Laboratory Evaluation of Perimeter Beam Integrity Detailing Requirements of ACI 318-19

Results from laboratory testing of three full-scale reinforced concrete frame sub-assemblages that were designed to evaluate ACI 318-19 integrity reinforcement provisions for perimeter beams are presented. The specimens were detailed in accordance with structures in low seismic regions in the United States (Seismic Design Category A). Continuity of bottom longitudinal reinforcement was accomplished by splicing bars at different locations near the beam ends as permitted by ACI 318-19. A sudden decrease in force was observed in all specimens shortly after they reached their peak force indicating marked differences in behavior from elements designed for high seismic regions. The limited rotation capacity of the beams in the specimens and shear strength degradation that resulted from diagonal crack widening are believed to have influenced the response of the specimens. Modifications to current detailing requirements of integrity reinforcement in perimeter beams are proposed.