Story‐Drift, Shear, and OTM Estimation from Building Seismic Records

Abstract

A method of determining story drift, shear, and overturning moment (OTM) from building seismic records is presented. A system‐identification technique based on modal synthesis is used first to obtain parameters of dominant modes in the building response. Mode shapes are then constructed for the determination of story drift, shear, and overturning moment. The method is a refinement over an evolving procedure used by engineers and researchers in analyzing recent building seismic records. There are two new features in this method: (1) Mode shape determination based on shear and flexural modes and orthogonality conditions; and (2) story shear and overturning‐moment estimation based on displacement modal responses. Verification and error assessment are conducted using data generated from a model building over a wide range of parameters. It is found that story shear and overturning moment may be estimated accurately while certain error is associated with story‐drift estimates. Results of the error assessment may be used as guidelines for the selection of floor locations for the deployment of accelerometers. The method is also demonstrated over the actual seismic record of two buildings.