Evaluation of the Response Modification Factor of Regular Steel Buildings with "Linked Columns Frame" System

This paper evaluates the "Response Modification", "Reduction due to ductility" and "Over-strength" factors for steel frames with "Linked Columns Frame" as dual systems. Since, LCF is a relatively modern lateral load resisting system, the necessity of a more comprehensive study is felt for performance evaluation of these frames under strong ground motions. In this regard, steel frames equipped with the linked column frame with 3, 5, 7, 9, and 11 stories are designed based on the Iranian earthquake design code (Standard No. 2800, 4th version) and implemented in Opensees software. Response modification factor (R factor) is calculated based on the result of incremental dynamic analysis (IDA), linear and nonlinear dynamic analysis under far-field earthquakes which have been presented in FEMA-P695. For a more accurate assessment, the shear and flexure performance of link beams is investigated in this study. The results show that R factors change in the height of steel frames with LCF. However, the mean values of the R factor do not necessarily increase or decrease as the number of stories increases. In most cases, R factors for LCFs with shear links are larger than the related result of steel frames containing flexural links. Also, the R factor does not need to consider more than 6.0 for regular LCFs with studied shear link beam.