An Economical and Behavioral Comparison of Steel Special, Intermediate, and Ordinary Moment Resisting Frames

Document Type : Original Manuscript


Civil Engineering, Shiraz University, Shiraz, Iran


The Iranian Standard of Seismic Design of Structures No. 2800, IBC 2018, ASCE 7-16 and AISC 341-16 suggest that a response factor, R (also referred to as the R-factor), should be used as a measure to account for some characteristics of the structure such as ductility, degrees of indeterminacy and inherent over-strength capacity. This factor can be applied to buildings of special, ordinary and intermediate Moment Resisting Frame (MRF) systems. This paper presents an investigation of the economic significance of the R-factor on buildings. Previous studies, which focus on construction details of MRF systems, their design criteria and their associated ductility under cyclic loads for domestic manufacturing purposes, are rather limited. The need for such important data became the basis of performance investigation of different moment resisting connections in the present study. A number of 3D regular frames were designed and their regular construction expenses were estimated and compared. Finally, an average of used steel per unit area was derived to provide a measure for quick design inspection of an arbitrary MRF system.