Stability Analysis And Wind Resistance Study Of Long Span CFST Arch Bridge In Hoisting Construction

Concrete-filled steel tube arch bridge has the advantages of high bearing capacity,good stability and good economic benefits.It has good prospects in the construction of long-span bridges in China.With the rapid development of bridge theory,technology and materials,concrete filled steel tube arch bridge is developing in the direction of larger span and lighter quality.Because cable hoisting cantilever construction method is often used in construction,it is very important to study the stability analysis and the influence of wind load on different construction stages.Based on the Matan Hongshui River Bridge with a span of 335 meters in Laibin City,Guangxi,this paper establishes structural models at different construction stages by using the finite element software Midas Civil,and carries out stability analysis under dead load and static wind load at different construction stages.The main achievements are as follows:1)Based on Midas finite element software,a high precision finite element model of each cable hoisting construction stage is established,and the methods of model parameters,loading,analysis,calculation and result processing suitable for different construction stages of concrete filled steel tube arch bridge are put forward.The analysis results show that the CFST arch bridge meets the engineering requirements in the aspect of wind resistance stability.2)The wind load parameters at the bridge site are determined and the wind speed of each arch rib segment is calculated to obtain its equivalent static gust load,which provides reliable data support for bridge construction control.3)Based on the finite element model,the displacement,internal stress and stress changes of arch rib hoisting construction stage,bridge deck hoisting construction stage and bridge completion stage under dead load and static wind load are analyzed respectively,and the relevant data nephogram is obtained and the most disadvantageous construction position is determined.By comparing the influence of different levels of wind load on construction stage,the transverse bridge displacement variation rules are obtained.The law is basically the same.The maximum axial force of the transverse bridge is obtained in the closure state,and the wind has a great influence on the structural bending moment.4)By studying the variation of displacement internal force,the influence of wind load on long-span concrete filled steel tube arch bridge is analyzed,and some suggestions for wind protection during construction are put forward.The results of stability analysis show that the most dangerous construction stage is the maximum cantilever stage.The first kind of elastic stability factor is 5.815,the safety factor is low,and the mode of instability is local lateral instability of temporary hinges.