The Manhattan Bridge was built from 1901-1912 using a device
known as the Warren Truss.
That “W” design dawned on British engineer James Warren
way back in 1848.
If he alternated triangular supports, the resulting truss was very light, and remarkably strong.
It worked well in big planes, too.
Today it’s called a “bar joist” and it is still used
in all kinds of buildings.
So of course they tried a bridge.
In fact our Manhattan Bridge is the first ever to be based
on the Warren Truss.