Study On Wind-induced Response Of High Pier Continuous Rigid Frame Bridge Construction By Suspension Casting

The continuous rigid frame bridge with high pier and long span is widely built in mountain valleys,spanning mountains,rivers and lakes.It is a bridge structure form with mature construction technology and widely used,which has the advantages of large clearance under the bridge and good technical economy.Because the structure usually has the characteristics of high pier,long span and large clearance under the bridge,and the bridge needs to be in a strong wind field environment for a long time,Therefore,the wind-induced response of the bridge structure during the construction of complex wind field study to become a work.Based on the wind resistance design theory of highway Bridges and chattering time domain analysis method,this thesis takes the structure of the main bridge section of Hanchenghe Bridge as the research object,combines Fluent,Midas Civil and Matlab software to carry out numerical simulation calculation of the wind field of the main section of Hanchenghe Bridge.The distribution of chattering displacement,chattering stress and internal force at each beam of the main bridge structure under chattering response is studied.The main contents of the thesis are as follows:First of all,according to Seoul river bridge bridge site actual landform,the terrain information model is established,based on the modeling calculation.Comply with the specifications for design of highway bridge wind resistance theory,establish the bridge bridge in the benchmark of wind speed,using Matlab software and according to the harmonic synthesis method to simulated bridge bridge site of fluctuating wind field,the structural 27# pier on both sides of the main simulation calculation of 31 typical cantilever beam blocks of fluctuating wind speed time history,again using quasi-steady wind load calculation theory is transformed into wind load time history,In the simulation process,the power spectrum is compared with the target spectrum,and the accurate and reliable time history of the fluctuating wind speed is obtained,which lays a foundation for the chattering response analysis.Then,Based on the basic theory of computational fluid dynamics,the topographic files in IGS format are obtained by the topographic processing software such as Globalmapper and Imageware,so that the completed main bridge structure model can be fused with it in the subsequent Gambit software.The three-component force coefficients of lift,drag and static moment of 31 typical box beam sections of the main bridge structure model under different wind attack angles are simulated.Matlab software was then used to fit the relationship between the three component coefficients and the variable wind attack Angle and its derivative function.Finally,using the chattering time history analysis method,set up 27# pier girder during the construction in the software structure model and structure model of bridge condition,then an analysis of the operation model and view the results find the buffeting response of the bridge structure influence the most unfavorable position.The study found that during the construction of 27#,-15# and 15# pier girder structure buffeting displacement is the biggest piece of beam,transverse bridge buffeting displacement is greater than the vertical bridge buffeting displacement;The result of chattering internal force shows that compared with other main block positions,the chattering internal force is the largest at the positions of beam block-1#,1# and 2#,which needs to be paid attention to and monitored at all times.Into a state under transverse bridge to the displacement is always than the vertical to the displacement,it shows that the main structure of horizontal direction are more susceptible to the influence of the wind.The force and torque at the position of the beam block at the 31 st span with larger chattering displacement are not large,indicating that the position at the31 st span of the main is more susceptible to wind influence.The internal force diagram and stress distribution diagram of each beam block are consistent under the condition of completion.forces of the larger value always appear around the bridge location,so in the process of design and construction,these parts need to cause enough attention.