Abstract: The basement floor heave hazards are frequently encountered in thick soft soils with high groundwater level as urban Shanghai area. This paper presents a case history of the mitigation design and construction of the floor slab heave of a singlestory underground garage in Jiading District of Shanghai City. The distress causes, design principles and mitigation construction major steps are also presented in the paper. The observational results from two years after the mitigation construction indicate that the pressin steel pipe piles by using ground anchor as the reaction is both technically sound and cost effective.

Key words: single-story underground garage, floor slab heave, pressin steel pipe pile using ground anchor, mitigation