Understanding your house and some real time tips to make it possible
.. so I would like to say those houses which were built before earthquake and was fine have passed the test and you can be sure of at least that structure because it pass that 7.8 rector scale. Even for engineer, we got opportunity to learn many behaviors of house and soil profile during Gorkha earthquake and have enhance our confidence because even I used to think that less rector impact could have catastrophic situation in densely populated areas like Kathmandu and it proved us wrong and it make me realize.....
".... soil profile in many areas of Balaju showed catastrophic ..."
A decade of my experience have taught me many things about safe construction and green buildings and about sustainability but each time I visit the sites and do the assessment, the queries from private client about their structure makes me excited and worried because there are very less people who have understand about their house and I think the need of this knowledge is imperative today and I would like to share some of the ideas that you can assure how your house is and get assured about some of the interesting fact of your house which you might not have ever considered. Firstly, understanding your house is the must because your house is considered as your family member and if you are unaware about it how would you take care of, how would you present your problem to the concerned people. Let me tell you the fact that for the client who have better understanding of your house and about its component would get less chance of being tricked by any dealer or contractor or anyone and you can save lots of time and money during this process. Now, let me drive in to basic understanding of your house, Initially the type of house makes major difference, if your house is load bearing house, walls plays vital role and special attention should be given for those houses because these houses are considered to be weaker in compare to framed house and more parameters of engineering need to be considered during construction as well as during retrofitting and for non-load bearing house or framed house, pillar, column and foundation plays vital role so these houses are considered to be more rigid. The first thing you need to understand about your house is about the dimension, the plinth of your house, total area of the floors, length and breath and height of your house, individual floors and your room’s dimension and about its proper direction as per the plot. This helps to calculate different costing for retrofitting, any future modular design and such. The open space in your house is another major consideration to consider, during any catastrophic situation, the open space near your house or outside your house would play vital role so considering such brain mapping need to be done and any obstruction in the way to those places need to be removed and even open space in the community need to be identified well in advance.
The third thing to consider is about getting basic knowledge about the soil profiling of your area, soil profile of your place plays vital role during earthquake for instance weak soil profile in many areas of Balaju showed catastrophic impact in the houses, some houses were tilted during the earthquake so knowing your areas soil profile is important and to draw the rough conclusion about it, you can refer the Gorkha earthquake of 7.8 magnitude, if the impact during Gorkha earthquake in your house and 500 meter periphery have major cracks in soil, major destruction in asset around than new building or even retrofitting need soil test and profiling to estimate the load distribution chart during earthquake and if no major cracks in soil or no much destruction in the house implies the soil is of good quality. Soil behaviors during rainy condition would be different so this condition also need to be considered. Another parameter to consider is crack in house and I find many people’s concern regarding this as you need to understand that cracks can be generated by different condition and minor cracks is obvious in Nepal where quality workmanship is not considered. If you go to the newly constructed house which do not have encounter earthquake might have so many minor cracks and its still good to go and considered good structure. Basically, in framed structure wall is considered as a flexible which can be replaced easily as per your convenient. Minor cracks in any structure also drag concern of the house owner but hair size crack need not be of much concern, if the crack is up to 6mm, it shouldn’t bother you if its bigger than 10 mm proper retrofitting need to be done and in load bearing structure more concerned need to be given. The cause of crack needs to be identified for instance, crack from earthquake, crack due to poor workmanship. For some houses, portion of the plaster get detached after some interval and this is caused due to poor workmanship during construction. In some houses the basement is seen to be with some minor or even major cracks and this is due to load of your building and this is ok, normally building load settle the soil profile and minor cracks or settlement of it makes no concern but more uneven settlement need prompt stabilization of soil and for the slopy areas, more concern need to be given and boundaries need to be reinforced if such case arises. More concern needs to be given if neighboring new houses are to be constructed, the proper stabilization of soil need to be done and use of heavy dozer need to be avoided in such areas. Normally, concrete has an age of 90 years but it depends on different parameters so old house with more than 80 years also need more retrofitting and service for its effectiveness. Maintaining waste water, water and drainage way, day lighting balance, indoor and outdoor air quality, recycling organic and reuse of inorganic waste, cross ventilation, energy efficiency can help for sustainability of the building and improve quality of life. Position of pillars, load of pillars as per the height of the building and such can help to identify the strong place in your house during earthquake and help you get out in time. Identifying weak points as portion in structure with more load in pillar and beam, unnecessary projections, weak staircase and such need to be avoided during earthquake. Underground water tank, septic tank and such need to be avoided in the main structure, this unit should be constructed separately for safety of main structure as it would weaken the stiffness of the structure during earthquake causing serious impact to the structure. Moreover, people have perception about the house which has encounter the earthquake, they think its not good for them but remember one thing, we reinforce building with different materials during construction and one motto of an engineer is to make the house withstand any impact and earthquake helped to test the house, so I would like to say those houses which were built before earthquake and was fine have passed the test and you can be sure of at least that structure because it pass that 7.8 rector scale. Even for engineer, we got opportunity to learn many behaviors of house and soil profile during Gorkha earthquake and have enhance our confidence because even I used to think that less rector impact could have catastrophic situation in densely populated areas like Kathmandu and it proved us wrong and it make me realize to do research from new perception and I feel fortunate about it.
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