The centre was conceived as an extension of the town with its sweeping form matching its windswept site
Offsite construction provided an ideal, if nail-biting, solution for Southend’s new cultural centre, which is now in place at the end of the pier. Amanda Birch reports.
“Relieved and relaxed that it’s all over” is how Kier’s Roy Francis sums up his feelings on the day after the “Big Lift” — the lowering into place of a 170-tonne £3m cultural centre onto its new home at the head of Southend Pier from a 400 tonne marine sheer leg crane. “We only had two hours either side of high tide when the lift could happen — it was a very small window of opportunity and it all went very smoothly,” says Francis, senior contracts manager at Kier Construction, Eastern.
The 350m2 multi-purpose arts space was conceived by Swedish architect White Arkitekter with structural engineer Price & Myers as an extension of the town, with a sweeping form to match its windswept site. It walls and roof are constructed of steel triangular panels, sitting over floor-to-ceiling glazing.
Over two days in May, the pre-fabricated steel structure was towed by two tugboats on an adapted barge from Tilbury Docks where it had been constructed to Southend.
During the Big Lift itself, a wind speed of no more than 4 on the Beaufort scale, or a moderate breeze in non-sea faring terms, was required during the operation to lift the steel structure from the barge. A slight change in the conditions could have forced the operation to be called off until they improved.
The steel structure was transported by barge from Tilbury
To complicate matters, the building could only be lifted from the barge at high tide, when the water is deep enough for the huge crane to operate close to the pier. The building was lowered at a rate of 2mm a minute to minimise possible impact damage to the pier’s cast iron piles.
But the Big Lift was only the finale to a project that began months earlier. The first key decision for Kier and Francis was where and how the centre should be built. There had been plans to construct it at the end of the 2,158m long grade II listed pier, but this proved too expensive. Instead, the decision was made to fabricate offsite on a wharf at Tilbury, where a lock system allows water levels to be controlled — an important factor when it came to lifting the structure onto the barge.
Norwich-based steelwork contractor DGT Structures was selected to build the steel structure. DGT was chosen because it demonstrated it could deliver to the exceptionally tight programme — the structure was finished in just two months — while producing the quality demanded.
While work progressed at Tilbury, minor repairs and modifications had to be carried out to one of the piles and the rest of the pier structure to prepare it for the new building. The preparation work took place during winter on an exposed, windy site over 2km out to sea, where materials could only be delivered by barge or along the pier itself. Ecologists also monitored noise levels of building works which had to be kept at a minimum due to the nesting period of the turnstone, a protected bird species local to the area.
Francis was effectively overseeing two building projects, one offsite and one at sea, each with its own unique set of challenges. “We had to have two sets of safety plans and documents, but this is no worse than having two building sites,” says Francis. “The main challenge is that we have two end dates, one in Tilbury when the building was lifted off the wharf and the other in the summer, when the building finally opens.”
But the contracts manager has clearly relished the job. “It’s been a completely different experience from conventional building projects because it’s on the sea and you’re dealing with people that don’t typically deal with construction,” says Francis. “I would like to do another, but these projects don’t come up that often”.
Kier’s task now is to clad and glaze the exterior of the centre ahead of fit-out and a grand opening later this summer.
The team had a two-hour slot to complete the lifting operation
The pier had to be carefully prepared before the structure arrived
The building was lowered at a rate of 2mm a minute to avoid too much stress
News in brief
Shape of things to come
A closed-panel timber-framed system has been configured into an innovative S-shape to form the The Serpentine, Thames Valley Housing Association’s flagship affordable housing development in Aylesbury, Buckinghamshire.
Designed by Make Architects, The Serpentine is a modern interpretation of the Victorian terrace. The new community development comprises 94 homes and is designed to aid sustainable living.
Stewart Milne Timber Systems supplied and erected the high-spec timber frame for the S-shaped development of houses and flats. Its Sigma II Build System enabled Thames Valley Housing Association to create affordable housing without compromising on aesthetics, quality or delivery times, says Stewart Milne.
The use of timber frame and cladding also reduces the environmental impact of the development, which will meet Level 3 of the Code for Sustainable Homes.
Buildings from Californian-based Connect:Homes can be shipped anywhere in the world thanks to the company’s modular system which allows the units to be transported like shipping containers. Modules are 90% complete at the factory, surpassing industry standards that are typically closer to 50%, says the firm. This reduces finish time and construction costs considerably.
It could be just the ticket for those tempted by the £30m fund set up by Grant Shapps to encourage a surge in self build. www.connect-homes.com
Offsite versus traditional build study
The Construction Sector Network Yorkshire & the Humber and Leeds Metropolitan University are planning to study a mix of offsite and traditionally built new homes to assess the post-occupancy “performance gap” in both types of construction. The research team is currently speaking to private sector, local government and manufacturer partners to identify a suitable new-build site, and also hopes that BIM can be used to maximise efficiencies in both types of build.
A further planned output of the project is training and guidance for SME housebuilders in the use of SIPs and other offsite housebuilding systems. “If you provide these people with help, it will open up the market. Anecdotally, offsite is far cheaper than traditional build, but only if you have the right people putting it together correctly,” said CSN chief executive Karl Redmond.