Deep foundations north of the border

On completion, Haymarket Edinburgh will provide more than 380,000 sq. ft of Grade A office buildings, a hotel, retail space and a vibrant landscaped public area designed to be inclusive for the benefit of the local neighbourhood and the city’s business community.

Cementation Skanska has been involved on all five phases of the Haymarket development. Working in close collaboration with Sir Robert McAlpine and the project team, we designed a solution to instal piles in-between and around the tunnels that would ensure no loading from the new buildings could be transferred onto the tunnels. This was a complex element of the works, with the design of the piles critical to its success.

This project was dependent on close collaboration with Sir Robert McAlpine, Network Rail’s Asset Protection Team and Arup, maintaining exemplary safety standards throughout. Despite it being a complex and constrained city centre site, the foundation works were completed to the highest quality standards, without incident or any Loss Time Accidents.

The project to develop a new headquarters for Barclays Bank was a corner stone of this revitalised quarter of Glasgow with Cementation providing piling and ground engineering solutions at the sites known as Buildings 1 and 2.

Having demonstrated our capabilities on the first two sites, we were appointed to work on Building 3, a new university student campus, and Building 5, a 240-unit residential apartment block commissioned by Legal & General. More recently, we also completed Building 6, a 75,000 sq. ft. office spread over six floors.

On Buildings 1 and 2, the depth of the underlying bedrock, at 35-40m below ground level, meant that the installation of piles using standard temporary casing was not an option. Instead, the most effective piling solution for the project was large diameter rotary bored piles using bentonite support fluid. This is a piling technique that we have used successfully over the years throughout Glasgow city centre.

Bentonite is an absorbent, swelling clay and our solution involved sinking bentonite piles to support the main structures using the bentonite as a support fluid for each pile bore. Prior to concreting, the old (dirty) bentonite was removed, cleaned, and sent back to support the excavation, we also reused cleaned bentonite for further piles. This activity all took place from the bentonite farm we installed on site.

To deal with the complex and varying conditions across the different sites of Buchanan Wharf, we worked closely with our customers to develop bespoke solutions for the specific challenges of each location.

Despite working in a tight, busy, city centre location we maintained an exemplary safety record with no lost time accidents reported. All piling work was completed on time, on budget and to the right quality standards.

For TSH, our existing knowledge of Glasgow’s ground conditions and other site constraints was a real advantage – enabling us to develop a solution using three different piling techniques. Full depth segmental (rotary) bore piles were used next to Argyle Street to protect the nearby Network Rail tunnel. For the core of the building and highest load areas we used CFA piles and elsewhere on the site, soil displacement piles.

In moving on to the Build-to-Rent scheme, the on-site experience gained from the first phase meant we were able to modify our approach to the very specific local ground conditions. As a result, we employed rotary bentonite instead of full depth casing on the segmental piles and used more CFA rather than soil displacement piles. A total of 638 piles were successfully installed across the two phases.

Our work in Scotland also involves significant activity in the energy sector, helping to deliver energy and connect communities by installing piles and bases for electricity pylons in some of the most remote and challenging areas of the Scottish Highlands. In 2021, Cementation was awarded a contract on behalf of Scottish and Southern Energy Networks, to construct the bases for 22 new electricity pylons in the Scottish Highlands.

We are enormously proud of our presence and history in Scotland and look forward to continuing to bring our expertise and foresight to a further 75 years of success in the country.