Location: UK
Client: Balfour Beatty
RMD Kwikform supplied a façade retention scheme for the Grade A listed façade of one of Edinburgh's landmark buildings, the old GPO sorting office building alongside Waverley Station. The Victorian building, which has stood empty for over five years, is to get a new lease of life as a six-storey retail and commercial centre, retaining five existing façades on all four elevations to Waverley Station, Waterloo Place, Calton Road and North Bridge Road.
When redeveloped, the 27.6-metre high, city-centre building will have more than 20,000 square metres of floor space. The total area of retained façade is 6410m2, making it the largest and most complex facade retention project ever undertaken by RMD Kwikform. Traffic congestion and narrow footpaths dictate that the majority of the façades, which are constructed of dressed stone and are up to 2.5metres, will be retained from inside the perimeter shell.
RMD Kwikform's designers used 3D analysis to devise horizontal truss and tower solutions based around the company's high-load-capacity Megashor and Megashor Plus systems. The solution had to accommodate the façades complex shape, vehicle access requirements , the existing internal structure and the reconstruction process. A number of new components were specially developed for the project, and the façade was tied back to this support structure wherever possible through existing window openings and apertures.
Of the five supported façades, the two key ones were North Bridge Road and Waverley Station. On North Bridge Road, 56m long by 5.5m deep Megashor Trusses span between the return walls. This removed the need for temporary foundations and allowed clear access for the construction of the new foundations. At Waverley Station, 30m tall Megashor towers were been utilised. These are founded on steel pile caps and specially bored piles. Once the demolition was complete, the formation was reduced beneath the pile caps to create an additional basement level.
The demolition contractor initially explored the option of using structural steel to provide the lateral restraint to the facade. However, the cost, versatility and speed of the RMD Kwikform solution, coupled with the ease with which the inevitable modifications could be made on site, led to the adoption of RMD Kwikform's proposal.
