Simulated Seismic Loading of Spandrel Beams

The most critical components of coupled shear wall structures are the short and often relatively deep spandrel beams, formed between door or window openings. These may be subject to high intensity alternating flexure in the presence of large shear forces when the structure is exposed to seismic disturbances. The behavior of these beams, when subjected to monotonic one way loading, was previously reported by the writer. In this paper the more interesting features of the performance of relatively deep spandrel beams, subjected to seismic type of alternating static loading, are presented. In the experiments the performance of the flexural reinforcement, the deterioration of the stirrups with high intensity alternating loading was observed. The principal modes of failure were identified and the stiffness degradations were evaluated from rotational measurements. Some evidence is presented with respect to the available ductilities for two types of steel arrangement and the effectiveness of beam repair.