New PH atlas to help engineers build structures that could resist Intensity VIII quake – Phivolcs

Published March 23, 2021, 11:33 AM

by Ellalyn De Vera-Ruiz

The Philippine Institute of Volcanology and Seismology on Tuesday, March 23 launched the Spectral Acceleration Maps of the Philippines (SAM PH) Atlas as it aims to provide reference to engineers, building designers, and urban planners in the design of essential and critical structures that can withstand “very destructive” Intensity VIII earthquakes.


“The 1990 magnitude 7.2 Luzon earthquake collapsed the Hyatt Hotel in Baguio City and damaged several buildings in Luzon. I also remembered the 1968 magnitude 7.3 Casiguran earthquake that caused the failure of the Ruby Tower in Manila and damaged other buildings in NCR (National Capital Region). Similarly, the immense force of earthquakes in Central Luzon and Mindanao in 2019 was manifested when structures crumbled and consequently left many people homeless and some lifeless,” Department of Science and Technology (DOST) Secretary Fortunato dela Peña said during Tuesday’s virtual event.

“Amidst the landscape of devastation are buildings that survived. These structures which were designed and compliant to the standards, they have been slightly damaged but did not have brittle-type collapse. My message I want to impart here is vivid and clear as these illustrations. Safe structures save lives,” he said.

Dela Peña said the SAM PH Atlas is an “apt and very timely” support to the government’s Build, Build, Build program.

It was turned over to the Department of Public Works and Highways (DPWH) and Association of Structural Engineers of the Philippines during the event.

The atlas, together with the previously rolled out Earthquake Model Atlases for the Philippines, Metro Manila, Metro Cebu, and Metro Davao published by DOST-Phivolcs in 2018-2019, can provide science-based information for urban development, risk assessment, and site-specific insurance rates and coverages, he added.

DOST Undersecretary and Phivolcs OIC Renato U. Solidum Jr. said the SAM PH Atlas will help in designing earthquake-resilient structures and facilities, such as hospitals, dams, power plants, roads, bridges, and railway systems.

It can also be used for the assessment and retrofitting of existing structures to conform to the building standards.

“This is an improved version of the Philippine earthquake model by considering the maximum considered earthquake using probabilistic seismic hazard analysis and we hope that this will be adopted in the revision of the seismic provision in the National Structural Code of the Philippines,” Solidum said.

“We firmly hope that this latest atlas will be utilized by all stakeholders for decision-making in building safer structures and facilities, and for strengthening the resiliency of our communities,” he added.

Aside from the national and regional scale spectral acceleration maps, the Atlas contains maps of historical earthquakes from 1619 to 2015, and active faults and trenches in the country.

“It will certainly help DPWH in preparing the design and identifying which structures need to be retrofitted, strengthened, repaired, and totally rehabilitated,” DPWH Undersecretary Maria Catalina Cabral said.

“Our Bureau of Design together with our PMOs (project management offices) for buildings are going to adopt and apply this as well as the other codes that we are using, such as the National Building Code, the Philippine Green Building Code and other tools that are adopted by DPWH and institutionalized by department orders. (It) will certainly be very helpful in finishing all that we have committed to deliver under the Build, Build, Build program,” she added.

Phivolcs said the spectral acceleration maps will likely be adopted in the 8th Edition of the National Structural Code of the Philippines planned for release in 2022.

A digital copy of the atlas will also be made downloadable for free on Phivolcs website