Optimization Of Steel Truss Construction Scheme Based On Fuzzy Evaluation

With the rapid development of economy, the steel structure is widely used because of its excellent homogeneous, high strength, aseismatic performance. In recent decades, various types of long span steel structures such as stadiums, museums,hangars and so on are developed rapidly in the world, the span and the scale become bigger and bigger, and new materials and new technologies are applied and developed more and more.The common construction methods of long span steel structure include high altitude bulk method, itemizing or blocking installation method, aerial sliding method, integral lifting method, the method of integrally jack-up and ascension. Each method has its own technological and technical characteristics, so, it is necessary to choose a method or the combination of several methods based on the actual situation when compiling the construction schemes. At the same time, with the development of technology and the accumulation of experience, some new techniques have appeared and been applied.For the long span steel structure, not only the structure design and analysis stage are of great importance, but also the selection of construction scheme and the determination of construction techniques are crucial in the process of construction, so reasonable construction scheme and scientific analysis of construction process can ensure the safety and economy of structure. How to scientifically and reasonably select proper implementation scheme with the minimum cost and maximum interests has attracted more and more attention in the building trades.Based on the background of actual engineering, combined with the theory of system engineering, the thesis utilizes the method combination of fuzzy evaluation method and improved method of analytic hierarchy process to establish a fuzzy comprehensive evaluation model of optimization of long span steel truss construction scheme,and verify its validity and practicability of the model through an example. Besides four aspects are explored in the thesis:â‘ The establishment of the index system. The construction of steel truss is related to many factors, so the index system of the optimization of the steel truss construction scheme shall be determined after repeatedly selection.â‘¡The rasising of steel truss construction scheme. According to the actual conditions, feasible and reasonable alternatives shall be formulated.â‘¢The determination of indexes weights by the improved analytic hierarchy process (ahp). Since the birth of the analytic hierarchy process, it has been used widely in various fields for its advantages. For its disadvantages, traditional ahp has been improved and group analytic hierarchy process (ahp) based on index scale is established and the indexes weights are calculated.â‘£The establishment of evaluation matrix. The set-valued statistical method is introduced to construct the evaluation matrix, reducing the random errors and the malpractice brought by the individual subjective judgment when experts evaluating the each indexes. Therefore, the calculated results will be more reliable.