Do you know Why are Rollers present in the bridge?
They are there to release any strains induced due to shrinkage or expansion of the bridge girder (primarily due to temperature, creep and shrinkage of concrete). If there were no rollers, then both the deck as well as the column / foundation (especially) would have to be designed for much higher loads.
They’re part of the design because the structural members of a bridge span expand and contract with variations in temperature. Rockers serve to support the span vertically while allowing for horizontal movement of its members.