Ultimate Bearing Capacity And Dynamic Response Analysis For The T-beam Bridge Of Simply Supported–Continuous System

The beam bridge of simply supported-continuous system combines the advantages of the simply supported girder bridge and the continuous beam bridge,which make it used more and more widely. However, few efforts have been devoted to the study about the ultimate bearing capacity and dynamic response caused by vehicle-bridge dynamic interaction of this type of beam bridges. Hence, the thesis takes Xi’ Zhang County Bridge as the example, and carries out the research about the characteristics of the T-beam bridge of simply supported-continuous system,including the force and failure mechanism, ultimate bearing capacity, vehicle-bridge coupling vibration, shock factor and vehicles’ operating comfort on the bridge. The proposed analysis methods are of great theoretical significance and practical value to the development and rational application of the beam bridge of simply supported-continuous system. Main research contents are as follows.(1)The 3-D finite element computing model is established using software Midas/FEA. The model considers the nonlinear material, and calculates the failure patterns, failure load and safety factor under different working conditions.(2)The whole loading process of the T-beam bridge with simply supported-continuous system is simulated, and then the ultimate bearing capacity is obtained. Internal forces on the initial state of the bridge are also studied, which reveal the effects of construction technologies on the ultimate bearing capacity.(3)A dynamic analysis model is proposed, in which the bridge and vehicles are regarded as an integrated time varying system. The load frequency and vibration mode are calculated using a self-designed program. Moreover, the load frequency and no-load frequency are compared. And effects of tire stiffness, suspension stiffness, unsprung mass and sprung mass on the load frequency are discussed.(4)Dynamic response of the vehicle-bridge time varying system and displacement impact coefficient of the bridge are computed. Impacts of elements such as the number of vehicles, vehicle spacing, different lanes, vehicles’ speed and road surface roughness are also explored. Vehicles’ operating comfort on theT-beam bridge of simply supported-continuous system is evaluated. Furthermore,effects of vehicles’ speed and road surface roughness on the comfort are analyzed.