• Journal of the Korea institute for structural maintenance and inspection
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• v.8 no.2
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• pp.213-220
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• 2004

The purpose of this study is to evaluate the shear strength of SFRC beam that has no stirrups by steel fiber strengthening factor. To achieve the goal of this study, two stage investigation, which is material and member level, is studied with literature and experimental side. From the reviewing of previous researches and analyzing of material and member test results, strengthening parameter of SFRC is defined as steel fiber coefficient. Based on above results, steel fiber strengthening factor is proposed. And by reviewing the proposed equation of shear strength estimation, equation of Shin was well estimated the shear strength of SFRC beams. Therefore, shear strength equation of SFRC, which is composed by Shin's Eq. and steel fiber strengthening factor, is proposed by regression analysis of test results.

• Steel and Composite Structures
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• v.37 no.1
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• pp.91-98
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• 2020

Steel plate shear walls are recently used as efficient seismic lateral resisting systems. These lateral resistant structures are implemented to provide more strength, stiffness and ductility in limited space areas. In this study, the seismic behavior of the multi-story steel frames with steel plate shear walls are investigated for buildings with 4, 8, 12 and 16 stories using verified computational modeling platforms. Different number of steel moment bays with distinctive lengths are investigated to effectively determine the deflection amplification factor for low-rise and high-rise structures. Results showed that the dissipated energy in moment frames with steel plates are significantly related to the inside panel. It is shown that more than 50% of the dissipated energy under various ground motions is dissipated by the panel itself, and increasing the steel plate length leads to higher energy dissipation capability. The deflection amplification factor is studied in details for various verified parametric cases, and it is concluded that for a typical multi-story moment frame with steel plate shear walls, the amplification factor is 4.93 which is less than the recommended conservative values in the design codes. It is shown that the deflection amplification factor decreases if the height of the building increases, for which the frames with more than six stories would have less recommended deflection amplification factor. In addition, increasing the number of bays or decreasing the steel plate shear wall length leads to a reduction of the deflection amplification factor.

• Journal of the Korea Concrete Institute
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• v.17 no.5 s.89
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• pp.717-726
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• 2005

Shear test data have been extracted from previous experimental research and compiled into a database that may be the largest ever made. In this paper, the shear database (SDB) was used for evaluating shear design provisions for both reinforced concrete (RC) beams and prestressd concrete (PSC) beams. A discussion on the use of the results of this evaluation related to calibration and strength reduction factor for the shear design provisions was also provided. It was observed that the shear design provisions did not provide good predictions for RC members and gave very poor predictions especially for RC members without shear reinforcement. On the other hand, the limit on shear strength contributed by transverse reinforcement was observed to be lower than necessary. The shear design provisions gave very unconservative results for the large RC members (d>700mm) without shear reinforcement having light amount of longitudinal reinforcement $(\rho_w<1.0\%)$. However, for PSC members the shear design provisions gave a good estimation of ultimate shear strength with a reasonable margin of safety. Despite of a large difference of accuracy in prediction of shear strength for RC members and PSC members, the shear design provisions used a same shear strength reduction factor for these members. As a result, the shear design provisions did not provide a uniform factor of safety against shear failure for different types of members.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.12 no.5
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• pp.73-79
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• 2003

In this paper, RKPM is extended for solving moderately thick and thin beams. General Timoshenko beam theory is used for formulation. Shear locking is the main difficulty in analysis of these kinds of structures. Shear relaxation factor, which is formulated using the difference between bending and shear strain energy, and corrected shear rigidity are introduced to overcome shear locking. Analysis results obtained reveal that RKPM using introduced methods is free of locking and very effectively applicable to deep beams as well as shallow beams.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05a
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• pp.410-413
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• 2006

The ㄱ type perfobond rib shear connector is a ㄱ type flat steel plate with a number of holes punched through. This connector can be effectively used in girder with high shear. The ㄱ type perfobond rib shear connector exhibit very stiff behaviour under service load conditions and also had the characteristic of retaining a significant amount of load after the attainment of ultimate capacity. The ㄱ type perfobond rib shear connector with safety factor of 3 is applied shear connector of CFT composite girder. From static test result of CFT composite girder, relative displacement of 0.01mm measured at the service load moment. At design of the ㄱ type perfobond rib shear connector, applying safety factor of 3 was more conservative than test result.

