Recent ICT-IDOT research reports online

The following reports from recently completed IDOT-sponsored projects are now available on ICT’s website.

R27-111: Effectiveness Evaluation of a Modified Right-Turn Lane Design at Intersections. Ten right‐turn approaches in the Peoria, Illinois, area were selected and reconstructed with a modified right‐turn lane design. The major purpose of the modified design was to improve the line of sight for passenger vehicles attempting to turn right, while also accommodating semi‐tractor trailer trucks. While the actual changes varied among intersections, the final result at each was an improvement to the approach angle for right‐turning vehicles stopped to view cross traffic. Recommendations on the characteristics of good candidate sites for the installation of the modified right‐turn lane design in Illinois are presented in this report.

R27-115: Integral Abutment Bridges Under Thermal Loading: Numerical Simulations and Parametric Study (Interim Report). Because of their lower maintenance and construction costs, as well as longer service life, integral abutment bridges (IABs) have gained popularity throughout the United States, although design practices still vary widely across the country and certain aspects of their structural behavior are still not fully understood. Most existing IAB research has focused on substructure demands, which have driven the design limit states considered by entities such as IDOT. However, recent studies showed that significant forces might develop in the superstructure and, therefore, superstructure behavior should not be ignored in design. The goal of this research project was to investigate a broad range of parameters associated with IAB superstructure behavior in order to provide better-suited design recommendations

R27-134: Load Rating and FRP Retrofitting of Bridge Abutment Timber Piles. This report details Phase II of the study titled “Strengthening of Bridge Wood Piling Retrofits for Moment Resistance.” Phase I (R27-082) focused on developing a load rating method for eccentrically loaded pier timber piles and experimentally examined a retrofitting method for posted timber piles using fiber-reinforced polymer (FRP) composites. Phase II was focused on load rating and FRP retrofitting of abutment timber piles as well as studying the long-term performance of FRP-wrapped timber piles. This report also includes finite element analysis results for three timber pile retrofitting alternatives using wide-flange and round HSS sections.

R27-139: Bridge Decks: Mitigation of Cracking and Increased Durability. The application of pre-soaked lightweight aggregates (LWA) as an internal curing agent in concrete to reduce the cracking due to drying shrinkage was studied. It was determined that although LWA can significantly reduce autogenous shrinkage, its effect on drying shrinkage is minimal and in some cases it can even increase the drying shrinkage. The combined effects of LWA and expansive cement (Type K) and LWA and shrinkage-reducing admixtures (SRAs) on drying shrinkage was also studied. It was shown that addition of Type K cement or SRA to mixtures containing LWA can significantly reduce drying shrinkage and make the mixture more volumetrically stable.

R27-140: Effectiveness of Exterior Beam Rotation Prevention Systems for Bridge Deck Construction. Bridge decks often overhang past the exterior girders in order to increase the width of the deck while limiting the required number of longitudinal girders. The overhanging portion of the deck results in unbalanced eccentric loads to the exterior girders, which are generally largest during construction. These eccentric loads come primarily from the bridge placing and finishing equipment as well as fresh concrete and other construction live loads that can create rotation of the exterior girders in the transverse direction. The rotations can also affect both the global and local stability of the girders as well as the bridge. In this study, the current bracing systems used by IDOT were evaluated through field instrumentation, finite element analysis (FEA), and the use of the Torsional Analysis Exterior Girders program. Alternative bridge bracing systems were proposed and evaluated through both experimental testing and FEA.

R27-144: Estimation of Peak Discharge Quantiles for Selected Annual Exceedance Probabilities in Northeastern Illinois. This report provides two sets of equations for estimating peak discharge quantiles at annual exceedance probabilities (AEPs) of 0.50, 0.20, 0.10, 0.04, 0.02, 0.01, 0.005, and 0.002 (recurrence intervals of 2, 5, 10, 25, 50, 100, 200, and 500 years, respectively) for watersheds in Illinois based on annual maximum peak discharge data from 117 watersheds in and near northeastern Illinois. One set of equations was developed through a temporal analysis with a two-step least squares-quantile regression technique that measures the average effect of changes in the urbanization of the watersheds used in the study. The resulting equations can be used to adjust rural peak discharge quantiles for the effect of urbanization, and in this study the equations also were used to adjust the annual maximum peak discharges from the study watersheds to 2010 urbanization conditions. This report also provides (1) examples to illustrate the use of the spatial and urbanization-adjustment equations for estimating peak discharge quantiles at ungaged sites and to improve flood-quantile estimates at and near a gaged site; and (2) the urbanization-adjusted annual maximum peak discharges and peak discharge quantile estimates at streamgages from 181 watersheds.