基于实测索力的预应力空间结构模型修正方法研究

Research on method of model updating for prestressed space structure based on measured cable force

预应力空间结构在国内外大跨结构工程特别是大型体育场馆中应用日益广泛,针对其使用阶段的结构检测与评估逐渐成为一个重要的课题.相比传统结构,预应力空间结构通过拉索施加预应力来保证结构受力状态、提供结构整体刚度,拉索实测索力是反映结构真实受力状态的最重要参数.由于有些预应力空间结构拉索之间存在明显的相互影响效应,已有的模型修正方法求解效率不高,本文提出一种基于索力敏感度分析的有限元模型修正方法.利用有限元软件计算得到索力敏感度矩阵信息,将其代入结构零状态和初始态循环迭代的过程,最终得到能够准确反映结构实际受力状态的数值模型.以某实际体育场工程为例,进行了索力实测、模型修正、受力分析的结构状态评估全过程.在索力修正的过程中通过与其他方法的对比研究,表明本方法具有较高的准确性和效率,为以后类似结构的检测与评估提供了参考.

The prestressed space structure is widely used in large-span structural engineering at home and abroad, especially in large stadiums. The structure detection and evaluation for its use stage has gradually become an important issue. Compared with the traditional structure, the prestressed space structure is prestressed by the cable to ensure the structural stress state and provide the stiffness of the structure. The measured force of the cable is the most important parameter reflecting the true stress state of the structure. Because some prestressed space structure cables have obvious mutual influence effects and the existing model correction methods are not efficient, this paper proposes a finite element model updating method based on cable sensitivity analysis. The finite element software is used to calculate the cable sensitivity matrix information, which is substituted into the structure zero state and the initial state loop iteration process, and finally obtains a numerical model that can accurately reflect the actual force state of the structure. Taking an actual stadium project as an example, the whole process of structural state assessment of cable force measurement, model correction and force analysis was carried out. In the process of cable force updating, the comparison with other methods shows that the method has high accuracy and efficiency. It provides a reference for the detection and evaluation of similar structures in the future.