Abstract
In metropolitan areas where an enormous number of evacuees are expected, residents of high-rise buildings will be requested to stay in their home even after an earthquake as much as possible. The residents are not familiar with such fire protection systems and are not likely to notice damage on them. It is expected that the residents would decide to stay home in the aftermath of the earthquake if the building has no structural problem even if the fire protection systems are damaged.
If the residents continue to live in a high-rise building, it is necessary to check fire safety to avoid a disaster in case of a fire after checking that the building has no structural problem. However, there will be no easily accessible method of assessing fire protection feature of the damaged buildings by checking damage conditions after an earthquake. It is socially significant to construct simple methods for residents, management company and specialists to inspect fire protection features of a damaged building and judge if the building can be safely used against a fire after an earthquake. The purpose of this research is to develop a method of assessing fire safety of the buildings damaged by an earthquake. In this paper a survey was conducted on the action taken by residents and management company and the damage, inspection and restoration of fire protection systems after the great earthquake.
The following three issues are studied based on the survey results; (1)who will be able to conduct the inspection, (2)time phases after an earthquake and (3)necessary conditions to continue living in a high-rise building.
The study results are as follows;
- People who inspect the buildings and fire prevention systems vary with the lapse of time. The residents need to conduct the inspection for a certain period of time after the earthquake.
- Fire prevention features get lower immediately after the earthquake and gradually recover to normal as the surrounding situation improves (people returning home, lifeline restoration (electricity and water supply), and reunited fire brigade) and the fire prevention features are restored by inspection and repairs.
- It may be difficult to encourage the residents to evacuate from the high-rise building after the earthquake even if the fire prevention features have some failures. Keeping safety against a fire by lowering a fire risk with fire usage restriction will be a practical method if the residents continue to live in the building with lower fire prevention features.
It can be concluded the following is important to make the assessment method more efficient, considering the above.
- Divide the period after the earthquake into several time phases based on the time elapsed (hereafter referred to as “phase”) and clarify the minimum fire prevention features required for each phase in order to assess safety of high-rise building against a fire after an earthquake in a viewpoint of “whether the residents can continue to live in the building.”
- Check whether the building maintains required features by inspection of the fire prevention features and lower a fire risk properly. Impose more stringent limits or encourage evacuation if no features are maintained.
This study divides the period from the earthquake occurrence to the normal condition (fire protection features) into four time phases and shows which restoration stage each phase indicates, approximate period of each phase, fire protection features required and a reduction of fire risk imposed per each phase.
