Introduction
Edgewater Contracts & Specialist Joinery appointed Groundforce Shorco to supply a propping solution for the excavation element of a new mixed-use scheme in Edinburgh, to include a new boutique hotel an extension to the formerly named Jurys Inn, on Jeffrey Street together with residential blocks, retails units, and the creation of public space.
Located in the heart of Edinburgh city centre, the site is steeply sloping from the royal mile down to Jeffry Street and surrounded by listed buildings of historical significance on all sides including listed churches.
Challenges
Given the contours of the site, a problem arose when trying to find a suitable method of retaining the surrounding buildings as they were being undermined by a depth of up to nine metres on the south side of the site towards the Royal Mile.
A series of tests were carried out to establish if the vision for the site was even possible. After a GI report failed to provide what Edgewater considered to be adequate information to start development, several additional checks were undertaken to assist with research and design, including: load take downs of all surrounding buildings; slip circle analysis; ground movement assessment; and continuous robotic monitoring of surrounding properties.
A pre-cast concrete construction was chosen for this scheme from both a logistical and speed perspective. when Edgewater started to develop the design for it, they realised that pre-cast construction on its own would not be suitable.
The excavation area is roughly 50 metres across by 50 metres back. It’s an L-shape of contiguous piled wall solutions with a capping beam on top. The capping beam undulates up and down around the perimeter, which was a challenge. It was not only going up and down, but also raking left to right to allow construction of the structure internally. Therefore, it was not a straightforward design as it incorporated quite a lot of different connection details.
Solution
The city centre location also provided a number of challenges, the first of 
which was access to the actual site itself. Deliveries have had to be carefully timed to avoid rush hour traffic.
Once the piling solution was confirmed, an appropriate temporary propping solution was then required. Groundforce Shorco supplied MP150 props which were installed around the site.
Groundforce Shorco were tasked with holding back/retaining the surrounding area. Before, the site was totally built up and was just a giant slope, and with so many buildings being up shored by their props, it was paramount that nothing moved.
Groundforce Shorco engineers worked with Quinn Piling and Edgewater to achieve a specific stiffness criterion. The position of the props was almost dictated to by the permanent structure itself. Groundforce set all the props out to avoid the permanent structure, as they had to be constructed around it and still removed from in between them.
Working together with Edgewater at an early stage achieved a more cost-effective solution, and by default, less material was used so there were environmental savings as well.