Determining the Right Monitoring System for the Project No matter the type, monitoring systems provide more than measurement By Boris Skopljak and Riley Smith
can be collected at frequencies ranging from hundreds of measure- ments per second to hourly or daily updates. Factors that drive decisions for implementing a deforma- tion monitoring system Graphs, charts, reports, and alarms showing physical movement and trends is the primary output of deformation monitoring, but there are several other notable returns on investment (ROI) when employing either manual or automated systems. The most compelling reasons to implement a deformation monitoring system include: • Compliance with legal and regulatory requirements: This is the most com- mon driver for implementing a fully automated 24/7 deformation monitoring system. This is typically directed at the state or federal level by authorities such as DOTs (Departments of Transportation) issuing licenses for construc- tion or operations such as mining. These regulatory bodies typically specify implementation of automated systems and require a certain movement ex- ceeding the threshold to be reported with a clear escalation and mitigation path to protect the safety of everyone involved. • Protecting safety of life: In highly dynamic environments such as infrastruc- ture, mining, or areas where there is a known landslide or avalanche potential, sudden or unexpected movement can have catastrophic impact on site work- ers or the general public. Monitoring systems collect data that provides critical information in order to help prevent or anticipate a catastrophe. Very often there is guidance from regulatory bodies, but the implementation of accident prevention is the responsibility of general contractors or owners/operators. • Increased productivity by eliminating multiple site visits and manual data interpretation: Installing an automated monitoring system removes the need for regular site visits to take measurements once the system is set up. There is no more traveling to and from the site or multiple equipment setups. This allows the site surveying team to take on additional projects with the same manpower while still keeping tabs on critical movement at the monitored site, thereby enhancing team productivity. Automatic reporting and real-time alarms are also gained from automated systems, which keep stakeholders informed of movement levels and conditions. • Increased project control and visibility of asset conditions: Similar to the safety benefits afforded by a monitoring system, the data collected can alert the project team of trends and potential structural failures as a result of any movement. Having the ability to prevent a failure before it happens helps to ensure a project stays on track and on budget. In the case of dams or mines, assets can be observed over a longer period, from months to years. Having historical surveying data can aid in very accurate modelling of asset behavior and serve to identify trends that support preventive versus scheduled main- tenance, resulting in optimizing the cost to maintain the asset. Along with the benefits, there are several additional points to consider. Manual monitoring systems require an on-site operator, and manual upload and storage of the data. There is also a reduced repeatability of measurements, mainly due to environmental factors, and less ability for the field survey crew to make strategic decisions while on site. In the case of automated monitoring, it is important to account for ad- ditional up-front costs associated with the installation and preparation
Deformation monitoring is a key component to site safety and is re- quired for many construction projects around the globe. Oftentimes, manual monitoring by a site surveyor will suffice, but there are other instances when automated, real-time monitoring would provide the critical safety component while also affording several productivity gains. Ultimately, selecting the right monitoring system is important for project success. Why monitor deformation? Deformation monitoring, the task of measuring an object's movement over time, plays a crucial role in assisting the construction process and understanding a structural asset's health. Owners, operators, and contractors rely on monitoring systems to measure and report on the movement of certain structures or earthen formations to ensure public safety, protect the asset and make informed decisions. Manual and automated monitoring systems Manual (also called periodic or campaign-based monitoring) monitoring schemes are not new in the industry. Typically, these are performed when a low frequency of measurement (e.g., once a week or month) and instal- lation of instruments on site is not required (e.g., tripod, total station, and data collector). Manual monitoring is generally used for monitoring an object during the construction process by observing a defined set of dis- crete points within or surrounding a construction site or during specific operations such as moving a large load over a bridge where the project duration can be less than a day. These types of projects typically require a survey crew to be on site at all times. Often, manual monitoring can be used to detect and track trends on slow, subtle movements such as natural land drift and seasonal structure movement. With advancements in connectivity and power supply options, auto- mated monitoring systems have become the norm for infrastructure construction and asset maintenance. When safety of life and fast reac- tion times are required after movement has been detected, an automated monitoring and alarming system is required. Automated systems allow for continuous measurement and analysis, often combining a number of geodetic (e.g., Global Navigation Satellite Systems (GNSS) and to- tal stations) and geotechnical (e.g., crack, tiltmeter, and inclinometer) sensors. Instruments are permanently or semi-permanently installed on site (e.g., concrete pillar in housing for total station mount connected to permanent infrastructure) to reduce the need for repeat site visits by enabling autonomous data collection and integration. To ensure owners and contractors timely reactions to any unexpected movements, data
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January 2021
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