Photo Credit: Alex Mead
This is a regular steel member utilizing rivet construction on a bridge built in 1886. The cool trait about this member, however, is the maker’s mark on the middle. If you look closely you can see the name CARNEGIE raised. Carnegie was the owner of a steel company called Carnegie Steel Company that eventually was sold to help form the conglomerate U.S. Steel.
Photo Credit: Alex Mead
What you are looking at is the steel that is in all the reinforced concrete structures around you. The large number of bars that you see are meant to hold the tension force in the foundation of this underground parking structure. One of the main costs in reinforced concrete construction is the labor to place all the resteel where it is needed. As you can see from this photo the number of resteel bars is staggering. Rest assured though, each bar has its proper place calculated by a competent structural engineer!
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.