Investigation of the Collapse of LAmbiance Plaza

Abstract

Results from an investigation of the collapse of the LAmbiance Plaza building on April 23, 1987 are presented. The building was being constructed using the lift-slab method; collapse occurred during construction. The investigation included examination of debris at the site of the collapse, review of eyewitness accounts of the collapse, review of project documentation, laboratory and field tests and analyses of the structure. Several potential failure mechanisms were investigated. The most probable cause of the collapse was determined to be loss of support at a lifting jack in the west tower during placement of a group of three floor slabs. The loss of support was likely due to excessive deformation of a shearhead lifting angle, which caused a lifting nut to slip off its lifting angle. This failure mechanism was duplicated in laboratory experiments.