Improving Bridge Load Rating Accuracy.

摘要

Nearly one-quarter of Alabamas bridges are deemed structurally deficient or functionally obsolete. An additional seven percent of Alabamas bridges were posted bridges in 2010. (Federal Highway Administration, 2011) Accurate bridge load rating can potentially reduce, and even remove, bridge postings throughout the state. Analytical structural bridge models were used to define new load ratings for ALDOT Bridges 005248, 005318, and 012296. With past methodology, Engineers ratings tend to be inaccurate. This is due to the indefinite information in regards to actual traffic loading on bridges. This inaccuracy can lead to either over-estimates of bridge safety or excessive conservatism in repairs. Gaining further knowledge regarding the actual behavior of bridges with the help of analytical models can help reduce inaccuracy in calculations. The University Transportation Center for Alabama (UTCA) tasked The University of Alabama at Birmingham (UAB) to develop and verify analytical models from which accurate load rating could be obtained. ALDOT performed load testing and calculated ratings for bridges 005248 and 005318. The UAB team worked with ALDOT in gathering strain data for bridge 012296 via the Bridge Weigh-In-Motion (BWIM) technique. Bridge models for 005248 and 005318 proved capable of accurate load rating per data comparison as presented, and 012296 was load rated using Finite Element Modeling.