Load rating of Rock Island Bridge 00275
Garner, Sharon B. (Sharon Bellue); Diaz-Alvarez, Henry.
Technical ReportAbstract: This report describes the load rating of Rock Island Arsenal Bridge 00275. This bridge was originally a two-steel-girder railroad bridge constructed in 1907. In 1967, the bridge was retrofitted to carry vehicular traffic consistent with an HS-16 loading. The retrofit used the original stringers, built up floor beams and girders, with the addition of welded cover plates and new connections at some members. Due to construction on an alternate route, the bridge will now be required to carry daily traffic consisting of a mix of heavy trucks and cars with an average daily traffic (ADT) of approximately 1,000. Occasional permit loadings of up to 127 kips are expected during the rerouting period. As a first step in the investigation of the safety of the bridge under the prospective loadings, a Load and Resistance Factor Rating (LRFR) was performed. Due to the reported condition of the original bridge, reduced sections were used to determine the capacity of the floor beams and girders, while design sections were used to determine the dead loads. The minimum operating load rating factor under the HL-93 loading for the reduced section of an interior floor beam in flexure was 0.78. This operating rating factor less than 1.0 required that the bridge be rated for American Association of State Highway and Transportation Officials (AASHTO) legal loads, prior to rating for the permit loadings. The legal load rating was controlled by the Type 3 vehicle loading of the interior floor beam reduced section. Rating factors for the floor beam under this loading were 0.72 for two lanes of Type 3 and 1.07 for one lane of Type 3. All rating factors for permit loadings were greater than 1. The recommended posting for this bridge is 36 tons for two lanes of Type 3 loading. No posting is required for a single lane of Type 3 loading. Due to fatigue considerations, the owner should consider limiting bridge traffic to light vehicles once the alternate route becomes available.
Geotechnical and Structures Laboratory (U.S.)Engineer Research and Development Center (U.S.)
AASHTO Compact section Cover plates Fatigue-sensitive Flexural capacity Flexural resistance HL-93 HS20 Lateral distribution Legal loads Load rating LRFD LRFR MCEB Noncompact section Plastic moment Plastic section Service limit state Shear resistance Slender section Steel girder bridge Strength limit states Superstructure Rock Island, Illinois Rock Island Arsenal
ERDC/GSL TR ; 10-52.
Approved for public release; distribution is unlimited.