Research Of Reasonable Calculation Model On Large Span Riveted Steel Truss Bridge

Now in the calculation of riveted steel truss bridge structure,generally USES the assumption that:(1)the node is hinged;(2)the center line of the bar straight intersect in the center of the node;(3)through truss node load line.For plane truss also requires that all bar axis line and the load on the same plane.Meet the assumed that the structure of the above,the bar only by the effect of axial force,bar stress on the axial direction are called normal stress.However,in the actual structure,these assumptions may not fully establish.Truss node connection in with what kind of connection form,are difficult to achieve ideal articulated,member of the joint of the end node,inevitably produces constraints to the rotation of the node,this makes the secondary stress bar.In fact,in addition to the axial forcethe secondary bending moment and shear force.The resulting stress become secondary stress,the secondary stress makes nodes in a semi-rigid state,namely node in ideals hinged and rigid between nodes.Paper collection of secondary stress at home and abroad are summarized and semi-rigid nodes connection reference literatures and research results,combining with the chongqing Jialing river horn Tuo bridge static load experiment,the analysis of riveted steel truss bridge model is obtained by using the ideal articulated and just answer two corresponding bar under the stress,in combination with theory and experiment data,comparing the calculation mode for long-span riveted steel truss bridge calculation is reasonable.Thesis mainly carried out some research work:(1)For secondary stress research status at home and abroad are analyzed,and the development of dynamic(2)Contrast when calculating the steel truss bridge is analyzed for the influence of secondary stress processing method,and the influence factors of secondary stress.(3)Establish a node is connected only form two different finite element model,calculate the stress of the bar,the change trend of stress analysis of two kinds of calculation mode.(4)In order to get a reasonable calculation model that adopts the hinged two calculation model that is more reasonable,just pick up the load experiment,the corresponding bar strain results are obtained.(5)According to the theory and actual testing results,analysis of bar under the condition of different changes of the secondary stress and regularity.Analysis for riveted steel truss bridge is calculated using just answer and articulated as a whole,the calculation method is reasonable.This article adopts the research method of combination of theory and experiment of long-span riveted steel truss bridge is reasonable calculation mode for research,mainly relying on chongqing horn Tuo jialing river bridge load experiment,the whole bridge ideals articulated and just answer model for research.And in the relevant calculation and analysis on the basis of the upper chord and bottom chord,a quarter of diagonal across the computation model of the articulated compared with the actual situation of the bridge stress close,vertical and diagonal breaking 1/2 cross-section bar used just answer calculation model and the actual stress of the bridge is more close to the conclusion.