Seismic Performance Of Beam-column Joints Research Articles

Evaluation of the Seismic Performance of Beam-column Joints Jacketed with Ultra-high Performance Concrete Mixed with Composite Fibers

Evaluation of the Seismic Performance of Beam-column Joints Jacketed with Ultra-high Performance Concrete Mixed with Composite Fibers

Seismic Performance of Beam-Column Joint With Different Compressive Strength Ratio’s

In this study, exterior beam-column joints with various concrete compressive strengths were investigated for their seismic performance. Using ANSYS software, a total of three external beam-column junctions were created and examined under reversed cyclic loads. Column-to-beam joints were affected by the concrete's compressive strength ratio. Modelling and analysis are performed on specimens with column-to-beam concrete compressive strength ratios of 1, 2, and 3 while maintaining a constant concrete compressive strength for the beam. The findings show that as the compressive strength of the concrete in the column is raised, the overall performance of the beam-column junction improves.

Seismic behavior of beam-column joints with different concrete compressive strengths

This study experimentally evaluated the seismic performance of beam-column joints with different compressive strengths. A total of three exterior beam-column joints were fabricated and tested under reversed cyclic loading. The primary test parameter was the ratio of the concrete compressive strengths of the column and beam. The crack patterns and failure mechanisms, load-displacement relationships, envelope curves, stiffness degradation, energy dissipation, behavior of longitudinal reinforcement in the beam, and transverse reinforcement in the joint were analyzed in detail. Experimental results revealed that the overall seismic performance of the beam-column joint was improved as the compressive strength of the concrete in the column increased. In particular, the specimens with the column-to-beam concrete compressive strength ratios of 2.3 and 3.2 showed over 9% greater joint shear strengths than the one with a monolithic joint. However, the strains of transverse reinforcement in the joint also increased with a high ratio of the concrete compressive strengths of the column and beam. Therefore, when the compressive strength of the column concrete is greater than that of the beam concrete, it is recommended that additional transverse reinforcements be incorporated in the joint region.

Evaluation on Seismic Performance of Beam-Column Joints of Fabricated Steel Structure with Replaceable Energy-Dissipating Elements

This research proposes a beam-column hinged joint with additional replaceable energy-dissipating elements, which is highly industrialized and fully fabricated. In this structure, steel beam and steel column are hinged with pins, at which corners a replaceable energy dissipation element is added. The energy dissipation element is rigidly connected to the steel column through a section of H-beam and high-strength bolts and is hinged to the steel beam using high-strength bolts. The main materials, such as energy dissipation elements, steel columns, and steel beams, are all steel with a design yield strength of 345 MPa. Under the condition that the vertical clear distance between the energy dissipation element and the steel beam is constant at 0.2 m, and the size and section of the beams and columns remain unchanged, six groups of different test samples are constructed by changing the thickness and the horizontal length of the energy-dissipating element. Through the experimental research and numerical simulation of 6 groups of specimens, the strength, stiffness, ductility, hysteresis curve, energy dissipation coefficient, equivalent viscous damping coefficient, and failure mechanism of the joints are obtained, and the horizontal section of the energy dissipation element is mainly analyzed. The effects of parameters such as the ratio of length to span and its ratio to the linear stiffness of steel beams on the seismic performance of the joints were compared with those of traditional welded steel frame beam-column joints. The research results show that the joints can be fully assembled, the energy-consuming components can be replaced, and the beam-column connection joints can be controlled in practical applications. The deviation between the experimental results and the numerical simulation results is less than 10%, which is in good agreement. The failure mode of the node conforms to the seismic performance concept of “energy-dissipating elements are destroyed first and easily replaced after earthquakes”; when the ratio of the horizontal length to the span of the energy-consuming components is 0.225, and the ratio to the linear stiffness of the steel beam is 0.7, the seismic performance is close to or superior to that of traditional welded steel frame beam-column joints, that is, equal to or better than traditional welded steel frame beam-column joints.

