Determination of prestress and construction order of cable-supported frames.

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1.An optimization method has been developed far long-span frames supported by cables. The optimal cable forces at the final state are found by solving a mathematical programming problem under constraints on the stresses and displacements due to service loads and the externa1 loads that represent static earthquake loads and wind loads. The objective functions are maximum value or the deviation of the cable farces. It has been demonstrated that the computational cost for obtaining the optimal cable forces is very small if an exact reanalysis method is used.2.An approximate to method has been presented for finding optimal order (schedule) of introducing cable farces and removing temporary supports, where the intermediate states during construction is traced inversely from the final state. Heuristic objective functions are used to represent the maximum capacity of the equipments and the total energy for construction.3.The exact optimal solution has been found for the scheduling problem by a dynamic programming approach. It has been shown, by comparing the results by the approximate and exact methods, that a good approximate solution can be found by the approximate method. Since the computational cost of the approximate method is very small the proposed method can be effectively used for practical application.4.Optimal tensioning schedules have been found for cable-supported frames of various types, and the characteristics of the optimal solution have been discussed.5.An interface program has been developed for converting the data between the tools developed in this project and the commercial analysis package (NASTRAN) to fully utilize the tools in practical application.