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Davao City, Philippines

Dress rehearsal for Davao City

November 08, 2019 - Friday 4:11 AM by Jimmy Laking

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The series of strong earthquakes that shook Davao City are proving more and more a blessing in disguise.

With the condemnation of two residential buildings, this city is rid of two structures of dubious integrity.

If the buildings were unable to withstand a 6.5 magnitude earthquake, how much more when an earthquake goes up to 7.0 magnitude and beyond (the scale when it is considered destructive).

Together with land developers and the association of structural engineers, City Hall should  assure investors and would-be buyers that Davao City’s condo units and high rise building units are earthquake-proof and should be able to withstand earthquakes of greater magnitude than the recent tectonic visitors.

Along with typhoons, earthquakes come with the territory. No country is immune from them.

It is in coping with them that countries produce different results.

All too often, reference is made as to how the Japanese build their buildings in the face of earthquake threats.

Filipino structural engineers are no second fiddle. They rate high up there among the best. It is when human greed comes in that their products are sometimes compromised.

I took the liberty of lifting a story posted by Lamudi.com.ph, arguably the leading real estate platform in the Philippines. Here goes:

“Condos offer a variety of advantages, topmost of which are their proximity to key establishments and central business districts, and their great potential as investment properties. But in light of numerous news updates regarding earthquakes, people are becoming wary of living in multi-level buildings, thinking that such a high structure might not be stable enough to withstand strong seismic activities.

This fear is not without basis either. On July 16, 1990, a 7.8-magnitude earthquake that hit Baguio led to the collapse of 28 buildings. In fact, it was this major catastrophic event that prompted the critical revision of the National Structural Code of the Philippines in 1992.

Most recently revised in 2010, the National Structural Code of the Philippines is based on the National Building Code of the Philippines enacted by Congress in 1972 following the 1968 7.3-magnitude earthquake in Casiguran, Aurora. It offers a set of requirements for developers and construction companies that if followed strictly will keep buildings from sustaining major structural damage. Designed to protect homeowners and building occupants, the Code includes such guidelines as safe locations for constructing buildings and the use of high-quality materials.

Major condo developers and construction companies assure buyers that their projects are generally safe. In an interview with GMA News, Megawide Construction Corporation vice-president Ronald Paulo said that compared to buildings in other Asian countries, structures in the Philippines are designed to be able to endure up to magnitude-8 earthquakes. Paulo explained that the country’s structural engineers are well aware that the Philippines is prone to earthquakes (being situated along the Pacific Ring of Fire), and thus they design our buildings with this consideration in mind. In addition, building specifications are reviewed every few years.

In a separate interview with GMA News, Association of Structural Engineers of the Philippines (ASEP) head Engr. Carlos Villaraza said that as long as a building complies with the Code, it can withstand a magnitude-8.4 earthquake, regardless of its proximity from a fault line.

However, in an Inquirer.net piece by University of the Philippines Institute of Civil Engineer professor Benito M. Pacheco, he pointed out that a number of new low-, mid-, and high-rise buildings are still noncompliant with government standards. This might be because some buildings are non-engineered structures, some are built based on a much older set of standards, and some engineers reportedly “optimize” their structural design to reduce the initial construction cost.”
The article concluded with a guide for buyers in choosing “condo that’s as close to being indestructible as possible.” The first refers to location based on the Valley Fault Map System released by PHIVOLCS.  With the map comes the warning that “ structures built directly above the fault line or is within the 10-meter-wide buffer zone (five meters on each side of an active fault) are at the highest risk of heavy earthquake damage.”

The second to consider is the company behind the structure, citing the preference for people to buy only from reputable developers “because these companies know the importance of following structural safety standards, both for their buyers’ safety and their brand’s reputation. It is also important to ensure that the condo was built by duly licensed engineers, architects, and contractors, who are more likely to follow the updated building code.”

As in all transactions, a building should be able to produce a certification for structural soundness. This is considered a public document. No certification, no deal. 

It also pays to have an expert see to it that the building has no structural damage such as foundation cracks that would compromise stability.