Photo Credit: Alex Mead
Pictured above is the Sixth Street Bridge in Grand Rapids, Michigan. It spans the Grand River and was built in 1886 using wrought iron. The bridge is made up of four Pratt trusses on stone piers and is the longest and oldest metal bridge in Michigan. When this bridge was built it cost a whopping $31,000!
Photo Credit: Alex Mead
This is a steel rail road bridge over the Huron River in Ann Arbor, Michigan. It has concrete piers which is typical of bridges of this type. Concrete is excellent in compression, widely available throughout the world, and relatively affordable. For these reasons concrete is used for many civil engineering applications.