Structural Control of Dynamic Blast Loading

Abstract

The purpose of this paper is to evaluate the effectiveness of Fluid Viscous Dampers (FVD) when used to control blast loading responses on lateral load resisting frames. In particular, this paper addresses the following issues: 1) Development of a blast loading time history for a 3,000 pound TNT blast, 2) Blast effects and performance comparisons of a conventional special moment resisting frame (SMRF), SMRF with FVD, and a conventional shear wall building. Nonlinear dynamic force history analyses were conducted on three different types of structures: 1) Conventional SMRF, 2) SMRF with FVD, and 3) Conventional concrete shear wall. The lateral load resisting frames of these structures were designed to conform to the 1994 Uniform Building Code, Zone 4 criteria. Nonlinear computer models with and without FVD were subjected to a dynamic blast loading from 3,000 pounds of TNT at 100, 40, and 20-foot standoff distances. Nonlinear analyses indicated that structures with FVD provided a cost effective way to control displacement and plastic hinge rotation of lateral load resisting frames under blast loading. Blast Loading Time Histories For A 3,000 Lb Charge Of Trinitrotoluene (TNT) The intent of this report is to study the relative performance of structures subjected to transient pulses caused by the detonation of explosives. Most explosives are developed and used primarily by the military and government agencies. Very little data is published in the public domain concerning blast pulse magnitudes and wave forms. The transient pulses presented here are for reference only. They were assembled entirely from an unclassified database of public domain material, and were appropriately scaled for use. In general, the frequency content from the time history of a detonation is at least an order of magnitude higher than the structural frequencies of a conventional building. Thus, it is not necessary to utilize high precision transients. Since only conventional buildings were to be studied, the extremely short explosive pulse durations also indicated that integrated pulse content was much more important than a highly precise wave form. For these reasons, all pulses were rendered generic by reducing them to an equivalent triangular wave form. The resultant time histories provide what