The recent earthquakes that jolted the Philippines within 24 hours, from the northern region of Luzon, to the southern part of Visayas (and just this recent, in Davao Oriental), has again sparked fear and panic among the Filipinos nationwide. With intensities ranging from 5 to 6.5, it has caused devastation (and claimed lives) closest to the epicenter. Because of its location on the Pacific Ring of Fire, the Philippines is prone to earthquakes and volcanic eruptions caused by the movement of tectonic plates.
After the quake has subsided (and safe from aftershocks) and your occupants are out of harm’s way, a post-earthquake inspection is in order. This assessment clears your building for reoccupation and identifies structural damage you need to address.
Invite an engineer to your facility for a walk-through. Not only does this provide them with familiarity of your building, but they can make suggestions about reinforcement strategies. It is also important to have your structural drawings available and organized. Often they’re in a state of disarray, which impedes the inspection process.
An engineer starts with a visual evaluation of the building’s exterior, looking for tilting and land shifts. Once inside, damage to structural members is critical to identify. Impaired columns, shear walls, and gravity or lateral supporting systems often imply the building is unsafe.
Minor damage is also pinpointed, such as cracks, ceiling and floor issues, elevator and lighting damage, and roof failures. Note that a structural engineer will not address systems such as mechanical, plumbing, or IT.
There are two types of evaluation methods:
Rapid Visual Inspection – This occurs up to 24 hours after an event and uses a red, yellow, and green tag system. A volunteer or state-contracted engineer will take approximately an hour to assess the building’s safety, erring on the conservative side.
Detailed Structural Evaluation – These inspections are specific to your situation. They take place several days after an event and a thorough assessment takes one or two days. The time required for an inspection is dependent on your building type – a box store requires a different level of attention than a high-rise building.
The following four-step approach will help you work out if buildings are safe.
Step 1 - Initial assessment
- Initial assessment by owner/operator. If this finds significant issues/damage further assessment is required.
- You should hire a chartered professional engineer if there is any doubt.
- If there is any concern about the structural integrity of the building, do not enter. Seek professional chartered engineering advice and guidance and advise occupants that the building is not to be occupied.
Step 2 - Engineer inspection
- Chartered engineer inspects key elements of the building structure. This may include invasive techniques. It is recommended that the same engineer/engineering company do this for continuity and familiarity of the building.
- Buildings are not to be occupied until the engineer declares that it is safe to occupy.
Step 3 - Check building systems
- Once the engineer has declared the building safe to occupy, organise an inspection of building services and systems by suitably qualified professionals / Independent Qualified Person, e.g. fire protection, electrical, water, lifts, heating and air conditioning or security.
- If any services/systems are damaged, you may not be able to occupy the building until they are fixed.
- Any other damaged areas needing repair also identified are remediated in this stage.
- A final check is done to ensure that the building is safe to occupy in accordance with building warrant of fitness and building code regulations and policies.
Step 4 - All clear to occupy
Building is cleared and fit to reoccupy.
Sources:
http://www.huttcity.govt.nz/Services/Building-and-resource-consents/earthquake-strengthening/after-an-earthquake/
