High Strength Reinforcing Steel Bars : Concrete Shear Friction Interface.

2017PDFTech ReportBarbosa, Andr\ue9 R.Trejo, DavidNielson, DrewOregon State UniversityOregon. Dept. of Transportation. Research SectionUnited States. Federal Highway AdministrationOregon State UniversityOregonHigh strength steelReinforcement (Engineering)Bridge designBars (Building materials)Reinforced concrete bridgesInterfacesShear strengthFrictionFHWA-OR-RD-17-08High-strength steel (HSS) reinforcement, specifically ASTM A706 Grade 80 (550), is now permitted by the AASHTO LRFD Bridge Design Specifications for use in reinforced concrete bridge components in non-seismic regions. Using Grade 80 (550) steel reinforcement instead of Grade 60 (420) steel reduces material and construction costs. However, state highway agencies (SHAs) only allow Grade 80 (550) reinforcing steel in bridge structural elements that are not expected to undergo large strain reversals. AASHTO and SHAs have concerns with using Grade 80 (550) reinforcement in elements designed for concrete shear interfaces experimental data and currently limit the design value to the yield value of the Grade 60 (420) reinforcing steel bars. The report presents research developed to date on performance of Grade 80 (550) steel in resisting interface shearing actions, which is critical for characterizing the performance of precast girders and shear-keys in which Grade 80 (550) reinforcing steel may be used. A push-off test based experimental program was designed using ASTM A706 Grade 60 (420) and Grade 80 (550) reinforcing steel. A total of twenty push-off specimens were constructed and tested to discern if the design can account for the higher strength-steel nominal yield values.95