Investigation of the seismic performance of braced low-, mid- and high-rise modular steel building prototypes

Abstract

For buildings with repeatable units, modular construction provides an alternative to traditional on-site construction. Modular steel buildings (MSBs) are composed of prefabricated volumetric modules that are produced in a controlled environment such as a factory to be transported and assembled on-site to form a larger, permanent building. Although the studies on the dynamic behavior of modular buildings are limited to up to 10-story MSBs, the recently completed 32-story MSB in New York showcased the applicability of this type of construction beyond mid-rise structures. Additionally, in the National Building Code of Canada both the ductility modification factor and the overstrength modification factor are determined based on the type of the seismic force resisting system, regardless of the building height. Previous studies indicated that neglecting the correlation between these design factors and the height of the building could lead to inadequate design as the building height increases. The current paper assesses the seismic design factors and the seismic performances of 6-, 12, and 32-story MSBs by means of pushover analyses and bi-directional nonlinear time history analyses. The seismic performance is evaluated in terms of interstory drift, residual drift, and base shear. Pushover curves indicated that both overstrength and ductility factors decrease as the height of the building increases. Data from the time history analysis revealed that high-rise MSBs tend to exceed collapse prevention limit and develop column plastic hinges under severe ground motions. On the other hand, the residual drift ratio was found to be more pronounced in low- to mid-rise MSBs.