Relocating plastic hinges in reinforced concrete beam-column joints by mechanically anchored diagonal bars

The implementation of strong column-weak beam concept in reinforced concrete (RC) moment-resisting frames results in the formation of plastic hinges at the beam ends, which could lead to the strain penetration of beam longitudinal reinforcement into beam-column joint (BCJ) cores. This causes high shear forces inside joint cores, bonding deterioration of longitudinal reinforcement and consequently jeopardizes the seismic behaviour of BCJs. Plastic hinge relocation by mechanically anchored diagonal bars has been proposed to mitigate such potential damage to BCJ cores. This paper investigates the effect of relocating distance of plastic hinge on the seismic performance of BCJs with mechanically anchored diagonal bars. Five interior BCJ specimens including one control specimen reinforced with conventional stirrups and four others reinforced with mechanically anchored diagonal bars were tested under cyclic load. Test results indicate that the plastic hinges can be generally relocated by different distances to the anchorage ends of diagonal bars. Increasing the relocating distance can enhance the loading capacity and stiffness of BCJs, but also increase the potential of joint shear failure. The ductility, energy dissipation and joint shear deformation of BCJs are first improved then reduced as the relocating distance increases. Although the strain penetration of beam longitudinal reinforcement into the joint cores can be gradually alleviated as the plastic hinges are moved farther away from the joints, the induced bending moments at the beam ends are amplified and subsequently increase the joint shear forces. Moreover, increasing the length of anchorage segments increases the forces sustained by the mechanically anchored diagonal bars. Therefore, a lower bound of the relocating distance of plastic hinges is recommended to take advantage of the benefits from reduced strain penetration, while an upper limit needs to be specified to avoid joint shear failure. In addition, an analytical model is developed to predict the failure modes and loading capacities of BCJs with the plastic hinges relocated by different distances. A satisfactory agreement between the prediction and the experimental results is obtained.

Cyclic loading tests of thin-walled square steel tube beam-column joint with different joint details

To study the seismic performance of a thin-walled square steel tube beam-column joint of a light steel frame, 8 kinds of thin-walled square-hollow structural steel (HSS) and concrete-filled steel tube (CFST) beam-column joints with different joint details were designed and manufactured. The joint details were divided mainly into welded joint, plate joint, angle joint and angle with stiffener joint. A total of 14 specimens of beam-column joint specimens were tested using a low reversed cyclic loading test. The failure characteristic, load-bearing capacity, hysteretic property, stiffness degradation and energy dissipation were compared. The results showed that the different joint details had a great influence on the seismic performance of the beam-column joint. The bearing capacity and failure rotation of the welded joint were poor. The bearing capacity of the plate joint was close to that of the welded joint, but it showed improved bearing capacity, failure rotation and energy dissipation capacity of the joint. The bearing capacity of the angle joint was poor. With the angle welded stiffener, the bearing capacity, stiffness and energy dissipation capacity of the joints were significantly improved. The number and height of the stiffener can improve the seismic performance of the joint. The stiffness and energy dissipation capacity of the CFST beam-column joint was better than that of the HSS beam-column joint with the same joint detail. The classification of the joint is discussed, and a simplified M-R calculation model is proposed.

PERFORMANCE ASSESSMENT OF RC BEAM-COLUMN JOINT REINFORCED WITH DIFFERENT SUPER ELASTIC SHAPE MEMORY ALLOY TYPES

Superelastic Shape Memory Alloys (SE SMAs) are smart materials that have the ability to undergo large inelastic deformation upon stress removal (superelasticity) or heating (shape-memory alloy effect). If such smart materials can be used in the plastic hinge regions of reinforced concrete (RC) beam-column joints as reinforcement, they can undergo large deformations during an earthquake and can return to their undeformed/ original shape after the earthquake. This paper represents the seismic performance of beam-column joint reinforced with three different types of SMA (e.g Ni-Ti, Cu-Al-Mn, Fe based) and compared the result with regular steel-RC beam-column joint. An analytical investigation has been considered to evaluate the seismic performance of smart RC beam-column joint and regular steel-RC joint under reversed cyclic loading. The performance of the beam-column joint is compared in terms of load-story drift ratio and energy dissipation capacity. All SMA-RC beam-column joints show nearly 40-60% higher displacement than steel-RC joint before yielding. Among three types of SMA Ni-Ti dissipate 24% higher energy than any other types of SMA.

