Retrofitting and Strengthening Evaluation from Stiffness Variations of a Damaged Building from Ambient Vibration Recordings

Abstract

The rigidity of a six-story shear-wall building, damaged by the May 21, 2003 Boumerdes earthquake (Algeria) has been evaluated before the event, in its damaged state, and after retrofitting, by estimating its natural frequency. damping factor, and modal shape. Pre-event parameters are estimated through a numerical analysis, based on the structure drawings, complemented by an ambient vibration investigation of all identical non-damaged building located oil the same site. Parameters of the damaged and retrofitted states were obtained from ambient vibration recordings. Variations of the modal parameters, for the three states of the building, allow evaluating rigidity changes, and thus checking of both the retrofitting and strengthening of the building.