The acquisitions boost the size of WSP by more than 500 employees, taking its worldwide workforce past 8,000.
Sells is a transport and infrastructure engineer with expertise in bridge design and engineering. CBP Consulting Engineers is a German engineering and project-management group.
WSP chief executive Chris Cole said: “Both Sells and CBP are regarded as leaders in their respective fields, and I am delighted we have secured the services of the entire management teams of both companies who are committed to the vision and values of the WSP Group.”
Sells operates from eight offices across eastern USA and is currently working on a number of major transport projects in New York, including the £250M interim reconstruction of the four-mile long Gowanus Expressway Viaduct and the £125M replacement of the approach structures to the Bronx Bridge.
It is also a recognised name across the eastern USA in bridge inspections, which is likely to be a booming market in the wake of the Minneapolis bridge collapse.
CBP is based in Munich and current projects include work on Berlin International Airport; the planning coordination of terminal extensions at Frankfurt Airport; project management of the convention and conference centre at the Mercator Hall in the Duisburg City Palais and multidisciplinary services for a 39,000m2 mixed-use development in the centre of Munich.