8-storey CLT building dynamical properties analysis and monitoring from construction to operating phase

Abstract

Driven by climate change and the quest for new low-carbon construction, there is an urgent need for full-scale, real-time observations in buildings to calibrate and validate behavior and design models. The science related to timber structure design could be improved by processing the vast amount of data on actual responses in real wooden buildings. One of the first 8-storey timber buildings in France was equipped with four three components sensors for permanent instrumentation, from its construction phase through to operation, i.e., once the occupants had moved in. First, the modal analysis of the building was obtained using temporary network, then the modal parameters (frequency and damping) were monitored over several months to observe the dynamic response of this type of buildings. The results show a significant fluctuation in parameters as a function of increasing stiffness, but above all as a function of mass during the construction and moving in phases, due to the lightweight of this type of building compared with more conventional structures (e.g. reinforced concrete or masonry structures). Once the building was in full operation, significant variations appeared depending on weather conditions (temperature, humidity, wind speed), with high sensitivity to wind, especially for damping, revealed by the nonlinear elasticity response observed. Finally, the amplitude of the vibrations was compared with the ISO10137 standard for admissible mechanical vibration, thus validating the design and opening new perspectives for a longer monitoring phase.