A review of procedures for the analysis and design of concrete structures to resist missile impact effects

Abstract

Concrete containment walls and internal concrete barrier walls are often required to withstand the effects of missile impact. Potential missiles include external tornado generated missiles (steel rods, steel pipes, wooden poles, and automobiles), aircraft crash, and internal accident generated missiles (turbine blade, and steel pipe missiles resulting from pipe break). Impacting missiles can be classified as either 'hard' or 'soft' depending upon whether the missile deformability is small or large relative to the target deformability. This paper only deals with the effects of 'hard' missile impact. Missile velocities between 100 and 1500 ft/sec are emphasized. 'Hard' missile impact results in both local wall damage and in overall dynamic response of the target wall. Local damage consists of spalling of concrete from the front (impacted) face and scabbing of concrete from the rear face of the target together with missile penetration into the target. If damage is sufficient the missile may perforate or pass through the target. This paper reviews the various empirical procedures commonly used for determining penetration depth, perforation thickness, and scabbing thickness for concrete targets subjected to 'hard' missile impact. Results obtained from these procedures are compared with test data results for low velocity impacts (200-1500 ft/sec). Design recommendations to prevent detrimental local wall damage are presented. Overall dynamic response of the target wall consists of flexural deformations and a potential flexural or shear failure if the strain energy capacity of the wall does not exceed the kinetic energy input to the wall by the striking 'hard' missile. Simplified procedures are defined for determining the dynamic response of the target wall and for preventing overall failure of the wall. Included are procedures for defining the effective target mass to be used in determining the fraction of the total missile kinetic energy which is transferred or 'input' into the target wall. Also included are procedures for defining the total strain energy capacity of the target wall as determined from the moment and rotational capacities of flexural yield hinges and the yield line deformation pattern of the wall. Lastly, criteria for preventing a premature shear failure are presented. © 1976.