• Proceedings of the Korea Concrete Institute Conference
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• 2005.05a
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• pp.435-438
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• 2005

The use of new hybrid systems that combine the advantages of steel and reinforced concrete structures has gained popularity. One of these new mixed systems consists of steel beams and reinforced concrete shear wall, which represents a cost- and time-effective type of construction. A number of previous studies have focused on examining the seismic response of steel coupling beams in a hybrid wall system. However, the shear transfer of steel coupling beam-wall connections with panel shear failure has not been thoroughly investigated. The objective of this research was to investigate the seismic performance of steel coupling beamwall connections governed by panel shear failure. To evaluate the contribution of each mechanism, depending upon connection details, an experimental study was carried out The test variables included the reinforcement details that confer a ductile behaviour on the steel coupling beam-wall connection, i.e., the face bearing plates and the horizontal ties in the panel region of steel coupling beam-wall connections. It investigates the seismic behaviour of the steel coupling beams-wall connections in terms of the deformation characteristics. The results and discussion presented in this paper provide background for a companion paper that includes a design model for calculating panel shear strength of the steel coupling beam-wall connections.

• Steel and Composite Structures
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• v.21 no.2
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• pp.267-287
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• 2016

The seismic performance of the ordinary steel reinforced concrete (SRC) columns has no significant improvement compared to the reinforced concrete (RC) columns mainly because I, H or core cross-shaped steel cannot provide sufficient confinement for core concrete. Two improved SRC columns by constructing with new-type shaped steel were put forward on this background, and they were named as enlarging cross-shaped steel and diagonal cross-shaped steel for short. The seismic behavior and carrying capacity of new-type SRC columns have been researched theoretically and experimentally, while the shear behavior remains unclear when the new-type columns are joined onto SRC beams. This paper presents an experimental study to investigate the shear capacity of new-type SRC joints. For this purpose, four new-type and one ordinary SRC joints under low reversed cyclic loading were tested, and the failure patterns, load-displacement hysteretic curves, joint shear deformation and steel strain were also observed. The ultimate shear force of joint specimens was calculated according to the beam-end counterforce, and effects of steel shape, load angel and structural measures on shear capacity of joints were analyzed. The test results indicate that: (1) the new-type SRC joints display shear failure pattern and has higher shear capacity than the ordinary one; (2) the oblique specimens have good bearing capacity if designed reasonably; and (3) the two proposed construction measures have little effect on the shear capacity of SRC joints embedded with diagonal cross-shaped steel. Based on the mechanism observed from the test, the formulas for calculating ultimate shear capacity considering the main factors (steel web, stirrup and axial compression ratio) were derived, and the calculated results agreed well with the experimental and simulated data.

• Journal of the Korea Concrete Institute
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• v.16 no.1 s.79
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• pp.10-17
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• 2004

Shear tests were performed on four ends of full scale U-type beams which were designed by optimum process for the depth with a live load of 4903Pa. The ratio of width to depth of full scale 10.5 m-span, composite U-type beams with topping concrete was greater than 2. Following conclusions were obtained from the evaluation on the shear performance of these precast prestressed beams. 1) Those composite U-type beams performed homogeneously up to the failure load, and conformed to ACI Strength design methods in shear and flexural behaviors. 2) The anchorage requirements on development length of strand In the ACI Provisions preyed to be a standard to determine a failure pattern within the limited test results of the shallow U-type beams. 3) Those all shear crackings developed from the end of the beams did not lead to anchorage failure. However, initiated strand slip may leads the bond failure by increasing the size of diagonal shear crackings. 4) The flexural mild reinforcement around the vertical center of beam section was effective for developments of a ductile failure.

• Journal of the Korea Concrete Institute
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• v.27 no.6
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• pp.591-602
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• 2015

In this paper, cyclic loading test was performed to evaluate the seismic performance of the steel coupling beam and RC shear wall. The test parameter was reinforcement detail of the shear wall. For the shear wall which was designed in accordance with the current design codes, a premature bearing failure occurred at the face of the wall. On the other hand, the bearing failure of walls was prevented due to the new type of reinforcement details. Test results indicated that the vertical reinforcements were more affected to the shear strength of the coupled shear wall than the horizontal reinforcement. Based on the failure mode, concrete stress distribution above and below flanges of the embedded steel beam was proposed. Assuming proposed concrete stress distribution, load resistance was predicted and it was agree well with test data.

• Journal of the Korean Society of Hazard Mitigation
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• v.8 no.4
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• pp.1-8
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• 2008

RC beam of existing structures often encounter shear problems for various reasons. The shear failure of RC beam is sudden and brittle. Strengthening technique jacketing with external bonding of steel plates(or CFRP and CFS) with epoxy is many use to in practice. This study presents test results on strengthening shear deficient RC beams by external bonding of slit type steel plates. Test parameters are width, interval, length, thickness and angle of slit in steel plates. The purpose was to evaluate the reinforcing effects, failure modes and shear capacities for RC beams of strengthened with various slit type steel plates. The test result confirmed that all slit steel plates improved the stiffness and strength of the specimens significantly. Failure modes of SV series and SD series showed shear fractures and flexure fractures at ultimate state respectively. SD series were ductile rather than SV series.

