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In this paper, the influence of the following parameters on different modes of vibration response of model footings on sand is studied: (vertical, rocking and pitching load amplitude and frequency). To achieve the objective of this study, the model footing was selected to be rectangular footing with an aspect ratio (L/B= 1.33) i.e (L= length and B= width). A physical model was manufactured to simulate a steady-state harmonic dynamic load applied at different operating frequencies with the same load amplitude (0.5 ton). A total of (9) cases was performed taking into account different parameters. The loading frequency ranged from (0.5) to (2) Hz and the footing was rectangular with an aspect ratio (L/B = 1.33). The soil type used was dry sand having a relative density of (50%). The behavior of the soil underneath the footing was examined by measuring the strain using a shaft encoder and the amplitude of displacement using a vibration meter. It was found that the change in vibration mode made little effect of the final strain values under the same frequency and the amplitude of displacement in (Z) direction, while the amplitude of displacement in (Y) is higher, occuring under rocking vibration and higher value amplitude of displacement in (X) direction under pitching vibration under the same frequency.

Growth of economic, demographic and building activities in Iraq has necessitated carrying out geotechnical investigations for soft soils to study behavior of foundation resting on these soils. The laboratory test has been carried out to analyze the effect of tire as reinforcement to decrease the excessive settlement of soft soil. The influence of depth and area of tire layer is examined on the settlement of shallow foundation. For this purpose, a square foundation (60 *60) mm is used for the model test. All tests are conducted on the surface of homogeneous soil layer 250 mm; in a box steel (600 x 300 x 300) mm. The undrained shear strength of soil is 12 kPa. The reinforcement layer (tire layer) has been placed at depth 0.5B, B and 2B (B is the width of the square foundation) in the soft soil under foundation. The area of tire layer (B x B), (1.5B x 1.5B) and (2B x 2B) are investigated too. The analysis of the test results indicated that using tire layer under foundation has a significant effect on the settlement improvement (St/Su). It is worth noting, that the settlement improvement (St/Su) is decreased with the increase of the depth of tire layer. The results shows that the maximum increase in bearing capacity reaches approximately to 130% at area of tire layer (B x B) and depth equal to 0.5B.