Abraham Quarter, Oldenburg

A new residential and commercial building is being built as a mixed-use property on a site covering approximately 2,700m² in Oldenburg’s pedestrian zone. The building will accommodate retail and restaurant spaces on the ground floor and 121 micro-apartments on the upper floors. PORR Building Construction Region North is the general contractor for the turnkey construction. Stump-Franki was responsible for the deep foundation work. The execution planning was realised by PORR Spezialtiefbau Planung.

After the old buildings had been demolished, the former cellars were filled with demoliton waste. A total of 157 full displacement bored piles were used as deep foundation elements. In order to achieve the necessary load-bearing capacity, the piles were guided through the floor of the back-filled cellar by means of well rings and coredrilling.

Schedule compliance despite logistical challenges

Adherence to deadlines was the employer’s number one priority. Fulfilling this requirement under the conditions of inner-city construction posed significant challenges for the team.

The cramped construction site was located in a pedestrian zone, making it difficult to deliver large drilling equipment, reinforcement cages, and ready-mixed concrete. Some of the piling was carried out right in front of existing buildings and required the utmost precision and care. Given the inner-city location, it was essential for the construction work to be quiet and vibration-free. Full displacement bored piles were the method of choice to reduce construction noise and minimise vibrations. The specialist civil engineering experts solved the task with flying colours and right on time thanks to comprehensive planning, a detailed logistics plan, and long-standing expertise.

Full displacement piles ensure a low carbon footprint

Full displacement piles have the advantage of completely displacing the soil during construction, thereby significantly improving the quality of the subsoil. No soil was extracted. This reduced the costs for the employer and cut back on the CO₂ emissions associated with transport and disposal journeys. Another advantage: full displacement bored piles can be used with smaller pile diameters than conventional bored piles, while maintaining the same load-bearing capacity. This saved large quantities of concrete and also contributed to reducing the carbon footprint.