marți, 8 ianuarie 2008
Structural bearings help maintain silence at convention centre
One of the prime design criteria for the International Convention Centre (ICC) in Birmingham, UK was perfect acoustics despite a main rail-line running beneath it. Andre laminated natural rubber bearings from Trelleborg Engineered Systems were used to support and isolate the eleven auditoriums. Recent tests on these revealed virtually no signs of creep or aging after more than 15 years in situ.
Birmingham’s International Convention Centre (ICC) was built in 1991 to house several halls and auditoriums, including the Symphony Hall, home of the world-famous City of Birmingham Symphony Orchestra. Seen across its broad approach plaza, the ICC rises bright and shining above the noise and bustle of the city centre. Few visitors would dream that the entire massive structure is in effect floating, mounted on more than 2,000 rubber bearings.
Once inside, the noise stops and within the Symphony Hall silence is absolute.
In fact, you have to be careful what you say, as everything is clearly audible in the far corners of the hall. To achieve this the design team - including Over Arup, architects Percy Thomas Partnership and the Artec acoustic consultancy - faced a variety of challenges, notably the fact that a rail tunnel runs directly under part of the site. The solution was to isolate the building raft on Andre rubber laminated bearings from Trelleborg Bakker, an operating unit of Trelleborg Engineered Systems, a business area of Trelleborg Group.
The final design involved over 2,000 bearings each measuring 300mm x 300mm x 125mm deep (12 inches x 12 inches x 5 inches). These were precisely compounded to take working loads of up to 40 tonnes each and to isolate dominant frequencies of around 40Hz. Positioned in groups of eight on the column heads rising from the piled foundations, they carry the concrete raft from which the superstructure of the building rises. The rubber supports provide a physical barrier between the building and its foundations.