MANILA, Philippines – Is your house ready for the next big earthquake?
A new tool for assessing the earthquake readiness of Philippine houses was launched on Wednesday, February 19 by the Philippine Institute of Volcanology and Seismology (Phivolcs), the Department of Science and Technology (DOST), and the Japan International Cooperation Agency (JICA).
The tool is a checklist that homeowners themselves can use to find out whether or not their house will collapse in the event of an earthquake.
The guide, with the title “How Safe is My House? Self-check for Earthquake Safety of Concrete Hollow Block Houses in the Philippines,” specifically looks into the features of a concrete hollow block (CHB) house, one of the most common types of houses in the Philippines because of its affordable construction cost. Read the checklist here.
The team behind the earthquake safety checklist went around the entire country assessing the performance of CHB houses during recent earthquakes like the October 15 7.2-magnitude quake in Bohol.
They found out that many of these houses were not designed according to the Building Code and Structural Code of the Philippines, which stipulates guidelines on building an earthquake-resistant house. Most of the time, especially in the country’s poorest communities, these houses are built by the village carpenter or mason who sometimes do not know the government building standards.
Substandard buildings and structures are a major cause of death during earthquakes, said Phivolcs Director Renato Solidum.
“If we can reduce the collapse of houses or damage to houses we will significantly reduce deaths due to earthquake.”
Checking for readiness
An earthquake-resistant house is a house that will not collapse during an intensity 8 earthquake, said Solidum. (READ: MAP: Strongest earthquakes in the Philippines)
The Do-It-Yourself checklist notes down the features a CHB house must have for it to be earthquake-resistant. These features are specific – everything from the thickness of the concrete hollow blocks used to the kind of soil the house should be built on.
|Concrete hollow block wall||6 inches thick (400 x 200 150mm)||4 inches thick (400 x 200 x 100mm)|
|Vertical steel bars||10mm diameter spaced 40cm from each other||6mm diameter spaced 90cm from each other|
|Horizontal steel bars||10mm diameter spaced 60cm from each other or laid every 3 layers||6mm diameter spaced 60cm from each other or laid every 3 layers|
|Mortar mix (Cement : sand)||1:4 Compacted||1:4 Not compacted|
|Roof frame/roofing||Wood/Galvanized iron sheets||Wood/Galvanized iron sheets|
The checklist asks homeowners to see if their homes have all the right features. One point is given for every earthquake-resistant feature in the house. If the feature is missing or the homeowner does not know if the feature exists, a score of zero is given for that item.
The higher the total score, the higher the level of earthquake readiness.
To further test the recommended features, Filipino and Japanese experts conducted a full-scale shaking table experiment in Japan using concrete hollow blocks and other building materials from the Philippines.
True enough, the house with all the features imposed by the Building Code and Structural Code (Model A) fared better than the house (Model B) that did not follow the standards.
Watch the video of the experiment here:
But a house with all the right components is not completely safe from any damage, emphasized Solidum.
The homeowner should still prepare for falling debris. They should still protect their heads and necks or hide beneath a sturdy table. If possible, it would be safer to run outside in an area clear of tall objects or structures.
An attempt at “laymanizing” disaster preparedness, the self-check tool aims to link regular Filipinos with the science of earthquake resilience.
But does the tool oversimplify the matter and make Filipinos complacent with their houses? What if human error in checking the features leads to a fatal mistake?
Solidum emphasized that no matter what score attained, homeowners are instructed to consult a civil engineer or architect. He allayed fears that this would be costly to the homeowner, because citizens can tap local government engineers to provide the expertise.
PHIVOLCS has also partnered with the Association of Structural Engineers of the Philippines (ASEP) to provide a two-day workshop in various parts of the country open to all homeowners. The workshop will teach participants how to use the earthquake safety checklist and will allow them to consult with engineers on how to retrofit their homes if they are found to be unsafe.
The reality is that many poor Filipinos build their own houses, he said. The checklist is one way Filipinos can make sure the homes they do build on their own or with their village carpenter or mason conform to safe standards.
Solidum hopes to reach all Filipino households with the help of the Department of Interior Local Government (DILG) who, during the launch, committed to spreading a circular to all local government units about the checklist.
“We will also develop a 12-point questionnaire for a wooden house and we will also prepare the Tagalog version. We have to be very careful in using the right Tagalog words because some of these are engineering terms,” said Solidum.
A computer simulation software that will allow engineers to test their designs in various earthquake scenarios is also in the works. The software is based on field data, experiments and the Structural and Building Codes. – Rappler.com