Abstract
The paper describes the testing of three reinforced concrete haunched beam-column assemblies under incremented-static cyclic loading. The half or full size test units were based upon typical interior joints of external frames of multi-storey buildings designed to the current NZ loading code. Hinge formation occurred in the beams and stable hysteretic behaviour was obtained up to model displacement ductilities of 6 (worst unit) to 18 (best unit). Corresponding prototype building ductilities are shown to be slightly higher. Tests results indicated the importance of matching the yield moment strengths in the haunch with the combined seismic and gravity load distribution.
Highlights
Under severe seismic loading of structures with conventional beams, plastic hinging tends to concentrate at the beam ends with opposite sense on either side of the column
At relatively low building ductility factors, (DFs), the high section curvatures and consequent high flexural compressive strains required near the beam ends encourage concrete spalling and buckling of the compressive steel
Because the haunch spreads the zone of plastic hinging, crack widths are smaller at corresponding deflections and more shear load can be carried by the concrete
Summary
Under severe seismic loading of structures with conventional beams, plastic hinging tends to concentrate at the beam ends with opposite sense on either side of the column. At relatively low building ductility factors, (DFs), the high section curvatures and consequent high flexural compressive strains required near the beam ends encourage concrete spalling and buckling of the compressive steel. Because yield of the flexural steel can penetrate well into the beam-column joint, the bar length over which the steel stresses change from yield tension to yield compression may be small and bond slip may occur. These problems are largely circumvented with carefully designed beam haunches. Relatively small maximum section curvatures will allow large beam rotations to develop without excessive cracking or concrete spalling
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: Bulletin of the New Zealand Society for Earthquake Engineering
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
