Title: Drift Demands on Reinforced Concrete Structures Subjected to Strong Ground Motions
Author(s): Lucas A. Laughery and Santiago Pujol
Publication: Structural Journal
Appears on pages(s): 103-115
Keywords: drift; drift demand; earthquake simulation; high-strength steel; reinforced concrete
Four reinforced concrete portal frames were tested on an earthquake simulator. Columns in two frames had conventional steel longitudinal reinforcement. Columns in the other two frames had smaller-diameter, ultra-high-strength steel longitudinal reinforcement (fy >120 ksi [830 MPa]). Test results suggested that peak drift was driven by the initial period of the frames (based on uncracked sections). To examine this observation in more detail, a database was used to evaluate an equation in which peak drift is expressed in terms of initial period and peak ground velocity (PGV), neither of which are sensitive to reinforcement ratio, yield stress, or displacement history. This database includes results from more than 160 laboratory tests and the measured responses of three buildings to earthquakes. For motions representative of what has been observed in the field and in the ranges considered, this expression provided a reasonable upper-bound estimate of drift for tests in the database.