Showing papers on "Embedment published in 1973"

Failure Loads of Vertical Anchor Plates in Sand

Abstract: There are many situations in civil engineering where vertical earth anchors must be used to withstand horizontal loading. A series of tests is described on model anchor plates in sand. The results are presented in the form of dimensionless force coefficients and shape factors relating failure loads to the geometry of the anchor and its depth of embedment. The method of stress characteristics is used to produce comparable theoretical values which agree well with experimental results at both model and field scales. The measured shape factors are independent of the size of the plate, and this contrasts with the force coefficients which decrease with increasing anchor size. A theoretical solution has been developed which allows φ to vary in a failure zone, depending on stress levels in the computations, and the effect is shown to be important. Difficulties in selecting suitable φ-values for design are outlined, and possible design procedures examined.

Torsional and coupled vibrations of embedded footings

Abstract: An approximate analytical solution is presented for torsional vibrations of footings partially embedded into a semi-infinite medium or a stratum. Simple formulas derived for pure torsional motion make it possible to apply a correction for the effect of embedment to the known solutions of surface footings. The solution completes an approach to the analysis of all modes of footing vibrations, including the coupled modes. The approach to coupled modes is illustrated by the solution of coupled response involving horizontal translation, rocking and torsion. Formulas are presented for stiffness and damping coefficients that can be used in the analysis of embedded footings or structures supported by such footings Field experiments were conducted with concrete footings featuring circular, square and rectangular bases and variable embedment depths. The experimental results were compared with theoretical predictions of pure torsional vibrations.

Response of embedded footings to vertical vibrations

Abstract: Field vibratory tests have been carried out to study the effect of embedment on the vertical response of footings. Steady-state vibration tests indicate decrease of maximum amplitudes of motion and increase of resonant frequencies as a consequence of embedment. A lumped parameter analog with the inclusion of Coulomb friction damping is suggested to explain the dynamic behavior of embedded footings. A simple procedure by which the constant frictional force of the Coulomb friction damping can be evaluated has been described. The suggested procedure takes into consideration the relevant physical characteristics of the interface between the foundation walls and the surrounding soil. The field test data obtained by the writers as well as those published by other investigators elsewhere are compared with the values predicted by the proposed analog. The correlation between the available experimental data and the predicted values is satisfactory.