A
typical RC building is made up of horizontal members (beams and slabs) and
vertical members (column and wall), and supported by foundation that rest on
ground. The system comprising of RC columns and connecting beams is called RC
frame, the frame participates in resisting the earthquake forces. Shaking due to
earthquake develops the inertia forces in the building which are proportioned to
the building mass. Earthquake-induced inertia forces preliminary develop at the
floor level of these forces downwards through slab and beam to columns and walls
and then to the foundation from where they are dispersed to the ground. Inertia
forces accumulate downwards from the top of building. The columns and wall at
the lower storey experience higher earthquake-induced forces and are therefore
designed to be stronger than those in stores above.When beams bend in the
vertical direction during earthquakes, these thin slabs bend along with them.
When beams moves with column in horizontal directions, the slab usually forces
the beams to move together with column in horizontal direction, the slab usually
forces the beams to move together with. This behavior is known as rigid
diaphragm.

For building to remain safe during earthquake shaking; the columns (which
receive forces from beams) should be stronger than beams and foundations (which
receive forces from columns) should be stronger than columns. Connection between
beam and columns, columns and foundation should not fail before the failure of
beam.