TO INVESTIGATE ECCENTRIC BEAM COLUMN JOINT BEHAVIOR AT CORE SECTION WITH SEISMIC FORCE

2020 ◽  
Vol 14 (7) ◽  
1986 ◽  
Vol 2 (3) ◽  
pp. 537-564 ◽  
Author(s):  
Roberto Leon ◽  
James O. Jirsa

Fourteen reinforced concrete beam-column joint subassemblages were tested to investigate the effects of load history, beam reinforcement size, beam geometry and floor slabs on joint behavior under cyclic bidirectional load reversals. The full-scale specimens were loaded biaxially to simulate the worst loading condition on the joints of a multi-story ductile moment-resisting frame. The tests showed that biaxial effects can have a significant impact on joint behavior due to the deterioration of column strength, that the beam and slab geometry can significantly affect the joint shear response, and that bond conditions and column-to-beam flexural capacity ratio control the design of such subassemblages.


Author(s):  
Surya SS ◽  
R Sajeeb

The behavior of beam-column joints plays a crucial role in the performance of Reinforced Concrete (RC) moment-resisting frames in earthquake-prone areas. In beam-column joints with high strength concrete and shear reinforcement in joints, the plastic hinge is formed at the beam-column joint interface, which is an undesirable failure mode. Predicting the behavior of plastic hinges subjected to large inelastic deformations caused by extreme loads such as earthquake plays an important role in assessing maximum stable deformation capacities of framed concrete structures. The present paper reviews the plastic hinge characteristics of beam-column joints of RC moment-resisting frames. A careful study and understanding of joint behavior are essential to arrive at a proper judgment of the design of joints. Various types of joints and the influence of bond strength characteristics, forces acting on joints, reinforcement detailing, and the concept and formation of plastic hinges in the joints are thoroughly reviewed.


2021 ◽  
Vol 11 (6) ◽  
pp. 2652
Author(s):  
Jung Han Kim ◽  
Ick-Hyun Kim ◽  
Jin Ho Lee

When a seismic force acts on bridges, the pier can be damaged by the horizontal inertia force of the superstructure. To prevent this failure, criteria for seismic reinforcement details have been developed in many design codes. However, in moderate seismicity regions, many existing bridges were constructed without considering seismic detail because the detailed seismic design code was only applied recently. These existing structures should be retrofitted by evaluating their seismic performance. Even if the seismic design criteria are not applied, it cannot be concluded that the structure does not have adequate seismic performance. In particular, the performance of a lap-spliced reinforcement bar at a construction joint applied by past practices cannot be easily evaluated analytically. Therefore, experimental tests on the bridge piers considering a non-seismic detail of existing structures need to be performed to evaluate the seismic performance. For this reason, six small scale specimens according to existing bridge piers were constructed and seismic performances were evaluated experimentally. The three types of reinforcement detail were adjusted, including a lap-splice for construction joints. Quasi-static loading tests were performed for three types of scale model with two-column piers in both the longitudinal and transverse directions. From the test results, the effect on the failure mechanism of the lap-splice and transverse reinforcement ratio were investigated. The difference in failure characteristics according to the loading direction was investigated by the location of plastic hinges. Finally, the seismic capacity related to the displacement ductility factor and the absorbed energy by hysteresis behavior for each test were obtained and discussed.


2021 ◽  
Vol 183 ◽  
pp. 106737
Author(s):  
Hao Wang ◽  
Youde Wang ◽  
Zongxing Zhang ◽  
Xiaogang Liu ◽  
Shanhua Xu

2021 ◽  
pp. 136943322110015
Author(s):  
Ting Guo ◽  
Na Yang ◽  
Huichun Yan ◽  
Fan Bai

This study aimed to investigate the moment carrying behavior of typical Tibetan timber beam-column joints under monotonic vertical static load and also evaluate the influence of length ratio of Gongmu to beam (LRGB) and dowels layout on the structural performance of the joint. Six full-scale specimens were fabricated with same construction but different Gongmu length and dowels position. The moment carrying performance of beam-column joints in terms of failure mode, moment resistance, and rotational stiffness of joints were obtained via monotonic loading tests. Test results indicated that all joints are characterized by compressive failure perpendicular to grain of Ludou. Additionally, it was found that greater LRGB leads to greater initial rotational stiffness and maximum moment of the joint by an increase of restraint length for beam end; however, offsetting dowels toward column resulted smaller stiffness and ultimate bending moment of joints, particularly, offsetting Beam-Gongmu dowels toward column changed the moment-rotation curve pattern of the beam-column joint, accompanied by a hardening stiffness at last phase. Furthermore, a simplified trilinear model was proposed to represent the moment-rotation relationship of the typical Tibetan timber beam-column joint.


Author(s):  
Andrea Belleri ◽  
Simone Labò

AbstractThe seismic performance of precast portal frames typical of the industrial and commercial sector could be generally improved by providing additional mechanical devices at the beam-to-column joint. Such devices could provide an additional degree of fixity and energy dissipation in a joint generally characterized by a dry hinged connection, adopted to speed-up the construction phase. Another advantage of placing additional devices at the beam-to-column joint is the possibility to act as a fuse, concentrating the seismic damage on few sacrificial and replaceable elements. A procedure to design precast portal frames adopting additional devices is provided herein. The procedure moves from the Displacement-Based Design methodology proposed by M.J.N. Priestley, and it is applicable for both the design of new structures and the retrofit of existing ones. After the derivation of the required analytical formulations, the procedure is applied to select the additional devices for a new and an existing structural system. The validation through non-linear time history analyses allows to highlight the advantages and drawbacks of the considered devices and to prove the effectiveness of the proposed design procedure.


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