Between February 2020 and October 2020, Implenia Spezialtiefbau GmbH constructed the pile foundation with pile cap for Stadtwerke Rostock's new heat storage facility. The project is located in Rostock's Schmarl industrial estate in the immediate vicinity of the Warnow river and the Rostock overseas port.
The 55 m high heat storage facility has a diameter of 35 m and stands on 151 DU 900 mm large-diameter drilled piles with an average pile length of 37 m.
A new 55 m high hot water reservoir (DU 35m) is being built on the premises of the Rostock public utility company. For the load transfer of the reservoir, with a volume for 45 million litres of water, 151 DU 900 mm reinforced bored piles and a reinforced pile head plate were constructed.
This was preceded by a public invitation to tender with extensive prequalification for performance in the special boundary conditions of construction time, subsoil, cased bored piles and geometry and quality of pile head slab. Implenia Spezialtiefbau GmbH was awarded the contract.
The subsoil is divided into fill and alternating layers of boulder clay and sand. The groundwater level was approx. 1.50 m below the working level. First, an excavation pit with closed groundwater drainage was constructed for the installation of the base course as working level for 2 large drilling rigs and one lifting rig.
Prior to the construction of the bored pile foundation, a static and a dynamic pile test load and later on 3 further dynamic pile test loads were to be carried out on structural piles. The bored piles were fully cased to a maximum depth of 38 m with two reinforcement joints each.
Subsequently, the reinforced pile head slab with a diameter of 37 m and a thickness of 1.35 m, raised 17 cm in the middle, was produced by our subsidiary Implenia Regiobau GmbH. Afterwards, 4 to 5 cm of mastic asphalt was applied as a damping and levelling layer and the edge areas of the excavation pit were backfilled.
Services in detail
1 piece static pile test load with foot pressure load cell and 6 measuring horizons for deformation measurement
4 dynamic pile test loads
151 reinforced bored piles, DU 900 mm, 5,700 m
7,100 m³ excavation and disposal of drilling material
10 wells with closed dewatering
1,700 m³ base course installation
1,400 m³ reinforced pile head DU 37 m and height 1.35 m