| With the ever increasing concerns about the structural adequacy of buildings and infrastructures, particularly in harsh environments with limited funding for ongoing maintenance, a significant need exists to develop highly durable and rapidly constructed structural systems. To this aim, recent advances in the development of high-performance material allow for the introduction of innovative girder configuration systems using the ultra-high performance fiber-reinforced concrete (UHPFRC) material as flange and direct embedded steel plate as web. The proposed composite member will result in a durable building or bridge superstructure construction with reduced life-cycle cost, longer life span, and enhanced environmental sustainability (Hegger 2006, Graybeal and Tanesi 2007, and Rauscher 2011). To cope with the higher cost of the high-performance material, innovative designs should be implemented in detailing of composite members to make sure that the material is best used where it is most required. To date, however, there has been very limited research on the structural behaviour of this member configuration.;The second phase of the research focuses on the development of a composite connection system, which ensures an efficient composite action between embedded steel web and concrete flanges. A commercially available finite element package, ABAQUSR 6.11 was used to simulate the response of the composite connection system subjected to the pull-out load and to minimize the need for full-scale structural testing. A total of 42 specimens were designed, constructed, and tested to capture the experimental response of the composite connections subjected to the pull-out loading. The influence on the pull-out capacity of the composite connection from shape and size of holes (which is cut through the embedded web), embedded length of steel plate, plate thickness, fiber content, double headed stud (which is passed through hole), and concrete member depth are investigated. In addition, comparisons of the connection specimen performance to those constructed with conventional fiber-reinforced concrete (FRC) material were completed. It was found that compared to connection systems constructed with FRC material, the use of UHPFRC can substantially enhance the load carrying capacity and ductility of the connection systems subjected to the pull-out and push-out loading.;The objectives of the current study are twofold. The first phase focuses on development of a UHPFRC material incorporating 0-5% randomly distributed short steel fibers using the conventional moist curing technique without added heat or pressure to be representative of potential applications requiring in-situ casting. The addition of steel fibers to the UHPFRC matrix was found to significantly enhance the mechanical properties of the UHPFRC material in compression, flexure, tension and shear. In addition, the peak compressive, flexural, equivalent tensile strength, and shear strengths of the material were found to decrease with an increase in the specimen size, indicating that a size effect exists for members constructed with UHPFRC material. |
