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A pratt truss bridge design includes vertical components and diagonals that slope down towards the center. It was invented in 1844 by Thomas and Caleb Pratt. It was a common solution for railroad bridges when wood truss elements were replaced for metal. Here you can learn more about its history, its basic capabilities, and some of its most famous bridges that use it.
Beam bridge is the oldest and the simplest type of the bridge. It appeared when the first tree fell over the stream and a human crossed it. Today we still make bridges that use similar principle.
A howe truss bridge design includes vertical members and diagonals that slope up towards the center. Its diagonals are under compression under balanced loading. It was invented in 1840 by Massachusetts millwright William Howe. Howe truss design proved to be instrumental not only in the development of several notable bridges at the end of an era of fully wooden bridges but also as an inspiration for the creation of other popular designs.
Over the last 3000 years, engineers and architects have devised many ways of building bridges. Here you can see for yourself bridge types that are in use today, from what materials they are made, and for what uses are they built.