Monitoring system for execution control applied to a steel arch footbridge

The construction of innovative structural systems and the use of unconventional erection procedures need refined tools to assess the phased behaviour and control the site operations. The combination of a specific monitoring system with a detailed numerical model constitutes an adequate tool to assist bridge construction. The application of this tool to the construction of a 275 metre long footbridge, displaying innovative structural characteristics, is discussed in the paper. A dedicated monitoring system, including strain gauges and thermal sensors was implemented to monitor critical cross sections during both the construction process and in-service. A detailed numerical model was developed and applied for the prediction of the phased construction behaviour and to help in the interpretation of the experimental measurements. In this paper the focus is driven to the aspects related with the installation of the monitoring system, the implementation of the bridge model and the discussion of the results obtained during the construction stages, namely the removal of the propping system. The unusual but direct construction procedure used to build the footbridge greatly relied on the monitoring predictions and continuous assessment to control and reduce the inherent risks of the adopted construction process.     

土体流变特性与基坑支护的监控量测

本文结合浦东新区某工程的基坑开挖，研究土体的流变特性及其在基坑支护监控量测中的应用。采用最小二乘法原理将实测位移一时间曲线拟合为多项式，并在此基础上利用位移反分析方法获得三元件粘弹性模型的各项参数，进而得到一个综合线弹性模量Ｅ（ｔ），从而以简单的线弹性有限元程序计算出各时刻的位移值ｕ（ｔ）。计算结果表明三元件模型能较好地反映上海地区软粘土的流变特性。