Evaluating the Ductility of X-braced Frames which are Braced in two Middle Adjacent Spans

مهندسی عمران فردوسی

Article 5, Volume 27, Issue 2 - Serial Number 17, March 2016, Pages 57-74   

Document Type: پژوهشی

DOI: 10.22067/civil.v27i2.33325

Author

Abazar Asghari^*

Urmia University of Technology.

Abstract

In this study, for evaluating ductility of ordinary concentrically braced frames (OCBFs) and special concentrically braced frames (SCBFs) which are X- braced in two adjacent middle spans, 16 steel ordinary concentrically braced frames and 16 special concentrically braced frames are studied. The results confirm that, although most of ordinary concentrically braced frames, which are X-braced, cannot experience the corresponding target displacement, but because of their high designing force level expected ductility can be obtained. Also results confirm that the response modification factor of SCBFs which is proposed by Iranian seismic design code (2800 standard forth edition), R=5.5, is more logical than ASCE's one, R=6. According to the results, the response modification factor of 5 is proposed for special concentrically braced frames, which have an analytical period of more than one second (frames more than 10 stories).

Keywords

Ductility Reduction Factor; Concentrically Braced Frame; Pushover Analysis; Target Displacement

Supplementary Files

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