Japanese technology pooh poohs threat of ‘Big One’

Seasons Residences shines light on structural design

Local government investigators recently unveiled chilling security footage taken at the height of the  6.1 magnitude earthquake that shook Luzon last April 22,  showing supporting beams “exploding” inside a four-story supermarket in Porac, Pampanga.

Japanese technology pooh poohs threat of ‘Big One’
Earthquake-resistant buildings not a pipe dream.  Structural engineer Raul Manlapig, of  Ove Ar up & Partners Hong Kong, Ltd. and Keisuke Sugihara (below), general manager of PNS Advanced Steel Technology., Inc. discuss tall buildings design, seismic design and evaluation of buildings, structural behavior under seismic loads, and vibration control devices that can save lives.
The quake caused the building’s steel and concrete foundations to crumble within a mere seven seconds, giving victims inside the supermarket no chance to escape as governed in the Philippines’ building code.

The footage strengthens suspicions that the steel used in the construction of the supermarket were of “poor quality”. Specifically, “quench-tempered” (QT) steel bars, that were mislabelled and not suitable for welding, caused the beams of the building to give way prematurely even before victims inside had the opportunity to “duck, cover and hold.”

As a country located in the Pacific Ring of Fire, seismic activity in the Philippines is a given.  Luckily, these earthquakes are often short and weak, and far in between. Only three significant quakes were felt by Metro Manila in more than ten years. This long interval, coupled with the recent 6.1 magnitude and the two smaller ones that followed in quick succession suggests the possibility of a “big one” soon to follow. Are we ready for it?

Good news and bad news

The good news is that the Department of Trade and Industry (DTI) is reportedly moving to standardize the manufacture and labelling of quality steel reinforcing bars, particularly for high rise buildings. Industry sources revealed to the Manila Standard that the DTI will implement the  the distinct embossing on each rebar of the steel grade of a product to properly identify its quality, within the year.

This follows a law filed earlier this year by  Congressman Scott Davies S. Lanete (House Bill 8871) seeking more stringent labelling, testing, enforcement and penalties, among others, for  steel rebars.

The labelling , or “embossing” of grades which reflect the actual type of steel, is a welcome move, industry observers say, as well as much needed reforms reportedly in the works, namely,  “cyclic loading tests” for locally manufactured steel rebars, which calls for  these to be subjected to repeated, fluctuating intensity stress tests; and minimal steel  grade requirements (grade 60) for rebars to be used in high rise buildings and other major infrastructure.

 The bad news is that the reforms may not be able to address the danger faced by the plethora of high rise buildings that have already risen, particularly in Metro Manila over the past ten years, when the “big one” hits. 

Many of these buildings, direct beneficiaries of the property boom over the past ten years,  including mushrooming government infrastructure such as airports and mass transport facilities, were built using substandard steel rebars sold using the color-coded  labelling process. 

A major controversy in the industry over the past decades have been steelmakers who market their supposedly tested and correctly-labelled products rebars as grade 60 in strength when these are only grade 40.  

Experts agree that such practices put into question the structural integrity of high rise edifices  during times of a major earthquake. In other seismic-prone countries, the testing grades can be up to 80 to 100. The Philippine government has been slow to adopt this safety-driven process, and has simply relied on using painted marks to identify rebar types over the past decade. This has been a source of fraud in the industry as the paint can be erased or painted with another color.

Japanese technology pooh poohs threat of ‘Big One’

More alarmingly, a leading industry player that has stridently advocated for color-coding of rebars instead of embossing — and has been unloading thousands of these mis-labelled rebars in the market— recently claimed that it had built over 50 percent of the high rise buildings in Metro Manila during much of the same period. 

Last week’s earthquakes measured 5.6 to 6.1 intensity (Richter scale) at their epicenters, respectively, and left at least 19 dead and more than 80 people injured. The terrible structural damages to buildings in Pampanga and the Visayas  happened at only intensity 4. Based on the claim of this local steelmaker, should an earthquake at intensity 8 hit Metro Manila, over half of the high rise buildings in the metropolis would be flattened due to the substandard steel used in their construction.

Tremors, a daily part of life in Japan

Japan considers earthquakes as a part of daily life. It’s something that locals have come to expect, and have grown accustomed to. When tremors happen, earthquake drills are automatically performed like clockwork, after which everything goes back to normal. This nonchalance is owed to Japanese confidence that advanced measures are in place. If a big quake does hit, they’ll be safe. 

Japan has through the years adapted their buildings and infrastructure to resist various natural disasters, gaining a unique insight one can only attain from first-hand experience. Through these seismic events, they’re able to gather information that help plan for the future. One of their biggest innovations in earthquake vibration control technology, the Visco-elastic dampers (VCDs), is actually used by the world’s tallest buildings like Tokyo Skytree and Taipei 101. 

The soon-to-rise Seasons Residences at Grand Central Park in Bonifacio Global City (BGC), Taguig, will be using this damping technology. 

The Seasons Residences is a joint project of Federal Land’s and  Japanese conglomerates Nomura Real Estate Development Co., Ltd. and Isetan Mitsukoshi Holdings Ltd.

The mixed-use, lifestyle center will feature the marriage of Japanese innovation and design with the Philippines’ unique brand of community. A major part of this innovative drive will be the use of VCDs technology, typical of over 300 buildings across the world from Japan, Taiwan, Canada, Mexico and the United States. 

“No price tag on people’s lives”

Federal Land held a short talk last week on the VCDs technology, featuring Keisuke Sugihara, general Manager of PNS Advanced Steel Technology, Inc. (Nippon Steel Engineering Group) and Raul Manlapig, managing director of Ove Arup & Partners Hong Kong Ltd.

The panel tackled topics from earthquake preparedness, structural design, and the intricacies behind the damping technology of the Seasons Residences. One of the features highlighted was the use of the VCDs system which acts as shock absorbers to ensure that residents are safe and comfortable during earthquakes and typhoons.

Aside from the damper systems, the Seasons Residences will also adhere to the Philippines’ National Building Code to further ensure an earthquake-resistant structure. 

To be sure, the VCDs system, and steps to adhere strictly to the building code, carries a higher price tag for sustainable structural projects such as the Seasons Residences.

But as Sugihara pointed out last week, as in Japan, the issue of structural design integrity  “holds great economic impact on all of our lives.” 

Manlapig agreed, reminding  participants at the discussion that in a seismic-active country, “safety should never be sacrificed for a few pesos of savings. You can’t put a price tag on people’s lives.” 

Topics: Earthquake , Keisuke Sugihara , Nippon Steel Engineering Group , Raul Manlapig
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