Combined subsidence phenomena in high-rise built urban areas: numerical study for Frankfurt am Main

In many megacities, excessive population growth and urban development have brought to heavy concentration of structural loads and marked increase of water demand leading to huge ground water extraction. This paper addresses the effects of both factors on ground settlement magnitude in areas where high-rise buildings prevail. For this purpose, referring to the case study of Frankfurt am Main (Germany), a numerical analysis of soil settlements under structural loads was performed for a selection of high-rise buildings resting on combined pile-raft foundations in overconsolidated clays. Then, at the scale of the single building, the contribution of groundwater withdrawals to the total predicted settlements was quantified via 2D-FEM model, thus highlighting the key role of pore pressure changes on settlement occurrence