Innovation in the design of cross laminated timber for long span floors

Abstract

Cross Laminated Timber (CLT) construction is now considered a viable and sustainable alternative to traditional building techniques within the multi-storey building sector. This is primarily due to the high level of prefabrication possible with CLT construction, its high strength-to-weight ratio and its potential as a carbon negative building material. As a result, an increasing number of developers and architects are requesting a CLT design option for multi-storey buildings using CLT wall and floor panels. The latter, especially long span floors, provides a challenge for engineers. Long span CLT floors have a lower natural frequency and are light in weight, which can cause noticeable vibrations. This paper examines existing analytical design procedures available to calculate floor vibrations and provides a preliminary design for floors spanning 9 m. Innovations in CLT panels are introduced, including increased connection rigidity and the use of hardwood timber species, resulting in increased panel stiffness and reduced floor vibrations. Whilst CLT has been extensively researched and tested in Europe and Canada, only limited research has occurred within Australia and New Zealand. This paper also discusses Australian and New Zealand standards and codes and the use of locally grown soft and hardwood timber species for CLT panels.