Mitigation of wind induced accelerations in tall modular buildings

Abstract

This paper compares two methods of mitigating wind induced vibrations in tall modular buildings. Tall buildings experience wind induced motion which can result in serviceability and habitability issues associated with occupant discomfort. Modular construction, in which volumetric modules are assembled around a reinforced concrete core, can be particularly susceptible to wind induced accelerations due to the tall slender form of the core and the small and uncertain contribution of the modules to global lateral stiffness and damping. This study analyses the acceleration response of modular buildings. Broadly speaking, for this form of construction, two approaches exist to mitigate excessive vibrations; increasing core dimensions or the addition of auxiliary damping. This study evaluates these two approaches for a large number of archetype modular structures in order to investigate which method is more effective. Of more than 6000 archetypes studied, it was found that over 40% required vibration control measures to meet ISO acceleration limits. Installing a Tuned Liquid Damper (TLD) proved significantly more efficient than increasing RC core dimensions; a 1% increase in damping achieves a similar level of acceleration reduction to approximately a 2100 mm increase in core breadth and depth. The estimated level of auxiliary damping available from a TLD is sufficient to control accelerations for the majority of archetypes considered. A method for developing curves defining the maximum feasible height of a modular building based on its dimensions and the provision of an optimum TLD is also developed. The results show that modular buildings can be used as a viable form of construction for high-rise buildings and quantify the extent to which the maximum heights of modular tower buildings can be increased using existing vibration control technologies.