Cast stone from UKCSA Full Member Plean Precast was used for the finish to the three pavilions in the Union Terrace Gardens project which not only allowed the architects create the symbolically important “tram” form, but also provide a finish that would complement the historic Granite heritage.
The high degree of precision in the design and manufacture of the panels allowed the elements to come together seamlessly on site, with panel joints minimised and set out to the architect’s specification. Structurally, there were several considerations in forming the components, which are both light and slender at the upper level, and heavy and expansive at the lower levels. The overall system was designed as self-supporting from foundation level, avoiding the need for any intermediate vertical support from the primary structure and ensuring consistency of the panel joints.
Achieving the profiles demanded careful consideration by Plean in respect of reinforcement and cover to the leading curved edges. Detail coordination was paramount and all components (including reinforcement and cast in fixings and brackets) were modelled and detailed to BIM Level of Detail 400, to ensure a precision fit throughout production and assembly.
Small section sizes and component durability, particularly to the upper mullions and transoms, were achieved through considered detailing and specification of cover, tolerances and testing. The provision of concealed lifting and fixing points also presented challenges and drove the development of bespoke restraint brackets and cast-in plates. This required effective collaboration between designers, the cast stone manufacturing UKCSA Full Member Plean Precast, and installer to successfully deliver the architectural vision in a buildable and robust manner.