دانلود رایگان مقاله انگلیسی عملکرد لرزه ای اتصالات لحظه ای شبکه کاهش یافته - اشپرینگر 2015

Abstract

Seismic behavior of beam-to-column connections can be improved by shifting the location of inelasticity away from the column’s face. Such connections can be achieved by reducing the flange area at a specific distance from the beam-column connection, called reduced beam section (RBS), or by reducing web area by introducing a perforation into the web, called reduced web section (RWS). This paper presents a parametric study that is carried out on the effect of the perforation size, perforation location, and the beam span length in the RWS connections, using finite element modeling. Next, an interaction formula is derived for design purposes, and a step by step design method is developed. Finally, a frame is analyzed to verify the reliability of the proposed design process and assess the impact of the RWS connections on the behavior of special moment frames. The study concludes that RWS connections can effectively improve seismic performance of special moment frames, causing plastic hinges to form around the perforation away from the column’s face.

9. Conclusion

Investigations were carried out on seismic behavior of steel moment frames with RWS connections, which includes a perforation at the beam’s web just away from the column’s face. Eighteen finite element models were analyzed and a parametric study was done on the effect of the perforation size, location and beam span length of RWS connections. Then, a step-by-step design procedure was developed and a special moment frame was designed based on the developed design procedure. The main concern was whether or not the RWS connections can improve the behavior of the conventional special moment frames. Major conclusions of this study are drawn as follows:

(1) Perforation height should be chosen between 65% and 85% of the height of the beam to satisfy the seismic demands. Lower values will result in developing plastic strain in the beam at the column’s face, which is not desired. On the other hand, the upper bound causes significant strength degradation in the reduced section which is not acceptable.

(2) Width over height of the perforation (shape factor) should be larger than one and less than two.