L'Ambiance Plaza
Collapse
Bridgeport, Connecticut
April 23, 1987
Group 15
David Conneely
Jonathan Heney
David Misstear
Roisin Smith
Background
16-storey residential project in Bridgeport,
Connecticut
 ‘Lift slab’ system used for floors
 Hydraulic lifting apparatus used to put slabs into
position
 At time of collapse, the building was a little over
half complete
 Collapse of one slab triggered collapse of whole
building
 28 workmen killed

Building Layout
Possible Technical Factors
Contributing to the Disaster
 Overloading
of lifting jacks
 Floor slabs placed incorrectly
 Post-tensioned tendons arranged
incorrectly
 Substandard welding
 Inadequate shear walls
Hydraulic Lifting Assembly
(L'Ambiance Plaza Collapse, Martin R., 1994)
Human and Managerial Factors
Contributing to the Disaster
 Gross
negligence on part of management
 Sloppy practices (e.g. placing concrete in
sub-zero temperatures)
 Corners cut to save money (e.g. crushed
rock used instead of hard surfaces for
temporary structures)
 Building regulations not sufficient for
innovative ‘lift slab’ method
Lessons to be Learnt



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Responsibility for each aspect of a project as well as
overall venture should be clearly allocated
Construction should be constantly monitored by
qualified engineers - frequent and adequate testing
The lateral stability of a structure under construction
using the “Lift Slab Method” should be ensured:
temporary bracing, cribbing, sway bracing
The Building Authorities should set aside adequate
resources to approve building designs and to send
independent engineers to check progress.