By Beatriz Marie D. Cruz, Reporter

BUILDING EXPERTS are concerned about the readiness of buildings and the lack of public spaces in case of a major earthquake in Metro Manila, after a 7.7-magnitude quake killed thousands in Myanmar on March 28.

A magnitude 7.2 quake — also called “The Big One” — could happen soon, they said.

“I recommend an architectural and structural audit, as well as a mechanical, electrical, plumbing, sanitary engineering, and fire protection audit of all buildings that were built before 2015,” Felino A. Palafox, Jr. a veteran architect and founder of Palafox Architecture Group, Inc., told BusinessWorld by telephone.

It was only in 2015 when the National Structural Code of the Philippines was updated, he pointed out.

The code, published by the Association of Structural Engineers of the Philippines, Inc., is a comprehensive set of regulations for the design, construction and maintenance of structures in the Philippines. It guides structural and civil engineers and incorporates advancements in structural engineering and lessons from past disasters.

Experts have warned that a 7.2-magnitude earthquake triggered by the movement of the 100-kilometer West Valley Fault along Metro Manila, also called “The Big One,” could lead to thousands of deaths and cause widespread damage to infrastructure.

A strong earthquake along the West Valley Fault recurs about every 400 to 600 years, according to the Philippine Institute of Volcanology and Seismology (PHIVOLCS). Its last recorded movement was in 1658 or 367 years ago.

“The Big One could occur before the 400-year mark or after 600 years,” Ma. Mylene M. Villegas, chief science research specialist at PHIVOLCS, told BusinessWorld in an e-mail. “Given that stress has been accumulating along this active fault for the past 367 years, an earthquake could occur at any time.”

Mr. Palafox likened the fragility of Metro Manila’s buildings to a paper clip, which can break if damaged several times.

“You bend the paper clip once, it will not break, but if you bend it several times, it will break,” he said. “So, if your building has survived several earthquakes, maybe your steel bars are already tired.”

A 2004 joint study by the Japan International Cooperation Agency, Metropolitan Manila Development Authority and PHIVOLCS noted that a 7.2-magnitude quake on the West Valley Fault could kill 33,500 people.

The major quake could heavily and partially damage 38% of Metro Manila’s residential houses and 35% of its public buildings, it added.

The West Valley Fault passes through the cities of Taguig, Muntinlupa, Parañaque, Quezon, Pasig, Makati and Marikina, and the provinces of Rizal, Laguna, Cavite and Bulacan.

The Philippines is also situated in the Pacific Ring of Fire, a seismically active belt that could trigger earthquakes, volcanic eruptions and tsunamis.

Nigel Paul C. Villarete, a civil engineer and senior advisor at technical advisory group Libra Konsult, Inc., said Presidential Decree No. 1096 or the National Building Code of the Philippines contains the latest provisions on earthquake-resistant design. 

“We belong to the highest category (IV), which considers the more probable and stringent earthquakes, so we can be assured our building should have been designed with the most recent and strict standards,” he said in a Viber message.

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“Of course, design is one thing, construction is another, so we must also ensure that our buildings are built with the highest standards and without unnecessary deficiencies that may be caused by carelessness, or worse, cost-cutting or corrupt practices,” he added.

If the country’s structural and building codes are followed, the Philippines should be “comparatively more ready than most countries” against earthquakes, Mr. Villarete said.

However, some contractors lower building specifications to cut costs, said Paulo G. Alcazaren, an urban planner and landscape architect.

“Anecdotally, there have been a good number of public buildings and infrastructure that were adequately designed by registered and licensed civil and structural engineers, but contracting firms have had to shortcut or reduce specifications to bring down costs to create enough profit to pay off government officials and ensure margins,” he said in an e-mailed reply to questions.

Mr. Alcazaren, the co-founder of PGAA Creative Design, also cited the lack of open spaces such as parks or sidewalks in Metro Manila, where people can safely evacuate.

“In our very congested business and condominium residential districts, there is obviously not enough area to stay clear of falling debris, shattered glass and also to seek refuge,” he said.

He also noted that billboards on top of buildings could fall during a major earthquake, causing significant damage.

“Even if they are well designed, who maintains and inspects them? I have never seen these being repainted, inspected or repaired,” Mr. Alcazaren said.

Mr. Palafox said it is more cost-efficient for the government and private sector to invest in disaster prevention than rehabilitation.

“It’s 90% less expensive to address the hazards before they become disasters, and they should be addressed by good planning, design, architecture and engineering solutions,” he added.

Meanwhile, the Department of Public Works and Highways (DPWH) said it has assessed 21,000 public buildings for earthquake readiness and compliance with the building code.

“As of today, we have assessed more than 21,000 public buildings, and many of them are recommended for retrofitting,” Public Works Undersecretary Maria Catalina E. Cabral told a news briefing at the presidential palace.

“We have also completed several retrofitting projects. Essentially, retrofitting raises a building’s standard to comply with international earthquake standards,” she added.

She cited the agency’s 2020 deal with the World Bank to retrofit and upgrade 425 buildings in Metro Manila, including schools and health centers, to ensure they can withstand high-magnitude earthquakes.

Ms. Cabral said DPWH regional directors were assessing the structural integrity of buildings and bridges as part of the agency’s yearly efforts to look after local infrastructure.

“This is an ongoing effort — not just now, and not solely because of the incident in Myanmar, but as part of our annual program,” she said.

“Every year, all bridges, national roads and especially national bridges must be assessed to evaluate their structural integrity. This allows us to plan whether they need repairs, rehabilitation, replacement or retrofitting,” she added.

At the same briefing, Civil Defense Undersecretary Ariel F. Nepomuceno said President Ferdinand R. Marcos, Jr. had ordered his agency to craft long-term solutions for The Big One and ensure Metro Manila is ready for quakes similar to the one in Myanmar.

“If we start doing things correctly today, the process will still take time because it involves millions of houses that may need retrofitting and structural integrity audits,” he said. “So, it’s not hard to do; it just takes time.” — with John Victor D. Ordonez