Joint shear behaviour of reinforced concrete beam–column connections

2009 ◽  
Vol 61 (2) ◽  
pp. 119-132 ◽  
Author(s):  
J. Kim ◽  
J.M. LaFave ◽  
J. Song
2003 ◽  
Vol 19 (4) ◽  
pp. 863-895 ◽  
Author(s):  
Leslie M. Megget

The seismic performance of eleven half-scale and three full-sized reinforced concrete beam-column knee joints was tested under inelastic cyclic loading. Twelve joints were designed to the current New Zealand Concrete Standard, NZS 3101 while the remaining two were designed to the 1964 New Zealand Code, which contained few seismic provisions. All the 1995 designs approached or exceeded their nominal beam strengths in both directions and only degraded in strength at displacement ductility factors greater than 2, while the 1960 designs failed prematurely in joint shear at about 70% of the beam nominal strengths. Many of the half-scale joints failed when cover concrete split off in the joint zone, allowing loss of anchorage and slip of the top beam bars. Two full-scale joints were designed to carry the maximum specified code joint shear stress (0.2 fc′), and one subsequently failed due to joint shear when the concrete compressive strength did not reach the specified design value. A third full-size joint was tested with distributed beam reinforcement. This joint performed in a ductile manner to displacement ductility 4 but failed in the second cycle at that displacement, due to buckling of several rows of beam bars.


◽  
2019 ◽  
Author(s):  
Hikotsugu Hyodo ◽  
◽  
Ryoichi Sato ◽  
Kenji Kawai ◽  
Ken-ichiro Nakarai ◽  
...  

2020 ◽  
Vol 23 (15) ◽  
pp. 3171-3184
Author(s):  
Ebrahim Emami ◽  
Ali Kheyroddin ◽  
Mohhamad Kazem Sharbatdar

Recently, the single haunch with specifications such as less invasive and architectural consistency, and easy to practice have been adopted as one of the considered retrofitting options for deficient reinforced concrete beam-column joints. In this article, by analytical evaluation, the influence parameters such as haunch to beam stiffness ratio, haunch inclination angles, and mounted position were investigated. Analytical equations were also proposed for haunch to beam stiffness ratio in terms of both shear interaction between haunch and beam-column members and reduction of joint shear demand. Moreover, five exterior beam-column joint sub-assemblies were fabricated afterwards four of those retrofitted by various cross-sectional area of single steel haunch. Then, all of these beam-column joints and remaining one (as-built joint) were experimentally subjected to cyclic loading. To validate the analytical results, the experimental responses in four limit states including first diagonal core crack in as-built joint, drift ratio 2%, the first diagonal core crack in all the joints, and ultimate state (peak load) were provided for comparison. Also, by definition of an index as vulnerability index in fraction ratio of available joint shear force to joint shear strength predicted by international codes, the obtained vulnerability index of experimental responses were compared to analytical results.


2008 ◽  
Vol 400-402 ◽  
pp. 881-886 ◽  
Author(s):  
Li Xue Jiang ◽  
Shi Ju Zheng ◽  
Wei Ping Zhang ◽  
Xiang Lin Gu

Eight weak reinforced concrete beam-column connections and two strong ones subjected to cyclic loads were tested. Effects of the one-way slab, top reinforcement ratio of the beam as well as the transverse reinforcement ratio inside the joint on the seismic behavior of reinforced concrete beam-column connections were primarily investigated. Tests results show that, when subjected to the negative moment, the beam flexural resistance increases notably due to the presence of the slab. However, failure mode of the weak connection transforms from the beam flexural failure to the joint shear failure, resulting from the increased joint shear brought by the slab participation. Besides, the presence of the slab reduces the ultimate relative rotation, ductility and energy-dissipation capacity of the connection. Generally, weak connections can receive more benefit from the one-way slab than strong connections. Connections with less amount of top reinforcement in the beam exhibit better ductility and energy-dissipation capacity, which indicates that it is not always good to strengthen the beam negative moment zones in existing structures. The transverse reinforcement inside the joint has little effect on the seismic behavior of the weak connection with a one-way slab.


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