Our Experience
As we observed numerous houses and evaluated them, we were
amazed, baffled and sometimes vexed by the ignorance of ours considering our own
safety. We found every case a different one and every decision a critical one.
We were completely amazed to see few five story load
bearing, mud mortar house with minor cracks only, in the locality where most of
ancient monument had been destroyed. Similarly, observing a partially collapsed
structure which wasn’t further damaged by the earthquake of moment magnitude (Mw)
of 7.8 Mw was a sight to see.
We were literally annoyed when we saw a load bearing- mud
mortar structure with cement mortar wall constructed above, such building were
severely damaged by this earthquake. Again, construction of whole room or a
portion of room on a cantilever area showed height of our ignorance, such
buildings were also heavily damaged. Further,
we found cases in which the building as whole was a combination of load bearing
and framed structure; basically those building housed stair portion in
loadbearing part and other dwelling portion in framed portion. What the hell,
right? The worst part is that, in most of the cases the load bearing part is
completely damaged and the framed portion is not.
The poor workmanship during the construction has been found
to be a major cause of failure as well. Improper mixing of concrete, faulty
pouring concrete leading to segregation and bleeding, haphazard spacing of
stirrups, inadequate cross-sectional area of the reinforcement bars, splicing
of the reinforcement bar in wrong way at a wrong place and insufficient clear
cover in the beam and columns are some of many factors which have triggered the
failure of the structure.
When there is inadequate number of reinforcing bars then the
column cannot take the load acting on it and it fails. If there is absence of
stirrups or if they are largely spaced then there is high probability of shear
failure as all the shear force will not be resisted by the concrete and
longitudinal steel only. The splicing of the reinforced bar at the column-beam
joint and splicing of more than fifty percent rebar at the same level makes the
corresponding level weak and there is risk of failure at that point. Again the
splicing should be done in such a way such that the load exerted from the
centerline of one bar is transferred to the centerline of another rebar. These
things should be considered while designing the building.
A Civil Engineer is a person who has specialized in the
field of safe and economic construction of the structure, construction without
the consultation of the engineer can have lethal consequences; most of us might
have realized this by now. Whilst evaluating structures, we found many
structures constructed without the technical assistance of the engineer. We
came across many cases in which the structures were bought after construction
by someone else; in such case we found the owner unknown about the structural
features of the house. We found most of such owner raising the story without
engineering consultation, so that they can rent the excess flats. Many of such
houses are brutally damaged by this earthquake. These improperly constructed
building have also greatly affected the neighboring house having sound
structural feature. The buildings which were constructed properly following the
building code, consulting engineer and using proper material have survived this
earthquake with little or no damage and those buildings would have stood even if
the earthquake was much greater.
Let’s take technical advice from the engineer while
constructing our house, let’s get the construction supervised during the
construction, and let’s be safe and happy. Yes, the engineers do charge some
amount of money, but isn’t it worth for the safety of ours and the ones we
love?
PS During the Barpak Earthquake 2015 while working in Bhukampa.net as volunteer.
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