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Question 13: We received a heart breaking email on 3 August 2014 late evening, this is the extract: ‘I’m writing this email to you with a heavy heart as some of my relatives and friends have been much affected by the recent Yunnan Earthquake started on 3 August 2014. Hundreds have lost their lives and thousands have displaced. I’m not too sure if Yunnan is classified within the earthquake zone and I wonder if there is any ways to reduce the casualties and damage if the same thing is going to happen again….’
Our Answer:
We have been following the aforesaid News on TV since last evening and we want to send our condolences to you, all the victims and their families and we hope that you will slowly recover from grief and go on bravely in life. Know that our hearts are with you and many people around the World wants to show you their sympathy and they are praying for the victims and the souls of the departed. We want you to be convinced that the departed souls are now in good hands and God is now kissing them and welcoming them back home where all of us will meet again in future…
I will give you a very simple summary, avoid all technical jargons and hope that you will understand:
For a building to be constructed in an area prone to earthquake, it is prudent to AVOID bricks construction such as using bricks columns to support the structures and using other bricks in-fills as internal and external walls UNLESS they are specially constructed under Earthquake Provisions. These bricks which is cement together could easily displace and eventually become hazards for the people during an earthquake event where there is massive vibrations in the horizontal and vertical directions.
Any Reinforced Concrete Structures and Steel Structures NOT designed and /or constructed according to the earthquake provisions WILL experience serious damage and become deadly hazards to the people. Due to the highly unpredictability of the earthquake forces and related oscillation directions, it is common for the aforesaid structures to experience some damage even they have been designed according to the various design codes and with computer simulations. Any reinforced concrete or steel structural element badly deformed after an earthquake is as good as “trash” and must be replaced, even it is for aesthetic considerations.
If a building to be constructed in the earthquake zone is not more than 3 Storey high, I would highly recommend that it to be constructed using timber materials; as properly designed timber structures are known to have good resistant to earthquake forces as compared to reinforced concrete or steel structures. Even they are badly deformed after an earthquake; they could be replaced with relatively low costs.
What constitutes a good timber structure for earthquake provisions? - Dampers / Shock Absorbers to be provided at the foundation level to minimize earthquake impacts so that whatever earthquake forces transmitted to the structure above is within control. This is applicable for Reinforced Concrete and Steel Structures.
- Design and provide column-beam joints where they are able to exercise the required rotation in an earthquake event. This is usually done by using stiff spring connections at the desired locations and they are excellent in allowing the timber structure to undergo some displacements without damage. Braces are always installed to improve Earthquake Resistance of all Well Designed and Constructed Earthquake Timber Structures.
- Avoid having a tiled roof just above your head. It is prudent to have a strong timber slab (supported by timber beams) above to ensure that any falling tiles won’t become a hazard for you in an earthquake.
- Good Insulated timber wall provisions with proper heating system for cold weather.
We want to highlight that the above mentioned are just a brief summary and there are other important considerations not stated in order not to confuse a reader who does not have any engineering knowledge. This is a Specialist’s work and it must be performed by Engineers familiar with Earthquake Structures Design and Construction.
We hope that we have given the basic idea on how to protect yourself and your structure in an earthquake. Do not hesitate to contact us if you need our help. Please take care and know that our hearts and our prayers are with you always.
Written by:
Er. Goh Cheow Leng Maria (First drafted on 4 August 2014)
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