Tunnel entrance parking garage Korte Zeekant in Scheveningen

Variant analysis and preliminary design

A redevelopment of the area between the Gevers Deynootweg and the Boulevard in Scheveningen is taking place. A new, wider and lowered walking route is being constructed as part of the project “De Kust Gezond” (A healty coast). The aim is to widen the passage from the Gevers Deynootweg to the Boulevard on the Korte Zeekant.

A parking garage will also be built below the boulevard. The entrance to the car park is located on the road devider of Zwolsestraat at approximately 150 m from the Boulevard and will be connected to the car park under the Boulevard with a tunnel at approximately 1.5 m below the Gevers Deynootweg and the Korte Zeekant. A very important point of attention is the short distance from the tunnel to the surrounding buildings.

In a variant analysis of the tunnel various types of retaining walls were considered, namely secans pile wall, steel sheet piling, diaphragm wall and CSM wall. After a Trade-off Matrix and cost estimates a preferred variant was chosen in consultation with Ingenieursbureau Den Haag. The result was a best scoring variant in which the tunnel is constructed using a temporary CSM wall, in which a definitive tunnel construction is constructed. In this design, the foundations of the adjacent buildings need to be reinforced by means of jet grout columns, such that the ground level can be lowered as desired.

This variant has been further elaborated in a preliminary design. Various PLAXIS calculations were performed to test the tunnel construction and assess deformations of the adjacent buildings. The new foundations of the buildings (reinforced with jet grout columns) and a new to be constructed bridge were tested on vertical bearing capacity using foundation analysis. These results were incorporated into a preliminary design that will be used when the work is put out to tender.

Tunnel entrance parking garage Korte Zeekant in Scheveningen Tunnel entrance parking garage Korte Zeekant in Scheveningen Tunnel entrance parking garage Korte Zeekant in Scheveningen