隔板式曲线组合梁施工阶段开口薄壁钢梁受力特性研究

Research on Stressed Behavior of Open Thin-walled Steel Girders of Curved Composite Beams Stiffened by Diaphragms in Construction Stage

在无支架施工中,隔板式曲线组合梁的承载结构为曲线开口薄壁钢梁。以横隔板数量N及跨度与曲线半径的比值(跨径比)为参数,对5片试验梁进行混凝土浇筑过程中的模型试验,并基于M/r法,采用ANSYS软件分析曲线开口薄壁钢梁在混凝土湿重作用下的受力特性。结果表明:在混凝土湿重作用下,曲线开口薄壁钢梁的竖向位移、径向位移、切向应力及翘曲正应力与弯曲正应力的比值(应力比)均随均随跨径比的增大线性增加,随横隔板数量N的增加非线性减小,N从0块增加到3块的过程中变化较大,之后变化较小;端横隔板和跨中横隔板对曲线钢梁的弯扭效应影响最大;跨径比是反映曲梁受扭程度的一种显性指标,应根据应力比限值考虑跨径比的大小来确定曲线开口钢梁的横隔板。

For the curved composite beam stiffened by diaphragms,the bearing structure in the construction stage is the open thin-walled steel girder.In order to reveal its behavior,taking the diaphragm＇s number and span-radius ratio as parameters,model tests were conducted on five curved open thin-walled steel girders during the process of casting concrete.On the basis of the M/r method,the stressed behaviors of curved open thinwalled steel girders under the wet height of concrete were analyzed with Software ANSYS.The analysis results indicate as follows：Under the action of loading of wet concrete,the vertical displacement,radial displacement,tangential stress and the ratio of wrap stress to bending stress all increase linearly with increasing of the spanradius ratio and decrease nonlinearly with increasing of the diaphragm＇s number N,and the changing amplitudes are large when Nbeing in the range from 0to 3and are small when N≥5;the end diaphragms and middle diaphragm have the most great effect on the bending-torsion behavior of the curved steel girder;the span-radius ratio is a dominant index to reflect the torsion level of the curved open thin-walled steel girders,and the layout of diaphragms in the curved open steel girder should be determined according to the ratio of wrap stress to bending stress and with reference to the span-radius ratio.