The Project 

We were awarded the contract to undertake the piling works associated with the renovation and extension of the Scottish National Gallery in Edinburgh. The aim of this project was to create a new suite of exhibition spaces, extending from existing basement foundations, that would be directly accessible from Princes Street Gardens.

The Challenge 

The project was not without its challenges: extensive monitoring was carried out on the Scottish National Gallery building throughout the duration of the work. The 300 mm and 450 mm diameter piles needed to be installed while in restricted access, which included low headroom conditions through deep basement voids and existing foundations.

We tackled potential challenges by implementing rigorous safety measures, including extensive monitoring of the building and tight vibration limits, which were never exceeded. Preliminary load-testing and the installation of permanent slip liners to de-bond the piles from the building ensured the stability of the existing structure. The final phase of work involved the installation of temporary retention and needle piles inside the existing building, which were put in place to support the building when the link corridor was later constructed.

The Solution 

The project involved the installation of 450 mm and 600 mm diameter temporary cased, rotary bored piles adjacent to (and inside) the historic building in the city centre using Soilmec SM-4 and Hutte 205 minipiling rigs. The piles were designed and installed to facilitate the construction of a new basement and to carry axial loads associated with the complex temporary work inside the existing building.

Despite the challenges faced, we completed the project, meeting all safety requirements and adhering to government guidelines. The installation of the new suite of exhibition spaces, directly accessible from Princes Street Gardens, provides a light-filled home for numerous collections of national art to be exhibited. The project has helped to showcase Scottish art and culture to a global audience while preserving the historic Scottish National Gallery building for future generations.