Royal Plaza Hotel
Nakhon Ratchasima
Thailand
Group 24
Background
Collapsed Fri 13th August 1993
Collapsed in less than 10 seconds
379 people in the Hotel buried, 137 killed
and 227 badly injured
Structural Background
Originally Designed: 3 stories high with 1
underground level
Structure modified (1990): addition of 3
extra floors
No record of foundation/column
strengthening
The Collapse
Unique collapse happened 3 yrs after
modification.
Collapse not caused by earthquake, storm
etc….
Technical Investigation
Test of Concrete Strength – was in the range
of 10 – 15 MPa with 95% reliability.
Test of Rebar – steel was found to conform to
standards.
Soil Test - bearing capacity sufficient for
foundation even after the modification.
Cause
Adding 3 floors: dead and live loads over the
older columns reduced original F.O.S to
almost zero.
Micro cracks developed as columns were
carrying a dead load of 70-80% of strength
capacity.
This Lead to Creep Deformation.
“Progressive Failure” – failure of 1 column
increased load on the other columns, causing
sudden failure.
Measures undertaken
218 buildings were investigated for safety.
Registration of engineers: more strictly
controlled.
Public buildings: must carry license, must
be renewed every 5 years.
Design of future public buildings: must be
cross-checked by a third party engineer
who will also be held responsible.
Any questions?