Experimental and analytical investigations of reinforced concrete beam-column joints retrofitted by single haunch

2020 ◽  
Vol 23 (15) ◽  
pp. 3171-3184
Author(s):  
Ebrahim Emami ◽  
Ali Kheyroddin ◽  
Mohhamad Kazem Sharbatdar
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beam ◽  
Peak Load ◽  
Vulnerability Index ◽  
Reinforced Concrete Beam ◽  
Stiffness Ratio ◽  
Limit States ◽  
Joint Shear Strength ◽  
Analytical Results ◽  
Joint Shear

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.

scholarly journals Influence of geometric and material characteristics on the behavior of reinforced concrete beam-column connections

2017 ◽  
Vol 44 (5) ◽  
pp. 377-386
Author(s):  
R.K. Vandana ◽  
K.R. Bindhu
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beam ◽  
Ductile Failure ◽  
Reinforced Concrete Beam ◽  
Lateral Loads ◽  
Joint Shear Strength ◽  
Weak Beam ◽  
Aspect Ratios ◽  
Moment Resisting ◽  
Energy Dissipation Capacity

The design of reinforced concrete moment-resisting frames and hence beam-column connections is of great importance in earthquake prone areas. Beam-column joints, which should be sufficiently strong to resist and sustain lateral loads, are designed on the basis of the strong-column weak-beam concept so that they undergo ductile failure. The present study describes the cyclic loading performance of six interior beam-column connection specimens designed to be seismic-resistant with varying aspect ratios, concrete compressive strengths, and beam bar yield strengths. Results indicate that joint ductility and energy dissipation capacity can be enhanced by maintaining a unit aspect ratio. Moreover, joint shear strength can be improved significantly by increasing concrete compressive strength. Beam bar yield strength is observed to influence joint ductility considerably.

Joint shear strength of FRP reinforced concrete beam-column joints

2011 ◽  
Vol 1 (1) ◽  
Author(s):  
Jagadeesan Saravanan ◽  
Ganapathy Kumaran
Keyword(s):  
Shear Strength ◽  
Concrete Beam ◽  
Concrete Strength ◽  
Reinforced Concrete Beam ◽  
Constant Load ◽  
Reinforcement Ratio ◽  
Joint Shear Strength ◽  
Element Analysis ◽  
Glass Fibre Reinforced Polymer ◽  
Joint Shear

AbstractAn assessment of the joint shear strength of exterior concrete beam-column joints reinforced internally with Glass Fibre Reinforced Polymer (GFRP) reinforcements under monotonically increasing load on beams keeping constant load on columns is carried out in this study. Totally eighteen numbers of specimens are cast and tested for different parametric conditions like beam longitudinal reinforcement ratio, concrete strength, column reinforcement ratio, joint aspect ratio and influence of the joint stirrups at the joint. Also finite element analysis is performed to simulate the behaviour of the beam-column joints under various parametric conditions. Based on this study, a modified design equation is proposed for assessing the joint shear strength of the GFRP reinforced beam-column specimens based on the experimental results and the review of the prevailing design equations.

The Seismic Design and Performance of Reinforced Concrete Beam-Column Knee Joints in Buildings

2003 ◽  
Vol 19 (4) ◽  
pp. 863-895 ◽  
Author(s):  
Leslie M. Megget
Keyword(s):  
Reinforced Concrete ◽  
New Zealand ◽  
Concrete Beam ◽  
Reinforced Concrete Beam ◽  
Knee Joints ◽  
Joint Zone ◽  
Displacement Ductility ◽  
Cover Concrete ◽  
Joint Shear ◽  
And Performance

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.

Experimental Investigation on the Flexural Behaviour of Patched Reinforced Concrete with Unsaturated Polyester Resin Mortar

2015 ◽  
Vol 754-755 ◽  
pp. 457-462 ◽  
Author(s):  
Agus Supriyadi ◽  
Stefanus Adi Kristiawan ◽  
Sandy Raditya
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beam ◽  
Polyester Resin ◽  
Unsaturated Polyester ◽  
Peak Load ◽  
Reinforced Concrete Beam ◽  
Unsaturated Polyester Resin ◽  
Flexural Behaviour ◽  
Control Beam ◽  
Unsaturated Polyester Resin Mortar

This research is aimed to investigate the flexural behaviour of patched reinforced concrete beam with patching material made from unsaturated polyester resin mortar. The variable studied is the dimension of patching zone as compared to the control beam (without patching). Based on the load-deflection observation of the beam under a four-point bending loading, it is confirmed that the flexural behaviour of the patched reinforced concrete beam is similar to that of control beam at a loading up to about peak load. After this load the patched reinforced concrete beam tends to behave more ductile. The patched reinforced concrete beam show less cracking density compared to control concrete.

Cyclic Loading Behavior of Weak Reinforced Concrete Beam-Column Connections

2008 ◽  
Vol 400-402 ◽  
pp. 881-886 ◽  
Author(s):  
Li Xue Jiang ◽  
Shi Ju Zheng ◽  
Wei Ping Zhang ◽  
Xiang Lin Gu
Keyword(s):  
Reinforced Concrete ◽  
Energy Dissipation ◽  
Seismic Behavior ◽  
Concrete Beam ◽  
Reinforced Concrete Beam ◽  
Transverse Reinforcement ◽  
Negative Moment ◽  
Energy Dissipation Capacity ◽  
Joint Shear ◽  
The One

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.

Performance-Based Seismic Design of Reinforced Concrete Beam-Column Joints

2011 ◽  
Vol 255-260 ◽  
pp. 2500-2504
Author(s):  
Bin Wei ◽  
Zhong Guo Guan ◽  
Jian Zhong Li
Keyword(s):  
Reinforced Concrete ◽  
Seismic Design ◽  
Concrete Beam ◽  
Limit State ◽  
Reinforced Concrete Beam ◽  
Rational Analysis ◽  
Limit States ◽  
Stress Strain ◽  
Performance Based Seismic Design ◽  
Relationship Of

A performance-based seismic design approach for reinforced concrete beam-column joints has been proposed in this paper. Instead of adopting empirical analysis such as in ACI 318M-08 building code, the proposed approach is based on rational analysis of the stress-strain state of the joint. Two limit states are considered in the design: serviceability limit state and life safety limit state. Performances of the joint at these two levels are determined respectively, with due considerations of capacity design philosophy and post-earthquake repair requirements. Then stress/strain analyses of the joint panel using the Mohr circle in conjunction with the softened stress-strain relationship of concrete are adopted simultaneously to design the joint to achieve the predetermined performance level. Effectiveness of proposed method are validated by using the model to interpret the behaviors of joints observed in previous experiments.

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