What can I do by FRPs for Kumamoto’s eartchquakes?
I am really sorry about the disaster by Kumamoto's earthquake.
I was outside of Japan when the news of Kumamoto's earthquake, and it is was reported in the several TV programs. I could not find the proper words how to explain my feeling.
" What can I contribute to them by FRP technologies? "
This was the question to myself at that time.
I write this column thinking about the answer of the question above.
The abnormal of the earthquake in Kumamoto is;
" The high magnitude quake is happened continuously. "
I have created my design logic in the aeronautical engineering as;
" Structure life shall be evaluated by LCF（ Low cycle fatigue ）と HCF （ High cycle fatigue ）as the application requirement."
LCF is the specific load at each event and HCF is the normal stress in the usual use.
In the case of the architecture (houses or buildings), LCF is the load by;
– People walking or running
– Vibration by the outside truck or automotive
– Small magnitude of earthquakes
– Thermal expansion by the temperature range from the morning to the night
I set the HCF design value, based on the infinite life.
On the other hands, HCF is the load by;
– Relatively high magnitude earthquake (once happened in a few years)
– Very large typhoon
– Thermal expansion by the change of the season
HCF design value was set at the defined cycle times, based on the structure usual life time.
Very few events shall be also considered like;
– Very large typhoon
– Tsunami
– Giant earthquake
But the structures will be basically designed as "NOT RUINED" against the abnormal events like above. The structure will be replaced with the new one after the event.
I am not the specialist of the design of the houses or buildings but the logic would be similar, I believe.
When we see the case in Kumamoto, the event is unexpected as the design logic because the giant earthquake, assumed as once or twice events during the whole life span, happened more than 5 times in 2 weeks.
The human knowledge is far from understanding the nature power. I should regret the current severe condition of the people in Kumamoto also as one of the engineers and researchers.
I try to think about how FRP can contribute the disaster.
One of the idea is;
" Preliminary repair of the houses or buildings by FRPs "
There are many houses or buildings which are not totally collapsed but partially damaged. Such houses could be used as the shelter and the persons would like to stay their own houses as much as possible.
Reinforcing the houses by the field curing type of FRPs would be the candidate. If their own houses can be used as the shelter, the privacy level will be much improved because many people is still staying in their CARS.
I have written the column regarding the reinforcing of the tunnels before.
Of course the houses reinforced by FRPs are the preliminary use only. And the private houses are more proper than the building as the target of partially reinforcement.
This concept can be applied also to the other construction fields too.
At the same time, we need to think about the future too though now the people in Kumamoto face the difficulty on the front. In Europe, FRP will be applied to the wide range of houses or buildings to improve the thermal efficiency though FRP is not allowed to use the material of the because of the concern of the flammability.
Below is the one of the examples in Europe.
Prospect for new guidance in the design of FRP has been already released.
We are at the stage of thinking about the design concept of;
“ Preliminary space shelter space can be kept even after the serious abnormal events after happened ”
FRPs are of course very tough materials but the structures by them are very stiffened if the proper design concept is applied.
For example, the living rooms, bed rooms, kitchen, toilet, or bathroom are stiffened by FRP to keep the living space and infrastructure in the house to prepare the disaster.
Full FRP houses are very expensive but partially stiffened houses would be close to the reality. Such houses, partially stiffened by FRPs, would be the proper space for citizens against the disaster.
It will take long time to recover normal life in Kumamoto but I try to do my best with my partner companies to contribute people in the problem by FRPs.
