Gothenburg is taking an unusual and creative approach in its hunt for attractive land to develop. An artificial peninsula is being constructed in the River Göta from Masthugget, a historic city district where masts were once made for large sailing vessels. COWI is playing a key role in the planning and coordination of this new peninsula, which brings with it new geotechnical and design challenges.
The world’s waterfront cities are currently experiencing growing pains. At the same time, there is a longing for the traditional values that harbours, shipping, water and rivers represent. However, this link has often been weakened in modern cities over time, while the demand for residential properties and offices in attractive locations has increased. Gothenburg shares these problems with many other port cities around the world.
But this is about to change! As part of Älvstaden, the biggest urban development project in the Nordic Region, central Gothenburg will be linked together, almost doubling in size. This is an enormous challenge and the first, important step will be to create an artificial peninsula, covering two hectares. COWI has produced the technical requirements and conditions that are set out in the tender documentation, and contractors will be appointed in the autumn of 2021. The team is now working on technical coordination, planning, and design solutions.
“This is a once-in-a-lifetime assignment,” says Jennie Karlsson, a Project Manager at COWI and the Project Manager for COWI’s work in this project.
“This will be a flagship project; a point of reference to be incredibly proud of, not only for us at COWI, but also for the city and the developers. Working together, we will show people that it is possible to create new land areas in the water, even in locations where the ground conditions are tricky.”
Älvstranden Utveckling is part of the City of Gothenburg and has been commissioned to turn this vision for Älvstaden into a reality. The peninsula at Masthuggskajen plays an important role in the project as it links the city together and gives it a closer connection to the water. Älvstranden Utveckling is going to be the client for all the foundation work for the peninsula, which will soon have residential properties, offices, including Global Business Gate, business premises and a new quayside area.
“The peninsula will stretch 100 metres into the River Göta and the construction will involve extensive building work in deep, loose clay. But this clay is only part of the complexity of this extensive project. In-depth expertise will be required from everyone involved. Therefore, we’re so happy to have such a strong team of consultants in the planning work,” says Ida Fossenstrand, Project Manager at Älvstranden Utveckling.
Anders Malmcrona, Technical Project Manager at Elof Hansson, which is going to build Global Business Gate, agrees:
“The project is extremely challenging, both technically and organisationally, with a rare level of complexity. The coordination of all the work is incredibly important if we’re going to succeed,” he says.
The work on this new peninsula is already causing something of a stir, and rightly so. Staffan Lindén, Assistant Project Manager at COWI and the Technical Manager for this project, gives us an idea of the many technical challenges involved:
“One of the most complicated aspects is working on the design of the quay. This is because it also has to offer collision protection to make sure that the properties on the peninsula will not be damaged if a ship goes off course,” he says.
The peninsula is along a stretch of water where there is heavy shipping, with both ferries and freight traffic heading up the River Göta. Although collisions should not happen, they cannot be excluded.
“The design of the quay therefore has to be flexible and be able to absorb energy. Of course, it’s not normal to build residential properties and offices, which see high levels of footfall every day, in areas where there is heavy shipping. We have therefore had to create everything from scratch. The technical solution is unique from start to finish,” says Staffan Lindén.
As mentioned earlier, the infamous Gothenburg clay is also incredibly challenging. And the peninsula is going to be built in a place where the clay layer is unusually deep. COWI performed a trial drilling with a record borehole of 117 metres – but this was still not enough to reach the bedrock.
As a result of the loose clay, the entire peninsula will be built on a foundation of long piles. However, not all the piles will reach the rock, so subsidence will occur. A detailed analysis must therefore be made of this subsidence, both in the clay layer when piling and at existing and future developments, as well as the massive displacement caused by the piling itself. However, the experts at COWI believe that they can handle this mighty clay using their existing knowledge and precision.
“There is not very much ground that has been better documented than the Gothenburg clay, and it’s also extremely homogeneous,” says Leif Jendeby, Senior Geotechnical Adviser at COWI.
Leif Jendeby is an Associate Professor in Geotechnology and wrote his thesis on the Gothenburg clay back in the 1980s at Chalmers University of Technology – and since then there have been many different theses written on the same theme.
“Of course, there’s no room for carelessness. Although the solutions that are required aren’t extremely complicated, they are complex. We have to get everything properly into place as it will form the basis for the next step in the construction work, which will need different kinds of foundation and will have different requirements. With the right levels of willingness, respect, and precision, we can do this,” says Leif Jendeby.
While COWI’s engineers and experts are working on technical details and solutions, the overall urban development project is also garnering attention. Masthuggskajen was recently named the Citylab Project of the Year in the Green Building Awards, a competition for sustainability. The jury said that “Masthuggskajen is very much an influencer in sustainable urban development” and praised in particular the unique and coordinated investment in social sustainability.
COWI has also been involved in the climate work, as climate proofing is required not only for the completed city district but also for the design phase. COWI’s Environmental Officer, Emelie von Bahr, has been involved in developing the climate requirements for the construction phase.
“This kind of construction project produces high levels of greenhouse gas emissions. There is a lot of transport required and high levels of steel and concrete are used,” says Emelie von Bahr.
The clients are highly motivated and have set ambitious goals for minimising the emissions from the use of materials and construction,” she explains.
“The scope and strict quality requirements of the project have, for example, led us to look beyond Sweden’s borders to investigate the possibilities of sourcing recycled materials. We’ve also had to carefully adapt the proposed measures to the sensitive marine environment where this project is taking shape.”
COWI’s Project Manager, Jennie Karlsson, has been extremely busy and has had a high workload to deal with. But she feels confident and is looking forward to seeing the progress in this project.
“The peninsula at Masthuggskajen is an incredible project, which I think many cities and developers will be inspired by. Of course, it’s complex – we have to look closely and carefully at each issue, and drill down into the details and the risks – but this is going to be something unique,” she says.
“There’s something really satisfying about being involved in realising a project as important as this,” says Jennie Karlsson.
“This is something we at COWI have done before! Major challenges are part of our day-to-day work and we feel confident as with have such a competent team.”