Supplemental Vertical Support as a Means for Seismic Retrofit of Buildings

A large number of concrete buildings in seismically active areas throughout the world exhibit a common deficiency. Weak columns, in one or more stories, lose vertical load-carrying capacity as a result of lateral distortion. This chapter presents a conceptual strategy for retrofit comprising the installation of supplemental vertical supports to prevent collapse. This procedure utilizes a risk-based perspective based on recent research on the realistic capacity of concrete columns, dynamic instability, and the effects of in-cycle degradation of strength in building systems and components. An example building is used to illustrate the application of the concept.