Parametric Study for Assessment of Bridges to Meet Specialized Hauling Vehicle Requirements in Ohio PDF Download

Author: Himal Gyawali
Publisher:
ISBN:
Category : Bridges
Languages : en
Pages : 87

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Book Description
According to the FHWA (Federal Highway Administration) memo dated November 15, 2013, state Departments of Transportation (DOTs) are required to incorporate SHVs (Special Hauling Vehicles) in their load rating scheme and, if necessary, post bridges. Ohio-DOT uses its own set of legal trucks (2F1, 3F1, F1 and 5C1) in place of AASHTO (American Association of State Highway and Transportation Officials) type 3, 3-S2, and 3-3 legal trucks for load rating. A comparison of moments produced by the AASHTO SHVs showed an increase of up to 25\% over the Ohio legal trucks. To reduce the population of total bridges to be load rated for SHVs, it was hypothesized that Ohio bridges with a span of less than 200 feet, and a rating factor (RF) greater than or equal to 1.35 for Ohio legal loads, will have a load rating factor greater than 1.00 under the new SHV loads. This thesis presents the research work to assist ODOT (Ohio Department of Transportation) in parametrically demonstrating the above-mentioned hypothesis. The parametric study examines theoretical single and multiple span bridges of uniform stiffness. For the parametric study of simple span bridges, the ratio of controlling RFs increased from fifteen to eighty feet, having 1.35 ratio at a span of seventy feet, and a maximum ratio of 1.36 for spans eighty feet followed by a decreasing trend. A ratio of 1.36 meant the controlling RF for SHV could fall to 0.99 for a bridge if its controlling RF for Ohio legal load is 1.35. Shear did not control in any of the cases The parametric study of multi-span bridges was done in two stages. Since thousands of span combinations were possible in the inventory, the first stage was to find the most conservative span configurations. It was found that two-span bridges are more conservative than other multi-span configurations, except for negative moment when the ratio of exterior to interior span is equal to or greater than 0.96. When the ratio of exterior to interior span is greater than or equal to 0.96, positive moment controls over negative moment. Therefore, a two-span bridge configuration always produces conservative load rating results. Analysis was performed only on a series of theoretical two-span bridges. The second stage of the parametric analysis was to evaluate the ratio of controlling RFs for the series of two span configurations. For multi-span bridges, none of the ratios of RF fall below 1.35 for positive moment and the critical configuration was eighty-five feet-fifty-five feet which had a rating factor of 1.35. The critical ratio of RF for negative moment was found to be 1.37 for a 30 feet-20 feet span.