By Catherine J. Teves
MANILA, (PNA) –- Director Renato Solidum of the Philippine Institute of Volcanology and Seismology (Phivolcs) sees urgency in stepping up structural assessment of houses and other buildings nationwide to determine which of these can still be retrofitted for occupants’ safety.
He said such assessment must be increasingly undertaken as earthquakes are common nationwide since the country lies in tremor-prone Pacific Ring of Fire.
“Structures that can’t be retrofitted anymore must be condemned already,” he added.
The assessment is important even for houses since not all of these were constructed in accordance with building regulations and in consultation with engineers, he noted.
Seismic retrofitting is the process of strengthening existing structures to make these more resistant to earthquakes.
Soil type, structural design, building materials used and manner of construction affect an earthquake’s impact on a structure, Solidum said.
Structures built on soft soil and located near an earthquake’s epicenter are generally subject to “strong” shaking, he added.
Phivolcs boosted its call for compliance with the country’s building regulations as the 7.2-magnitude earthquake in Bohol province last month caused chaos, death and destruction there and in other areas.
Latest available information from the National Disaster Risk Reduction and Management Council (NDRRMC) shows 222 people were reported dead from the earthquake.
NDRRMC also reported that aside from affecting various public buildings and infrastructure, the earthquake damaged at least 73,002 houses in Bohol, Cebu, Iloilo, Negros Oriental, Negros Occidental, Siquijor and Leyte provinces.
Earlier, Quezon City building official Gani Versoza backed calls for assessing structural soundness of houses and other buildings.
”Those aged 15 years and older must be subjected to structural assessment,” he said.
He noted the Quezon City government continues undertaking such assessment to help protect life, limb and property.
”Over 500,000 residential and non-residential structures dot the city but given our limited manpower, we’re prioritizing those having three or more floors,” he said.
The city government tapped an additional 30 engineers for the undertaking, he continued.
Versoza also urged the public to check for cracks in their structures.
”Report such cracks to us as soon as possible so we can investigate these,” he said.
Cracks in buildings may either be structural or non-structural in nature.
According to experts, structural cracks are due to either incorrect design, faulty construction or overloading.
They said non-structural cracks result from various factors.
Among such factors are moisture changes, elastic deformation, chemical reaction, foundation movement, vegetation and settlement of soil, they added.