• Proceedings of the Korea Concrete Institute Conference
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• 1990.04a
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• pp.61-65
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• 1990

The purpose of this study was to investigate the effect of Bent-up Bars in Beam-Column Joint with High-Strength Concrete up to 800 kg/$\textrm{cm}^2$. 5 specimens were tested under reversed cyclic loadings. The primary variables were the number of the Bented Bars with Joint Core, compressive strength and loading patterrns. The results showed that bent-up bars in beam-column joint prevented crack from extending into core but the failure was concreterated at the face of beam-column joint. Thus shear stress constant value(Г) should be revised for High Strength Concrete Beam-Column Joint with Bent-up Bars.

• Proceedings of the Korea Concrete Institute Conference
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• 1990.04a
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• pp.72-77
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• 1990

Results are presented of the cyclic loading tests of there low-rise shear wall assembligies using high strength concrete. The possibilities of achieving an acceptable level of energy dissipation in one story shear walls, mainly by flexural yielding, are examined. Mechanisms of flexural and shear resistance are reviewed with emphasis on aspects of sliding shear. Detrimental effects of sliding shear are demonstrated together with improvement achieved by use of diagonal wall reinforcements. It is postulated that with suitably arranged diagonal wall reinforcements a predominantly flexural response mode with good energy dissipation characteristics can be achieved in low-rise shear walls.

• Journal of the Korea Concrete Institute
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• v.11 no.5
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• pp.107-118
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• 1999

10 RC bridge piers have been made on a 1/3.4 scale model, and six piers of them were retrofitted with glassfiber. The have been tested in the quasi-static cyclic load so as to investigate their seismic enhancement before and after retrofitting with glassfibers. The objective of this experimental study is to investigate how to strength the ductility of reinforced concrete bridge piers which have been nonseismically designed and constructed in Korea before 1992. Important test parameters are axial load, load pattern, retrofit type. Glassfiber sheets were used for retrofitting in the plastic hinge region of concrete piers. The nonlinear behavior of bridge columns have been evaluated through their yield and ultimate strength, energy dissipation, displacement ductility and load-deflection characteristics under quasi-static cyclic loads. It can be concluded from the test that concrete piers strengthened with glassfibers have been enhanced for their ductile behavior by approximate 50%.

• Structural Engineering and Mechanics
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• v.52 no.6
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• pp.1177-1191
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• 2014

Reinforced concrete (RC) shear walls are one of the most commonly used lateral-load resisting systems in high-rise buildings. RC Parallel redundancy walls studied herein consist of two parts nested to each other. These two parts have different mechanical behaviors and energy dissipation mechanisms. In this paper, experimental studies of four 1/2-scale specimens representing this concept, which are subjected to in-plane cyclic loading, are presented and test results are discussed. Two specimens consist of a wall frame with barbell-shaped walls embedded in it, and the other two consist of a wall frame and braced walls nested each other. The research mainly focuses on the failure mechanism, strength, hysteresis loop, energy dissipation capacity and stiffness of these walls. Results show that the RC parallel redundancy wall is an efficient lateral load resisting component that acts as a "dual" system with good ductility and energy dissipation capacity. One main part absorbs a greater degree of the energy exerted by an earthquake and fails first, whereas the other part can still behave as an independent role in bearing loads after earthquakes.

• Computers and Concrete
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• v.17 no.2
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• pp.227-240
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• 2016

An analytical study was conducted to investigate the effect of the shape and spacing of modified inclined studs used as shear connector between concrete and steel plate on the cyclic behavior of steel plate concrete (SC) shear wall. 9 different analysis cases were adopted to determine the optimized shape and spacing of stud. As the results, the skeleton curves were obtained from the load-displacement hysteresis curves, and the ultimate and yielding strengths were increased as the spacing of studs decrease. In addition, the strength of inclined studs is shown to be bigger compared to that of conventional studs. The damping ratios increased as the decrease of stiffness ratio. Finally, with decreasing the spacing distance of studs, the cumulative dissipated energy was increased and the seismic performance was improved.

• Computers and Concrete
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• v.17 no.4
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• pp.541-551
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• 2016

Asphalt pavements are exposed to complex weather conditions and vehicle traffic loads leading to crack initiation and crack propagation in asphalt pavements. This paper presents the impact of weather conditions on fracture toughness of an asphalt concrete, prevalently employed in Ardabil road networks, under tensile (mode I) and shear (mode II) loading. An improved semi-circular bend (SCB) specimen was employed to carry out the fracture experiments. These experiments were performed in two different weather conditions namely fixed and cyclic temperatures. The results showed that consideration of the impact of temperature cycling resulted in decreasing the fracture toughness of asphalt concrete significantly. Furthermore, the fracture toughness was highly affected by loading mode for the both fixed and cyclic temperature conditions studied in this paper. In addition, it was found that the MTS criterion correctly predicts the onset of fracture initiation although this prediction was slightly conservative.

• Structural Engineering and Mechanics
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• v.10 no.5
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• pp.491-504
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• 2000

This paper is a presentation of a physical model for the elastic-partly plastic behavior of rectangular hollow section pinned struts subjected to static cyclic axial loading and the evaluation of the compressive strength of retrofitted damaged struts. Retrofitting is achieved by welding stiffening plates along the webs of damaged struts. The shape of the elastic and permanent deformations of the strut axis satisfy the conditions at the ends and midspan. Continuous functions of the geometric variables of stress distributions in the yielded zone are evaluated by interpolation between three points along each partly plastic zone. Permanent deformations of the partly plastic region are computed and used to update the shape of the unloaded strut. The necessity of considering geometric nonlinearity is discussed. The sensitivity of the results to the location of interpolation points, the shape of the permanent deformation and material hysteretic properties is investigated.

• Structural Engineering and Mechanics
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• v.10 no.5
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• pp.505-516
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• 2000

This paper is a presentation of an experimental study about the elastic-partly plastic behavior of rectangular hollow steel pinned struts subjected to static cyclic axial loading and the evaluation of the compressive strength of retrofitted crooked struts. Retrofitting is achieved by welding stiffening plates along the webs of damaged struts. The material follows a quasi-kinematic hardening hysteresis path as observed from coupon tests. Test results are compared to those of an analytical model showing a good agreement for both standard and retrofitted struts. The comparison of different stiffener plate dimensions shows that more efficient strengthening is achieved by using long thin stiffeners rather than short thick ones.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2002.10a
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• pp.521-526
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• 2002

The seismic performance of structural walls subjected to the cyclic lateral loads are influenced by various factors, like sectional shape, aspect ratio, reinforcement ratio, arrangement of reinforcement, and axial load ratio etc. In this research, reinforced concrete structural walls with the T-shaped cross section were selected. The seismic performance of T-shaped wall was affected by the many (actors because T-shaped wall is irregular wall composed to two rectangular walls. Especially the seismic performance of T-shaped wall varies with the flange condition and the various factors including the flange condition were determined. Therefore, the objective of this study is to understand the factors to improve seismic performance of RC T-shaded tv using sectional analysis.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.05d
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• pp.404-404
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• 1996

In order to ensure a concrete expansion anchor is suitable for a given application, the load resistance behavior of the anchor must be known. ASTM E488 provides a standard method of testing expansion anchors for static and dynamic loads. Due to the many types of anchors available commercially and the large variability of applications, the ASTM does not delineate all details or requirements necessary to comprehensively determine the dynamic load behavior of concrete expansion anchors. A test program is presented in this paper which was developed and implemented to determine the cyclic load behavior of wedge-type concrete expansion anchors. Test results are also presented along with a discussion of the behavior of anchors, and their suitability for use.