In this paper, an adaptable and architecturally flexible lateral stiffening system for tall timber buildings between 50 and 147 m is developed and investigated. The system is based on a tube-in-tube concept. The internal tube consists of a braced timber core, and the external tube consists of a frame structure with semi-rigid beam-column joints in the façade. Based on a finite element framework, more than 500 000 simulations with different configurations are carried out to assess the performance of the lateral stiffening system subjected to wind loading. The resulting data is used to assess the feasibility of the tube-in-tube system and stiffness requirements for the beam-column joints.
The dynamic response of semi-rigid timber frames subjected to wind loads is investigated numerically in this paper. The dynamic response of more than one million unique frames with different parameters was assessed with the frequency-domain gust factor approach, which is currently adopted by Eurocode 1, and the time-domain generalized wind load method. In the generalized wind load method, the frames were simulated for three different wind velocities with five simulations per unique combination of parameters, resulting in more than twelve million simulations in total. Qualitative and quantitative observations of the dataset were made. Empirical expressions for the accelerations, displacements, and fundamental eigenfrequency were proposed by the use of nonlinear regression applied to the obtained numerical results and a frequency reduction factor was developed. The wind-induced accelerations obtained by the two methods were compared to the corresponding serviceability criteria according to ISO10137, providing insight about the feasibility of moment-resisting frames as a lateral load-carrying system for mid-rise timber buildings. Comparison between the theoretical gust factor approach and the generalized wind load method showed that the gust factor approach was nonconservative in most cases. Finally, the effect of uniform and non-uniform mass distributions was investigated, with a theoretical reduction in top-floor accelerations of 50% and 25% respectively.
Vibration serviceability of various types of timber floor systems has claimed much attention during past decades. Yet the definition of robustly reliable engineering design approaches has remained elusive, except in well-defined situations. Successful design depends on having appropriate vibration serviceability performance assessment criteria, and ability to predict floor response parameters used by those criteria. This paper addresses prediction of dynamic response characteristics of cross-laminated-timber (CLT) floor systems using finite element methods. Attention is focussed on systems that contain realistic construction features like intra-slab CLT panel to-panel joints, and variations in floor slab edge supports. Modelling assumptions are verified by comparing analytical predictions with test results.