An 11-storey timber-steel hybrid commercial development constructed in constrained conditions over an existing 5-storey basement parking structure. Detailed analysis of the ground minimised the strengthening works to the existing structure. An innovative lightweight floor of steel and timber slabs coupled with mass dampers effectively reduced vibration and minimised the weight of the new storeys, reduced waste and maximised commercial return for the client.
This is an excellent example of how to achieve high-rise office accommodation on constrained sites with low carbon outcomes through the intelligent reuse of an existing structure. By using steel and cross laminated timber (CLT) in floor dampers, and raking columns in place of transfer beams, the engineers were able to achieve lightweight floor construction and 14m spans using the existing foundations.
The lightweight approach meant more storeys could be constructed, significantly increasing the commercially available floor area, and making the project economically viable. The engineers successfully worked with existing structures, responding well to limitations and constraints, and demonstrated good interaction with the client.