WSP Group plc

WSP Group plc is a global business providing management and consultancy services to the built and natural environment.

Established in the UK in the 1970s and listed on the London Stock Exchange since 1987, the company has grown through strategic development into one of the largest international consultancy groups in the world employing ca 9500 staff worldwide. WSP operates as a specialist in the property, environmental, transportation and infrastructure sectors providing a full range of services from planning through to design, implementation and maintenance.

Thanks to its multi-disciplinary capability, WSP can offer fully-integrated delivery teams to local and global clients. We have a strong commitment to local business development and sustainability in all of the countries where we operate.

WSP Group has extensive international experience in America, UK, Europe, Africa, the Middle East, Asia and Australia, gained through working in over 60 countries and currently has permanent offices in 35 countries.

Our services
We constantly respond to the changing demands of the marketplace focusing on three key sectors: Property, Transport & Infrastructure and Environmental. We provide a diverse range of design and management services meeting all the needs of our three key sectors. These serve the demands of many different markets from defence to sport and leisure, and from aviation to urban regeneration.

WSP Civils Sweden
WSP Civils Sweden is the principal civil engineering division of WSP Group plc with ca 700 staff. We are large for a simple reason: it enables us to offer clients several advantages. We would like to briefly set these out. Large scale means we have experts in many diverse disciplines. We can therefore offer services to cover every phase of a project, from early pre-studies, inquiries and planning through to design, construction and management. In one organisation, we have engineers, landscape architects, planning architects, surveyors, geologists, urban planners and experts in many other disciplines. We can therefore form teams of people who have already successfully worked together many times before and achieved superb results. This saves time and money – efficiencies we pass on to clients enabling them to achieve more for less. We not only have all this expertise in-house; we combine it with local knowledge through an extensive network of offices around the world. This allows us to manage diverse disciplines across different countries, cultures and industries. WSP has built up a vast range of knowledge and experience from having completed some of the most challenging engineering projects of recent years. We bring these insights to every project, ensuring all our clients benefit from the latest innovations and technical advances.

We have emphasised our size, but what of our approach? What is it like to work with WSP? We are ethical so we take environmental concerns extremely seriously. We consider the impact of engineering projects on people’s lives and place great importance on improving quality of life through good design. One of the hardest things to convey is the excitement that comes from working with other disciplines and sharing ideas in pursuit of the best solution. Everyone’s contribution is valued at WSP, regardless of whether you are a generalist or a specialist; young or old. We believe that is why we consistently produce brilliant, original, and often very beautiful work. We organise our services into five core areas: Roads and Highways; Railways; Traffic and Transport; Bridges and Tunnels; and Technical Support Systems. In addition, we provide clients with many other specialist services.

The City Line, Stockholm

Solutions for Stockholm’s rail bottleneck
Some 3 million people live and work in Stockholm and the surrounding region. It is a market place for trade with goods and services, and a centre for culture and entertainment. A meeting place for people from all over the world. Many people also commute between work and their homes in the Region, and the investments made in the railways around Lake Malar have served to make the train an attractive alternative to the car. The City Line is a precondition for the long-term development of rail traffic and for creating an attractive and efficient public transport system that meets the demands and requirements of the future.

Stockholm is built on many islands. Water surrounding the city all sides gives it great natural beauty, but causes difficulties for city centre communications. In rail traffic terms, Stockholm is waspwaisted. There are at present only two railway tracks running through Central Stockholm that have to be shared by all rail traffic – commuter trains, regional trains from the Region, long-distance trains and freight trains, a situation which has existed since the railway first reached the city back in 1871. There is not much space – particularly in the rush-hour. Each day, these two tracks carry over 500 trains, about 60% of which are commuter trains. Eight out of every ten train journeys made in Sweden either begin or end in Stockholm. At the same time, a quarter of a million trips are made by commuter train every day.

The City Line is a £1.3 billion rail-tunnel project with two railway tracks running beneath Central Stockholm. The tunnel will extend from the commuter train station Stockholm South to Tomteboda, running in rock tunnels beneath Sodermalm, Riddarholmen, Norrmalm and Vasastan. Two completely new stations will be built – City Station and Odenplan Station. Work on the City Line will continue for some nine years. The City Line’s two new tracks will serve to double the capacity for rail traffic from the current 24 trains per hour in each direction to 48 – something that passengers both within and outside Stockholm will notice in the form of more frequent services, more punctual arrival and departure times, and shorter travel times.

The main part of the City Line will be in rock tunnels and the bedrock is consisting of younger granites and gneisses. From a construction point of view, the rock is very competent and water-tight along the main part of the tunnel. However there are weak parts with extensive cracks, predominately in east-west direction. The geology above the rock surface has great variations. The most important is the esker in the north-south direction i.e. almost in the same direction as the tunnel. The esker consists of sand, gravel and cobbles, and is the only groundwater resource in the city as well. The esker permits good conditions for foundation of the buildings and the areas on the esker is not sensitive for lowering of the groundwater. The strength of the rock is extremely stable, but takes its toll on tunnelling machine, wearing cutters and racking up maintenance cost, which means that drill and blast is preferred instead of using a tunnel boring machine. As the work progresses 25mm rock bolts between 2.4m and 7.0m long will be inserted in the walls to hold them stable and they will be protected from corrosion by an epoxy coating. The tunnel area varies between 25m 2 (for single track), 110m 2 (for double-track) and 220m 2 (for stations). The area of the service and rescue tunnel is 40m 2. A total of 4.0million tons of blasted rock and 100,000 tons of soil will be excavated as 45,000 tons of dredged material. The only section of the tunnel to be build differently will be the underwater section in the south of the city, where the tunnel passes under the lake, where the tunnel will be floated into position as an immersed tube. The length of this concrete tunnel will be 370m and the width 21m.

Building a new rail tunnel in a city centre between 10 and 40 metres below the surface is a very complex and high-risk undertaking – a huge challenge. In fact, the project’s geotechnical models are the most complex ever run in Sweden. The new tunnel intersects the existing subway in two locations, so blasting necessitates the relocation of the subway track. WSP’s proposals included the preparation of a new prefabricated bridge concept to carry traffic during the construction period. The Swedish Rail Administration has for some years ago appointed WSP to carry out conceptual design and project management for the permanent way, water and waste-water installations for the entire length of the tunnel, as well as undertake rock geotechnical investigations and conceptual design for rock tunnels and concrete works. Recently WSP won a huge contract. We are very proud to have been awarded one of the biggest and most prestigious projects in the history of WSP. Our multi disciplinary role includes preparing the tender documents and construction documents for the central parts of the City Line from Odenplan station to the southern dock of Riddarholmen; site supervision and project management of the Norrmalm tunnel and Norrstrom tunnel; and designs for the City station structure. This part of the project is worth around £20M.

For more information, contact:
Eskil Sellgren, Deputy Managing Director
WSP Sweden
T: +46 8 688 61 87, E: eskil.sellgren@wspgroup.se