Royal Plaza Hotel Korat, Thailand

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

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

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

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

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

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.

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.