STORY-DRIFT, SHEAR, AND OTM ESTIMATION FROM BUILDING SEISMIC RECORDS

A method of determining story drift, shear, and overturning moment (OT M) 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 cons tructed for the determination of story drift, shear, and overturning m oment. The method is a refinement over an evolving procedure used by e ngineers and researchers in analyzing recent building seismic records. There are two new features in this method: (1) Mode shape determinati on based on shear and flexural modes and orthogonality conditions; and (2) story shear and overturning-moment estimation based on displaceme nt modal responses. Verification and error assessment are conducted us ing data generated from a model building over a wide range of paramete rs. It is found that story shear and overturning moment may be estimat ed accurately while certain error is associated with story-drift estim ates. Results of the error assessment may be used as guidelines for th e selection of floor locations for the deployment of accelerometers. T he method is also demonstrated over the actual seismic record of two b uildings.