双工字钢-混凝土组合梁桥结构参数分析

Analysis of Structural Parameters of Bridge with Twin I-Shaped Steel Beams and Concrete Slabs

为了探究结构参数变化对钢-混凝土组合梁桥受力性能的影响,确定结构参数的合理取值,以某4×35 m的双工字钢-混凝土组合连续梁桥为背景,采用ANSYS软件建立全桥精细化有限元模型,分析翼缘板宽厚比、腹板高厚比、腹板竖向加劲肋厚度和间距及横梁间距和竖向位置的变化对桥梁总体受力性能的影响,提出各结构参数的合理取值建议。结果表明:组合梁桥的弹性稳定系数随翼缘板宽厚比增大和腹板高厚比的增大逐渐减小;翼缘板宽厚比小于12、腹板高厚比取100~120时,稳定性能得到保障;腹板竖向加劲肋厚度增大,组合梁桥的弹性稳定系数稍有增大,从施工及焊接角度考虑加劲肋厚度建议取12~16 mm;加劲肋间距越小,组合梁桥的极限承载力越高,间距取2.5 m左右可满足稳定性要求;横梁间距取8~10 m、布置在横断面稍微偏下的位置时,对钢梁受力较为有利。

To investigate the effects of variation of structural parameters on the mechanical property of the steel-concrete composite beam bridge and to obtain the reasonable values of parameters,a 4×35 m continuous beam bridge with twin I-shaped steel beams and concrete slabs was taken as the study background.The software ANSYS was used to establish the refined finite element model of the full bridge,to analyze the influence of a series of parameters on the global load bearing performance of the bridge,including the width-to-thickness ratio of the flange,depth-to-thickness ratio of the web,the thickness and spacing of vertical stiffeners of the web as well as the variation of the intervals and vertical position of cross beams.And the reasonable values of all the structural parameters were determined.The results show that the elastic stability coefficient of the composite beam bridge gradually decreases with the increase of the width-to-thickness ratio of the flange and the depth-to-thickness ratio of the web.When the width-to-thickness ratio of the flange is less than 12 and the depth-to-thickness ratio of the web is set at 100-120,the stability of the structure can be assured.As the thickness of the vertical stiffeners of the web increases,the elastic stability coefficient of the composite beam bridge slightly rises,and a value of 12-16 mm is suggested for the thickness of the stiffeners when construction and welding are concerned.The smaller the spacing of stiffeners,the higher the ultimate load bearing capacity of the composite beam bridge will be.When the spacing of stiffeners is around 2.5 m,the stability requirements of the bridge can be met.The intervals among cross beams draw the value of 8 to 10 m,and when the cross beams are arranged at the location a little lower than the cross section,the load bearing condition of the steel beams is favorable.