Methodology for Forensic Investigations of Seismic Damage

Abstract

A methodology is presented for conducting forensic investigations of earthquake‐damaged structures. Causes of unexpected damage, indicated by differences between predicted (expected) and observed damage, are significant to the engineering and construction professions. Due to the existence of uncertainties associated with randomness and vagueness, methods for conducting probabilistic and fuzzy‐set damage‐assessments are discussed. Measures are presented to compare expected‐ and observed‐damage assessments that are probabilistic or fuzzy. Methods for identifying, studying, and ranking causes of unexpected damage are presented. The use of fuzzy expert systems is proposed as a structured method for using expert knowledge to assess the effect of observed distress on structural integrity. Desiderata are proposed to ensure reliable conclusions. A fundamental desideratum is proposed to maintain uniform levels of precision in the required analyses. Results are presented in layers to determine the professional significance of the unexpected damage. This methodology is applied to the forensic investigation of a three‐story reinforced‐concrete office building damaged in the 1987 Whittier Narrows earthquake.