| Failure of beam-column joints in reinforced concrete structures contributes to structural collapse during earthquakes. Design strategies rely on providing ductile components and increasing energy dissipation to improve joint behavior and structural response. Although using conventional reinforcing steel bars is the common solution to achieve these design objectives, incorporating special reinforcement details might not be the most effective method in construction practice due to steel congestion and accompanied costs. Analytical researches on fiber-reinforced concrete (FRC) show that steel fibers would contribute to concrete ductility and fracture toughness. Experimental studies have also indicated that using steel fiber-reinforced concrete (SFRC) can be as effective as other reinforcing techniques; e.g., providing transverse reinforcement, to render ductility and confinement at joints. Further, conventional construction methods can easily incorporate application of steel fibers. Despite these researches, building code-writing bodies have not fully adopted design procedures for such application. Developing rational procedures for analytical modeling and design of SFRC joints require implementing performance-based methodology. This methodology incorporates probabilistic design approach to assess structural damage and collapse versus the expected performance through the lifetime of the structure.;This research provides analysis and design methodologies to assess performance of SFRC in beam-column connections. Literature studies include results of empirical and theoretical researches on material properties and constitutive models of FRC. An analytical procedure employs this information to perform sensitivity and parametric analysis. This procedure implements steel and concrete models, adjusted for presence of fibers, into a discretized assembly of concrete layers, steel bars, and steel fibers. Analytical model also represents statistical characteristics of the random distribution of fibers in the matrix. Generalized curves of force-deformation relationship represent nonlinear response of beam-column interface. A general structural analysis program can implement these relationships to reveal the effect of joint properties and characteristics on structural response to lateral loads. The assessment of structural performance provides the platform to develop design recommendations in code-friendly language. |
