桥梁康复: Monitoring a 40-year-old bridge in real-time before renovation

作者：T/F/D

The Edgar Cardoso bridge in Figueira da Foz, Portugal, is named after the famous civil engineer and professor of bridge construction. Cardoso was a pioneer of the experimental analysis of structures and developed his own high-precision measurement instruments. André Melrinho, Engineer Surveyor fromInfraestruturas de Portugal (IP)，相信Cardoso会批准在其最新翻新之前用于监视桥梁的新技术。Melrinho和他的团队使用了Leica Geosystems monitoring solutionsto collect and process data to show its structural behaviour. Maintenance plans for the bridge were prepared based on the results obtained, ensuring that it meets current safety standards and continues to support travellers across the Mondego river.

IP is a state-owned organisation that manages transport infrastructure in Portugal. Its purpose is to plan, design, construct, maintain and operate the national road and railway networks and rehabilitate, extend and modernise them when necessary. The Edgar Cardoso Bridge – 1421 m long, including a cable-stayed bridge and two approach viaducts – was completed in 1982. It is subject to regular maintenance. During the latest evaluation of the bridge, IP assumed the monitoring project to support and prepare recommendations for structural work. According to the IP surveying team, “measurements were essential to define the structural behaviour, and plan a proper and more efficient maintenance intervention.”

选择用于测量的精确工具

A bridge is an ever-changing structure that poses unique challenges for engineering surveyors. Equipment needs to be precise and sensitive, yet robust and weather-proof. Having used Leica Geosystems equipment on a previous similar project, the team chose a Leica Nova TM50i total station and 44 GPR112 reflectors; a meteorological sensor to monitor temperature and atmospheric pressure; andGeoMoS Monitor, GeoMoS AnalyzerandGeoMoS Now!用于数据处理和分析的软件。总站测量用于用毫米精度量化桥梁的运动。准确的信息对该项目至关重要，而解决方案产生的位移的体积和准确性是选择技术的决定因素。

从综合数据中形成结构预测

IP团队说，监测过程中收集的数据至关重要，“允许[美国]一致地了解桥梁的行为。”他们解释了一些进行的一些全面测量：“ TM50I收集水平，垂直角度和距离，从大气效应和处理所有观测后的位移得到适当校正。目的是评估结构位移”。The team needed to measure over an extended period to see how the bridge responded to different conditions, to “better define [the] structure’s behaviour when it’s under external factors, such as heavy traffic loads, severe atmospheric conditions, etc..” Being a cable-stayed construction, the behaviour of the bridge towers is of critical importance. “The vertical component will have a very relevant impact since more significant fluctuations in this component are expected.”

In addition to the movement data, meteorological information from the weather sensor was gathered and processed by the Leica GeoMoS software. Graphics and reports were generated by the GeoMoS Now! web application which the team used to communicate results to other IP colleagues.

Remote information and assistance

With numerous solutions for remote access, it is easy to access the Leica solution, check, modify, or adjust the processing and download the data from the database created by Leica Geosystems. The total station performs continuous measurements, which were automatically processed via GeoMoS Monitor and GeoMoS Analyser. Results were made available round the clock via GeoMoS Analyzer and GeoMoS Now! web-based application. Once set up, the team could monitor the bridge without needing to be on-site, saving considerable time. The IP team said that the system was “precise, continuous and automatically remotely accessible.”

IP团队还从Leica Geosystems支持团队获得了防火墙问题的快速远程帮助。“专业的Leica Geosystems技术人员有必要访问瑞士办公室的IP服务，以识别和解决防火墙冲突。一切都非常有效，几分钟后，发现了解决方案。”团队还对培训感到满意，该培训确保他们将系统发挥了最大的潜力。“我们与Leica Geosystems团队促进了联合培训课程，并进行了内部培训课程，这是一个持续的过程。最初的学习过程非常加速；[我们]在少于3到4天的时间内实现了该过程的自动化。”

Trusted partner and technology

When working on infrastructure, it is essential to trust your instruments. Following the successful completion of the monitoring, the surveying team at IP will use the Leica Geosystems solution on their next projects. They say, “the equipment, processes, and other accessories show great robustness and reliability. Due to the system's ease of integrating the various components and time saving, we expect to replicate this solution soon, namely in road and rail infrastructures.”

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