Computation And Analysis On Key Construction Process Of Long-span Suspension Bridges With Steel Truss Girder

Due to its high rigidity,good wind resistance stability,convenient transportation and convenient construction,steel truss girder is widely used in the construction of railway bridges.The steel truss girder is used as the stiffening beam of the suspension bridge.The construction method is more flexible than the common steel box girder suspension bridge construction,and the stress during the construction process is more complicated.For the large-span railway suspension bridge,the second-stage dead load has a large proportion and the linear requirements are high,which requires strict control of its construction process.In order to ensure that the long-span steel truss suspension bridge is in line with the design after completion,it is necessary to carry out calculation and analysis of the key construction process to make the eonstruction Process more reasonable.This thesis takes the second bridge of Lu Zhou Yangtze River as the engineering background,Based on the finite element principle,Midas Civil used the calculation and analysis of the key construction process of the bridge.The main research contents and achievements are as follows:(1)A brief introduction of long-span steel truss girder suspension characteristics,several factors affect the nonlinear suspension bridge construction process and construction process simulation calculations.(2)Introduction and analysis of the characteristics of the slab combined with stiffening beam.On the basis of summarizing the scholars’ simplified method of combining the slab and the stiffening beam,the simplified modeling method of simplifying the orthotropic bridge panel into a single beam is adopted,and the simplified model is compared with the refined model to verify Simplified model accuracy.Then a reasonable bridge state model of the Changzhou Second Bridge of Zhangzhou was established,and the calculation results of the reasonable bridge state of the bridge were analyzed.(3)Using the finite element software Midas Civil to establish a reasonable bridge state model for the second bridge of Lu Zhou Yangtze River,And analyze the reasonable bridge state calculation of the bridge.(3)The pre-bias value of the main tower pre-lifting value,the main cable saddle and the main cable saddle before the main cable erection is calculated,and the main cable air cable shape is calculated.Several parameters affecting the shape of the air cable in the actual construction were analyzed,and the parameters needed to be controlled by the main cable erection process were provided.(4)The three connection methods of the truss stiffening beam erection process are introduced,and the erection process is simulated in detail.The internal forces of the stiffening beam,the linear shape of the stiffening beam and the change of the main cable shape during the construction process under different connection modes are compared.As well as the Helong state,the advantages and disadvantages of the three connection methods of steel truss girder are determined,and the construction of steel truss girder is provided.