Collins has completed over 110 bridge load ratings for RIDOT since 2009, 35 of which have been completed under the current Master Price Agreement (MPA) for statewide bridge inspection services, which began in 2014. The load ratings use the Load and Resistance Factor Rating (LRFR) method, and conform to the AASHTO Manual for Bridge Evaluation and the RIDOT Load Rating Manual.
Load ratings were performed for simple beam and continuous girder bridges, as well as bridges with complex horizontal geometry and others with girders of variable web depth. Additional structure types include several curved steel plate girder bridges, a large multiple-span open spandrel column deck arch bridge, and several bridges with unusual (unique) framing and geometry.
Bridges were analyzed for Load and Resistance Factor Rating (LRFR) live loads, AASHTO legal loads, and several routine and special RIDOT permit vehicles. The determination of load ratings included use of AASHTOware’s BrR, Wyoming DOT’s BRASS load rating software where applicable, SAP2000, CONSPAN, or MDX/CSi Bridge software applications. Field-documented section loss was taken into account when assessing the capacity, which required hand capacity calculations to supplement the software.