An engineering marvel of yesteryear, the Pamban Bridge is 103 years old and still counting.
Typically, a bascule bridge span consists a curved structure (like roller) with a long span on one side and a counter weight on other side. Rails are mounted on the long span. The curved structure rests on a horizontal platform and can roll on this platform. The counter weight is heavier and at a higher level than the span and creates unstable equilibrium (by design) resulting in a rolling effect on the
Scherzer span. Thus, a natural upward lifting tendency is created on the span such that the span does not fall into the sea. On the Pamban bridge, the span weight is 184 tons and the counter weight itself is 234 Tons.
On the night of December 24, 1964, a super cyclone struck the area and the Pamban-Dhunskodi Passenger was washed away by a tidal wave killing all the occupants (around 115 passengers) on the way to Dhanushkodi. The cyclone caused many girders of Pamban bridge to be washed away but the Scherzer span withstood its fury.
Author: Ravi Sunderarajan