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

1.提出了一种大跨度索支撑框架结构的优化方法。通过求解数学规划问题，在使用荷载和代表静态地震荷载和风荷载的外部荷载的应力和位移约束下，找到最终状态下的最优索力。目标函数是电缆线的最大值或偏差。结果表明，如果采用精确的再分析方法，获得最优索力的计算成本非常小。提出了一种近似的方法来寻找引入缆索和拆除临时支架的最优顺序（时间表），其中施工过程中的中间状态与最终状态成反比。采用启发式目标函数表示设备的最大容量和施工总能量。利用动态规划方法找到了调度问题的精确最优解。通过比较近似法和精确法的结果表明，近似法可以得到较好的近似解。由于近似方法的计算量很小，该方法可以有效地用于实际应用。针对不同类型的斜拉桥架，找到了最优张紧方案，并讨论了最优解的特点。开发了一个接口程序，用于将本项目开发的工具与商业分析包（NASTRAN）之间的数据进行转换，以便在实际应用中充分利用这些工具。

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.