1. Royal Plaza Hotel Korat, Thailand

2. Background Friday 13th August 1993 collapse <10 seconds
burying 379, killing 137, badly injuring 227
Technical investigation

3. Historical Records Originally 3 storey high plus 1 underground
3 more storeys were added, no record of foundation/column strenghtening

4. Unique collapse Occurred 3yrs after last modification
No unexpected forces of nature eg. earthquake, storms

5. Reasons for failure
marginal F.O.S after 3 more storeys were added to the building
Columns carried dead load of 70-80% of strength capacity~microcracks causing creep deformation
“Progressive failure“- failure of 1 column increased load on the other columns, causing failure

6. Technical Investigation
Test of Concrete Strength- no deficiency, compressive strength 10-15MPa 95 % reliability
Test of Rebars- Reinforcing steel bars conformed to standard
Soil Test- bearing capacity sufficient for foundation even after the modification

7. Lessons entrepreneurs want to cash in with minimum investment efforts
able and honest professional engineers, who care more for the standard of the works than to obey the architects and the clients.

8. Short & Long Term Measures
Safety Review of 218 buildings
Registration of professional engineers more strictly controlled.
Indemnity insurance system.
Design of public buildings must be cross-checked and jointly responsible by third-party engineer.
Usage of public buildings requires a license ~ renewed every 5 or 10 years.