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.