Seismic vulnerability assessment of Palacio del Gobernador using fragility curve

Seismic vulnerability assessment of Palacio del Gobernador using fragility curve
Corresponding email: [email protected]

A B S T R A C T

Palacio del Gobernador is a 48-year standing 9-storey building located at Intramuros, Manila. Its location of about 10.4 km from the West Valley Fault makes it vulnerable to seismic activities that are expected to occur at the fault, including the “Big One.” This study assessed the seismic vulnerability of the Palacio del Gobernador by generating and analyzing its seismic fragility curves. The researchers generated the digital model of the building using SAP2000. The structural model was then subjected to a Pushover Analysis. Ground motion data of local and foreign earthquakes were collected from DOST-PHIVOLCS and PEER. These were subjected to Response Spectrum Analysis using PRISM in order to generate their response spectra. The results of the two analyses were used in the Capacity Spectrum Method using SAP2000 to generate damage rank frequencies. These values were then used to generate the seismic fragility curves. The values in these curves revealed that, under a 0.4g PGA ground motion, the Palacio del Gobernador has a 49-50% probability of no damage, 18-20% probability of slight damage, 9-11% probability of moderate damage, 6-7% probability of extensive damage, and a 5% probability of total collapse. In particular, the probability of reaching the exceeding extensive damage is under 10%, which is the reference value for 0.4g PGA ground motion based on Section 208.5.3.2 of the NSCP 2015. These findings indicate that the Palacio del Gobernador is resilient against extensive damage when subjected to an earthquake that is comparable to the “Big One” and does not require additional measures to mitigate potential earthquake damage.

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Development of fragility curves for seismic vulnerability assessment: The case of Philippine General 

Michael B. Baylon, Maria Emilia P. Sevilla, Miller DL. Cutora, Rikki Mae S. Villa, Princess Mherlene P. Reynes, Jhona May V. Montemayor
Corresponding email: [email protected]

A B S T R A C T

The Philippine General Hospital (PGH) is a tertiary hospital in Ermita, Manila, that was founded on August 17, 1907. It adheres to the philosophy of providing all Filipinos with internationally competitive, cost-effective, compassionate, and accessible health care. It was recently one of the COVID-19 facilities. The PGH sits 9.2 kilometers east of the West Valley Fault, making it more vulnerable to ‘The Big One,’ a 7.2 magnitude earthquake. Until present, no research has been done to examine the PGH’s seismic susceptibility in the case of a large-magnitude earthquake. In keeping with this, the study intended to analyze the seismic susceptibility of the Spine Building, one of PGH’s oldest structures. It focused on constructing fragility curves to assess if the building could sustain a 0.4g peak ground acceleration (PGA) earthquake with a maximum likelihood of exceedance of 10%, as required by the Philippine National Structural Code (NSCP) for Seismic Zone 4 sites. The study employed 12 worldwide and 12 local earthquakes from the Incorporated Research Institutions for Seismology, with PGA excitation levels ranging from 0.1g to 3.0g (with a 0.1g gap) (IRIS). The structural model of the PGH Spine Building was created using SAP2000, which was subsequently utilized to perform Pushover Analysis using the Capacity Spectrum Method (CSM). The PGH Spine Building might collapse with 0.538g PGA, which corresponds to Intensity VIII, according to the results of the developed fragility curves, producing significant structural shaking. Furthermore, for 0.4g PGA, the calculated highest likelihood of exceedance in the ‘collapse damage’ condition was 5.24 percent, with no results above 10%, implying that the PGH Spine Building complies with the NSCP seismic requirement for structures located in Seismic Zone 4. As a result, an adequate retrofitting strategy is not required for the PGH Spine Building.

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