江西省高速公路独柱墩桥梁横向抗倾覆安全性评估

为了解江西省高速公路独柱墩桥梁横向倾覆安全性能,对江西省高速公路独柱墩桥梁进行了调查,并选取济广高速鹰瑞段12座独柱墩桥梁开展横向倾覆安全性评估。在对桥梁进行专项检查基础上,通过软件Midas/civil建立桥梁有限元模型开展支座脱压验算和横桥向抗倾覆稳定性系数验算,综合判断独柱墩桥梁横向倾覆风险。

独柱墩桥梁横向抗倾覆计算分析及加固方案研究

在超载车辆造成的偶然偏心荷载作用下,独柱墩桥梁极易发生横向倾覆。本文以广州某封闭式收费城市快速路典型独柱墩桥梁为例,介绍了独柱墩桥梁横向抗倾覆安全性评估方法和加固方案,并重点分析了“超高墩”和“超矮墩”的加固特点和难点。结合该城市快速路桥梁加固工程实例,阐明加固完成后桥梁横向抗倾覆安全性能可大幅度提高,满足设计要求。

横风对双层集装箱平车运行稳定性的影响

采用流场数值模拟计算方法,计算了横风作用时的垂向气动升力系数、气动横向力系数和侧滚力矩系数,得出各系数与车辆速度和风速之间的变化关系。从动力学角度,根据力矩平衡原理推导了横风作用时车辆稳定性计算关系式,根据车辆运行的实际情况得出双层集装箱平车在不同装载情况下的临界倾覆风速和风速之间的关系,并分析了垂向气动升力、横向气动力和侧滚力矩对车辆倾覆稳定性的影响。结果显示,横风引起的力中气动横向力占主导作用;空车比重车的临界倾覆风速低;重车比空车的临界运行车速低。

剪叉式升降工作平台稳定性研究

为确定某剪叉式升降工作平台的抗倾覆安全性,结合使用条件,参照标准,计算稳定性系数,并通过现场验证,得出该产品抗倾覆安全的结论且提出改进建议。

Pseudo-dynamic analysis of overturning stability of retaining wall

A new method was presented to determine the safety factor of wall stability against overturning based on pseudo-dynamic approach. In this time-dependent method, the actual dynamic effect with variation of time and propagation of shear and primary wave velocities through the backfills was considered. Planar failure surface was considered behind the retaining wall. The results were compared with those obtained from Mononobe-Okabe theory. It is found that there is a higher value of safety factor by the present dynamic analysis. The effects of wall inclination, wall friction angle, soil friction angle and horizontal and vertical seismic coefficients on the overturning stability of retaining wall were investigated. The parametric study shows that both horizontal and vertical seismic accelerations have decreasing effect on the overturning stability of retaining wall.