Laboratory Investigation of Grouted Coupler Connection Details for ABC Bridge Projects, RB07-013, 2015

With an ever increasing desire to utilize accelerated bridge construction (ABC) techniques, it is becoming critical that bridge designers and contractors have confidence in typical details. The Keg Creek Bridge on US 6 in Iowa was a recent ABC example that utilized connection details that had been utilized elsewhere. The connection details used between the drilled shaft and pier column and between the pier column and the pier cap were details needing evaluation. These connection details utilized grouted couplers that have been tested by others with mixed results—some indicating quality performance and others indicating questionable performance. There was a need to test these couplers to gain an understanding of their performance in likely Iowa details and to understand how their performance might be impacted by different construction processes. The objective of the work was to perform laboratory testing and evaluation of the grouted coupler connection details utilized on precast concrete elements for the Keg Creek Bridge. The Bridge Engineering Center (BEC), with the assistance of the Iowa Department of Transportation (DOT) Office of Bridges and Structures, developed specimens representative of the Keg Creek Bridge connections for testing under static and fatigue loads in the structures laboratory. The specimens were also evaluated for their ability to resist the intrusion of water and chlorides. Evaluation of their performance was made through comparisons with design assumptions and previous research, as well as the physical performance of the coupled connections.

Laboratory Investigation of Bridge Strip Seal Joint Termination Details, SPR RB08-014, 2016

Bridge expansion joints, if not properly designed, constructed, and maintained, often lead to the deterioration of critical substructure elements. Strip seal expansion joints consisting of a steel extrusion and neoprene gland are one type of expansion joint and are commonly used by the Iowa Department of Transportation (DOT). Strip seal expansion joints are susceptible to tears and pull outs that allow water, chlorides, and debris to infiltrate the joint, and subsequently the bearings below. One area of the strip seal that is particularly problematic is where it terminates at the interface between the deck and the barrier rail. The Iowa DOT has noted that the initial construction quality of the current strip seal termination detail is not satisfactory, nor ideal, and a need exists for re-evaluation and possibly re-design of this detail. Desirable qualities of a strip seal termination detail provide a seal that is simple and fast to construct, facilitate quick gland removal and installation, and provide a reliable, durable barrier to prevent chloride-contaminated water from reaching the substructure. To meet the objectives of this research project, several strip seal termination details were evaluated in the laboratory. Alternate termination details may not only function better than the current Iowa DOT standard, but are also less complicated to construct, facilitating better quality control. However, uncertainties still exist regarding the long-term effects of using straight-through details, with or without the dogleg, that could not be answered in the laboratory in the short time frame of the research project.