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Posted by Tasha Weiss on May 25, 2011 at 8:55 AM.
The Iowa DOT has added a series of RS40-10 rolled steel beam bridge standards to its acceptable bridge design configurations. These off-the-shelf standards make it easier for bridge engineers to specify steel beams and are expected to drive better costs from fabricators as designs are built from standard templates, as well as reducing overall maintenance through the use of integral abutments, weathering steel girders and low maintenance bearings.
Developed by Stanley Consultants in cooperation with the Iowa DOT, the new RS40-10 rolled steel beam bridge standards replace the previous short span design standards. The new standards cover multiple spans for bridges up to 340 ft long and include base sheets and bridge standards designed for LRFD specifications. The standards cover pile bent piers, tee piers, skew bridges (0 degrees, 10 degrees, 20 degrees, 30 degrees and 45 degrees), 160-ft to 340-ft bridge lengths and symmetrical/asymmetrical 40-ft-wide bridge decks.
Although engineers still have to deal with geometry and coordination, the templates provide as much as 90% of the design and should reduce design and construction time. For example, to call out a specific bridge, the bridge engineer puts together a cover sheet that references the appropriate bridge standard sheet numbers. Follow-up sheets might include upgrades to substructures and foundations. The contractor pulls these same sheets from the website to determine quantities.
The DOT believes these standards should allow contractors and fabricators to develop consistent techniques and practices that will produce economies of scale and drive greater competition. Furthermore, the standardization of bridge design components should give all parties confidence in the performance and durability of bridges constructed throughout Iowa.
The Rolled Steel Beam Bridge Standards can be found at www.iowadot.gov/bridge/v8ebrgstd.htm (scroll to the bottom of the page). These standards join other Iowa DOT bridge designs, all of which use standards defined by the DOT and are approved by the state’s chief bridge engineer. They also are available to county engineers.
For additional information from the Short Span Steel Bridge Alliance, go to www.shortspansteelbridges.org.