bridge math

My first, second, and fifth bridges can be classified as a modified version of simple beam bridges.

This is a real beam bridge, they aren't meant to span as large lengths as other bridges
 The world's longest beam bridge is Lake Pontchartrain Causeway in southern Louisiana in the United States, at 23.83 miles
this is a real beam bridge that i found on google earth, it spans a river in cape coral florida:

My third, fourth, and fifth bridges can be classified as trestle bridges:

This is a regular trestle bridge. Trestle bridges work be evenly distributing the weight over the whole bridge. The same with inverse trestles. the worlds largest trestle bridge is tulip trestle in Greene county