针对构件长度误差会造成索杆张力结构的实际预张力偏离设计值这一问题,建立构件长度误差效应分析问题的数学模型,采用悬链线索单元及精确协调方程以确保计算精度.利用动力松弛法来进行求解,避免了刚度矩阵的建立.建立反映预张力偏差和长度误差关系的敏感性矩阵.考虑到结构的实际施工成形是以张拉索索力来控制的,基于牛顿法提出存在索力约束条件的长度误差效应求解方法.以一个实际工程中的索-桅杆张力系统作为算例,通过4种不同张拉方案下的长度误差效应敏感性分析,表明了索杆张力结构的张拉方案评价必须考虑长度误差效应的控制效率.
Member length error can substantially cause the prestress deviation of cable-strut tensile structure from design value.The mathematical model was conducted to analyze the effect of member length error,in which the catenary cable element and its precise compatibility equation were adopted to ensure the computational accuracy.The dynamic relaxation method was employed to solve the problem devoid of the establishment of stiffness matrix.A sensitivity matrix was established to analyze the relationship between the tension deviation and the length error.A numerical method based on Newton method was further developed to calculate the error effect with additional condition of given tension force of certain cable considering that the structural form in construction was controlled by the tension force of directly pretensioned cable.The structural sensitivity to member length error under four different pretensioning schemes were compared by an illustrative example of a practical mast-cable system.Results indicated that the control efficiency of member length error effect was indispensable for evaluating the pretensioning scheme of cable-strut tensile structure.