The number of people killed in Nepal
by two major earthquakes has
surpassed 8,500, making the disaster
the deadliest to hit the Himalayan
country on record
Construction Issue
The URM buildings are prone to shear movement
failure and can collapse entirely in the event of
earthquake. In fact, almost all the report suggest that
the majority of causalities were a result of URM
structure collapse. Houses built of unreinforced
masonry – bricks, hollow clay tiles, stone, concrete
blocks, or adobe – are very likely to be damaged
during earthquakes. The mortar holding the masonry
together is generally not strong enough to resist
earthquake forces. Anchorage of walls to the floor and
the roof is critical. These houses are weak (brittle) and
can break apart. Walls may fall away or buckle,
resulting in damage.
LESSONS LEARNT
General
The performance of buildings during earthquakes
reveals that if the earthquake resistant measures as
specified in building codes are adopted, buildings are
quite safe. Location of building has profound
influence on the performance of buildings. Site
selection should be based on local geology and the
subsoil properties which modify the earthquake
ground motion. A seismic micro zonation in high
seismic area will be helpful in the decision making.
The architects either have little or ignorant about the
earthquake resistant provisions in the building and
there is no method of fixing accountability.
Configuration
The layout of buildings should be as simple as
possible and there should not be any sudden change
in the distribution of mass or stiffness. Avoid
construction of heavy structures at the top such as
water tank, swimming pool, garden etc. Failure results
due to soft storey and weak storey conditions and
therefore should be avoided. Integrity of the whole
building should be achieved. Proper detailing of joints
and splicing should be made.
Design
The most of the Structural Engineers and Architects
are not conversant with the latest codal provisions on
earthquake resistance design. Buildings designed and
constructed as per Indian Codal practices have
withstood the earthquake well and therefore Codal
practices must be followed. Adequate strength in
both the longitudinal and transverse directions should
be provided. Avoid quasi resonance i.e. the
fundamental natural frequency of structure should be
away from the predominant period band of the