Comparative Study of Strength-Computation Methods for Rectangular Reinforced Concrete Columns

Comparisons of strengths determined from 354 physical tests of rectangular reinforced concrete columns available in the literature with the strengths calculated from selected computational procedures were conducted. The computational procedures compared in this study include ACI 318-99, Eurocode 2, and a commercially available nonlinear finite element modeling software. The physical tests used for comparison were conducted on tied, reinforced concrete columns that were pinned at both ends and subjected to short-term loads, producing pure axial force or axial force combined with symmetrical single-curvature bending. The study included only those columns for which the complete information required for analysis was available from the published physical test data and for which the compressive strength of normal density concrete ranged from approximately 2500 to 8500 psi (17 to 58 MPa). No further physical tests were conducted as part of this study. Major variables include the concrete strength, the end eccentricity ratio, the slenderness ratio, the reinforcing steel index, and the transverse reinforcement (tie/hoop) volumetric ratio. The comparative study provides a critical review of the reliability of the computational methods examined. Most of these methods are affected to some degree by at least some of the major variables studied. A recommendation for improving the ACI 318-99 procedure is also presented.