• Steel and Composite Structures
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• v.17 no.6
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• pp.777-790
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• 2014

The purpose of this study is to investigate the seismic performance of reinforced concrete (RC) frames strengthened by profiled steel sheet bracing which takes the influence of infill walls into consideration. One-bay, two-story, 1/3 scale two specimens shared same feature of dimensions, one specimen consists only beams and columns; the other one is reinforced by profiled steel sheet bracing with infill walls. Hysteretic curves, envelope curves, stiffness degradation curves and energy dissipation capacities are presented based on test data. Test results indicate that the ultimate load of strengthened specimen has been improved by 225%. The stiffness of reinforced by profiled steel sheet bracing has been increased by 108%. This demonstrates that infill walls and profiled steel sheet bracing enhanced the strength and stiffness distinctly. Energy dissipation has an obvious increase after 12 cycles. This shows that the reinforced specimen is able to bear the lateral load effectively and absorb lots of seismic energy.

• Proceedings of the KSR Conference
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• 2002.05a
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• pp.590-596
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• 2002

Contact wires are made by metallic materials and exposured at atmosphere. We have investigated mechanical properties and the present condition of air pollution as to the messenger wires and ACSR wires of these contact wires. Mechanical properties between new contact wires and used, the used one's tensile strength and elongations was decreased by effect from corrosion. We observed a fatigue properties which was investigated by fatigue test because contact wires were affected with amplitude vibration everytime the train passed through the railways. In the evaluation of fatigue test, it was also shown that fatigue life of the used wires was decreased 50 ∼ 60% compared with that of new ones in average by effect from corrosion.

• Elastomers and Composites
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• v.13 no.2
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• pp.89-98
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• 1978

1. The effect of reactive type antioxidant, G-1 in comparism to ordinary antioxidant, SP, which are used for NR and SBR has teen studied, and its recipes are equal. The effects against ozone aye been shown that ill ordinary antioxidant, SBR, no an particular effect both for NR and SBR was found, where as in reactive type, considerable influence was recogniged particulary in dynamic ozone test. 2. The influence of reactive antioxidants on velcanization has been studied by means of Mooney viscometer and Rheometer. 3. The ageing properties of vulcanizates containing reactive antioxidant have been studied in terms of tensile strength.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2002.04a
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• pp.53-60
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• 2002

It has been recognized that damage control must become a more explicit design consideration. In an effort to develop design methods based on performance it is clear that the evaluation of the inelastic response is required. The methods available to the design engineer today are nonlinear time history analyses, or monotonic static nonlinear analyses, or equivalent static analyses with simulated inelastic influences. Some codes proposed the capacity spectrum method based on the nonlinear static(pushover) analysis to determine earthquake-induced demand given the structure pushover curve. This procedure is conceptually simple but iterative and time consuming with some errors. This paper presents a nonlinear direct spectrum method to evaluate seismic Performance of structure, without iterative computations, given the structural initial elastic period and yield strength from the pushover analysis, especially for multi degree of freedom structures. The purpose of this paper is to investigate accuracy and confidence of this method from a point of view of various earthquakes and unloading stiffness degradation parameters.

• Steel and Composite Structures
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• v.18 no.3
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• pp.641-657
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• 2015

Application of reduced web beam section (RWBS) as a sacrificial fuse element has become a popular research field in recent years. Weakening of beam web in these connections may cause local web buckling around the opening area which can affect cyclic behavior of connection including: maximum load carrying capacity, strength degradation rate, dissipated energy, rotation capacity, etc. In this research, effect of local web buckling on the cyclic behavior of RWBS connections is investigated using finite element modeling (FEM). For this purpose, a T-shaped moment connection which has been tested under cyclic loading by another author is used as the reference model. Fracture initiation in models is simulated using Cyclic Void Growth Model (CVGM) which is based on micro-void growth and coalescence. Included in the results are: effect of opening corner radii, opening dimensions, beam web thickness and opening reinforcement. Based on the results, local web buckling around the opening area plays a significant role on the cyclic behavior of connection and hence any parameter affecting the local web buckling will affect entire connection behavior.

