Modeling Studies on the Response of Weapon Foundations in Soils

In this report, the author first describes the design of a portable model foundation loading device capable of applying square wave impulses with forces up to 1200 lbs. for durations between 10 and 120 milliseconds. The model loading device is used to simulate the load on the non-recoiling parts of a howitter foundation in both sands and clays. An important part of this program is the comparison between residual displacements and rotations resulting from loading a geometrically similar 1/5 scale, replica model and firing a 105 m. m. . M2A2 howitser. Through this program, considerable insight has been obtained into the dynamic response of artillery foundations. The foundation response lies in neither a quasi-static analysis nor an impulse analysis realm. Load level, the duration of loading, soil strength, the mass of the foundation, and the mass moment of inertia of the foundation are all significant In determining the response of artillery foundations. Furthermore, the vertical trsnslational, horizontal translations!, and rotational responses of the foundation should be coupled in any dynamic analysis of the response. This report includes plans for an experimental program to develop data for analysing the response of artillery foundations and closes with a discussion of some experimental results In clay soil.