Foundations for Tall Buildings on Alluvial Deposits—Geotechnical Aspects

Abstract

Design of heavily loaded foundations for tall buildings requires a realistic assessment of the design parameters. A comprehensive geotechnical investigation and in-situ tests such as static cone penetrometer tests, pressuremeter tests and cross-hole seismic tests in addition to deep boreholes can provide the inputs for selection of the design profile. The piled-raft concept can yield substantial saving in the design of tall buildings by reducing the number of piles due to the contribution of the intervening soils below the raft. To assess the settlement and load distribution beneath the raft, soil-structure interaction study should be done. A case study of a 38-storeyed building in the Indo-Gangetic Alluvium is presented to demonstrate the quality of data that can be obtained from a thorough geotechnical investigation and to illustrate the concept of piled-raft. While the reliability of the design is enhanced, the savings that can be achieved by such an approach can be substantial.