Construction time and cost for post-tensioned timber buildings

This paper describes post-tensioned timber alternative designs for a six-storey office building in New Zealand. The building has long-span timber–concrete composite floors supported on laminated veneer lumber beams, columns and walls. Lateral loads are resisted with moment-resisting post-tensioned timber frames in one direction and post-tensioned cantilever timber walls in the other direction. This paper compares the time and cost of timber construction with the concrete building actually being constructed. Construction times of the timber and concrete buildings are found to be almost identical. The cost of the timber alternative is approximately 6% more than concrete or steel designs. This paper demonstrates the opportunity for post-tensioned timber to compete with concrete and steel for multi-storey long-span office buildings, providing a more sustainable alternative.