Padang Indonesia Earthquake, Ambacang Hotel
Ambacang Hotel by Nick Alexander
This three star hotel has undergone several renovations over the past century. The original portion of the building was a Dutch-colonial style warehouse building facing North and was constructed in the early 1900’s. The structural system of the original two-story building consisted of a reinforced concrete frame with masonry infill. Within the past three years, additions were added to the original building in different phases. Initially, an additional three-story level was added on top of the existing construction. The structural system of the new upper addition consisted of a combination of steel gravity framing with concrete over a metal deck and a reinforced concrete frame with brick infill. Later on, a one-story segment concrete structure with brick infill was added on the Southwest of the original building, creating an L-shaped footprint. Finally, a six-story steel frame structure was added south of the original building, creating a U-shaped footprint with an interior court used as a pool in between the two wings.
After the 7.6 earthquake on September 30, 2009, the second story of the back portion of the original building segment collapsed towards the pool followed by the six-story south building segment also collapsing towards the pool. (MetroTV reported 30 fatalities but the locals seem to think that the estimate is too low).
Many of the buildings that collapsed in Padang have quite a similar history where floor additions were added several times during the life of the building. The original segment of Hotel Ambacang is an extreme case of these types of buildings, which are locally known as the ‘growing building’. It is unclear how strict the code enforcement and quality assurance for inspections are being conducted.
Some structural deficiencies, such as defects in the concrete material and non-ductile detailing, can be identified from the building damage. Non-ductile detailing was apparent from the lack of ties used in the concrete columns and poor detail practice observed from the exposed damage. The structural members are also very lightly reinforced. Poor splice detail between the additional structure and the existing structure also add to the list of the structural vulnerabilities observed in the building. It is likely that the additional segments were added butt-up against each other without consideration of pounding during an earthquake.
photos by Nick Alexander
