The mechanical behaviors of intersecting joints considering damage accumulation in steel tube structures is analyzed through the FE-program ABAQUS. The stress characteristic and failure modes of these joints are concluded. Especially, it has been analyzed influence of the change of geometric parameters to mechanical behavior of joints. Finally, the results indicate the joints have a good mechanical performance and good plastic deformation as to excessive local buckling of chord under the loads.

The pounding between adjacent segments of bridge has significant influences on its seismic performance, which is a complex nonlinear phenomenon involving many parameters. Based on Kelvin impact model, a simple-supported girder bridge was introduced to discuss the effects of impact stiffness and initial gap between joints. With dynamic analysis, it can be drawn the reasonable range for impact stiffness ratio and initial gap at expansion joint are respectively 0.05~0.2 and 0.04m~0.05m, which make the earthquake response of bridge reach a good balance.

Abstract. The inner plate can be used to stiffen square tubular T-joint in order to improve the performance of square tubular T-joint and the radial stiffness of square tube. In this paper, tow methods of experiment and numerical simulation have been used to study the strengthening effect. Three scales of welded T-type RHS joints have been designed and three corresponding finite element modes have been established. Their anastomotic deformations verify the accuracy of the finite element model, boundary condition and loading mode by comparing the experiment and numerical simulation results. The research in the paper proved that RHS joints with inner stiffened plate had better ductility, energy dissipation and seismic performance because of the change of failure mode of specimen.

The essence of the axle coupling vibration in case of random bridge deck is random vibration, therefore, it is quite necessary to research the effect of vehicle impact on basis of statistic analysis. With some large concrete-filled steel tube arch bridge as the object, by applying a self-made analysis program on axle coupling vibration that was demonstrated by a dynamic test, a dynamic response analysis on axle was implemented for many groups of random roughness swatches. On basis of the analysis result, a statistic analysis was conducted for the dynamic impact effect of bridge under the conditions of different deck status and vehicle speeds, in the determination of vehicle speed and roughness, the impact factor obeys the normal distribution. The analysis result shows that, the level of deck status may apparently affect the mean value and the MSD(mean square deviation), the differences of vehicle impact factors in case of different assurance rates are large. It will effectively improve the reasonableness and scientificalness of the value of a vehicle impact factor to determine the impact factor according to the level of bridge importance and a statistic analysis method.