Design & Acoustic Performance of a Spring Isolated Outdoor Rooftop Basketball Court

Alex Chambell , Lloyd Cosstick , Timothy Murray , David Yates

New Zealand Acoustics, 28(1), pp.4- 11 . (2015).

The proposal of a rooftop basketball court created an issue of significant impact/footfall noise and structural vibration ingress to the sensitive environment beneath. As part of a new building in a dense urban environment, a unique solution had to be designed due to the maximum weight capacity of the underlying rooftop structural slab and FFL design controls. Further challenges were faced in the form of fluctuations of up to 30 mm in the level of the underlying structural slab and subsequent excessive deflection caused by a relatively high live load. The final design incorporated the use of over 300 cast in ‘jack-up’ style mounts complete with 25 mm deflection springs within a 100 mm secondary concrete slab covering an area of approximately 630 m2. Installation of the court encountered few problems and upon completion small deflections of the slab could be felt underfoot however there were no unfavourable ‘trampolining’ effects generated by live loads. Completion testing showed a significant reduction in impact noise levels between the isolated court and an exposed portion of the structural slab