Hartford Arena Roof
Collapse
 January 18th 1978.
 Snowstorm.
 Roof plummeted 83 feet to the arena
floor.
 What caused the 300-x 360ft. roof to
collapse?
 Could this disaster have been
prevented?
 Who was responsible?
Technical Factors
 The space frame roof was designed by Fraoi,
Blum & Yesselman.
 Roof consisted of two main layers.
 30-ft diagonal bars, braced in the middle by a
layer of horizontal bars.
 The 30-ft bars in the top layer also braced.
Several factors.
 The design for the space frame roof used
cruciform section, which has a small radius of
gyration.
 The horizontal bars intersected at different
points than the diagonal bars making the
structure particularly liable to buckling.
 The computer analysis used did not take
buckling into account.
 Compression members in the top layer were
significantly overloaded. Up to 852%
 Differences between designs and the as
built structure.
 Reducing connections strengths.
 Only half of the bracing specified for the
exterior rods was used and interior rods
were only partially braced.
Human & Managerial Factors
 The guilty people, engineers and construction
managers.
 Contract was divided into 5 subcontracts.
 Construction manager in a coordinating role.
 Uncertainty about who was responsible for
certain aspects.
 Qualified structural engineer oversee the
construction.
 Construction manager refused, waste of
money.
 The engineers were notified of excessive
deflections in the roof of the arena on a
number of occasions.
 They dismissed the concerns saying that
discrepancies between the actual and
theoretical values were to be expected.
 Subcontractor questioned deflections.
difficulties while fitting steel frame
construction ,
“deal with the problem or be responsible
for delays”.
 Year after, a member of the public
notified the engineers of his concern at
the distinct downward deflection in the
roof.
“everything is fine”
 Connections were not assembled
according to the designs.
 Reduced strength.
 American Institute of Steel Construction
code violated.
 Bad management or incompetence on
the part of the engineer.
Lessons Learned.
 Save money, innovative design and state of the art
computer analysis.
 Several agencies were employed to illuminate the
cause of the collapse and attribute the blame
accordingly.
 Roof began failing as soon as it was completed due to
design deficiencies.
 Torsional buckling as opposed to lateral buckling.
 Six years after, out of court settlement.
 “Should one man / contractor hold ultimate
responsibility for such a project and do too many cooks
spoil the broth?”
 The roof designed was not the same as the roof built.
 Computer programme is only as good as its
programmer. In this case the programme in question
did not take buckling into account.
 More care with the design & redundancy employed, the
failure of a few members would not have resulted in
this huge collapse.
 A second opinion needed.
 Peer reviews are an essential safety measure.
 “Cut corner” project.
 It raises the question whether the factor of
safety should be increased for buildings of high
occupancy?
Space Frame Roof
Section of Roof