1. The Royal Plaza Hotel Collapse

2. Background on Collapse  Collapsed Friday 13 th August 1993 at 10:10 a.m.  The collapse took less than 10 seconds!  379 people were buried, killing 137 and badly injuring 227.

3. Structural History   Originally constructed with three storey’s and an underground level.   Planning permission granted in 1985 for addition of three extra floors.   In 1990, three extra storeys were added. No foundation or columns strengthening.

4. An uncommon Collapse  No modifications added to the building in the previous three years.  No extreme conditions in the environment or loading applied to the building.

5. The Investigation  The factor of safety of the columns was almost 1.  Over designing the initial structure led to the delay in the building collapsing.  Creep deformation occurred in the columns as they were carrying dead loads of 70-80% of their strength capacity.  ‘Progressive Failure’ – the collapse of the initial columns, caused the remaining columns to fail.

6. Tests Conducted  Test of Concrete Strength – strength was in the range of 10 – 15 MPa with 95% reliability.  Test of Rebar – steel was found to confrom to standards.  Soil Test – the bearing capacity of the soil was sufficient to support even the expanded 6 storey building.

7. Remedial Measures Taken  Public Universities were ordered to review the safety of a number of buildings.  218 buildings were investigated.  Registration of engineers must be more strictly controlled.  Public buildings must carry a license which must be renewed every five years.  Design of future public buildings must be cross- checked by a third party engineer who will also be held responsible.

8.  Any Questions?