Rare ground collapse threatening 20,000 homes in the Netherlands – Sweco’s seismic calculation experts helping to save residential area

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Rare ground collapse threatening 20,000 homes in the Netherlands – Sweco’s seismic calculation experts helping to save residential area

16 April 2019
Earthquakes can sometimes occur due to surprising reasons. They do not always take place over tectonic faults – they can sometimes happen on solid European soil. Safety experts are required to possess not only mathematical engineering expertise, but also skills in dealing with human emotions. Special expertise in seismic calculation was found in Finland.

In the Groningen area in the northern Netherlands, unexpected earthquakes have taken place in an exceptionally unfortunate place: the pumping of natural gas has caused sudden changes in the density of the soil in the area surrounding the gas field, and has thus led to tremors. There are approximately 20,000 homes in the area as well as offices and industrial buildings.

“The 3.6 Richter earthquake that happened a few years ago shook local people when structural damage began to occur in buildings within an area of approximately ten kilometres,” says Berthold Berger, a seismic calculation expert and Sweco’s Project Manager of sustainable construction from the Netherlands.

Smaller earthquakes have occasionally taken place in the past, but it was not until the larger earthquake happened that the cause was identified and it was understood that the probability of future tremors was very high. Together with the natural gas company, the Dutch government began to take action, and the durability of the buildings in the area is now being surveyed.

Results through the cooperation of European-wide network of experts

Sweco is one of the experts operating in the area, and the common objective for all parties involved is to survey the structure of people’s homes.

“Our client needs the best possible special competence for studying earthquakes. We at Sweco were able to rise to the occasion with the help of experts working in Finland. We thereby formed a team of experts from Sweco employees in Finland and the Netherlands, and we have worked together on this project since March 2018. Sweco has a unique chance to provide special competence, as our European expert network is both extensive and comprehensive,” Berger continues.

Kevin De Bleser leads a seismic calculation team at Sweco Finland, which is involved in the project to save the buildings in the Groningen area.

“Our team is collaborating closely with Sweco’s Dutch experts. In Finland, Sweco has special expertise in seismic calculation, i.e. examining the effects of earthquakes. Additionally, the company shares its multidisciplinary expertise in various challenges related to structural engineering, as well as static calculations. We are calculating whether the local detached houses are able to withstand an earthquake measuring 5.0 on the Richter scale. We will submit a proposal regarding reinforcing the structures based on these surveys. Our Dutch colleagues are also responsible of the geotechnical analyses and surveying the condition and restoration of the soil,” says De Bleser, discussing Sweco’s work.

People’s distress must be acknowledged and their questions answered

Many people’s homes have been damaged, and the locals are understandably very worried.

“We are talking about people’s most important belongings. The technical calculation work is only one part of our task. We need to be able to clearly explain the survey results to residents in the area and alleviate their worries. We are here to help them. Thus, communication plays a very important role, and we must be able to tell people about the progress and the phases of the project through different channels and in different ways,” says Kevin De Bleser, considering the challenges and background of the work.

“Our job is to make people’s everyday lives safer with our technical know-how. Sweco Finland has numerous special experts that can tackle structural engineering challenges at this level. Together with our Dutch colleagues, we are part of Europe’s leading expertise organization and our know-how has already been recognised.”