Behaviour of Piled Raft in Pyroclastic Soil

A piled raft is a composed foundation in which the raft is in contact with soil. The applied vertical load is transferred from the raft to the soil and to the pile heads. The load sharing between the piles and the soil is a function of the complex interaction among the raft, the soil and the pile. Considering the complexity of the problem, the best way to investigate about this interaction is to perform physical model tests at field scale. Vertical load tests on different types of foundations (single pile, unpiled raft, pile group with a free-standing cap and a piled raft composed by 5 piles) in pyroclastic soil have been performed. The raft settlement and the axial load distribution along the pile shaft were monitored during all the tests.