Reduction of Vibrations due to Foundation Slabs

This paper investigates the reduction of vibration due to the foundation slab both in horizontal and vertical directions. Similar reduction efficiency of the foundation slab was obtained among three-dimensional finite element analyses, field experiments, and the averaging scheme of the rigid slab theory. Then, two formulas fitted from numerical simulations were generated. Using those two simple formulas, one can estimate the reduction efficiency of horizontal and vertical vibrations due to foundation slabs. In summary, a suitable mat foundation can significantly reduce the horizontal vibration transformed from soil. The reduction efficiency depends on the size of the mat foundation over the soil wavelength. Enlarging the thickness of the foundation slab can decrease the vertical vibration transferred from soils. However, it is difficult to reduce vertical low-frequency vibrations for a reasonable slab thickness.