Floating raft system
（重定向自Raft foundation）
Floating raft is type of land-based foundation that protects against settlement and the liquefaction of soft soil due to seismic activity. It was a necessary innovation in the development of tall buildings in the wet soil of Chicago in the 19th century, where it was developed by John Wellborn Root who came up with the idea of interlacing the concrete slab with steel beams.