The concrete arches of the George Westinghouse Bridge work under compression , transferring the load of the deck and its traffic to the bridges piers and from there to the earth. The 16th Street Bridge is suspended from an arch, while further down the Allegheny are three bridges suspended from catenaries. The 16th Street Bridge is suspended from a steel arch. Notice the trusses stiffening the arch. Suspension bridges use the force of tension to counteract the bending forces on the deck of the bridge.
Many bridges combine techniques to handle their loads.
The filigree of trusses within in the Smithfield Street Bridge stiffen the larger lenticular truss, whose arch above and catenary below function like the leaf spring on a car. The Smithfield Street Bridge's unique design combines the qualities of arch and suspension construction to create the limber lentricular truss . The bridge, built in 1883, is Pittsburgh's oldest. Veteran's Memorial Bridge, Steubenville Bridge history Rich history and geography lessons also are evident in a study of our bridges, which suggest the evolution of commerce and transportation in the region. In the 19th century, Pittsburgh saw the advent of manufactories and the dawn of the steamboat era.