ABERDEEN, SD March 5, 2002 -- What weighs 1,813 tons, is over 59 feet wide, 39 feet high and 318 feet long, and was recently “launched” into place in Aberdeen? The single truss bridge that was constructed for the Highway 281 bypass is what!

The Aberdeen Area had the unique experience of constructing a bridge off-site and then moving it into place. This is only the second time this has been done in the nation.

The steel truss bridge was built off-site for safety reasons and to reduce the amount of down time for the Burlington Northern Santa Fe railroad since the bridge spans the railroad tracks. Industrial Builders Inc. from Fargo, North Dakota constructed the bridge with the steel being fabricated by Universal Structural in Vancouver, Washington. The first of 28 semi-loads of steel began arriving on September 21, 2001. 19,490 bolts and about six weeks later, the truss was completely assembled with final bolt-tightening operations completed by mid-November.

Industrial Builders, along with Vic’s Welding and Engineering Co., placed the truss on a rail system and on February 20th the truss was rolled 60 feet over the rail yard. This was the first step in moving the truss into its final position and allowed the contractor to place a trailer, located in the rail yard, under the truss. This work was completed outside of the 22-hour window of time the BNSF allowed as shutdown time while the bridge was actually moved across the tracks.

The 22-hour clock began ticking at 12 a.m. on Wednesday, February 27, as the contractor worked throughout the night placing rock chips and wood pads over the tracks. The cables to winch the truss across the opening were attached and at 10:35 a.m. the truss began to move across the rail yard. By 12:45 p.m. the truss was setting on the bearing pads of the south abutment. The contractor then moved the equipment back to the north abutment in order to raise the truss, removed the rail system and set that end on the bearing pads. As luck would have it, the wind came up and for safety reasons the bridge was not set into place at the north abutment until the following day. However, the contractor was able to remove the wood pads and with the help of BNSF the rock chips were removed and the rail yard was open by 5 p.m.

Work will now begin on placing the concrete bridge deck and completing the grading and concrete paving operations. The Aberdeen bypass is scheduled to be opened to traffic in the summer of 2002.