Seismic performance of fiber-reinforced concrete interior beam-column joints

Fiber-reinforced concrete (FRC), as an advanced alternative to normal concrete, has been increasingly used to construct beam-column joints which is one of the most congested parts of reinforcements in reinforced concrete (RC) structures because of its potentially beneficial properties. The present work aims to investigate the seismic performance of FRC beam-column joints experimentally and numerically. A total of eight beam-column joints, including both FRC beam-column joints and RC beam-column joint, were conducted to explore its seismically important features under quasi-static reversed cyclic load, mainly including the failure modes, hysteretic response, energy dissipation, stiffness degradation. It was found that the application of FRC can effectively improve the seismic performance of beam-column joints because it leads to higher load-carrying capacity and a greater deformation capability prior to the formation of the major diagonal cracks in the joint core zone. A numerical study, using the Open System for Earthquake Engineering Simulation (OpenSEES), was also conducted to study the seismic performance of beam-column joints deeply after its applicability and accuracy being validated with test data. The prediction from the proposed numerical model shows a good agreement with test data. Furthermore, a parametric study was generated to address and evaluate the effects on the seismic performance of FRC beam-column joints from different parameters, including the axial load ratios, transverse reinforcement ratios and FRC compressive strength. The results indicate that the increment of axial load ratios and FRC compressive strength can enhance the load-carrying capacity.

SEISMIC PERFORMANCE OF DUCTILE AND NON-DUCTILE DETAILED BEAM-COLUMN SUB-ASSEMBLAGES

Reinforced concrete(RC) framed joints are the crucial components as they are subjected to huge shear demandnearly 4-6 times larger than the adjoining members under earthquake. Hence, seismic performance of beam-column joints is evaluated for two scenarios viz.,i) beam column joints designed for seismic force but not provided with ductility detailing (nonductile specimen) ii) designed for seismic force and provided with ductility detailing according to code of practice. An exterior joint of a typical three storied three bay RC Framed building is considered for the study. The frame is designed considering all the combinations of loads specified in code of practice. The performance of the beam-column sub-assemblage is evaluated in terms of performance parameters, namely,loaddisplacement hysteresis, energy dissipation, strength and stiffness degradation. Even though the nonductile specimen has slightly higher beam reinforcement than the ductile specimen, the ductile specimen carried higher load than the non-ductile specimen in the view of detailing in joint region. This may be due to the confinement effect provided by the stirrups in the joint region in the view of closer spacing as per ductile detailing. The maximum load carried by ductile detailed specimen in the positive and negative cycles is 39% and 9% higher than that of non-ductile specimen. This signifies the importance of ductility detailing.

Strengthening of non-seismically designed beam-column joints by ferrocement jackets with chamfers

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.

Study on the Mechanical Properties and Seismic Performance of Beam-Column Joints of Wooden Structure Building

This paper mainly depends on experiment. Take theory and software analysis as supplement. Using pine and fir as test material, the quantitative analysis, using uniform design method to qualitative pine, fir wood block the relationship between mechanical properties and geometrical parameters in the case of triangle, failure characteristics through experimental phenomenon of different materials and different sizes of wood in the triangle block pressure, finally using finite element analysis software ANSYS/LS-DYNA to simulate and analyze test. By comparing the analysis result of test and software, find out the problems and corresponding correction. The final analysis laid the foundation for the whole static wood structure analysis and dynamic. To provide scientific and technical support for rural residential "seismic safety engineering", thus forming the new wooden structure node and reinforcement for clause.

Finite Element Analysis on Seismic Performance of Beam-Column Joint of Concrete Filled Steel Tube Structure

Rational finite element models established by ABAQUS to analysis the mechanical properties of square steel tubular beam-column joints under low cyclic loading. The two beam-column joints are connected with bolts, one is with welding extended steel sheets at the beam root and the other has no welding extended steel sheets. The calculation and analysis results show that the new joint style using concrete filled steel tube structure both in beams and columns has advantage on the seismic performance. The load-displacement hysteresis curve of the beam end is plump without significant pinching and the joint specimens showed good ductility. The comparative analysis reveals that the joint with welding extended steel sheets at the beam root is more superior in the seismic performance respected to the joint without welding extended steel sheets.

