| Long-span steel structure is often used in design and construction of the train station’s canopy.Along with the rapid development of the high-speed technology and a large number of high-speed rail lines being laid in our country,the station platform is being reformed and extendedconstantly,the canopy is also the same.Currently,research on the design and mechanical properties of large span steel structure canopy has been perfected,a complete analysis method has been formed and the relevant building codes and theories are quite mature.However,as for the large span steel structure canopy’s reconstruction technology,most of them are facing the shortage of theory technical support.Study on the mechanical properties and relevant building codes have been unable to give a systematic and complete research method.As for the transformation of the entire building structure,the lack of theoretical support for the design method is defective.Therefore,it is highly significative to come up with a research method of mechanical properties about the canopy before and after transformation with a reference value.Based on the finite element numerical simulation method,this paper made the mechanical property research of a train station’s large span no-station pole canopy with steel structure before and after transformation and a corresponding research method is given,The specific research contents are as follows:(1)Data collation,analysis and discussion of the monitoring scheme about a canopy reconstruction project on the key position.During the construction of the canopy,there will be a change in the state of stress on the existing member bars that around the new added structural members,which their stress and strain need to be monitored.As for the Canopy structure’s prestressed steel cable,which the significance to entire structure is being considered,need to strictly control the value of their force.In this paper,a introduction of the construction monitoring scheme of canopy reconstruction project is made,anexplanation of the monitoring instruments and their working principle was elaborated,and based on the monitoring data and the determination value of steel cable force on the monitoring site,andtheresearchresultsaresummarized.(2)Data collation,analysis and discussion of themechanical propertyabout the large span steel structure canopy before and after use under static load.During the construction reconstruction of the large span steel structure canopy,the force member and the stress surface of the roof are increased andthe internal force responseisredistributed,which the stress characteristics needs to be analysed.In this paper,structural models of the large span steel structure canopy before and aftertransformationare made and loads and displacements are applied,and comparison and analysis is done between numerical simulation results and construction monitoring data.Through these results,the safety and reliability of the large span steel structure canopy before and after transformation are verified and the accuracy of the numerical simulation method is proved.(3)Data collation,analysis and discussion of themechanical property about the large span steel structure canopy before and after use under earthquake action.Under the action of earthquake,the seismic wave is applied in the form of inertia force to thestructure,which may bring a significant increase of the stress and strain.Therefore,seismic response analysis is essential to the large span steel structure canopy before and after transformation.Based on the seismic finite element analysis method,in this paper,the seismic wave is applied through the form of load step on the canopyand thestress and displacement time history data on flexion apparent position in modalanalysis is processed and analyzed.Through these results,the safety and reliability of the large span steel structure canopy before and after transformation under the action of earthquake are verified and the accuracy of time history analysis method is proved. |
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