Benchmarking linear analysis procedures for reinforced concrete moment frames in ASCE 41

Although linear procedures are used more often than nonlinear procedures for the comprehensive assessment of reinforced concrete (RC) buildings according to ASCE 41, there is much less research on their validation and calibration. This article presents the first of a two-part study on benchmarking linear procedures for RC structures. The main objective of this article was to perform a comparison between global metrics of deformation calculated with the linear static, linear dynamic, and nonlinear dynamic analysis procedures implemented according to the provisions of ASCE 41. The deformation metrics evaluated quantify mean and maximum response, as well as the distribution of deformations over building height. A parametric study was performed with RC moment frames where the following parameters were varied: quality of detailing, intensity of shaking, frame configuration, and effective stiffness. It was found that if the mean drift ratio calculated with the linear model exceeded 2%, the difference between deformations calculated with linear and nonlinear models increased with increasing lateral deformation and decreasing quality of detailing. Recommendations are provided to limit the use of linear procedures in buildings where the probability of collapse is significant. Effective stiffness coefficients for linear procedures were also evaluated. In structures with good detailing, effective stiffness coefficients in ASCE 41 were found to be low for the lowest levels of hazard and high for highest levels of hazard considered. In frames with poor quality of detailing the inferred effective mean stiffness coefficient had a large dispersion, so it is recommended that linear procedures not be used.