Friday, April 29, 2011

#55 Continuously Rotating Sewer Screens

Description:  Seen here are six screen units at an interceptor drain in Detroit, Michigan.  These screens are used to clear debris from the water flowing through the drain in order to protect the pumps later on in the drain.  The screens work by continuous rotating in a conveyer like motion to ensure that clean screen is always exposed to the flow.  This continuous rotation ensures that the screens will never be blocked off plugging the flow of water which would cause damage to the screens.

Thursday, April 28, 2011

#54 Containment Booms

Description:  The orange and black floating objects are containment booms used to isolate potential oil spills into the Rogue River in Michigan.  Containment booms are used stop an oil slick from contacting the shore as well as concentrating the oil slick to one place.  By concentrating the oil it becomes possible to use skimmers and vacuums to collect the oil and dispose of it properly.

Wednesday, April 27, 2011

#53 Equipment: Excavator with Demolition Claw

Description:  Featured above is an excavator fitted with a claw for demolition.  A machine with this type of configuration is very versatile for demolition purposes.  The claw can be manipulated quite accurately for pulling pieces of a structure down or for sorting material on the ground into piles for easier disposal and recycling.

Tuesday, April 26, 2011

#52 Flare to Burn Excess Gas

Description:  Pictured above is a flare, common to many industrial complexes around the world.  The purpose of a flare is to burn off unwanted gases, such as methane, which could pose a threat of explosion if they were allowed to collect.  The flare may seem like a waste of energy, but unfortunately it is not economical to actually capture this gas and use it.  However, as fuel prices rise, this uneconomical gas is becoming viable and in turn being captured and used by many flare operators.

Monday, April 25, 2011

#47 Silt Fence for Sediment Runoff Control

Description:  This photo shows a silt fence in the process of being installed around the perimeter of a construction site.  The purpose of a silt fence is to contain the fine silty material that is often agitated during construction activities and keep it from washing away. By keeping the silty material on site it effectively protects adjacent storm sewers and surface waters from contamination.  A silt fence is composed of a synthetic fabric and secured in place by wooden stakes.  This is a common method of erosion control used on a variety of projects.

Friday, April 22, 2011

#50 Bridge Week!: Bascule (draw) Bridge

Description:  Featured today is a bascule bridge, often called a drawbridge, which carries rail traffic over the Rogue River near Detroit, Michigan.  A bascule bridge allows the operators to lift the main span out of the way of the river when large ships need to gain access upstream.  The bridge works by using a large counterweight to displace the weight of the span.  The use of a counterweight allows for relatively easy opening and closing because less energy is needed per motion than if the motors of the bridge needed to raise and lower the total weight of the bridge all by themselves.

Thursday, April 21, 2011

#49 Bridge Week!: Simply Supported Steel Rail Road Bridge

Description:  A classic example of a steel railroad bridge is shown above.  This bridge is constructed of built up members of steel and is simply supported.  Look closely on the left side of the span and an actual hinge can be seen.  This hinge allows the span to rotate freely, but will inhibit any vertical and translational motion.  Simply supported beams allow for a simplified analysis as well as very predictable behavior under loading conditions.

Wednesday, April 20, 2011

#48 Bridge Week!: World Largest Double-Decked Lift Bridge

Description:  This is the Portage Lake Lift Bridge, officially the Houghton–Hancock Bridge, in Houghton, Michigan.  This bridge connects the Upper Peninsula of Michigan to the Keweenaw Peninsula, which today is technically the Keweenaw Island due to a man made shipping canal.  The lift bridge is the widest and heaviest double-decked lift bridge in the world, capable of elevating to a water clearance height of 100 feet!

Tuesday, April 19, 2011

#47 Bridge Week!: Steel Arch with Hanger Cables Bridge

Description:  This is the I-94, Telegraph Road Bridge near Detroit, Michigan.  This seemly out of place bridge is needed to span over Telegraph road to allow for unobstructed traffic flow beneath I-94.  It uses a combination of steel arches and tension cables to carry the load of the deck and passing traffic.  The road deck takes load to the cables, which are hung from the steel arches.  These steel arches then complete the load path by bringing the load to the ground.  If you look on the right side of the picture, the top of the foundation of the bridge can be seen where the blue arch contacts the ground.

Monday, April 18, 2011

#46 Bridge Week!: Mackinac Bridge - Suspension Bridge

As a tribute to the last week of classes for many undergraduate students around the country, Civil Engineering Photos will celebrate the end of the year with Bridge Week!  A week of photos featuring bridges of all sizes and types!

Description:  Pictured here is the Mackinaw Bridge, which connects the Upper Peninsula of Michigan to the Lower Peninsula.  This suspension bridge was finished in 1957, boasting a length of 26,372 feet (4.99 miles) and a longest span of 3,800 feet.  Suspension bridges are unique in the way the loads of the bridge are transferred to the ground.  The cables of a suspension bridge work in tension, carrying the loads to the two towers which work in compression against the foundations on the earth.  The cable ends are then secured in massive blocks of concrete that hold the tension in the cables completing the load path.

Friday, April 15, 2011

#45 History in our Infrastructure

Description: 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.  Carnegie eventually became one of the richest men in history.

