Cabauw measuring mast overhaul

Wind, temperature, humidity and radiation... For decades, the Cabauw measuring mast has been an indispensable source of meteorological data, both for the Royal Netherlands Meteorological Institute (KNMI) and for scientists outside the Netherlands. The mast tracks the longest-running measurement in the world of atmospheric processes and the concentration of greenhouse gases. The Central Government Real Estate Agency called in VolkerWessels Telecom to replace the guys of the measuring mast.

Replacement of guys: precision work


The measuring mast is within touching distance of the clouds. At 213 metres, the mast is almost twice as high as the Utrecht Dom Tower. The twelve guys that keep the mast upright are due for replacement after 47 years. “It was a technically complex job that required a particularly controlled approach',” says Peter Veldt, technical consultant at VolkerWessels Telecom. “We worked with a detailed step-by-step plan to guarantee that the tower wouldn’t topple over and that the meteorological measurements wouldn’t be disrupted.”

Maintaining stability of measuring mast

22,000 kilos – that’s the tension that’s on every guy. “To keep the mast upright, this tension could easily be a little less,” says Peter. “But for the measurements, the stability of the mast is essential.” As such, a measuring station accurately recorded all of mast’s deflections during the work. “We wanted to prevent the mast from bulging in the middle or arching out at the top,” explains Peter. The team also recorded all the work in a detailed scenario. “We passed that on to the customer, together with the measuring data. This allows scientists to calculate and correct any deviations in their measurements.”

Weather-dependent approach


The weather played an essential role in the smart planning of the work. The team kept a close eye on the weather forecasts. “That was very easy in this case,” says Peter, laughing. “We could read the data recorded by the mast in an app, so the information was extremely up-to-date.” For example, the team always chose a good day to remove the old guy and install the new one. “We wanted everything to be back in place by the end of the working day, to rule out any risks whatsoever,” explains Peter.




Replacement of guys

The team prepared how to switch the guys as much as possible. “We made a structure to hang the new guy next to the old one. This allowed us to quickly disconnect the old guy and hang the new one in it. We spent the rest of the day attaching the guy to the guy block on the ground.” A good approach, with excellent execution, Peter knows. “Team leader Marc Veldpape and his team have done a fantastic job. They took a particularly well-thought-out and controlled approach at each step. It all worked out perfectly.”