Survey Support Services | Construction Surveying

Mark Thomas has a long history of providing monitoring during construction to ensure that structures or other nearby infrastructure don’t move during excavation. We recently provided campaign monitoring services for a bulkhead wall holding back the San Francisco Bay from a site under soil stabilization. In addition to soil stabilization, soil remediation was also required. Our team provided reflectors to mount on the bulkhead wall so that they could be observed remotely without having to get survey crews within the area of remediation. As the contractor performed the stabilization work of injecting grout into the ground, the project team requested near real-time monitoring to make sure they were protecting the bulkhead wall while grout injection was taking place.

Our team utilized an automated monitoring system consisting of a total station mounted on a building well outside the area of construction, a modem link, and specialized software to remotely control the instrument. Several monitoring points outside the area of construction were also observed as checks in addition to the ones mounted on the bulkhead wall. During the peak of construction, the automated total station would measure the reflectors on the bulkhead wall every 20 to 30 minutes and report the readings to the office. This allowed the contractor to monitor the movement of the bulkhead wall during these peak construction hours and prevent movement that could have meant catastrophe to the project and environmental disruption in the Bay. In the end, the contractor was very satisfied with the frequency and automation of the system.