Thursday, April 14, 2011

#44 Slate Roof

Description:  Pictured here is a slate roof on a church in Ann Arbor, Michigan.  Slate roofs are considered by some to be the foremost type of roof that a building can have.  The reason is their extremely long lifetime, typically lasting numerous decades and sometimes even over a century!  Many times the failure of a slate roof is actually due to corrosion of the nails that hold the slate pieces in place and not failure of the slate pieces themselves.

Wednesday, April 13, 2011

#43 Rail-Road Tie Retaining Wall

Description: This is a soldier pile and railroad tie retaining wall.  These types of walls are common due to their relative ease of construction and the availability of materials.  Simply place the vertical members, brown tubes in this case, stack the railroad ties behind and connect the ties with spikes.  Back fill can then be placed behind the wall.  One major problem with this wall, however, is the placing of the railroad ties.  All joints should be staggered by many inches and secured with large spikes.  As you can see on the far left this is not done, and as a result greatly reduces the strength of the wall.

Tuesday, April 12, 2011

#42 Construction Crew: Concrete Placing Crew

Description: Seen here is a concrete pour crew in the middle of placing a mat foundation.  The process that is happening here is the beginning of leveling the slab of concrete to the final depth.  The tool the man in maroon is using is a called a screed and is basically a gas powered leveler.  The two workers behind the screed move excess concrete out of the way and add concrete to areas that are lacking to allow the screed to make a relatively flat surface.  Other finishing methods are then used to make a final slab that is within a tolerance of the specified depth.

Monday, April 11, 2011

#41 Demolition of a Small Structure

Description: This is a video taken during the demolition of an old clubhouse in Livonia, MI.  Demolitions like this are quite common today, as old buildings and infrastructure must be replaced with new and updated versions.  Most people think of a wrecking ball when they think of demolition, but as can be seen above, a standard excavator is the only equipment needed for this building.  Look closely near the excavator and a water stream can be seen spraying the debris to keep the dust down.  Dust control during demolition is of high concern to keep visibility clear for safety and to keep dust from covering adjacent land.

Friday, April 8, 2011

#40 Wood I-Joist for Form Construction

Description:  This is a stack of wood I-Joists used to span long distances between supports in a wood frame structure.  Wood I-Joists are typically made of solid wood flanges, the two fat outer parts top and bottom, and an OSB (oriented strand board) web, the skinny center part.  I-Joists like this are advantages because they carry load more efficiently than a comparable solid wood member, are lighter than a comparable solid wood member, and can be ordered in spans that would be prohibitively expensive to for solid wood members.  This job is using these wood I-Joists to prop up form work for concrete, and is thus going to make full use of the dozens of I-Joists bundled here.

Thursday, April 7, 2011

#39 Auger Cast Pile Wall Failure

Description: Seen here is the failure of an auger cast pile wall.  This type of wall is designed to be a watertight retaining structure for the construction of an underground project.  Although it is hard to tell from this photo, the wall appears to have failed due to weak concrete in the piles.  One pile broke and released the material it was suppose to keep out of the excavation.  This failure formed the mound of dirt seen in the photograph and a “sink hole” approximately 20 ft by 10 ft by 30 ft deep behind the green fence screen.  This is what a bad day looks like for a geotechnical engineer.

Wednesday, April 6, 2011

#38 Concrete Pour Runs into the Night

Description:  When pouring concrete contractors cannot simply begin or end placing concrete at any given location in a structure during a given pour.  Due to many reasons, including rebar placements and concrete’s inability to stick to itself once dry, pours need to be done in a manner that completes a predetermined structural element.  In some cases, this means pouring thousands of yards of concrete in one continuous operation for hours and even days.  Pictured above is a concrete pumper’s boom working into the night on a  2,000 yard pour.  The pour was comprised of approximately 200 trucks full of concrete and that lasted more than 12 hours.  In the background of the photograph is the job’s tower crane silhouetted against the setting sun.

Tuesday, April 5, 2011

#37 Equipment: Free Standing Jib Crane

Description:  Featured here is a free standing jib crane (the yellow column and beam assembly).  Cranes like this one are permanent pieces of equipment found in factories, fabrication shops, or adjacent to loading docks.  The main advantage of a free standing jib crane is its ability to pick up a load, rotate the load, extend the reach of the jib, and deposit the load, all in a very controlled and predetermined motion. This crane is in Ann Arbor, Michigan at the University of Michigan Power Plant.  It is used to unload trucks from the visible loading dock.

Monday, April 4, 2011

#36 Earthquake Retrofitting of Parking Structure

Description:  The parking structure above is in Berkeley, California and exhibits a perfect example of earthquake retrofitting a structure.  The crisscrossed red members on the front of the structure were added after the completion of the building to increase the strength in the event of an earthquake.  If you look closely the connections of the frame to the ground are pin connections.  These pin connections literally are large steel plates with simple holes connected by rods.  These pin connections allow for rotation of the joint, but do not allow it to move up, down, or side to side apart from ground motion.

Friday, April 1, 2011

#35 Coal Burning Power Plant

Description: Seen here is a black and white picture of the B.C Cobb Generating Plant on Muskegon Lake in Muskegon, Michigan.  B.C. Cobb is a 320 megawatt facility with a smoke stack over 600 feet tall.  Western United States coal is the primary fuel burned at this facility, totaling a consumption of about one million tons of coal per year.  The plant can also burn natural gas if it becomes economically viable.  Power plants like this one are crucial to keeping the electric power grid energized 24 hours a day, 365 days a year.