Good vibrations on the South Bank

When, in 1949, Robert Matthew, Leslie Martin, Peter Moro and Edwin Williams planned the Royal Festival Hall, which closed for an 18-month refurbishment on Friday, they were faced with a tight site indeed for a “people’s palace”.

The building, housing a 3,165-seat auditorium and London’s largest dance floor, had to fit on a 200ft2 site, hemmed in by the river, the Hungerford Railway Viaduct and the site for Lasdun’s planned National Theatre.

Mike Elks, project engineer with Taylor Woodrow, could only dream of such space when it came to adding an extension immediately next door. The four storey building, containing second and third floor staff offices intended to free up space in the RFH and ground floor retail, was designed by Allies & Morrison.

The proximity of the site to the main London to Kent and Sussex railway line has forced Elks and his team to resort to unusual methods when adding the skin of the building. The greatest risk came from a signal, which must be visible at all times, sited two inches from the outside wall and even dictated the design of the skin. This was originally designed at full elevation height to be pivoted into place from the ground, but later revised to comprise prefabricated unified panelling. This panelling will now be swung from the shorter side of the building around the corner on a monorail and dropped into place on the railway-facing side. The ½ tonne, 1.7m-wide, units will be restrained by steel rope to prevent them getting into the path of the railway.

The danger of objects falling from the overhang onto highly-trafficked areas has also meant that tower cranes could not be used. The steel frame, which took three months to construct, was built using scissor lifts.

All this explains why, even though the building is little more than a sleekly detailed box, its project planning and risk management have stretched even a man as experienced as Elks, who oversaw much of the recent work on the Heathrow Express. He calls it the most challenging and enjoyable project he has ever worked on. And it’s not just the trains the team needs to worry about. Altogether, six million people pass by the site annually, including commuters, on the rat run between Charing Cross and Embankment stations and Waterloo, and tourists walking around the largest arts centre in the world and from the London Eye to the Tate Modern.

A main potential cost hindrance – possession orders, which would have seen trains on the rail line stopped during designated hours – has been avoided due to solutions put in place by project managers, Bovis Lend Lease. Collaboration with Network Rail began six months before the project started in February and remained close throughout, with the track operators keeping a presence on site throughout construction. The train operators were even responsible for approving the new skin installation method.

Difficulties in building the RFH extension were compounded by the site having only one access point, meaning that everything had to be built from one end to the other.

But if the nearby railway provided headaches during construction, failing to take account of its potential effect on residents would have proved disastrous in perpetuity. The Royal Festival Hall was built with double concrete walls to prevent the sound of trains from ruining concerts. For the modern, steel framed extension, a modern solution had to be found. So, to eliminate vibrations, the structure was built on a grid of concrete longitudinal and traverse ground beams. These rested on pile caps under which are elastometric bearings, more typically used to reduce the effect of earthquakes on buildings. The extension does not touch the ground or the bridge. To bring noise levels to within health and safety standards, Paul Harding, in charge of interface design production for Taylor Woodrow, worked to find the optimum sized floor area and thinnest low-frequency acoustic wall that would block out train noise while maximising office space. To make matters yet more interesting, Network Rail told Harding that trains rumbled at different frequencies depending on the age and model.

Another key factor in pre-work cost planning was allowing for the uncertain nature of a much excavated riverside site. Richard Baldwin, from the project’s QS Davis Langdon, feared the surveys were not to be trusted and established a contingency sum in the budget that would take account of unknowns during the build. He was proved prudent when an unmarked six-foot deep piece of concrete was discovered and had to be incorporated into plans.

Taylor Woodrow and partners are pleased at how the project is progressing. Risk and project management have played a larger than usual part in the process. Even with all the work done upfront, Elks estimates that the site restrictions imposed 30-40% higher costs and 30% higher duration on the project.

Davis’ Baldwin points out that overruns were minimised thanks to the simple nature of the building.

It is no coincidence that Taylor Woodrow had managed the Royal Albert Hall restoration project. During foundation laying at RFH, care was also taken to avoid rehearsal and concert times. Construction, transportation and music could then take place together in near-absolute harmony.