Stress And Fatigue Analysis For Continuous Steel Truss Bridges With Small Curvature Radius

With the new structure and advanced technology in the construction of steel bridge construction.Steel bridge design work tends to be strict,more sophisticated manufacturing process,structural details become more complex.At the same time,the increasing traffic load has made the necessity and urgency of the work of steel bridge fatigue research.Based on the existing research results of fatigue,this paper studies the static performance of the whole bridge and the fatigue of the joints and joints of the steel with small curvature radius continuous steel truss bridge.In this paper,the finite element simulation software midas civil is used to simulate the whole structure of the small curvature continuous steel truss bridge.The results of the static characteristic analysis show that the inside force of the truss curve is more unfavorable than the outside.Through its dynamic analysis,the 6th order frequency and mode are solved,and the impact coefficient is calculated.Based on the analysis of the whole structure of the structure,the midas FEA is used to establish a more fine local finite element model for the four types of dangerous members,including the upper and lower chords,the upper chords and the upper and lower girders.By analyzing the influence of structural details on local forces,the stress distribution of various dangerous components is obtained,and the basis for subsequent fatigue analysis is provided.According to the general characteristics of urban traffic,the parameters of urban traffic flow are estimated based on the specific situation of Kunlun bridge.And the mathematical simulation of the load spectrum is carried out by using the probability random method.The simulated load spectrum is obtained by this method.Based on the nominal stress analysis method and the midas FEA finite element fatigue analysis software,the fatigue analysis and life estimation of the dangerous components were carried out for three different structural details,different load spectra and different stress states.The results show that the upper chord gusset plate is the fatigue life control component of the truss bridge,and the most unfavorable bar is the upper chord of the support.The fatigue load spectrum is estimated by the highway normative fatigue load in the design of the urban steel truss bridge.The fatigue life of the joint plate in the space stress state is slightly lower than the plane stress state,and the damage distribution rule is similar.