High-profile foundation work at Wilhelminasluis Zaandam

In downtown Zaandam, the 111-year-old Wilhelmina Lock, along with the adjacent Beatrix Bridge and Wilhelmina Bridge, is being renovated. The current Wilhelmina Lock is in poor structural and technical condition. In addition, the dimensions are outdated. Commissioned by the province of North Holland, contractor Heijmans is carrying out the renewal. The lock will be made longer, wider and deeper, making the lock process more efficient for commercial and recreational shipping in the future.

Part of the foundation work at the Wilhelmina Lock is being carried out by Kandt BV Aannemings- en funderingsbedrijf, a company with more than 40 years of experience in (complex) foundation work. Willem de Meijer, company manager at Kandt explains what makes this project so unique. "The renewal of the lock in the city center of Zaandam is a far-reaching event, in which the disruption to the surrounding area must be minimal. This involves vibration-free, low-noise work and optimal communication with local residents. This inner-city project has little working space and monumental buildings around it, such as the excise houses. 

We work vibration-free with small and compact equipment. Sometimes we literally stand on top of the lock walls ... there is no more room!"

Challenges

De Meijer goes on to say that many original drawings of the Wilhelmina Lock are available. "Some of the surrounding foundations were partially built on wooden piles and the column walls were masonry. That was later renovated and re-poured. So we encounter different foundations and obstacles in the subsurface that we have to go through. By using proven techniques, we avoid surprises and can drill the LeKa piles through them. For the LeKa piles for temporary retaining structures for the Wilhelmina Bridge in large wall thicknesses, we use enormously strong equipment. In contrast, when drilling LeKa piles with smaller diameters for the lock heads, we work with very compact equipment with minimal weight." Drilling through the existing masonry of the lock walls and foundations and making a trench in the current masonry column wall to later install sheet piling is carried out with precision by Kandt. "We are doing this with several machines at the same time in order to ensure throughput and schedule."

Phased

The work will be carried out in multiple phases, in a tightly planned overall schedule that has been coordinated in lean sessions with Heijmans and the executing parties. "With multiple phases, it is enormously important that as a party you can switch quickly and be flexible. Not a problem for Kandt because we have all the facets to be able to do that in-house: we engineer, build and maintain our own machines, have in-house constructors and technicians, and we take care of the transport ourselves with our own fleet of trucks including low-loaders, crane trailers et cetera."

Ideal working method and reliable machinery

"In such a complex and challenging project, where you have to work vibration-free in an inner-city environment with compact equipment, our method of working as well as our reliable fleet of machines fit seamlessly. And if necessary, we build the machine specifically needed for certain projects. Because that's the fun part at Kandt:
by taking on challenges and continuing to evolve has also brought us to where we are today. Each project unique in terms of situation, complexity and challenges." De Meijer concludes, "If you consider it in advance and think 'how are we going to do that' and with the expertise of driven colleagues within Kandt BV can give a quality impulse and then get it done in the work together, that gives an enormous amount of energy!"