Suspended over a car park using a clever Vierendeel girder design, the new Adelaide Road surgery in London’s Swiss Cottage is an inspiring solution to severe space problems for a busy, urban group medical practice.
The main structural problem that needed to be overcome was that of spanning the existing car park without inhibiting clear floor space. A clever Vierendeel form steel girder was designed that was deep enough to span the car park but also maintain free circulation within the floor space. The system took the form of a top and bottom member connected with vertical column members only. There are no diagonal members, and the loads are carried within the framework. The main girders, which have a span of 20m, are supported on columns, bearing onto concrete piles.
Clever material selection
The most innovative aspect of the new surgery is the way in which different materials have been used to work together. The building has a very striking appearance due to the total contradiction that wood and steel have when used together. This is what gives the building its “swiss cottage” feel. The architects were mindful of the clients wishes not to go over budget with the project, but at the same time wanted to provide a long term cost effective structure. The client was advised to opt for low maintenance finishes, and unpainted and naturally weathering surfaces were specified. These were chosen for their durability and long maintenance free life.
The timber cladding is a western red cedar that exudes a resin which acts as a natural preservative, giving a 60 year maintenance free life. Many of the steel elements used in combination with the timber have been hot dip galvanized. All the window frames are galvanized with timber surrounds, as are the external door frames. The tubular V-stays that support the overhanging eaves are also galvanized.
The most imaginative use of galvanizing is perhaps the access walkway which is formed from a combination of concrete and steel panels. The steel panels have been galvanized with the word “Surgery” punched through them. This becomes most effective at night, when imaginative lighting picks out the zinc crystal patina of the galvanized panels, adding a whole new dimension to the walkway. Many smaller items have also been galvanized including the guttering elements, “Z” purlins and the flashings.
The above photos were taken on a recent visit to the surgery. Ad-hoc coating thickness readings were taken that showed well in excess of an 85 μm coating for the majority of the steelwork. This will provide at least another 50 years of protection. In total, a maintenance free life of more than 70 years will be achieved. The galvanized steel used for the access walkway in particular looks as if it was installed a few months ago rather than 22 years.
Images © Iqbal Johal