ArcelorMittalApplicationsCase studiesUnderground car park | Sint-Martens-Latem | BE (2002)

Underground car park | Sint-Martens-Latem | BE (2002)

Sint-Martens-Latem is a small town of 8 000 inhabitants situated in the Belgian province of East Flanders, right next to Ghent.

In 2002, the Mercedes-Benz and Smart dealer built a new showroom. The outer wall of the single level underground car park was designed as a steel sheet pile retaining wall. These function as a permanent impervious excavation enclosure, and are an essential part of the load bearing structure of above showroom.

ArcelorMittal’s in-house design department carried out a preliminary design of the sheet pile retaining wall, based on the geometry defined by ELD Partnership and on the bore logs from Bureau Geosonda who carried out several cone penetration tests (CPT). The log files report soft, cohesion-free silt (CPT of 4 MPa) to a depth of 15 m. The borehole was stopped when a dense sand layer was reached just below EL -15 m. Groundwater was encountered just below the surface (EL -0.5 m).

Due to the presence of existing buildings, the sheet piles had to be installed with a minimum of vibrations. The contractor Wedam Bvba from Ghent used a rig-mounted ABI hydraulic press to drive the 8.5 m long AZ 18 sheet piles, in steel grade S 270 GP. Equipped with four clamps, the press is able to push four piles at once into the ground. The force of the press can be adapted to the existing soil conditions, thus preventing damage of the pile’s head. The inclinable telescopic leader allows accurate positioning of the piles.

Lowering the groundwater outside the building pit was not allowed in order to avoid potential settlements of adjacent foundations. After excavation and pouring of the concrete floor slab, the interlocks of the sheet piles were seal-welded in order to achieve 100% watertightness of the wall. A special connection with studs, injection tubes and water-stopping strips ensures complete imperviousness of the connection slab / sheet pile. Vertical anchors at the bottom of the excavation prevent uplifting of the concrete base slab.

The surface of the sheet piles was coated after installation which enhance the aesthetical aspect of the underground car park.

 
Project owner
Mercedes Benz Ghent | BE
Consulting engineer
Bureau Jaspers | BE
Project management
ELD Partenership | BE
Contractor
Democo NV, Wedam Bvba | BE
Steel sheet piles
AZ 18 | S 270 GP | 8.5 m
Quantity
175 t
First published: 2006
Latest revision: 01/2019
Last modified: January 10, 2019