Effect of vertical component of ground motions on tall buildings: An rc dual system case study

The standard practice in analysis and design of buildings is to magnify dead loads as a surrogate for the effect of the vertical component of ground motions. An emerging body of evidence, however, shows this substitution is inaccurate and vertical component of ground motions can have an adverse effect on structures, especially given individual site conditions. This study quantifies the effect of the vertical component of ground motions on a 42-story reinforced concrete dual system tall building (Building 2B from PEER's Tall Building Initiative) located at a highly seismic site. The building is designed using the performance-based seismic design procedures. The nonlinear model of the building was built in OpenSees and Perform 3D, and response history analyses were performed for near-field and far-field records with various faulting mechanisms. This study shows that inclusion of the vertical component of ground motions can elevate column axial forces; maximum interstory drift ratio and story shear response remain relatively intact. The vertical component of ground motion has a significant effect on slab peak vertical acceleration and displacement. The paper lays out a path for future studies including the effects of the vertical component of ground motions on tall buildings with different lateral load carrying systems as well as investigating methods for applying vertical ground motions to tall buildings by quantifying vertical-to-horizontal ratio (V/H) of peak ground acceleration.