Seismic response of reinforced concrete frames on pile foundations

The paper focus on the effects of soil-structure interaction on the seismic response of reinforced concrete frames founded on piles. The substructure method is adopted and 6-storeys 3-bays frames founded on 3 different two-layered soil deposits are considered. For each soil deposit two foundation typologies are adopted: mono-pile and double-pile foundations. Soil-structure interaction effects on the seismic nonlinear response of the structures are evaluated by means of incremental dynamic analyses. Results are compared with those achieved from fixed base analyses demonstrating that soil-structure interaction effects are more evident for moderate earthquakes, inducing early structural damages, and for soft soil deposits. The mono-pile foundation, suitably designed in conjunction with stiff tie-beams, is able to guarantee an efficient degree of restraint at the base of columns, comparable with that provided by the double-pile foundation.