Civil Engineering Photos

Photo Credit: Karl Jansen

This photo is of the Mackinaw Bridge, which connects spans between the Upper Peninsula of Michigan and the Lower Peninsula over Lake Michigan/Huron. The Mackinaw Bridge is suspension bridge and was completed in 1957. The length of the bridge is 26,372 feet (4.99 miles) and its longest span is 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.

Photo Credit: Alex Mead

Seen here is a fully braced moment connection in a hybrid steel and wood structure. After the 1994 Northridge, California and 1995 Kobe, Japan earthquakes, however, fully braced moment connections were determined to be inadequate in resisting the forces generated by earthquakes due to many failures observed in building inspections after the event. Now days, as a result of work done at the University of California at Berkeley and elsewhere, reduced moment beam connections were determined to be a solution. The reduced beam can be seen just to the left of the beam column connection. See here for a brief explanation of how reduced moment connections work.

Photo Credit: Alex Mead

Seen here is a full moment connection between a beam and a column. Note the numerous welds, bolts, and stiffener plates required to get a full moment transfer from the beam to the column. The careful observer will also notice in this example that the beam is actually part of a plastic hinge inducing connection. This is evident by the reduced flange in the beam on the right side of the picture. This reduced section is purposely placed here to force the beam to form a plastic hinge in this location and draw the damaging plastic behavior into the beam away from the column. This connection is part of a strong column, weak beam design approach and allows the structure to absorb substantial amounts of energy in an event such as an earthquake without failing in a story collapse mechanism.

Photo Credit: Karl Jansen

Pictured here is the steel structural frame of the new Sangren Hall building currently being constructed at Western Michigan University. The load paths can be seen nicely here: the beams which are connected to the girders, and then to the columns which transfer the loads down to the foundation where it is loaded safely upon the earth.

Photo Credit: Karl Jansen

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.