A fuzzy integrated methodology for evaluating conceptual bridge design

Choosing the most suitable superstructure is vital for the success of a small to medium-span highway bridge design. Numerous attributes must be considered and evaluated in terms of many different conflicting criteria in the conceptual design of a bridge, leading to a large set of subjective or ambiguous data. Furthermore, integrating experts’ knowledge and experiences to make appropriate decisions is a commonly used method. In order to solve this problem, project managers and design engineers need to evaluate their initiative designs carefully and make accurate decisions. For this reason, a systematic decision process for selecting the best design idea by means of a novel integrated optimization-based methodology is proposed. In the first phase, Quality Function Deployment (QFD) is employed for translating the project requirements into design requirements. In the second phase, Technique for Order Performance by Similarity to Ideal Solution (TOPSIS) is utilized to select the best superstructure as an alternative, based on the weighted criteria achieved from the first phase. In this study the rating values regarding to each alternative and criteria throughout the phases are described in a fuzzy environment by means of linguistic variables. Finally, a case study is provided to illustrate the implementation process of the integrated methodology for bridge superstructure design. For this purpose, an expert team has been formed to collect and verify the expectations of the project, which located in Tehran, Iran. The results demonstrated that the proposed methodology could be successfully applied in the highway bridge projects as a useful tool to facilitate decision making.