Strategies for Structural Design of Buildings Subject to Blast Loads

BY:     ERNESTO GASULLA, P.E.

            JATIN N. SHAH

BAKER ENGINEERING AND RISK CONSULTANTS, INC.

ABSTRACT

One of the most difficult hazards to manage in petrochemical operations is explosions that lead to impacts on population of buildings. Unlike fire and toxic hazards, explosion hazards do not provide any time to react to the event. Therefore, many traditional alternatives to minimize process hazards may still not provide enough level of risk reduction. Often times, the reviewer needs to provide structural upgrading of existing buildings or design of new buildings to minimize the impact of blast events and bring overall risks to a tolerable level. Unfortunately, providing blast resistant structural design is often a high cost alternative, and therefore should be considered only when lower cost risk reduction measures fail to obtain the desired results.

This paper presents a number of strategies for dealing with blast design of new and/or upgrades of existing buildings, including both consequential and risk-based analysis methods. The concepts of pressure-impulse curves, component damage level, building damage level, occupant vulnerability, and their relation to individual and population risks are explained. Different construction types often found in petrochemical sites, including construction types commonly used in Latin America, are evaluated for adequacy to safely withstand blast loads and, should they be required, their potential for upgrade. Methods of blast structural analysis and most widely used acceptance criteria are discussed. The analysis covers the incidence of non-structural components such as windows, doors, suspended utilities, and internal partitions.

The presentation includes captions and excerpts from design cases applying different software tools developed by BakerRisk for different uses including the design and upgrade of buildings subject to blast loads, and how they allow the user to achieve a more efficient risk reduction with the lowest possible overall cost.