Thermal behavior of IDOT integral abutment bridges and proposed design modifications.

PDFTech ReportFHWA-ICT-12-022R27-55Bridge abutmentsBridge designParametric analysisField studiesJointless bridgesSkewed structuresPile foundationsThermal stressesStructural analysisIllinoisIllinois Center for TransportationOlson, Scott M.Holloway, Kurt P.Buenker, Jason M.Long, James H.LaFave, James M.University of Illinois at Urbana-Champaign. Dept. of Civil and Environmental EngineeringUnited States. Federal Highway AdministrationIllinois. Dept. of TransportationUS Transportation CollectionThe Illinois Department of Transportation (IDOT) has increasingly constructed integral abutment bridges (IABs)over the past few decades, similar to those in many other states. Because the length and skew limitationscurrently employed by IDOT have not necessarily been based on rigorous engineering analyses, an extensive 3-D parametric study has been performed, complemented by installation of field monitoring equipment on tworecently constructed bridges, to potentially expand the use of IABs in Illinois. Some notable findings from thisstudy include: (1) IAB configuration with extreme skew (> 60\uc2\ub0) can perform well with proper detailing; (2) H-pilewebs oriented parallel to the longitudinal axis of the bridge, regardless of skew, substantially reduces weak-axisbending; (3) compacted backfill reduces pile stresses; (4) live loads affect thermally induced pile stresses; (5)longer intermediate spans tend to increase pile stresses; and (6) time-dependent behaviors, such as concreteshrinkage, may significantly influence maximum pile stresses. Based on these findings, a more rigorouslydeveloped set of recommendations for maximum IAB lengths and skews in Illinois are proposed