• Journal of Korean Society of Steel Construction
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• v.10 no.4 s.37
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• pp.721-730
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• 1998

In this paper, an experimental study have been many studies on the joints of steel structure, for it has great influences on the safety of structures. Research on block shear rupture of the joint receiving pure tension have been done in foreign countries, but not in Korea. This study focuses on the propriety of block shear design code, according to limited state design criteria of steel structures recently established in Korea, by an experiment on the joint of angle tension members. The methods of this study were to compare other study results on block shear rupture mode and ultimate capacity, and to evaluate the propriety of the criteria design code. The result is that tension yield shear ruptures and shear yield tension ruptures happened at the joint, and the experimental rupture load was 15% higher than the capacity entered in the criteria design code. We conclude that it is necessary to revaluate the block shear design code presented by many studies on the limited state design criteria of steel structures.

• Transactions of Materials Processing
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• v.10 no.4
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• pp.319-328
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• 2001

Quantitative evaluation of the tribological conditions at the tool-workpiece interface in metal forming is usually accomplished by the ring compression test. This paper describes an experimental investigation into friction factor under warm forming conditions according to the lubricants and the lubricating methods using the ring compression test. Four different lubricants, two water based graphite and two oil based graphite lubricants, and three different lubricating methods were applied in the experiments. Calibration curves with the friction shear factor were obtained using FEM analysis and verified by the experimental results. The influence of lubricant and lubricating methods on friction are discussed. In the ring compression test, the lower friction factor got to spray the oil based lubricant on die and billet in warm forging temperature.

• Steel and Composite Structures
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• v.48 no.3
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• pp.353-365
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• 2023

Shape memory alloys (SMAs) have emerged as a novel functional material that is being increasingly applied in diverse fields including medical, aeronautical and structural engineering to be used in the active, passive and semi-active structural control devices. This paper is mainly aimed at evaluating the ductility and response modification factor of the steel plate shear wall (SPSW) frames with and without the Ni-Ti shape memory alloys. To this end, different configurations were utilized, in which the walls were used in the first, third, middle, and all stories. The models were numerically analyzed using OpenSees Software. The obtained results indicate that improving the shape memory properties of alloys can greatly enhance the ductility and response modification factor. Furthermore, the model whose first and third stories are equipped with the SMA shear wall was found to be 290% more ductile, with a greater response modification factor compared to the unequipped frame.

• Journal of Advanced Marine Engineering and Technology
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• v.20 no.5
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• pp.58-67
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• 1996

In the present study, the pressure distribution, wall shear stress distribution and friction factor of developing turbulent pulsating flows are investigated theoretically and experimentally in the entrance region of a square duct. The pressure distribution for turbulent pulsating flows are in good agreement with the theoretical values. The time-averaged pressure gradients of the turbulent pulsating flows show the same tendency as those of turbulent steady flows as the time-averged Reynolds number $(Re_{ta})$ increase. Mean shear stresses in the turbulent pulsating flow increase more in the inlet flow region than in the fully developed flow region and approach to almost constant value in the fully developed flow region. In the turbulent pulsating flow, the friction factor of the quasi-steady state flow $({\lambda}_{q, tu})$ follow friction factor's law in turbulent steady flow. The entrance length of the turbulent pulsating flow is not influenced by the time-averaged Reynolds number $(Re_{ta})$ and it is about 40 times as large as the hydraulic diameter.

• International Journal of Concrete Structures and Materials
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• v.5 no.1
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• pp.35-42
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• 2011

In this paper, a design equation for the punching shear capacity of steel fiber reinforced concrete (SFRC) slabs is proposed based on the Japan Society of Civil Engineers (JSCE) standard specifications. Addition of steel fibers into concrete improves mechanical behavior, ductility, and fatigue strength of concrete. Previous studies have demonstrated the effectiveness of fiber reinforcement in improving the shear behavior of reinforced concrete slabs. In this study, twelve SFRC slabs using hooked-ends type steel fibers are tested with varying fiber dosage, slab thickness, steel reinforcement ratio, and compressive strength. Furthermore, test data conducted by earlier researchers are involved to verify the proposed design equation. The proposed design equation addresses the fiber pull-out strength and the critical shear perimeter changed by the fiber factor. Consequently, it is confirmed that the proposed design equation can predict the punching shear capacity of SFRC slabs with an applicable accuracy.