Study On The Mechanical Properties And Seismic Response Of PC Rigid-frame-continuous Beam Combined-system Bridge

The prestressed concrete combined-system bridge about rigid-frame bridge andcontinuous beam bridge combines the advantages of the two types of bridges. It has certainadvantages in terms of mechanical properties, using functions and terrain adaptability. Inorder to further promotion and application of thenew bridge structure, the mechanicalproperties and seismic response characteristics of the new bridge structure should be masteredin detail. Therefore, carrying out the research of the mechanical properties and seismicresponse characteristics of PC combined-system bridge about rigid-frame bridge andcontinuous beam bridge has important engineering value and bright future.In this paper, the research of the mechanical properties and seismic responsecharacteristics about the new bridge structure for the example engineering were carried out.The main contents of the dissertation were as follows.(1) The finite element model of the bridge was established by the finite elementsoftwares-Midas/Civil. Then, the calculation models were updated by combination the actualmaterial properties and boundary conditions. According to the design construction process ofthe example engineering from the design and construction drawings, the finite element modelwas appropriately divided. It could lay the good foundation for the subsequent analysis of themechanical properties and seismic response characteristics about the new bridge.(2) The static mechanical properties and dynamic characteristics were analyzed byusing of the sophisticated finite element model of the bridge structure. The safetyperformance of the bridge structure under different load combinations at ultimate carryingcapacity limit state was analyzed. The normal cross-section crack resistance, oblique sectioncrack resistance and structural stiffness checking under different load combinations at normalusing limit state were analyzed.The structural stresses at Persistent status were checkedincluding normal pressure of the normal cross-section and oblique section. According to theconstruction phase analysis and the existing design specifications of bridges,The cambersetting and allocation of the bridge were determined. The free vibration characteristics of thebridge were analyzed by using the lanczos method, the method was suitable for solving largeeigenvalue problems. It could lay the good foundation for the subsequent analysis of theseismic response characteristics about the new bridge.(3) On the basis of summarizing the existing research on the seismic response, theresponse spectrum analysis method and dynamic time history analysis method were used toanalyze the seismic response of the bridge.The response spectrum analysis method considered the action of E1and E2earthquake. The dynamic time history analysis method was based onthe updating typical strong motion records EL-Centro wave according to the actual situationof the bridge. In order to learn the seismic response characteristics of the bridge, the changeconditions of internal forces and displacements for the main beams and piers under differentload combinations were analyzed. In order to check the correctness of he response spectrumanalysis method and dynamic time history analysis method, the calculation results of theresponse spectrum analysis method and dynamic time history analysis method were comparedand analyzed.The relatively reliable calculation basis for the seismic design for the newbridge would be guaranteed.