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Illinois Live Steamers!
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Illinois Live Steamers!
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| ILS Bridge Project - Part 1 or... The Bridge over Carlson Creek By Carl Baskin The ILS bridge project began in part to use up some earth fill. By chance, there was a location on the 7.5” railroad where the amount of fill needed could be reduced if a bridge was built to span the opening. As luck would have it, the ILS already had several key steel structural components for the primary trusses. And so, it was decided that a-bridge-building-we-would-go! The main structural members would be 3”x3”x24’ long, 1/8” wall, square tube. Forty 1.25”x1.25”x8’ long, 1/8” wall, square tubes were traded for several large I-beams that the ILS had “in stock”. Still, additional 3” square tubing was needed to complete the truss ends. Other materials purchased included: 1/8” flat stock in various widths for gusset plates and 2”x3” angle for tie/track supports. A scrap length of 1”x3” rectangular tubing was scavenged from the club “metal depot” for the bridge cross stringers while scrap ¼”x1/2” flat stock would be used to complete decorative latticework across the top cross members. All that was left to purchase…a 50 lb. box of 1/8” welding rod. To begin, the 3” square tubes were cut to length. After determining the location of the vertical and angle truss member joints, slots were cut in two of the span members. The ends of these beams were raised. When the slots closed, they were welded. These formed the two (2) upper arch side truss members. The upper and lower truss members were laid on their side and centered. The location of the vertical truss gusset plates was transferred to both members. The 1/8” thick flat stock of various sizes and shape were cut, de-burred and welded in place. Large I-beams were set up on cinder blocks to form a “work table”. Extra 1.25” tubes were spread across the I-beams to support the side trusses during fabrication. It was determined that the center vertical truss member would be 7’-6” long. Vertical members at the ends of the span would be 8” shorter (the height differential in the center of the arch). The center truss member was squared and welded in place. The remaining vertical members were cut and welded too. The distance between opposite corners of the truss was checked (with very little “tweaking” needed). Side truss angle members were cut and welded. More gusset plates were cut and welded to dress the “inside” of the bridge structure (see photos #22-23).
About 50 man-hours was spent to finalize the bridge design, cut the primary span members, cut and prepare gusset plates and “glue” the first side truss together. It is estimated that the 2nd side truss will take another 20 man-hours to complete. The two (2) halves of the bridge will then be joined together. Exterior dimensions of the bridge span will be 24’ long, by 4.5’ wide by 8’ high. The bridge end openings will be 4’ wide by 5.5’ high (approx). When complete, the entire structure is estimated to weigh about 1700 lbs. Photo #24 will give viewers an idea of the size of the side truss.
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