Royal Plaza Hotel,
Thailand
Presentation 27th Oct 2006
Background




Collapse of Hotel Building occurred on Fri 13th
August 1993
From initial failure to total collapse < 10
seconds
379 people in the Hotel buried, 137 killed and
227 badly injured
This incident led to a major investigation in
Thailand
Structural Background





The structure originally designed to be 3 above ground
(+ 1 underground) stories high
Structure was modified in 1990 with the addition of 3
extra floors
No record of added column or foundation strength
being added during modifications
Soil bearing capacity was tested
This did not take into account the fact the load bearing
structure within the building itself was insufficient to
carry additional loading
An uncommon collapse




Most building collapses occur during or just
after construction
In the Plaza Hotel case collapse happened 3 yrs
after major modifications!!
Most building collapses after a long period of
use were caused by unexpected forces of nature
(earthquakes floods, etc)
This was not the case in this situation
Findings of the Investigation




Addition of 3 floors of dead and live loads over the
same set of columns reduced original F.O.S to almost
zero
The extent to which the original structure would have
been over engineered may explain the delay between
modifications and final failure
Columns carried dead load of 70-80% of strength
capacity, leading to development of microcracks which
in turn lead to creep deformation
“Progressive Failure” – failure of 1 column increased
load on the other columns, causing sudden failure
Tests Conducted



Tests of concrete Strength- no deficiency,
compressive strength 10-15 Mpa
Test of Rebars-conformed to standards
Soil Test-bearing capacity sufficient for
foundation even after the modification
Lessons learned



The desire for profit from investors lead to poor
safety standards being enforced
Engineers work need to be closely scrutinised
and checked by independent consultants during
design and construction
When a doctor makes a mistake, he kills one;
when an engineer makes a mistake, he kills many
(AIT Thailand)
Remedial measures taken




Safety Review undertaken by Thailand
universities, of more than 218 buildings
Professional Engineers registration more tightly
controlled
Setting up of Indemnity insurance system
Design of public buildings must be crosschecked and jointly reviewed by third-party
engineer
End of presentation


Sum up
Any questions?