Study on comprehensive evaluation and decision-making method for all-composite bridge structure design scheme

A comprehensive evaluation and decision-making method for all-composite bridge structure design scheme with multiple structural parameters as variables was proposed. First, four types of structure layouts were designed according to the designed conditions. Combining grey correlation analysis and entropy weight method, a comprehensive efficiency evaluation model for the design scheme was established, and the I-beam bridge was selected as the optimal scheme. Then, the detail-structure optimization and lay-up design of the I-beam bridge were carried out by using equi-strength design and stiffener design. Finally, all-composite bridges including box-girder bridge, I-beam bridge, truss bridge, and arch bridge, as well as stiffened I-beam bridge, were manufactured by using molding method. The four point bending test was used to verify the optimum design. The results show that I-beam bridge has highest structural efficiency, then followed by box-girder bridge, and truss bridge has the least structural efficiency, which is consistent with the comprehensive efficiency evaluation results. The damage location of the test and numerical analysis are basically the same. The ratio of load to mass for stiffened I-beam bridge reaches 48.88 N g-1, which is 38.16% higher comparing with that of the initial design. The effectiveness of the optimum method was verified by the experimental results.