双边箱钢主梁剪力滞效应分析

Research on Shear Lag Effect of Double-sided Box Steel Girder

以简支和悬臂钢主梁体系为研究对象,采用数值分析方法对不同宽跨比下的双边箱钢主梁剪力滞效应进行计算分析。通过引入有效分布宽度系数,结合理论分析结果,应用回归分析法提出以宽跨比为自变量的双边箱钢主梁有效分布宽度系数计算公式,并将计算结果与有限元分析结果进行对比。结果表明:在均布荷载作用下,当宽跨比η由0.5减小到0.1时,对于双边箱简支梁而言,剪力滞系数最大值位于边箱腹板顶部,其值由1.305减小为1.019,变化幅度约为21.9%;对于双边箱悬臂梁而言,剪力滞系数最大值位于桥面中心处,其值由1.189减小为1.002,变化幅度约为15.7%,随着η逐渐减小,截面正应力分布趋于均匀。实用计算公式的结果与有限元分析结果的相对误差小于1%,满足精度要求,并得到适用于公路新桥规的有效宽度分布系数计算的修正值,为后续相关规范的完善提供一定参考依据。

Taking simply supported and cantilever steel girders as the research objects,the influence of shear lag effect on double-sided box steel girders with different width-span ratio was investigated by numerical analysis method.By introducing effective distribution width coefficient and combining the results of theoretical analysis,the practical formula was proposed to calculate the effective distribution width coefficient of double-sided box steel girder,which took width-span ratio as its independent variable.The results of formula calculation were compared with those of finite element calculation.The conclusions of research are as follows:when width-span ratio decreases from 0.5 to 0.1,for simply supported double-sided box girder,the shear lag coefficient reduces from 1.305 to 1.019,and it reduces by about 21.9%.The maximum value is at the top of the side box web.For cantilever double-sided box girder,the shear lag coefficient reduces from 1.189 to 1.002,and it reduces by about 15.7%.The maximum value is at the center of the deck.With width-span ratio decreasing,the normal stress distribution tends to be more uniform.Effect of the main beam varies the most under uniformly distributed load.The relative error between the results of the practical calculation formula and the results of the finite element analysis is less than 1%,which meets the requirement of precision.And the correction value of the effective width distribution coefficient for the new highway bridge gauge is obtained,which provides a certain reference for the improvement of the subsequent related specifications.