Techno Press
Techno Press

Earthquakes and Structures   Volume 8, Number 5, May 2015, pages 1017-1038
DOI: http://dx.doi.org/10.12989/eas.2015.8.5.1017
 
Strengthening of non-seismically designed beam-column joints by ferrocement jackets with chamfers
Bo Li, Eddie Siu-shu Lam, Yuk-kit Cheng, Bo Wu and Ya-yong Wang

 
Abstract     [Full Text]
    This paper presents a strengthening method that involves the use of ferrocement jackets and chamfers to relocate plastic hinge for non-seismically designed reinforced concrete exterior beam-column joints. An experimental study was conducted to assess the effectiveness of the proposed strengthening method. Four half-scale beam-column joints, including one control specimen and three strengthened specimens, were prepared and tested under quasi-static cyclic loading. Strengthening schemes include ferrocement jackets with or without skeleton reinforcements and one or two chamfers. Experimental results have indicated that the proposed strengthening method is effective to move plastic hinge from the joint to the beam and enhance seismic performance of beam-column joints. Shear stress and distortion within the joint region are also reduced significantly in strengthened specimens. Skeleton reinforcements in ferrocement provide limited improvement, except on crack control. Specimen strengthened by ferrocement jackets with one chamfer exhibits slight decrease in peak strength and energy dissipation but with increase in ductility as compared with that of two chamfers. Finally, a method for estimating moment capacity at beam-column interface for strengthened specimen is developed. The proposed method gives reasonable prediction and can ensure formation of plastic hinge at predetermined location in the beam.
 
Key Words
    strengthening; beam-column joints; plastic hinge relocation; seismic performance; ferrocement jackets
 
Address
Bo Li, Eddie Siu-shu Lam, Yuk-kit Cheng: Department of Civil & Environmental Engineering, The Hong Kong Polytechnic University, Hong Kong, China

Bo Wu: School of Civil Engineering & Transportation, South China University of Technology, Guangzhou, China

Ya-yong Wang: Institute of Earthquake Engineering, China Academy of Building Research, Beijing, China
 

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