弦支穹顶由单层网壳和下部索杆组成。在零状态时给结构中索杆单元施加一组既定的初始应变,计算后结构便会得到一组确定的单元内力值,依据这一对应关系,提出了一种求解零状态时,索杆单元所需施加初始应变值的迭代计算法,并给出了相应的计算公式与计算流程。为了准确、可靠地指导弦支穹顶的实际施工,确保施工的顺利进行,该文结合具体的张拉方案,利用迭代计算法,将零状态下索杆单元所需的初始应变确定后,依据各单元在初始态与零状态下无应力长度之差确定的原则,提出了基于初始应变不变的施工模拟计算法,并对一跨度为122m的弦支穹顶,在已定施工张拉工序的基础上进行了施工张拉模拟计算。计算结果表明:迭代计算公式高效准确,施工模拟计算法的计算假定与计算流程更加符合实际施工过程。这一施工模拟计算法可在实际结构施工张拉模拟计算过程中采用。
Suspen-dome includes single-layer dome and the bottom tensegrity system. To guide practical construction of suspen-dome reliably and to ensure construction trouble-free operation, an iterative method to calculate initial strains of the bottom tensegrity system under zero state was presented on the base of the relationship between initial strains under zero state and induced inner forces. The corresponding iterative formulas and computation sequence were also given. When the required initial strains of the bottom tensegrity system under zero state were obtained according to the construction sequence, the element length without stress under initial state and zero state is fixed. The construction simulation method based on the invariance of initial strains under zero state was presented. A 122m span suspendome's construction process was simulated according to the construction simulation method after its practical construction process was given. Results show that the iterative formula is accurate and reliable. Presuppositions and computation sequence of the construction simulation method accord with practical construction process. The construction simulation method can be utilized during structure construction simulation.