of bridge seismic.2) Using midas / Civil2012 structural analysis software and build dimensional model to analyze the impact that dynamic characteristics and modes of the structure gives to Xin bian he bridge in Su zhou.3) Using the response spectrum method to analyse elastic seismic response of Xin bian he bridge in Su zhou under the earthquake load, and compare the impact of different damping ratio response spectrum to analysis results.4) Using time history analysis method to analyse seismic response of Xin bian he bridge in Su zhou,and compare the results between time history analysis method and the response spectrum analysis method.