Structural Characteristic Study On Large Span CFST Arch Bridge

In order to study actuality of CFST arch bridge, based on the investigative result of "total bridge model test of Chunan Nanpu bridge", the nonlinear structural internal forces, nonlinear stability and seismic resistance of large span CFST arch bridge have been studied in this paper.Rib vertical displacement of Nanpu CFST arch bridge is biggish, considering the geometrical nonlinearity and material nonlinearity, and the value is about 105% of elastic result; the horizontal displacement is biggish also, with the value is approximate 113% of elastic result. If considering the double nonlinearity, the rib vertical displacement will increase approximate 10% and horizontal displacement will increases approximate 22%. The results show that nonlinearity must be considered in calculating structural internal forces of large span CFST arch bridge.Stability coefficient of large span CFST arch bridge is less than that of considering the geometrical nonlinearity, its numerical value decreases approximate 11%; and stability coefficient of large span CFST arch bridge decreases approximate 57% with taking into account material nonlinearity; Stability coefficient of large span CFST arch bridge taking into account geometrical nonlinearity and material nonlinearity is smallest, and the numerical value is about 39% of elastic stability coefficient. Therefore collective action of geometrical nonlinearity and material nonlinearity must be considered in computing the stability coefficient of the large span CFST arch bridge.Structural internal forces and deformation caused by seismic load are bigger than that caused by automotive load. Seismic load controls the designing of large span and small "width-to-span" ratio of large span CFST arch bridge. The seismic resistance is bigger than that with considering combination of various directions, so seismic load combination of various directions should been taken into account during design of large span CFST arch bridge. Response spectrum method is not exact for analyzing large span CFST arch bridge.In order to study the practical stability performance of Chunan Nanpu bridge, a total bridge model test was carried through. The design method of "spar to spar" modeling method was firstly introduced in this test. The test results are significant forconstruction and management of Chunan Nanpu bridge; excessively, the test results are significant for design and construction of large span CFST arch bridge also.