施工误差对弦支穹顶结构性能的影响分析

邱先伟;唐寅

（重庆交通大学；土木建筑学院；重庆400074）

摘要:基于概率统计理论，采用蒙特卡洛法，开展了弦支穹顶结构性能对施工中上部节点安装误差和下部环索预应力损失敏感性分析。对于上部网壳节点定位偏差，弦支穹顶整体结构对上部结构节点定位偏差最敏感位置为第一圈节点Z向定位，结构极限承载力最大下降率为36.67%。对环索预应力偏差在5%范围内、10%范围内及15%范围内的敏感性分析，研究表明弦支穹顶整体结构受力性能对最外圈环索预应力损失最敏感，构极限承载力最大下降率为6.6%。

关键词：弦支穹顶；初始缺陷；节点误差；预应力损失；

Analysis of Influence of Construction Errors on Structural Performance of Suspen-dome

QIU Xianwei;Tang Ying

(School of Civil Engineering & Architecture，Chongqing Jiaotong University，Chongqing 400074，China)

Based on the probability and statistics theory, Monte Carlo method was used to analyze the sensitivity of the string-supported dome structure to the installation error of the upper node and the loss of the lower cable prestress. For the positioning deviation of the upper reticulated node, the most sensitive position of the overall structure of the chord-support dome is the Z-direction of the first-circle node, and the maximum reduction rate of the ultimate bearing capacity is 36.67%. For the sensitivity analysis of the cable prestress deviation in the range of 5%, 10% and 15%, the study shows that the overall structural stress performance of the string-supported dome is most sensitive to the prestress loss of the outermost ring cable. The maximum reduction rate of bearing capacity is 6.6%.Based on the probability and statistics theory, Monte Carlo method was used to analyze the sensitivity of the string-supported dome structure to the installation error of the upper node and the loss of the lower cable prestress. For the positioning deviation of the upper reticulated node, the most sensitive position of the overall structure of the chord-support dome is the Z-direction of the first-circle node, and the maximum reduction rate of the ultimate bearing capacity is 36.67%. For the sensitivity analysis of the cable prestress deviation in the range of 5%, 10% and 15%, the study shows that the overall structural stress performance of the string-supported dome is most sensitive to the prestress loss of the outermost ring cable. The maximum reduction rate of bearing capacity is 6.6%.窗体底端

Abstarct:Based on the probability and statistics theory, Monte Carlo method was used to analyze the sensitivity of the suspen-dome structure to the installation error of the upper node and the loss of the lower cable prestress. For the positioning deviation of the upper reticulated node, the most sensitive position of the overall structure of the suspen-dome is the Z-direction of the first-circle node, and the maximum reduction rate of the ultimate bearing capacity is 36.67%. For the sensitivity analysis of the cable prestress deviation in the range of 5%, 10% and 15%, the study shows that the overall structural stress performance of the uspen-dome dome is most sensitive to the prestress loss of the outermost ring cable. The maximum reduction rate of bearing capacity is 6.6%.

Keywords: suspen-dome; initial defect; node installation error;prestress loss

0引言

基于张拉整体思想提出的弦支穹顶结构由上部单层网壳和下部索撑体系两部分子结构组合而成(如下图 1)。在安装过程中可能出现的安装误差包括节点位置定位偏差、杆件初弯曲和初偏心、杆件尺寸及截面尺寸偏差、杆件安装初始应力等^[1]。下部索撑体系由于预应力张力施工工程中张拉设备和索力测量系统的局限性，预应力实际值与预应力设计值存在不可避免的误差^[2]。单层网壳结构对初始缺陷甚为敏感，索撑体系需施加合理预应力后方能发挥结构优势。因此，施工过程中的各种误差引起的网壳初始缺陷和索撑体系的预应力偏差，必将对结构造成不容忽视的影响。

目前，研究此类结构的方法有两类方法：一、一致缺陷模态法^[3]；主要方法是通过 ANSYS 软件线性屈曲求解，得到缺陷分布模式，再通过施加比例因子控制缺陷大小，最后，通过非线性分析求解。二、随机缺陷模态法^[3]；此方法亦基于 ANSYS 软件，通过 PDS 模块对缺陷进行随机分布，通过大量数据循环模拟符合施工中的随机缺陷分布状况。对上部网壳施工中的缺陷进行特征值屈曲分析，并没有将上部网壳结构细分出每一种缺陷，然后研究对整体稳定性的影响，进而去指导施工中进行上部网壳结构安装应重视的缺陷以及各种缺陷所对应的敏感位置。本文将采用随机缺陷方法研究弦支穹顶上部网壳结构安装节点误差和下部索撑体系预应力损失对整体性能影响。

1工程背景

本文以某弦支穹顶屋盖实例为背景，其立面图如图 2所示，由上部单层网壳（图3）和下部索撑体系（图4）组成。体育馆上部结构采用单层网壳结构，网格使用凯威特网格划分，一共设置 8 圈，杆件之间的连接采用铸钢球节点连接，其杆件布置