Reliability evaluations of reinforced concrete columns and steel frames.

摘要

Approaches for the time-independent and time-dependent reliability analysis of reinforced concrete (RC) columns considering the correlation between the axial load and bending moment or the uncertainty in the load eccentricity are proposed. The approach for the time-independent reliability analysis is based on the efficient first-order reliability method (FORM) while the approach for the time-dependent reliability analysis recursively uses the FORM. The inverse normal transformation is employed in both approaches to deal with the modeling error which depends on the load eccentricity. The proposed approaches are more efficient than the ones used in the literature for the reliability analysis of RC columns since they do not require the use of simulation techniques and distribution fitting methods. These approaches are used to study the sensitivity of the reliability of short RC columns to the time-dependent live load effects and to the correlation between the axial load and bending moment.; Probabilistic analyses of the modeling errors of several selected strength prediction models for short and slender RC columns are carried out. The dependency of the modeling errors on concrete compressive strength and the load eccentricity is investigated. Probabilistic analyses of the modeling errors are carried out by using the pseudo-likelihood estimation method. Sets of probabilistic models of the modeling errors by considering different analysis approaches are suggested for short and slender columns.; Based on the reliability analysis approach and the modeling errors developed in this study, comparison of reliability of short and slender RC columns designed according to CSA A23.3–94 is presented. Effects due to the reinforcement ratio, slenderness ratio, live to dead load ratio, and the correlation between the axial load and bending moment on the column reliability are also investigated.; A comparative study of the member and system reliability is presented for several moment resisting two-dimensional steel frames designed per AISC LRFD Specifications. The member reliability is evaluated using the resistance of the beam-column element and the elastic load effects that indirectly accounts for the second-order effects. The system reliability analysis is evaluated based on the collapse load factor obtained from a second-order inelastic analysis.