BGW and VBG Prevention Centre, Hafencity, Hamburg

On a site directly beside Hamburg’s Elbe bridges, the Professional Association of Health and Welfare Workers (Berufsgenossenschaft für Gesundheitsdienst und Wohlfahrtspflege – BGW) and the Professional Association of Administrative Workers (Verwaltungs-Berufsgenossenschaft – VBG) are working to build a shared Prevention Centre with a gross floor area of 42,000m². Completion is scheduled for 2024. The building will allow the two statutory accident insurance providers to offer their member companies training and development courses on the topic of occupational health and safety. It will also provide a base from which to provide personal advice and training for policyholders and for hosting professional events. PORR Spezialtiefbau was part of a consortium charged with establishing the construction pit with pile foundations. The PORR subsidiary’s duties specifically involved creating a bored pile wall with concrete top plates and internal bracing, a soldier pile wall with two-layer back anchoring, a jet-grouted floor in the lower section, and a reinforced concrete floor. A total of 840 partial displacement piles were used to create the foundations. 

Finances optimised thanks to 3D planning

The specialist civil engineering experts at PORR have been working in Hamburg’s Hafencity district for years. The ground in this flood-prone area, which lies beyond the main dike line, offers little stability and often presents unknown soil conditions and incalculable obstacles. Combined with significant fluctuations in the groundwater level,

construction in this area requires specialist expertise, experience and meticulous planning. In the case of the construction pit created for the BGW and VBG Prevention Centre , execution planning was carried out in-house by PORR Spezialteifbau Planung GmbH. The 3D plans of the construction pit with anchor-collision checks significantly improved the cost-effectiveness of the pile foundation construction.

Location necessitated stable pit lining with minimal deformation

The construction pit was established in close consultation with Hamburger Hochbahn, the company that operates the city’s underground railway system. Due to the site’s location immediately adjacent to a U-Bahn line, any vibrations, deformation, settlement or back-anchoring against the U-Bahn station were entirely out of the question. Consequently, at the eastern side of the site adjacent to the Elbbrücken U-Bahn station and in the lower section towards the Elbe, the construction pit was secured with an extremely stable and deformation-resistant reinforced concrete bored pile wall (approx. 1,950m²). Instead of back-anchoring with grouted anchors, the bored pile wall was reinforced internally with inclined tube struts. In addition, boring holds to remove debris made it possible to overcome numerous obstacles, such as old sheet-pile walls and remains of past foundations. The floor of the construction pit below the groundwater level was sealed using the jet-grouting method.