i } 4 Project 3.1-- Difference in Effect of Short and Long Duration Blast Loading on the Response of Structures - Capt R.©. Grubaugh The objective of this project was to investigate experimentally the effect of the positive phase duration on damage to full scale industrial type structures, Three drag-type and three semi-drag type structures were exposed ies, Measurements were made to determine the response of the structures and the blast parameters in the vicinity of each structure. The measurements consisted of deflection of roof system, acceleration, strain in column, side-on overpressure, and dynamic pressure. It was intended that the results of this experiment be compared af . with the results of Operation TEAPOT for the necessary comparison of duration effects. The results from the two operations are listed in the accompanying table 3.1-1. It has been concluded that for a drag-type structure, there is a significant bonus effect from a long duration blast wave if peak pressure is considered the criterion in producing structural damage, Thus, as positive phase duration is increased, the peak pressure required to produce a given level of damaze, say collapse, is reduced, No conclusion can be drawn for the semi-drag type structure at this time. Cop, lLan pete