Development of frequency curves for cross-laminated timber (CLT) floors using dynamic stiffness method

Abstract

Cross-laminated timber (CLT) panels have an increasing market share and extensive application in civil engineering practice, as full size walls or floor structures. CLT provides a compelling alternative to the concrete and steel (as conventional building materials), providing a low carbon footprint and comfortable living conditions. However, the orthotropic elastic material behavior of wood and the crosswise lay-up yield a relatively complex kinematics of CLT, characterized by high shear deformation across the thickness. This complicates the appropriate and accurate kinematic description of CLT and further prolongs the design phase of the real engineering structure.

Due to the relatively low weight, CLT floors are particularly prone to human-induced vibrations, causing vibration serviceability issues such as annoyance to human occupants and dysfunction of vibration sensitive equipment. Therefore, for the accurate response prediction of CLT under dynamic loading, its fundamental dynamic properties should be derived first.

In the paper, dynamic stiffness-based FREEVIB software, previously developed by the authors, has been used for modeling and prediction of the free vibration characteristics of CLT floor structures. Frequency curves taking into account: (i) span-to-thickness (a/h) ratio, (ii) plate aspect (a/b) ratio and (iii) different combinations of end constraints, have been developed using FREEVIB and systematized to be easy for use in engineering practice, especially in the conceptual design phase of CLT-based buildings. The results have been compared against the current CLT design recommendations.