TRANSIENT LOADING TESTS ON A RIGID CIRCULAR FOOTING.
MICHIGAN UNIV ANN ARBOR
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This report presents data obtained from transient loading tests on a one-foot-diameter relatively rigid footing resting on the surface of a bed of sand. Results are presented showing the load applied to the footing and the resulting acceleration of the footing. Two types of load pulses were applied to the footing, having rise times of approximately 4 msec and 20 msec. The magnitude of the loads was such that the response of the footing was essentially elastic. This allowed a direct comparison to the theory for the response of a footing resting on an elastic half space acted upon by a transient load. The mass of the footing was varied to produce different footing response characteristics. The results of the tests show that the theory leads to a reasonable prediction of the response of the of the footing to transient loads. The critical part of the analysis is the procedure for evaluating the effective shear modulus of the soil under the footing for the range of deformations to be encountered. A brief description of the application of the phase plane method of analysis to the footings subjected to transient loads is given. This is shown to be applicable to footings subjected to loads causing permanent deformation as well as elastic deformations. Author
- Soil Mechanics
- Structural Engineering and Building Technology