Buildings compliant with structural code can resist up to magnitude 8.4 quake –expert

Buildings that are designed in accordance with the National Structural Code of the Philippines (NSCP) are safe no matter their proximity from a fault line, according to an engineer who specializes on earthquake-resistant infrastructures.

In an interview with GMA News, Engr. Carlos Villaraza, who heads the Association of Structural Engineers of the Philippines (ASEP), said a building compliant with the code “can resist up to a magnitude 8.4 earthquake, which is the highest possible earthquake that will hit the Philippines.”

Philippine Institute of Volcanology and Seismology (PHIVOLCS) director Renato Solidum, in a forum Monday, said that low-rise and residential buildings in Metro Manila remain vulnerable to a projected 7.2-magnitude earthquake.

Studies show that up to 13 percent of all low-rise and residential buildings in the metro will either be heavily damaged or will collapse in the event of a killer quake.

“Maraming bahay ‘yan na ang gumagawa ay hindi engineer, hindi rin kumuha ng permit ‘yan. Marami d’yan ay gumagamit ng sub-standard materials. D’yan tayo magkakaroon ng problema kapag may lindol kasi sila ang unang babagsak, “ Solidum said.

While it is best—although costly—to hire an engineer, Villaraza said there are “first aid” retrofitting measures that can be applied to existing houses that are non-compliant in design.

One technique, he said, is installing “cross-braces” across a poorly reinforced hollow block wall. The braces could be ordinary, inexpensive lumber.

Villaraza said bracing the walls minimizes the chance of collapse. —KBK, GMA News