Component proportioning and design based on ACI 318

This chapter summarizes key requirements and recommendations for design and detailing of reinforced concrete components in regions of high seismic hazard, as put forward by the American Concrete Institute and applied in American practice. It discusses the most important requirements and recommendations applicable to the most ductile building systems. Transverse reinforcement consisting of hoops or stirrups is required over the entire length of a special moment frame beam. Loss of column support can cause collapse or partial collapse of multiple stories. Column transverse reinforcement provides ductility to column sections yielding in flexure and contributes to shear strength. To provide ductility, the transverse reinforcement must provide sufficient lateral restraint to longitudinal bars to delay buckling to larger strains, and must laterally confine the concrete enclosed within the transverse reinforcement. Beam-column joints must satisfy dimensional requirements and shear strength requirements; attention to detailing is needed to ensure that reinforcement congestion is manageable during construction.