城市轨道交通U型梁的施工风险和成本控制

摘要

作为新型的桥梁上部结构,U型梁因其低成本、低噪音以及低风险等优点正逐步代替原有的传统桥梁结构.U型梁结构复杂,受施工条件限制等各种不确定因素的影响,施工过程中难免会发生风险事故,给施工成本造成不利影响.利用模糊故障树分析方法,提出了U型梁施工风险事故模糊成本重要度指标,利用该指标衡量U型梁施工过程中各风险对施工总成本的贡献大小.将最小割集中底层事件的发生概率看作梯形模糊数,给出了梯形模糊数相乘的精确算法,利用该方法求出了U型梁施工的模糊成本重要度.最后通过实例分析验证了本方法的有效性.%As a new kind of bridge structure,U-beam features many advantages,such as low cost,safety,low noise and low risk,it is replacing the traditional bridge beams gradually.However,due to complex structure and the influences of various uncertain factors,risk accidents are inevitable during construction,the cost will also increase correspondingly.By employing fuzzy fault tree method,the important index of fuzzy cost in construction risk accidents for U-beam is proposed.This index is used to weight the contribution of construction risks to the total cost,the probabilities of bottom event in the MCS (minimal cut sets)is taken as the trapezoidal fuzzy number,thus the accurately multiply algorithm of trapezoidal fuzzy number is derived,which is employed to compute the fuzzy cost importance degree.The presented method is finally verified through a case analysis.