In constructing a 256-m-high skyscraper on a reclaimed land, there are two problems awaiting solution; one is negative friction of piles due to consolidation settlement of alluvial clay layer under the reclaimed soil layer and settlement of diluvial clay layer locating deeper than the bearing stratum of the building. These were handled in conducting subsurface exploration, foundation design, study on construction methods and construction work at the site controlled by measurements. Land settlement due to construction of a building should be estimated not only by evaluating increase in load and volume compressibility but also by considering 1) changes with time in ground-water table during excavation work and 2) load re-distribution effect due to rigidity of superstructure as a whole