• Steel and Composite Structures
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• v.34 no.3
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• pp.441-452
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• 2020

Within the French CIFRE research project COMINO, an innovative type of composite beam was developed for buildings that need fire resistance with no additional supports in construction stage. The developed solution is composed of a steel U-shaped beam acting as a formwork in construction stage for a reinforced concrete part that provides the fire resistance. In the exploitation stage, the steel and the reinforced concrete are acting together as a composite beam. This paper presents the investigation made on the load bearing capacity of this new developed steel-concrete composite section. A full-scale test has been carried out at the Laboratory of Structural Engineering of the University of Luxembourg. The paper presents the configuration of the specimen, the fabrication process and the obtained test results. The beam behaved compositely and exhibited high ductility and bending resistance. The shear connection in the tension zone was effective. The beam failed by a separation between the slab and the beam at high deformations, excessive shear forces conducted to a failure of the stirrups in this zone. The test results are then compared with good agreement to analytical methods of design based on EN 1994 and design guidelines are given.

• Steel and Composite Structures
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• v.21 no.3
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• pp.537-551
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• 2016

A new type of composite beam which consists of a wide flange steel shape beam and an innovative type of composite slab was introduced. The composite slab is composed of concrete slab and normal flat steel plates, which are connected by perfobond shear connectors (PBL shear connectors). This paper describes experiments of two large-scale specimens of that composite beam. Both specimens were loaded at two symmetric points for 4-point loading status, and mechanical behaviors under hogging and sagging bending moments were investigated respectively. During the experiments, the crack patterns, failure modes, failure mechanism and ultimate bending capacity of composite beam specimens were investigated, and the strains of concrete and flat steel plate as well as steel shapes were measured and recorded. As shown from the experimental results, composite actions were fully developed between the steel shape and the composite slab, this new type of composite beams was found to have good mechanical performance both under hogging and sagging bending moment with high bending capacity, substantial flexure rigidity and good ductility. It was further shown that the plane-section assumption was verified. Moreover, a design procedure including calculation methods of bending capacity of this new type of composite beam was studied and proposed based on the experimental results, and the calculation methods based on the plane-section assumption and plastic theories were also verified by comparisons of the calculated results and experimental results, which were agreed with each other.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.193-196
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• 2008

This paper proposes a method to predict the ductility capacity of reinforced concrete beam-column joints failing in shear after the formations of plastic hinges at both ends of the adjacent beams. The current design code divides joints into two categories: Type 1 for structures in non seismically hazard area and Type 2 in seismically hazard area. While there are many researches related to joint shear strength in Type 1, those in regard to joint ductility capacity of Type 2 are scarce. This paper classified the ductility capacity of beam-column joints into column, joint panel, and beam deformability. Since a brittle failure such as shear or bond failure in the columns must be avoided, column deformability was calculated by elastic analysis. The plastic hinges of the adjacent beams affect joint deformability. Therefore, the prediction of joint deformability was calculated with consideration to the degradation of the diagonally compressed concrete due to the strain penetration.

• Journal of Korean Society of Steel Construction
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• v.20 no.4
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• pp.539-548
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• 2008

This study aims to determine the applicability of the previously published T-type modular profile beam in the manner of producing specimens designed specially for the said purpose, determining their bending and shear behaviors depending on the presence of shear reinforcement, and analyzing the results in comparison with the theoretical equation of plastic deformation. The modular profile beam contributes to bending and shear resistance with the addition of the profile to the form function, and enhances the molding performance through the modular concept. The experimental results showed that the TS series specimens with shear reinforcement have bending behaviors superior to those of the T series specimens without shear reinforcement, which suggests that the used shear reinforcement appropriately bears the shear force. However, it was considered that all the specimens except for the T1-1 specimen failed to have adequate bending performance because of the intermodular slipping caused by the shear failure of the bolts. It is expected that further studies on the T-type modular profile beam, in which shear connectors will be considered as a variable,be performed to develop optimal intermodular connection methods.

• Journal of the Korean Society for Advanced Composite Structures
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• v.6 no.2
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• pp.105-117
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• 2015

The purpose of this study is to develop a new seismic resistant method by using precast concrete wall panels for existing low-rise, reinforced concrete beam-column buildings such as school buildings. Three quasi-static hysteresis loading tests were experimentally performed on one unreinforced beam-column specimen and two reinforced specimens with L-type precast wall panels. The results were analyzed to find that the specimen with anchored connection experienced shear failure, while the other specimen with steel plate connection principally manifested flexural failure. The ultimate strength of the specimens was determined to be the weaker of the shear strength of top connection and flexural strength at the critical section of precast panel. In this setup of L-type panel specimens, if a push loading is applied to the reinforced concrete column on one side and push the precast concrete panel, a pull loading from upper shear connection is to be applied to the other side of the top shear connection of precast panel. Since the composite flexural behavior of the two members govern the total behavior during the push loading process, the ultimate horizontal resistance of this specimen was not directly influenced by shear strength at the top connection of precast panel. However, the RC column and PC wall panel member mainly exhibited non-composite behavior during the pull loading process. The ultimate horizontal resistance was directly influenced by the shear strength of top connection because the pull loading from the beam applied directly to the upper shear connection. The analytical result for the internal shear resistance at the connection pursuant to the anchor shear design of ACI 318M-11 Appendix-D except for the equation to predict the concrete breakout failure strength at the concrete side, principally agreed with the experimental result based on the elastic analysis of Midas-Zen by using the largest loading from experiment.