Finite Element Analysis on the Resistance Capability of a New Precast Concrete Tube Column

A new type of composite structure, precast concrete tube column is proposed, and its axial compression performance and the seismic performance of beam-column joint are studied. Nine groups of precast concrete tube column models and three groups of common solid column contrast models with the same outer diameters (600,800,1000mm) were established by software ABAQUS, and a beam-column joint model for horizontal low cyclic loading was established combining with practical project. The results show that the ultimate bearing capacity of precast concrete tube column is higher than that of the common solid column with the same outer diameter by 5% to 20%, and it increases slightly as the thickness of tube increases. Displacement - load hysteresis curve of the beam-column joint is relatively full under cyclic load, and the slope of skeleton curve decreases slowly, which provides an important basis for engineering applications.

Numerical Analysis on Seismic Performance of Beam-Column Joints Strengthened by Top and Seat Angles in the Added-Storey Steel Frame

Based on the ANSYS platform, set up five finite element models of beam-column joints strengthened by top and seat angles, analysis its seismic performance and discuss how the width and thickness of the angle affect it. The results showed that: (1) Strengthened by top and seat angles can effectively reduce the stress of the weld in the column, relocated the plastic hinge, increased the ductility and the energy dissipation capability of the structure. (2) As the width and thickness of the angle increase, the bearing capacity of the joint improved, but its hysteretic behavior and energy dissipation were decreased.

Comparing the Seismic Performance of Beam-Column Joints with and without SFRC when Subjected to Cyclic Loading

The experimental work on two full-scale precast concrete beam-column corner joints with corbels was carried out and their seismic performance was examined. The first specimen was constructed without steel fiber, while second specimen was constructed by mixed up steel fiber with concrete and placed it at the corbels area. The specimen were tested under reversible lateral cyclic loading up to ±1.5% drift. The experimental results showed that for the first specimen, the cracks start to occur at +0.5% drifts with spalling of concrete and major cracks were observed at corbel while for the second specimen, the initial cracks were observed at +0.75% with no damage at corbel. In this study, it can be concluded that precast beam-column joint without steel fiber has better ductility and stiffness than precast beam-column joint with steel fiber. However, precast beam-column joint with steel fiber has better energy dissipation and fewer cracks at corbel as compared to precast beam-column joint without steel fiber.

Numerical Analysis on Seismic Performance of Beam-Column Joint in the Added-Layers Steel Structure

Using ANSYS for the three add-layers beam-column joints to non-linear analysis their seismic performance.The results showed that: Model’s hysteresis curve all showed a square spindle-shaped, smooth and full curve, but find the "pinched rope" phenomenon, and have strong energy dissipating capacity;The joint reinforced by Haunched plate has strong bearing capacity, stiffness and energy dissipating capacity, meanwhile, this type of joint contains highest yield strength, largest hysteresis loop area and ductility factor, and has good ductility and energy dissipating capacity. So, it can be used in the earthquake area;The local damage of these joints are start at one point, and out gradually spread. The first joint’s beam-column connection point destruction firstly, and the joint lose its bearing capacity because the components off each other. The third type of joint formed plastic hinges during the process of loading, plastic hinges can change the failure mode of the joint.

Experimental Investigation on the Seismic Performance of Beam-Column Joints Reinforced with GFRP Bars

Glass fiber-reinforced polymer (GFRP) reinforcing bars were used recently as main reinforcement for concrete structures. The noncorrodible GFRP material exhibits linear-elastic stress-strain characteristics up to failure with relatively low modulus of elasticity compared to steel. This raises concerns on GFRP performance in structures where energy dissipation, through plastic behavior, is required. The objective of this research project is to assess the seismic behavior of concrete beam-column joints reinforced with GFRP bars and stirrups. Two full-scale exterior T-shaped beam-column joint prototypes are constructed and tested under simulated seismic load conditions. One prototype is totally reinforced with GFRP bars and stirrups, while the other one is reinforced with steel. The experimental results showed that the GFRP reinforced joint can sustain a 4.0% drift ratio and can recover its deformation without any significant residual strains. This indicates the feasibility of using GFRP bars and stirrups as reinforcement in the beam-column joints subjected to seismic-type loading.