Predictions of structural response to dynamic loads of different loading rates

Abstract

Owing to the increased terrorist bombing attacks, as well as accidental explosions associated with the rapid economic development and urbanization, more and more civilian structures might experience blast loadings in their service lives. These increase the demands of more structures being designed to resist certain level of blast loadings. As a result, some structural engineers with limited or no experience or training on structural dynamics nowadays might need to deal with analysis and design of structures against high-rate blast loads. Although design guides are followed, lack of fundamental knowledge of structural performance under high-rate loadings might not necessarily lead to accurate structural response predictions because the design guides normally only cover the most general and common blast loading scenarios and structural response conditions. Similarly, some researchers who have abundant experiences in analysis and design of structures under relatively low-rate dynamic loadings such as earthquake ground excitations intend to directly apply their experiences in earthquake engineering to blast resistant designs. This sometimes leads to inappropriate actions, e.g., adapting inter-storey drift as a performance criterion, using active control devices or cross bracing as a blast loading mitigation measure. This paper discusses the fundamental theory of structural dynamics, basic differences of structural responses subjected to low-rate dynamic and high-rate blast loadings. The accuracy of commonly used approaches in structural response analysis to blast loadings, i.e., the Single-Degree-of-Freedom analysis, will also be discussed.