‘Transportation’ Category

Concrete Bridge Substructure

Photo Credit: Karl Jansen

This is the underside of a concrete bridge. Technically, this is known as the substructure, or the part of the whole structure that supports the superstructure, or the roadway in this case. You can see nicely the beams and girders that run laterally and longitudinally under the bridge superstructure, and the massive columns that extends vertically down to the ground to provide the support. The substructure is an important element of every bridge.

Failing Infrastructure

Photo Credit: Karl Jansen

This is the infamous Stadium Blvd Bridge in Ann Arbor, MI. For the past several years, this bridge has literally been falling down, waiting on funds for a rehabilitation project. What you see on the near side of the bridge is an exposed beam, which used to be the south side of the bridge. Last year, the south half of the bridge was removed for public safety reason, because officials were worried “football size” chunks of concrete would fall on a car or pedestrian. This fall, the City of Ann Arbor with its secured funding will finally undertake this long overdue project.

Traffic Light

Photo Credit: Karl Jansen

This is your typical traffic light in the USA: red on the top, yellow in the middle, and green on the bottom. The four individual signals are supported by the cantilevered mast arm. Traffic lights are seen all over the world, and help traffic flow safely in multiple directions. The design of the signal processing is done after a complete and thorough investigation of existing traffic flow is completed by a traffic engineer. The traffic engineer uses this information to formulate the optimal combination of light sequence order and timing, so that everybody gets along their way in good time and safely.

Cloverleaf Interchange

Photo Credit: Brian Wolfe

This is a great example of a classic cloverleaf interchange of a major road and a highway. The cloverleaf interchange gets its name from its shape. Half of the ramps, where the driver would normally make a right turn at an at-grade intersection, are smooth curves on the outer edges of this interchange. The other half of the ramps, where the driver would normally make a left turn to get on the other road, are 270-deg loops on the inner part of the interchange. They have been a popular choice by transportation engineers for many decades, but recently they are being replaced by safer and more efficient interchanges. The problem with the cloverleaf interchange has to do with the merging in/out of the loop ramps, especially when there is a heavy slow-to-accelerate truck in the mix which are also prone to roll-over accidents.

Locomotives used on Railroad Network

Photo Credit: Alex Mead

Seen above is a pair of machines that use one of the most widespread civil engineering systems in the world: the railroad network. These machines are known as locomotives and run on diesel fuel to transport everything from coal, to livestock, to people on the thousands of miles of track that comprise the rail network. Locomotives today are mainly diesel-electric in nature. That is, they burn diesel fuel in an internal combustion engine which turns a generator to make electricity. This electricity is then used to power motors connected to the wheels. This power system is advantageous because no transmission, a complicated mechanical component, is needed to transfer the power from the diesel engine to the wheels.

Swing Bridge

Photo Credit: Alex Mead

Seen above is a swing bridge over a small river near Detroit, MI. The concept of a swing bridge is similar to a draw bridge in that the bridge is movable to allow traffic to pass through the area it spans. This allows a smaller bridge to be built than would otherwise be necessary for height clearance purposes. The swing bridge operates by rotating around the central pivot of the span to clear the area above the water surface to allow vessels to pass. The bridge is currently in the “closed” position and would be perpendicular to the screen if it were rotated to the “open” position to allow traffic to pass.

Pedestrian Bridge over Highway

Photo Credit: Alex Mead

Seen here is a pedestrian bridge over I-75 in Detroit, Michigan. This type of bridge is important because it allows pedestrians to cross to the other side of the freeway without crossing on the road level or having to go to the nearest street crossing bridge. When new highways are being planned and approved features such as pedestrian bridges and sound barriers are many times included. These features are aimed at local people near the project to allow them to live and work near such highways as comfortably as possible.

Stalled Bridge Project

Photo Credit: Alex Mead

Seen here is the end of the Ambassador Bridge that extends from Detroit, MI, USA to Windsor, Ontario, Canada over the Detroit River. This particular picture is of the ramp up to a proposed second crossing. However, the permits were not issued and the project was therefore halted and now stands with a drop off to nowhere. The lesson from this is quite straight forward: get your permits before you start the project or you may end up with a useless piece of infrastructure.

Railroad Embankment Failure

Photo Credit: Karl Jansen

Pictured here is the aftermath of an embankment failure. The spring of 2011 has brought record amounts of rain to the midwest, and this rain has to go someplace. This railroad track in Ann Arbor was supported by approximately 30ft of earth and aggregate embankment. Water from rain runoff flows along side the embankment, and slowly infiltrates into the ground. However, with all the rain this spring, the water wasn’t able to infiltrate quickly enough and a pond formed. This pond of water had the strength to push approximately 2000 CYD of earth and trees onto the adjacent Plymouth Rd. It left nearly 200 ft of railroad track suspended like a roller-coaster about 25ft above the washed-out ground. Fortunately, no trains were scheduled to use the track before emergency personnel were notified and responded to the situation.