【摘要】 以宁波市东外环甬江大桥凸形钢箱拱肋截面为对象,应用预应力钢绞线的自平衡加载方式进行了1∶4的拱肋节段缩尺模型荷载试验,采用板壳单元和实体单元建立了有限元模型,进行了非线性分析,研究了考虑初始缺陷和局部屈曲的凸形钢箱拱肋截面的受力特性、实际承载能力和局部失稳机理。研究结果表明:各测点实测应力与截面平均应力较接近,根据测点实测应力与截面平均应力之间的关系可将凸形截面分成4类测点;有限元所得应力与实测应力趋势相同,数值相近;凸形钢箱拱肋截面的强度折减系数为0.94～0.98;纵向加劲肋和横隔板结构能有效防止凸形截面加劲板件的局部屈曲;在极限荷载作用下节段出现了凹凸的波节,由于各加劲板出平面位移过大而导致无法继续承载。更多还原

【Abstract】 The convex steel box section of arch rib for Yongjiang Bridge in East Outer Ring Road of Ningbo City was taken as object,the 1/4 scale-model loading experiment of arch rib segment was conducted by using the self-balanced loading mode of prestressed steel strand.A finite element model was built based on shell and solid elements,and nonlinear analysis was carried out.The mechanical characteristic,actual bearing capacity and local instability mechanism of convex steel box section of arch rib were studied considering initial imperfections and local buckling.Analysis result shows that the measured stress of each measurement point is close to section average stress,and measurement points can be categorized into four kinds according to the relationship between measured stress and section average stress.The stresses from experiment and finite element analysis show the same tendency and similar value.The strength reduction coefficient of convex steel box section of arch rib is 0.94-0.98.The local buckling of stiffened plate can be prevented effectively by longitudinal stiffeners and diaphragms.Segment has wave shape under ultimate load,and fails to resist applied load due to the larger out-of-plate deformation of each stiffened plate.1 tab,18 figs,12 refs.更多还原