The importance of building recording and monitoring

As a contractor you are obliged -when building a project- to prevent damage to the surrounding area as much as possible. Activities such as digging, pile driving, vibrating sheet pile walls and drainage can make the ground unstable, causing surrounding objects to subside. It is therefore important for all parties to identify these risks and minimize them as much as possible. This can be done by making an architectural survey of the risk area prior to a construction project and monitoring it during the work. 

The building survey makes the exact condition of each property in the area clear in advance. It also gives the contractor information about the risks of the construction work and the likelihood of damage. During the execution of construction work, the contractor monitors both the construction pit and site and the surrounding objects. He measures whether all objects are still at the same distance from each other and from the surrounding area. As soon as changes occur in those measurements, the contractor can take action. "A construction survey and monitoring are important to do for many reasons," says Barry Engelen, Geodesy Advisor at Topcon Positioning Netherlands.

Six reasons for building recording and monitoring

1. The recording is the legal basis to start the project;
2. The recording provides clarity on structural risks in the construction environment;
3. Recording and monitoring can prevent image damage;
4. Recording and monitoring can prevent failure costs (in time and money);
5. You can claim on the insurance if damage does occur; 
6. You are well prepared for the Building Quality Assurance Act (Wkb). 

So the need is clear, but how do you tackle it? How do you implement recording and monitoring into your work processes? We show how contractor Heijmans does it.

Part of the work process

"Fortunately, the likelihood of major, structural damage is relatively small on most projects. When working on large construction projects, where the impact on the environment is so great that constructive problems do arise, a structural survey and monitoring is a standard part of our work process," says Robin Dullens, project leader at Heijmans. "Beforehand, a structural survey of the risk area is made by a recording expert. Then a monitoring plan is made based on the design. This states what and how must be monitored and with what frequency. Of course, this also contains the control measures, as well as the limit values that must not be exceeded." Dullens explains that monitoring equipment is then set up and measurement data is sent to those involved. "If the signal value is reached, then the project manager, for example, receives a message that there are changes and the working method can be adjusted. If the intervention value is reached, then work must be stopped immediately. Of course, we do everything we can to prevent this. We want to build in a risk-based and controlled way and guarantee the structural safety of the object to be built as well as objects in the surrounding area."

Metro Grand Paris

Adequate monitoring is also underway in Paris for Project Grand Paris: a mega metro project that will double the size of the network. Construction of as many as 200 kilometers of new metro lines around Paris will involve some 20 tunnel boring machines. With such a large project under a busy city, safety is vital. Cementys is deploying Topcon monitoring equipment that will monitor adjacent construction, such as stations, tunnels, as well as adjacent roads, pylons and antennas, among other things. This detection technology notices even the smallest movement so that intervention can be taken if necessary. So all measurements must be correct: this is what makes or breaks such a project. Accuracy of the equipment is therefore crucial: under all weather conditions, it must be guaranteed, down to half a millimeter. The experts, with specialized equipment from Topcon in Paris, are providing a secure foundation for this mega-project.

Topcon, in collaboration with Cobouw, wrote a white paper on the importance of monitoring and how to incorporate risk area recording and monitoring into project workflow. Received? Check: https://bit.ly/467RLbn