TARRC revisits Albany Court, Marriott Hotel & Pelham Bridge
As part of the visit by Datin Paduka Nurmala Abd Rahim, Secretary General, Ministry of Plantation Industries & Commodities Malaysia, TARRC revisited Albany Court, an apartment building above St. James's Park tube station, The Marriott Hotel at Swiss Cottage and Pelham Bridge in Lincoln. (Right: Datin Paduka Nurmala Abd Rahim with Dr Kamarudin Ab-Malek, TARRC CEO and Dr Stuart Cook, TARRC's Director of Research, at Albany Court in London.)
These structures are important to TARRC due to their historical significance; Pelham Bridge and Albany court are the ‘firsts’ in the use of rubber-steel laminated bearings for bridge bearings and vibration isolation respectively.
TARRC (formerly known as the British Rubber Producers' Research Association (BRPRA), Natural Rubber Producers' Research Association (NRPRA) and Malaysian Rubber Producers' Research Association (MRPRA)) engineers were pioneers in the development of this technology and were instrumental in the design and some of the testing for these types of applications since the 1950s.
It started with the first bridge in the world to be placed on rubber-steel laminated bearings, Pelham Bridge in Lincoln, in 1957. In 1955 the firm of consulting engineers, W.S. Atkins & Partners, contacted TARRC (then known as BRPRA) to consult on the technical possibility of designing rubber bearings large enough to use between the bridge deck and its supporting piers. This would enable the deck freedom of movement to take up expansion, contraction, coping with the heavy vehicles braking and accelerating, weaving traffic and the cross thrust of wind.
(Above: Pelham Bridge carrying traffic over the train tracks in 2012.)
Pelham Bridge is a structure of considerable historical note, being that it is nearly a quarter of a mile long, passes over a main line railway, carries a dual carriageway and pedestrian pavements as well as being so near to the town centre with unobstructed views of St. Andrew's church to the south and the famous Lincoln cathedral to the north.
The natural rubber bearings designed specifically for this project consisted of specially compounded rubber layers laminated with steel plates to provide high vertical stiffness while offering soft horizontal stiffness to fulfill all the requirements of deck’s longitudinal movements and was confidently expected to have a long life with no maintenance. The longevity of the bearings was confirmed by tests carried out by TARRC on the bearings extracted in 1997, which showed no deterioration in the performance of the rubber bearings. The rubber bearings were manufactured by Andre Rubber Co. Ltd in Stoke-on-Trent. This project was instrumental in producing bridge bearings which solved past problems associated with steel roller bridge bearings.
(Above: Rubber bearings on top of the metal and concrete piers.)
The experience with Pelham Bridge project gave civil engineers the confidence to use rubber bearings in supporting heavy structures which led to adapting this technology to isolate buildings from ground borne vibration. In the mid 1960s W.S. Atkins approached TARRC (then known as NRPRA) with another ground breaking project.
Albany Court is a block of flats directly above St James's Park tube station in London and was the first building in the UK (1966) to be isolated from low frequency ground borne vibrations using rubber-steel laminated bearings. This was the first time it was possible to put living accommodation above a train station. If this structure was not on rubber bearings the occupants of the flats would be subjected to the vibrations of the trains arriving at and leaving the station only a few metres below street level. Using laminated rubber bearings was the cheapest means to fulfill this essential requirement, costing only around 2% of the total building costs.
(Above: The block of flats above the tube station and a diagram showing the flats directly above the train.)
In 1972, The Marriott Hotel Regents Park (then The Holiday Inn Swiss Cottage) was built just ten metres above one of the busiest train lines in Britain, the main West Coast rail line from Euston station. However, not a sound can be heard, nor a vibration felt in the hotel from either the high speed or the freight trains thundering below as the hotel is completely isolated from the ground by some 240 rubber-steel laminated bearings in the car park basement, the first hotel in London to be built this way.
(Above: The Marriott Hotel in 2012, the piers in the car park basement and the rubber bearings behind white fire protection panels.)
This technology paved the way for not only protecting buildings from the ground borne vibrations due to traffic and trains but is now being used against earthquakes. The former isolates the structure from high frequency low amplitude vertical vibrations where as in earthquake protection the ground movement is low frequency high amplitudes and predominantly horizontal.
The first building in the world to be protected from earthquakes using TARRC's (then MRPRA) high damping natural rubber bearing base isolation system was the Foothills Communities Law & Justice Center in San Bernardino, California, built on 98 rubber bearings and opened in 1985. The building subsequently survived the 1994 Northridge earthquake which struck at the Fernando Valley region of Los Angeles, Southern California and measured 6.7 on the Richter scale.
The University of California, San Diego recently completed giant shaking table tests on a mock five-storey hospital that confirmed the expectation that base isolation not only protects the building against earthquake ground motion but also the medical equipment and contents inside. This means that the hospital can remain in service after the seismic event. The artificial earthquake can subject the building to movements similar to that of real earthquakes. To read more on this please see BBC news website at www.bbc.co.uk/news/technology.
Base isolation is now considered as one of the preferred methods to protect buildings and their contents from the catastrophic destruction of earthquakes. For many years TARRC has continued its efforts to increase the awareness of this novel technique to structural engineers and decision makers throughout the seismic parts of the world. Recently their expertise has been used to base isolate the second Penang Bridge currently under construction in Malaysia, due for completion in November 2013.For further information on TARRC's continued research work in this area please contact Hamid Ahmadi.
Tun Abdul Razak Research Centre © MMXII