10-10-2014, 02:12 PM
An attempt has been made to study the response of the base frame of an
Electrical Circuit Breaker subjected to Earthquake Ground motion in horizontal
and vertical directions. Digitalized earthquake record of Elcentro, 1940 has been
taken for finding the response# The rotational effect on the response due to non
coincidence of stiffness centre and mass centre has been taken into account. A
bilinear hysteretic force and displacement relationship has been assumed. The
circuit breaker has been idealized as a single mass unit resting on the base frame
whose stiffness against horizontal and, vertical ground motion has been
determined assuming the stiffness to be lumped at the four corners of the frame
equally.
The response of the system has been obtained for
1. Horizontal ground motion with rotation in the vertical plane.
2. Vertical ground motion with rotation in the vertical plane.
3. Coupled horizontal and vertical ground motions-along with rotation in the
vertical plane, The influence of eccentricity, of the frame* viscous damping on
the total response in the case of vertical ground motion has been studied and the
response has been compared with that obtained from seismic coefficient and
Response spectrum Methods. The response of the base frame for horizontal,
vertical, coupled horizontal and vertical earthquakes has been compared for two
kinds of connection, i.e. Rigid frame without braces and pinpointed frame with
braces to know the effect of connections on the response. Also an attempt has
been made to arrive at an optimum section for the base frame subjected to
earthquake ground motions.