Why are bridges made with I shape pillers?

Because we need to give support to the larger size superstructure above the pillar & to get same large support from the base as well. Thus this will help to transfer the distributed load on the superstructure to the sub structure/footings through pillers of generally smaller size in comparison. read more

If you make a bridge that is made continuously, then frequent expansion and contraction due to heat will weaken it and eventually it will break down. To prevent this, bridges are made of several sections. The bearings provide the sections flexibility to expand or contract without affecting the strength of the bridge. read more