• Structural Engineering and Mechanics
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• v.72 no.6
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• pp.723-736
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• 2019

The efficacy of a technique for the rehabilitation and strengthening of RC beam-column connections damaged due to cyclic loading was investigated. The repair mainly uses epoxy resin infused under pressure into the damaged region to retrieved back the lost capacity and then strengthening using fiber reinforced polymer (FRP) sheets for capacity enhancement. Three common types of reduced scale RC exterior beam-column connections namely (a) beam-column connection with beam weak in flexure (BWF) (b) beam-column connections with beam weak in shear (BWS) and (c) beam-column connections with column weak in shear (CWS) subjected to reversed cyclic loading were considered for the experimental investigation. The rehabilitated and strengthened specimens were also subjected to similar cyclic displacement. Important parameters related to seismic capacity such as strength, stiffness degradation, energy dissipation, and ductility were evaluated. The rehabilitated connections exhibited equal or better performance and hence the adopted rehabilitation strategies could be considered as satisfactory. Confinement of damaged region using FRP sheet significantly enhanced the seismic capacity of the connections.

• Proceedings of the Korea Concrete Institute Conference
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• 1990.10a
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• pp.19-22
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• 1990

Based on the design concept of a "Strong Column - Weak Beam" in the design of reinforced concrete, recently, a design method which moves the plastic hinging zone of a specific length away from the column face, has been proposed for reducing the degradation of stiffness and strength in the beam-column joint. To analyze reinforced concrete structures designed by this method. It is necessary to establish the analytical model which can simulate the hysteretic behavior depended on the initial positions and enlargements of plastic hinges. In this paper, by the numerical assumptions and the regression of experimental results, an analytical model is proposed. To estimate the accuracy of this model, some example analyses are conducted and compared with experimental results. From these comparision. It is shown that the proposed model is a good to predict the behavior of members subjected go cyclic loads.lic loads.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.589-592
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• 2006

The durability of concrete involves resistance to freeze-thaw action, corrosion, permeation, carbonation, chemical attack and so on. Generally, properties of concrete have been well understood under the separate action of these deterioration mechanisms. However, in practice, the degradation of concrete usually is the result of combined action of physical and chemical attack and can be accelerated by the combined action of several deterioration mechanisms. In the present study, to evaluate the combined deterioration by freeze-thaw action and seawater attack, ground granulated blast-furnace slag or silica fume concrete with water or seawater as mixing water was exposed to 300 cycles of freeze-thaw action. Tests were conducted to determined the relative dynamic modulus of elasticity and compressive strength. Furthermore, The MIP analysis were performed on the deteriorated part of concrete due to freeze-thaw action and seawater attack.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2011.05a
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• pp.119-120
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• 2011

Dome structure to form a space-efficient, applied a lot of beautiful buildings with structural systems, as well as a large space structure in the form of new residential lots have been applied. And domestic demand for housing in the dome with increasing dome house using various materials, are becoming commonplace. But now the Dome House is mainly used in construction steel, wood, stone, FRP construction and building materials per unit area and the high cost, long construction time, energy efficiency, has some disadvantages such as degradation. And structural strength of the structure is weak, the natural ingredients used come from natural damage is so big. In addition, demolition of buildings in trouble when handling the environmental problems has emerged. Recently expanded polystyrene to improve these problems by using the various approaches and research is being attempted and there.

• KIEAE Journal
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• v.11 no.2
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• pp.45-57
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• 2011

As climate change and environmental degradation become more evident, the public's concern and knowledge on sustainable development requires planners to have regards to social impacts and long term economic viability, as well as environmental impacts. The main objective of this study is to analyze existing sustainability assessment tools for single detached houses. The most widely used oversea tools are selected. From analysis on the existing assessment tools, "Impact Estimator" by Athena Institute, "Bees 4.0" by NIST, "CASBEE for Home" by JSBC, "Envest for Housing" by Energy Saving Trust, "LISA" by Center for Sustainable Technology, "SBTool" by iiSBE (International Initiative for Sustainable Built Environment), it can be seen that the current sustainability assessment programs are in need of much improvement. The selected programs are analyzed on scope of program setting & running, data input & output, assessment categories, and strength & weakness. This study is to supplement the existing sustainability assessment tools for single detached houses, and provide information for the development of web-based program to assist architects or home owners to plan sustainable houses in Korea in the schematic design stage.