Reliability-Based Design Load Factors for Explosive Blast Loading
Publication: Journal of Performance of Constructed Facilities
Volume 29, Issue 5
Abstract
Reliability-based design allows the decision maker to select the level of reliability for a specific blast loading scenario and key to this is an understanding of airblast uncertainty. Hence, explosive field trials have been conducted in Australia that measured the variability of free-field blast loading caused by military standard plastic explosives. The results have revealed a high level of variability of peak incident pressure, impulse, and time of positive phase duration for repeatable tests where variability would be expected to be a minimum. The accuracy of predictive blast load models (model error) was also assessed. A probabilistic blast load computer model is revised to capture these observed variabilities. The effect of a 20% mass-increase safety factor typically applied to explosive mass on the probability of exceeding a design blast load is assessed. Reliability-based load factors are calculated where the nominal load is multiplied by the load factor to ensure that the actual load is equal to the reliability level. Reliability-based load factors are estimated for reliability levels of 0.05–0.99, for a range of scaled distances for military munitions. The load factor can be as low as 0.66 for a 0.05 reliability level and as high as 1.30 for a 0.99 reliability level.
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Acknowledgments
The support of the Australian Research Council Grant DP110101397 is gratefully acknowledged.
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Information & Authors
Information
Published In
Journal of Performance of Constructed Facilities
Volume 29 • Issue 5 • October 2015
Copyright
© 2014 American Society of Civil Engineers.
History
Received: Jun 10, 2014
Accepted: Oct 16, 2014
Published online: Dec 1, 2014
Discussion open until: May 1, 2015
Published in print: Oct 1, 2015
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