Date

2016

Document Type

Thesis

Degree

Master of Science

Department

Structural Engineering

First Adviser

Naito, Clay J.

Abstract

This paper proposes a methodology for mapping structural damage onto building frames due to exterior blast threats for use in a threat dependent progressive collapse assessment. The proposed approach contrasts with current practice, which typically relies on a threat-independent approach for progressive collapse analysis. Damage is mapped to the structure based on the calculated response of the discrete structural components (particularly the columns) to a blast-induced pressure time history. Contours of structural damage can then be mapped over the building face for discrete combinations of charges and standoffs. For a prototype reinforced concrete building frame, calculated distributions of damage for conventional explosive threats suggest that the current state of practice approach (in which damage is represented with a single column removal) may not constitute a generally conservative strategy for progress collapse resistant design. A set of uniform pushdown progressive collapse analyses was performed to assess the robustness of the prototype building frame subjected to a spread of blast-induced damage relative to its intended design loads. The proposed framework can be used to determine standoff distances needed to reduce progressive multi-column failure scenarios in building frames for high-risk facilities and can be used as input for a progressive collapse assessment of these frames.

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