1. This is Seismic Isolation, a means of protecting the structure against earthquake.
It detaches the structure from the ground so that earthquake motions are not directly transmitted.
Expansion joints are provided along the transverse direction to allow movement (expansion/contraction) of the construction materials without inducing stresses due to changes in temperature or other reasons.
Of course, they weren’t made to annoy you while driving!
3. The ratio of the length to width of a room is generally between 1.5 to 2.1 (India) so that we don’t feel like living in a box or tunnel!
4. This is called Mid-Landing –
The minimum height of each step (rise) should be 15 cm and width (tread) 25 cm.(India)
By the way, each stairway is a flight!