Performance of Hospitals: Yos Sudarso

October 15, 2009 by  
Filed under Structural Observations

Yos Sudarso Hospital is a multi-building 30,000 square meter hospital campus operated by the Catholic Archdiocese in Padang. This hospital has 145 beds and provides the full range of medical services including surgery, radiology, and even dental care. There are 7 main buildings on the hospital campus, almost of which are 3-story structures built with concrete moment frames with clay brick infill walls, concrete slab floors, and wood framed pitched roofs. The original building, which houses the hospital emergency department among other services, was constructed in 1971. The newest building, which houses the hospital’s intensive care units, was completed in 2003. There is also a single story wood framed lunch room built in 1993. All of the buildings are connected by either wood framed covered walkways or concrete framed connector buildings.

The Original 1971 Vintage Hospital Building

The Original 1971 Vintage Hospital Building

The primary earthquake damage occurred in the 3 story concrete framed building that connected the front building to the next building over. The columns supporting this building failed at the second floor, causing the floors above to come down. Remarkably, outside of a few cracks in the columns and slab the area below the second floor was undamaged and was still being used as a corridor by both patients and staff.

Collapsed Connector Building - 2nd Floor

Collapsed Connector Building - 2nd Floor

Hinged Column at Connector Building

Hinged Column at Connector Building

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Collapsed Corridor Building @ 3rd Floor

The original 1971 building also sustained damage, primarily at the second floor adjacent to the collapsed corridor where all of the concrete columns developed plastic hinges. A permanent 6” lateral drift was created at the third floor and roof. There was also damage to the roof overhangs and shear cracking in the brick infill. Interestingly, there is a gap between the concrete frame at the roof level and the roof framing as the concrete is below the roof trusses and the joists sit on top of the trusses. Despite the lack of a positive lateral load path there was no noticeable damage to either the main roof framing or the truss to concrete connections.

Column Hinging at the Second Floor Columns

Column Hinging at the Second Floor Columns

Newly Created Seismic Joint

Newly Created Seismic Joint

The other building that sustained extensive damage is the nurses housing building, a concrete frame/brick infill 3-story structure constructed in 1988. Many of the columns developed hinges directly below the second floor slab and many of the brick infill walls, both interior and exterior, sustained major damage and partial collapse. The two floors above had only minimal damage.

Nurses' Housing North Wall

Nurses' Housing North Wall

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Damage to the remaining buildings was mostly confined to shear cracks in the brick infill and cracking at the joints between the buildings. The joints were typically not constructed with any separations, so during the earthquake the buildings pounded against each other, causing the concrete to crack and spall at the battered joints.

Newly Created Seismic Joint

Newly Created Seismic Joint

The lack of separation between the buildings may have played a role in the partial collapse of the connector building. Another factor may have been the presence of several large water tanks on the roof of the connector building, which appear to have been installed long after the original construction.

Water Tanks on the Connector Building Roof

Water Tanks on the Connector Building Roof

Non-structural damage was extensive in the 1971 building that sustained the 6” of movement. Windows were shattered, cabinets were toppled, and many of the infill walls were damaged. The other building next to the collapsed corridor sustained similar damage but not to the same degree. Non-structural damage to the other buildings was minimal. The mechanical systems did not suffer major damage except for a major water line that ran through the collapsed corridor and was severed. Some of the radiology equipment moved in the earthquake but the hospital staff told us that none of them toppled over.

Hospital operations have been impacted by the earthquake. The emergency room is closed and emergency care is instead being provided within tents set up in the parking lot. There are also patients being treated in the undamaged lunch room building. The nurses who resided in the damaged nursing housing building have moved out and may not return. The hospital administrator told us that the total hospital capacity was down to 40% of what they could accommodate prior to the earthquake.

Emergency Services in the Parking Lot

Emergency Services in the Parking Lot

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