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Structural Monitoring and Maintenance
  Volume 5, Number 3, September 2018 , pages 391-416
DOI: https://doi.org/10.12989/smm.2018.5.3.391
 

Strengthening of concrete structures with buckling braces and buckling restrained braces
Moosa Mazloom, Pardis Pourhaji, Abbas Moosa Farash and Amir Hossein Sanati

 
Abstract
    he purpose of this article is to strengthen concrete structures using buckling and non-buckling braces. Connection plates are modeled in three shapes including the effect of 1.5t hinge zone length, 2t one and without the zone (1.5t-CP, 2t-CP and WCP). According to the verification perform with ABAQUS software, the connection plates which are superior in ductility and strengthening are found. The results show adding steel braces in concrete moment frames increase the strength and stiffness of the structures up to about 12 and 3 times, respectively. The frame strength increased about 21 and 25 percent with considering the effect of 2t hinge length in connection plates compared to 1.5t-CPs and WCPs. Also the ductility of retrofitted frames with 2t-CP improved 2.06 times more than WCP ones. Thus, 2t-CP sample is the best choice for connecting steel braces to concrete moment frames for retrofitting them. Afterwards, optimum conditions for elemental coating in braces with no buckling are assessed. The length of concrete coatings could be reduced about 30 percent, and buckling did not occur. Therefore, the weight of restraining coating decreased, and its performance improved. It is worth noting that BRBs could be constructed with only steel materials, which have outer steel tubes too. In fact, only the square cross sections of the tube profiles are appropriate for removing the filler concrete, and the rectangular ones are prone to buckle around their weak axis.
 
Key Words
    gusset plate connections; 2t hinge zone length; concrete frame; buckling restrained frame; steel tube
 
Address
Moosa Mazloom, Abbas Moosa Farash and Amir Hossein Sanati: Department of Civil Engineering, Shahid Rajaee Teacher Training University, Tehran, Iran
Pardis Pourhaji: Department of Civil Engineering, Iran University of Science and Technology, Tehran, Iran
 

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