You’ve been the site manager for our Baarermatte project since construction began. Where are you currently in the construction schedule?

Demolition is complete: The old building, including its foundation, is gone; we’ve either disposed of the material or stored it for reuse. Now we’re at the construction pit, secured by sheet piles that we drove 18 meters deep into the ground. In construction phase W1, the sheet pile work has already been completed. To keep the excavation pit dry despite the groundwater, we’re using a so-called wellpoint system: every two meters, a filter pipe is inserted into the ground that continuously draws water from the subsoil, much like a giant vacuum cleaner for groundwater. Without this technique, the water level in the pit would rise steadily. Currently, we’re creating foundation pits, installing waterproofing membranes, and laying utility lines—the actual foundation for what comes next: the floor slab reinforcement. The ground conditions are challenging, but we’re making good progress nonetheless.

The reused concrete elements from the existing structure are a central component of the project. How exactly is this being implemented on the construction site, and what were the biggest challenges during installation?

In September, what has so far only existed on plans will become visible: concrete elements from the demolition are being given a second life as wall elements in the stairwells. Suva and our construction management team have thoroughly reviewed and approved the installation plan. The real challenge lies in the details—specifically, in handling the elements as they’re placed into the formwork. That’s why safety is the top priority during installation. 

The existing pond was relocated. What was the biggest technical challenge involved, and how did you go about it?

Originally, the pond was located where the Mobility Tower will stand in the future. It has now found a new home in the northern part of the lot, closer to the Grienbach. The porphyry slabs from the old site serve as seating there. A field herpetologist—an expert in nature conservation and wildlife—oversaw the relocation of the amphibians to ensure none were harmed. The effort paid off: frogs, dragonflies, ducks, and other animals are already thriving in the new pond.

The “sponge city” principle shapes the landscape design of the Baarermatte. How is this currently evident on the construction site, and what are the next steps leading up to completion?

Once the landscaping work is complete, stored rainwater will handle irrigation, without any additional fresh water. This is made possible by retention systems—essentially buffers—with pumps at the individual buildings, as well as a pipe that directs rainwater from the Mobility Tower directly into the pond. This ensures the pond remains well-supplied with water at all times. And because wood and standing moisture aren’t a good combination, the wooden structure is built on piles. Water can either pool there temporarily or drain away without damaging the building’s structure.

What’s next?

The excavation is ready; now we’re moving on to the foundation slab. Then in September, there will be a highlight: the installation of the reused elements in the stairwells, as well as the start of timber construction work on the Mobility Tower.