The Analysis Of Optimization For The Arrangement Of Steel Braces On The Base Of Torsional Properties Of The Thermal Power Plant

The torsional effect is one of the most common problems found in the design of thermal power plant.In order to meet the requirements of productive process,the frame-bent structure often used in design of the thermal power plant.This kind of structure which connected two different types of structures shows great irrigation for the uneven distribution of mass and stiffness.Due to their irregular structural arrangement in vertical and horizontal direction,this structure tends to have lateral-torsional coupling and weak stories appear under seismic action.To ensure the safe operation of power system,it is necessary to analyse the torsional effect for the thermal power plant and take some necessary means to handle this problem.This article discuss the dynamic characteristics of a frame-bent structure for thermal power plant.The response spectrum analysis and elastic time history analysis methods were used,we analyzed natural vibration characteristics,the deformation on seismic behavior,the internal force of the structure and the parameters parameters for the vertical members'of torsion in the angle of both plane and space,to get the data of weak stories' distribution.The torsional properties,the irregular properties and the earthquake response are obtained.Based On the is basis results,we distribute steel bracings in consideration of requirements of productive technology in the thermal power plant.By changing the distribution of the brace,the difference of natural vibration characteristics and the torsional displacement ratio are analysed.Structure with optimized distributiont of the brace are studyed to find the impact the torsional effect on the deformation and the internal force for the structure.The analysis results for the thermal power plant model shows that:as the irregular arrangement of mass and stiffness,the structure shows the irregularity in both Vertical vertical and horizontal directions,and exsits many weak layers and has strong torsional effect.The analysis results for the the braced-thermal power plant model shows that:the adding of transverse braces could lower the the torsional index,enhance the torsional stiffness.The model with the steel braces dispersed in two ends not only shows the great enhancement in torsional stiffness,and decreases in for the torsional index,but also reduces the deformation magnitude of the structure.It is proved to be the reasonable brace distribution.