基于变权重和D-S证据理论的桥梁安全评估

桥梁结构的安全评估受环境侵蚀、材料老化、外部荷载等多源因素的影响，采用单一指标评价桥梁的安全性容易产生误判.因此，提出一种基于信息融合的多因素桥梁安全评估方法.该方法首先确定每种因素的变化区间，通过多工况数值计算提取典型的力学指标，利用信息熵和模糊层次分析法确定指标的变权重及单指标的等级划分原则并转化为基本概率指派函数.采用Dempster组合规则确定融合后的安全等级，从而建立桥梁的安全评估先验数据库.将该方法应用于预应力连续梁桥的安全评估中，结果表明该评估方法客观、合理，具有一定的工程实用性.

Safety Assessment of Bridges Based on Variable Weight and D-S Evidence Theory

The safety assessment of bridge structures can be affected by multi-source factors such as environmental erosion， material aging and external loads. Using single index to evaluate the safety of bridges is prone to misjudgment. Therefore， a multi-factor bridge safety assessment method based on information fusion was proposed. In this method， the variation region of each influence factor was first determined; then the mechanical indexes were extracted through numerical analysis under various load cases; and then the information entropy and fuzzy analytical hierarchy process were utilized to determine the variable weights of index and the grade criterion of single index so as to acquire the basic probability assignment function. The Dempster combination rules was used to determine the fusion safety level and establish the prior database of bridge safety assessment. The proposed method was applied to the safety assessment of a pre-stressed concrete continuous bridge， and the results showed that the proposed method is objective， reasonable and applicable to engineering practice.