索杆预张力结构杆件长度误差敏感性的理论分析与试验研究

Theoretical analysis and experimental research on element-length error sensitivity of cable-bar tensile structures

针对索杆预张力结构施工中存在的杆件长度误差,基于随机理论建立符合正态分布的随机误差模型,推导了结构预张力偏差与索长偏差的基本关系,并根据数理统计方法得到随机预张力偏差的统计特性,得到各杆件长度误差敏感性评价方法。通过设计跨度为5 m的空腹索桁架结构模型,并在其上调整索杆长度来模拟施工过程中产生的长度误差。分析了引入误差后体系预张力变化及结合ANSYS软件数值分析来考察验证各杆件的误差敏感性。结果表明:预张力结构不同杆件具有不同长度误差敏感性。空腹索桁架结构中环索误差敏感性最明显,脊索、斜索次之,桅杆最弱;试验结果与理论分析基本一致,表明理论分析和模型设计加工的有效性和正确性。

According to the element-length errors inevitably existing in the real cable-bar tensile structures,elementlength error model was formulated firstly based on the stochastic theory,and the fundamental equation of pretension deviation and element-length error was derived. In addition,pretention deviation statistics characteristic could be achieved with the help of statistical analysis. Then error sensitivity of the structures could then be evaluated. At last,the element-length errors were simulated by adjusting the element length on a tensile model with the span of 5. 0 m.The element-length error sensitivity of every element was analyzed by comparing the changes of the pretension with the help of the model experiment and ANSYS analysis. The theoretical analysis and experimental results both indicate that different elements have different length error sensitivity. The error sensitivity of the hoop cables is the most sensitive,the ridge cables and diagonal cables are lower and the struts are the lowest. The experimental results are almost consistent with the theoretical results,indicating that the proposed error sensitivity analysis method in this paper is accurate and the design of the model is effective.