Specialist welding A9: 21 kilometers of sheet piling to be welded off

Sheet pile walls play an important role in the widening and deepening of the A9 Badhoevedorp-Holendrecht motorway. After all, they provide a stable and durable foundation for the earth retaining walls. Construction consortium VeenIX works for Rijkswaterstaat and asked Marsé Montage to weld the sheet pile walls. And that means literally making meters, as it concerns no less than 21 kilometers.

Marsé Montage from Castricum is working on different parts of the A9 project. They burn sheet piles at height, weld rebar to these sheet piles and make a special mold of steel for the bridge girders of the viaduct. This makes Marsé Montage one of the larger steel suppliers on this project. The company specializes in making steel auxiliary structures, strut frames and anchors in construction pits and other earthworks. In fact, they make anything steel-related. They work mainly on projects in civil engineering. Previously, they helped build the xoutdam at IJmuiden, the Brittenpassage in Amsterdam, and they are one of the regular steel suppliers for the maintenance of the IJmuiden Sea Lock.

Reinforcement mold viaduct

"We were responsible for manufacturing the reinforcement mold of the concrete bridge girders of the A9 viaduct," says Job Hester, director of Marsé Montage. This reinforcement strengthens the concrete bridge girders so that they can properly carry the heavy traffic. "We custom-designed and made the jig according to the precise requirements of the project. It is modularly built in three parts. Thus, the dimensions can be easily adjusted, the mold is easily transportable and it can be applied to different bridges with different sizes of girders in this alignment."

Welding of dam wall locks

A second important job was the welding of sheet pile walls over a total length of 21 kilometers. The sheet pile walls are necessary for widening and deepening the A9 motorway near Amstelveen and for building canopies. Greenery, such as plants and trees, will later be placed on these canopies. Meanwhile, half of the sheet pile walls are nearing completion; the other half is expected to follow next year.  

Specialist welding

After the sheet piles are installed, Marsé Montage welds the rebar to these sheet piles. This work complies with strict regulations according to execution class 3 and ROK 1.4. "First we burn off the sheet piles at height," Hester explains. "Then we accurately weld the rebar to them. This is necessary to prepare the structure for pouring the cover sheet pile. This provides support for the ground around it and for traffic on the new A9. It is precise and technical work. The welding is done at height and at fixed points, with ever-changing lengths. In total, the work involves some 700 to 800 meters of sheet piling. Per meter, we weld an average of seven pieces of rebar."

Custom solutions

It is the size that makes the project non-ordinary for Marsé Montage. "But," says Hester, "it also shows that we have a lot of experience in providing customized solutions for large infrastructure projects."