Photo Credit: Nathan Shoemaker
Pictured above is a floor to ceiling crack in a masonry wall. Cracks like this can be seen in many buildings where differential settlement is occurring. Differential settlement is caused by a combination of weak or erodible soil, poor foundation design, and sometimes seismic loading of the sub-grade of the building.
Photo Credit: Nathan Shoemaker
Seen here is a night photograph of the I-196 crossing of the Grand River in Grand Rapids, Michigan. This highway is a major artery through the city and carries many cars and trucks from the west coast of Michigan to the metropolitan area of Detroit via Grand Rapids.
Photo Credit: Alex Mead
The bridge you are looking at is a purely pedestrian bridge for crossing the Grand River. As is obvious by the snow on the ground and ice build up near the piers this photograph was taken in the winter. Bridges like this one must therefore be very resilient against the forces of not only the water flowing in the river but also against the destructive forces of ice.
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
The dam pictured above is one of thousands of such dams spread across the United States. This dam is used to control the flow of water downstream by limiting the flow of the river over itself. Water volume is regulated by raising and lowering steel doors, called sluice gates, on top of the dam. During normal conditions this dam operates with two sluice gates partially open, but during flooding more gates can be opened to allow more water to pass. It is very important that too much water doesn’t build up behind the dam which could lead to dam failure.
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.
Photo Credit: Alex Mead
Featured in this picture is a complicated erection of scaffolding. Scaffolding configurations like this, and far more complicated systems, are used to gain access to the entire outside of buildings for renovation and repair purposes. In this photograph it can be seen that the outside of this church is being refinished for architectural reasons. The advantage of using scaffolding over a cherry picker or other means of access is the ability to have many workers at different parts of the structure at the same time. Scaffolding also allows for waves of work to move up or down the structure concurrently as is common with many construction schedules. If you look close you can see workers near the top of the steeple!
Photo Credit: Alex Mead
A perfect example of the crumbling infrastructure we all hear about in the media. The problem with this bridge pier is obvious to any civil engineer, but may be not understood from a simple look. The problem is the fact that the reinforcing steel (rebar) is exposed to the elements and is rusting. The rebar takes all tension loads, prevents shrinkage of the concrete, and provides shear resistance. When the rebar rusts strength is lost and the ability of the bridge pier to perform its job in supporting to above roadway is compromised.