Coupling Beams

Coupling beams greatly influence the behavior of coupled wall systems. In order to ensure adequate coupling beam behavior under earthquake-induced deformations and stresses, intricate reinforcement detailing is required for reinforced concrete coupling beams, typically in the form of diagonal bars and extensive confinement reinforcement. Such reinforcement detailing, however, creates major construction difficulties.

Furthermore, in slender coupling beams, where beam span-to-depth ratios are on the order of 3.0, the effectiveness of diagonal reinforcement is questionable because of its shallow angle (less than 20 degrees) with respect to the beam longitudinal axis.