预应力空间结构基于索力-位移观测值的预应力施工方案决策

Pretension scheme decision based on observation values of cable force and displacement for prestressed space structures

针对预应力空间结构设计要求为目标位移的情况,研究结构实际状态与理论分析模型存在较大差异时预应力施工方案的决策分析方法。以索力、位移递推公式为基础,建立了仿真预应力施工过程的递推系统,该系统包含四类参数:结构初始状态、张拉力方案、索力与位移影响矩阵、张拉完成后的结构状态。利用施工过程中的索力-位移观测数据可计算出系统状态参数影响矩阵,然后基于递推系统的并行计算,提出了基于索力-位移观测值的预应力施工方案决策方法。利用矩阵分析软件MATLAB,编制了递推系统及决策方法的实现程序,并结合有限元分析软件ANSYS对工程算例进行了模拟分析。结果表明:利用本文方法可求得下一次循环补拉完成时达到设计要求位移状态的张拉控制力方案,从而保证预应力施工达到设计要求。

In the displacement design of prestressed space structures, the pretension scheme decision method is important when structural state differs greatly with the theoretical model. Based on cable force and displacement formulation, the recursive system is derived to simulate the pretension process, which includes four parameters： structural initial state, tensioning forces scheme, cable forces and displacement influence matrix, and structural state after prestress. The state parameters influence matrix can be calculated using observation values of cable force and displacement. The parallel computation of recursive system is utilized to form the pretension scheme decision method based on observation values of cable force and displacement. Matrix analysis software MATLAB is adopted to program the recursive system and decision method, and the finite element analysis software ANSYS is also incorporated to carry out the simulative analysis on a engineering computational example. Analysis results show that the tensioning control force scheme meeting the displacement requirement when next cyclic supplemental tension can be obtained. Then the pretension process can be ensured to meet the design requirements.