Here's a photo of a bearing plate where a bridge reinforced concrete beam meets the earthfill
The bridge span is about 20 meters long and consists of two reinforced concrete beams each resting on two bearing plates like the one shown - one plate for each end of each beam, total four plates. The bridge holds a railway track designed for 25 tons per axle cars. The bearing plate is made of cast iron (or maybe steel) and consists of two large parts joined through a hinge.
25 tons per axle cars means the bridge bears something like several hundred tons when a train is passing which we can assume causes at least one hundred tons per bearing plate shown. Yes, I just ignored the bridge weight.
Not only the plate upper and lower surfaces are rather small but the plate further concentrates the accepted load and transfers it onto the hinge through even smaller surface. Basically this rather small hinge alone accepts more than one hundred tons. And this is designed on purpose.
Why is the load deliberately concentrated instead of being distributed or at least transferred through some part with uniform section?