Abstract Manager

Pre-construction condition surveys are a systematic, visual observation and documentation of properties adjacent to a construction site and are carried out before building construction begins. The purpose of the survey is to create a baseline identifying all pre-existing defects of structures adjacent to construction activity, of which may foreseeably cause damage to infrastructure and properties. Surrounding roads and sidewalks must be thoroughly inspected and reported. Within the City of Toronto, pre-condition surveys and vibration monitoring are a By-law requirement for building construction, By-law No. 514-2008.  Once all construction activity has ceased, a post-construction condition survey is carried out to determine if any new defects have appeared or if there have been any changes to the pre-existing conditions or defects.

The current method consists of surveyors and inspectors walking the site and reporting defects through images taken from hand-held cameras. Identifying each defect on site can be a tedious effort and can be error-prone if not done diligently. The paper-based reports only give a partial view of the entire area and often lack context.

In this joint Bentley and Monir Precision Monitoring presentation, we will be showcasing how using drone flights to capture the area’s entire 3D reality data model creates data-rich reporting. Having access to the pre and post construction 3D models at any time not only allows you to visually compare an inspect from the comfort of your office but enables analysis that were not previously possible. Artificial Intelligence-enabled defect detections, such as cracks or spalling, allow rapid and consistent comparisons between the different stages of construction.

Producing 3D reality models provides the added benefit of visualizing remote sensors and the data they provide in the same environment.  The addition of IoT sensors on-site for automated monitoring during construction allows for early detection of instability and movements. The real-time data collection can provide valuable and timely information allowing engineers and construction professionals to make proactive modifications to their means and methods and assist with evaluating critical design assumptions.  Creating a model can not only improve the reporting process but further the objective of minimizing damage to adjacent structures. Additionally, accurate and timely automated monitoring helps to minimize risks due to damage claims.

A data-rich digital twin with multiple 3D models produced over-time, combined with automated analysis and real-time measurement is key to having a reliable, consistent, and complete reporting of pre and post construction inspection.