Versatile monitoring expertise proves value in Utrecht Zeehelden neighborhood

With the combination of a varied range of services and years of experience, the Geertruidenberg-based consulting firm provides clients with clarity and certainty regarding the execution of a wide variety of architectural projects. One of these, the waterproofing of the Utrecht Zeehelden neighborhood, confirms the extensive expertise present within the organization. Director Fred Pannekoek tells more about it.

When it rains hard, residents of basement dwellings in Utrecht's Zeehelden neighborhood experience flooding. To make the neighborhood waterproof, a separate rainwater sewer must be constructed. The Municipality of Utrecht issued a separate tender for monitoring the work. The plan of approach made by Fides and the communication plan for the neighborhood were the best.

Work

In the Zeeheldenbuurt neighborhood, Fides is signing on for preliminary surveys, vibration monitoring and continuous deformation measurements using robotic total stations, among other things. For the latter work, the firm uses Trimble brand high-precision equipment. "Specifically, with the type S9, we deploy the 0.5-second version," Pannekoek explains. "It is a measuring device with a measurement accuracy of 1 millimeter. More accurate does not exist." 

On behalf of the GWW contractor, Fides also provides monitoring well monitoring via telemetric loggers. All work is carried out entirely in-house and with its own measuring equipment. "To discuss measurement results, planning and operations, we have regular monitoring meetings," Pannekoek says. "In addition, our measurement expert is in daily contact with the contractor regarding the timely relocation of the measurement systems. This prevents stagnation and ensures project progress."

Vibration Monitoring

Whereas the preliminary surveys in the seven phases of the specifications are carried out in accordance with BRL 5024, vibration monitoring takes place in accordance with BRL 5023 and SBR-A 2017. "The vibration meters are moved along with the excavation and trench backfilling in accordance with SBR-A," Pannekoek explains. "Because permission to mount the vibration meters has already been requested during the preliminary surveys, we can immediately respond to the contractor's actual progress. Besides stagnation, this prevents work from taking place without vibration monitoring." 

To stay below the level of the limit, Fides uses an alarm value of 90% of this limit. However, the assessment will be carried out in accordance with the SBR limit. "When the alarm value is exceeded, our measurement expert immediately puts himself in contact with the contractor," Pannekoek said. "On the one hand to identify the vibration cause, and on the other hand to optimize the working method when necessary."