Commonality Test Methodology for Residential Structures in Katrina Canal Breaches Class Action: Fid-Bau Portal

Commonality Test Methodology for Residential Structures in Katrina Canal Breaches Class Action

Nelson, Erik L. / DeLeon, Marco A. / Schober, Gregory G.

The question of commonality of damages was posed in a proposed class of members that was intended to represent the city of New Orleans as a whole. Were patterns of damage common such that they were identifiable by predictive means without individual site assessments? The authors were presented this question in the Katrina Canal Breaches Consolidated Litigation Levee with a putative class size of 36 members. Data collection efforts, which involved site specific testing, resulted in detailed class property information such as watermarks; levelness; plumbness; architectural and structural condition; and mechanical, electrical, plumbing (MEP) condition. Hurricane forces of wind and water and degradation of materials affected structures differently; the extent of subsequent material degradation was related to characteristics unique to each structure (age, design, construction, materials, soil condition, and maintenance). Focusing on flood damages due to canal breaches, predictability was not found due to unknown variables of building height, characteristics, and length of time flood water was present. The type and degree of damage varied considerably not only in the global putative class but also in the local subclasses, indicating a lack of meaningful subclass boundaries. Damages were not predictive by formula and therefore commonality was not present in the class. The only reliable method of damage assessment due to hurricane related distress is by individual site evaluation. Based on the scientific method, a test methodology is developed for assessing commonality of damages.