Monitoring Dublin commuters’ safety

作者：Renata Barradas Gutiérrez

Cities worldwide need to build, maintain and expand infrastructure, especially public transportation systems, to move people, be they businessman, shoppers or students, to keep a country and its economy going.

But,have you ever thought what goes behind moving people safely across a city?Although most likely building or repairing infrastructure first comes to mind, there are other crucial activities, just likemonitoring, that although unnoticed, help engineers and designers to understand the impact of structural movements of infrastructure and materials. Toreduce risk to infrastructure,earlyandprecise monitoringis necessary.

支持我们每个人的基础设施，无论是道路，桥梁，水坝，建筑物和铁路都会遭受危害，环境因素和负载压力。基础设施的压力和风险可能来自直接使用，也来自其他因素，例如附近的建筑工地和发掘。在爱尔兰都柏林的Luas轻轨系统的北部北部是这种情况，在那里，对一组商业建筑的建设（建造以应对对学生住宿的需求不断增长），以确保运输系统的完整性。

有六十七个站和42.5 kilometresof track, Dublin’s Luas light rail system safely carried41.8 million passengersin 2018. To minimise current and future concerns related to safety and structural integrity of Luas, Datum Monitoring Ireland (part of the Lloyds Datum Group), a specialised company inremote monitoring of earthworks结构和运输基础设施，通过专门的监测系统不断分析双Luas轻轨系统的数据。

Alert 24/7

Walls Construction要求LDG基准提供有效，准确和可靠的warning system这将operate 24/7and notify stakeholders in near real time, if a threshold exceeded specifications. The monitoring system needed to meet design requirements, local council regulations and Transport Infrastructure Ireland’s (TII) code of practice, without interrupting the railway operations at any time. The team at LDG Datum also had to ensure no physical object was on the tramway. Traditional Methods involved survey engineers taking physical manual readings on track, which creates its own inherent dangers.

Monitoring solutions involve geodetic, geotechnical and environmental sensors and monitoring software. LDG Datum’s monitoring solution for this project consisted of twoLeica Nova MS60MultiStations, oneLS15 digital levelandGeoMoS monitoring software。这个solution allowed non-intrusive movement monitoring; therefore, the area could stay open for the entire duration of the project with no disruptions for the public or rail services.

"Datum's on-site core activity was to provide continuous scanning of the dual Luas light railway tracks using Leica Geosystems' robotic MultiStation – the MS60. These instruments scanned the dual tramway continuously and hosted data directly onto a secure webpage for the relevant parties to review,”说LDG Datum主任Mark Hodgen。

团队也使用了vibration monitoringwith incorporated Sound Level Microphones to capture ground borne vibration arising from site works and used inductive displacement sensors to monitor the crack movements of existing cracks on neighbouring structures. Continuous dust monitoring stations, furthermore, where used to capture the levels of PM10 particles, or particle pollution, in the local area.

Capturing accurate data is just the start

The main monitoring tasks captured all heave or settlement [vertical elevation of ground] of the light way tram line through thelaser scanningwith the MS60. To keep the rail track area free from hurdles, no prisms on or near-by the track were mounted. Hundreds of mark points along the closest part of the rail were, therefore, measured with laser scanning. The captured scans consist of thousands of measurement points with X,Y,Z coordinates, allowing to detect outliers [blunders] and ensure that the wanted position [area] is measured in a reliable way, even under normal load of the rail track traffic and the adjacent pedestrian area.

三个初始扫描设置了基线以获得参考扫描。将所有随后的扫描与参考扫描进行比较，并计算参考文献和随后扫描之间的中位变形。该值用于与定义的阈值进行比较。TII的实践守则触发警报，如果发生位移。该系统提供了自动警报，当值超过指定阈值时，通知指定的利益相关者。

通过Geomos收集了这两个群集捕获的扫描数据，并在LDG Datum的Secure网站上托管，因此其客户端和TII可以完全了解当前和历史记录的值。这个tailor-made process, from the acquiring of the data to the deformation analysis, was完全自动化。

"Data was checked and compared to historical data allowing a safe protocol to be followed. Our bespoke physical on-street precise levelling captured by Geosystems LS15, was undertaken weekly, to provide the contractor with assurance and a back-up that the automated monitoring was working as planned. Vibration and noise monitoring were also carried out on surrounding buildings during the demolition, piling and construction phase,”说霍奇。“LDG Datum offered Walls Construction a complete remote monitoring systems package, so they can access and review data.”

Reducing risks

通过Geomos收集和处理的所有仪器数据都维持利益相关者在铁路附近的施工工作中通知Luas轻轨稳定性，同时阻止了对服务的任何中断。在该项目中获得了可靠的成功，基准正在复制此事automated monitoring system在其沿Luas系列的所有电车道项目中。

“Our primary focus for this project, considering the level of geotechnical and construction works, was ensuring that public infrastructure and surrounding buildings remain undisturbed. LDG Datum has a high level of credibility in the monitoring sector. Therefore, we engaged with Mark and his team who designed a suitable system that complied with the O’Connor Sutton Cronin (Consulting Engineers) specification and Transport Infrastructure Ireland’s Code of engineering practice for working on, near or adjacent the Luas light rail system,”说Cathal Healy, divisional director for Walls Construction。“ LDG数据提供了高度准确，可靠且在商业上可行的服务，我们很高兴能将它们参与这个项目。”

承包商，就像墙壁建设一样reduce their exposure to risks, before during and after construction通过不断监视该项目通过其生命周期进行的。地理系统的监视系统detect and help rectify potential problemsin any structure before a situation becomes critical or worse out of control.

LDG Datum网站 -www.lloydsdatumgroup.com