New construction of two office buildings

Back in 2017, ERNE dismantled and gutted an existing office wing with workshop. The old structure contained contaminated parts of the building, which were decontaminated and disposed of professionally. Once the buildings had been completely dismantled, the construction site for the new office buildings was ready.

The excavation for the three-storey basement, which will later connect the two office buildings, took place from mid-2017 to mid-2018. Around 70,000 m3 of gravel was excavated using a teledipper (telescopic grab), in some cases to depths of up to 15 meters. As the two new buildings will later be 4 m deep in groundwater, dewatering was necessary to protect the excavation pit from water ingress. The groundwater level was lowered using drilled filter wells. The excavation pit was supported with overlapping and disintegrated bored pile walls (with or without strand anchors), underpinning walls and vault walls (some with strand anchors), which were lined with both wood and concrete. The 1 m thick, solid floor slab for the basement could then be concreted.

The architects had designed beautifully shaped staircases for the interior of the building, which would later connect the individual floors. The floor plan of the staircase differs on the various floors, is never identical and the underside is inclined on several sides. Detailed floor plans were created using a BIM model of the staircase. Together with sister company HUSNER, specific, custom-made timber formwork was produced to enable optimal work on the construction site. Around 250 individual items of reinforcement were used for each staircase. It took two ironworkers over two days to lay the reinforcement. The staircase was constructed in fair-faced concrete quality.