• Computers and Concrete
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• 제12권5호
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• pp.681-695
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• 2013

In 1999 Marmara and 2011 Van earthquakes in Turkey, majority of the existing buildings either sustained severe damage or collapsed. These buildings include masonry infill walls in both the interior and exterior R/C frames. The material of the masonry infill is the main variant, ranging from natural stones to bricks and blocks. It is demanding to design these buildings for satisfactory structural behavior. In general, masonry infill walls are considered by its weights not by interaction between walls and frames. In this study, R/C buildings with infill walls are considered in terms of structural behavior. Therefore, 5 and 8-story R/C buildings are regarded as the representative models in the analyses. The R/C representative buildings, both with and without infill walls were analyzed to determine the effects of structural behavior change. The differences in earthquake behavior of these representative buildings were investigated to determine the effects of infill walls leading structural capacity. First, pushover curves of the representative buildings were sketched. Aftermath, time history analyses were carried out to define the displacement demands. Finally, fragility analyses were performed. Throughout the fragility analyses, probabilistic seismic assessment for R/C building structures both with and without infill walls were provided. In this study, besides the deterministic assessment methodology, a probabilistic approach was followed to define structural effect of infill walls under seismic loads.

• 한국구조물진단유지관리공학회 논문집
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• 제19권2호
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• pp.92-98
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• 2015

최근의 건축물은 복합적인 기능과 형태를 보이고 있으며, 크기가 거대해짐에 따라 구조물 건전성 감시 (Structural Health Monitoring)기술의 수요 또한 증가하고 있다. 구조물마다 고유한 동특성을 가지고 있으며, 다양한 외력의 영향을 받기 때문에 구조물의 건전성을 평가하는 다양한 방법들이 연구되고 있다. 이상거동 시점이란 구조물이 비정상적 (Abnormal)으로 진동하는 시점으로 손상을 명확히 검출하기 위해서는 이상거동의 시점을 기준으로 전과 후를 비교하여야 한다. 즉, 이상거동은 구조물 손상의 이상 징후이며, 정확한 이상거동 시점의 추정은 구조물의 안전과 직결될 수 있다. 이상 거동은 손상을 유발하고 이는 곧 막대한 경제적 피해 및 심각한 인명 피해로 이어지므로 본 연구에서는 시간-주파수 신호분석 기법인 힐버트-황 변환을 이용한 이상거동 시점 추정 기법을 제안하고 진동대를 이용한 모형실험을 통해 제안한 알고리즘의 검증을 수행하였다.

• Structural Engineering and Mechanics
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• 제30권3호
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• pp.297-316
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• 2008

This paper investigates the structural behavior of Korean traditional wooden structures on the basis of the structural analysis using the commercialized program, SAP 2000. All the structural systems were analyzed, and the rotational stiffness at each joint was inferred from the experimental result for a half scale model of Bongjeong-sa (a temple in South Korea). In addition, the artificial control of analysis parameters was prevented because the structural analysis was focused on the realization of the most exact structural behavior of real structures. The analysis was carried out for the horizontal and vertical static loads, and all the secondary members were excluded in the structural analysis. The obtained results show that the resisting capacity of the primary structural system is greater than that of the expanding structural system.

• 한국안전학회지
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• 제33권5호
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• pp.101-108
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• 2018

This study was carried out to obtain baseline data on the causes of industrial accidents and their prevention by investigating structural models between the Shipyard workers' egogram ego-states (CP: Critical Parent, NP: Nurturing Parent, A: Adult, FC: Free Child, AC: Adapted Child), safe and unsafe behaviors, and industrial accidents (frequency/severity). In order to achieve this goal, 378 workers from 3 locations of major corporations in Geojedo Island and Ulsan took a questionnaire, which was then analyzed with a structural equation model using the SPSS 23.0 and AMOS 24 statistics package, and the main results of the study are as follows. First, NP and A's ego-states had a positive influence on safe behavior, AC's ego-state had a negative influence on safe behavior, and A's ego-state had the largest influence on safe behavior. Second, CP and AC's ego-states had a positive influence on unsafe behavior, and A's ego-state had a negative influence on unsafe behavior. AC's ego-state had the largest influence on unsafe behavior. Third, safe behavior did not have a significant influence on industrial accidents. However, unsafe behavior had a positive influence on industrial accident frequency and industrial accident severity, both sub-factors of industrial accidents. This study, despite its limitations, such as sampling limitations, has the following significance. First, this study verified that ego-state, a psychological characteristic, is an important factor for predicting unsafe behavior that induces industrial accidents. Second, in order to reduce industrial accidents, there is a need to stimulate the A ego-states, and promote continuous safety management and safety education to neutralize the AC ego-state. Third, previous studies were limited in the area of practical methods for reducing unsafe behaviors, but this study presents practical methods for reducing unsafe behaviors by verifying the structural relationship between safe/unsafe behaviors and industrial accidents by selecting ego-gram ego-states, variable personality theory, as an independent variable.

• Steel and Composite Structures
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• 제17권4호
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• pp.405-429
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• 2014

In this paper, it is aimed to determine the structural behavior of suspension bridges considering construction stages and different soil conditions. Bosporus Suspension Bridge connecting the Europe and Asia in Istanbul is selected as an example. Finite element model of the bridge is constituted using SAP2000 program considering existing drawings. Geometric nonlinearities are taken into consideration in the analysis using P-Delta large displacement criterion. The time dependent material strength of steel and concrete and geometric variations is included in the analysis. Time dependent material properties are considered as compressive strength, aging, shrinkage and creep for concrete, and relaxation for steel. To emphases the soil condition effect on the structural behavior of suspension bridges, each of hard, medium and soft soils are considered in the analysis. The structural behavior of the bridge at different construction stages and different soil conditions has been examined. Two different finite element analyses with and without construction stages are carried out and results are compared with each other. At the end of the analyses, variation of the displacement and internal forces such as bending moment, axial forces and shear forces for bridge deck and towers are given in detail. Also, displacement and stresses for bridge foundation are given with detail. It can be seen from the analyses that there are some differences between both analyses (with and without construction stages) and the results obtained from the construction stages are bigger. It can be stated that the analysis without construction stages cannot give the reliable solutions. In addition, soil condition have effect on the structural behavior of the bridge. So, it is thought that construction stage analysis using time dependent material properties, geometric nonlinearity and soil conditions effects should be considered in order to obtain more realistic structural behavior of suspension bridges.

• Advances in concrete construction
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• 제10권5호
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• pp.455-462
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• 2020

This study investigated the effect of horizontal casting joints on the mechanical properties and structural behavior of sustainable self-compacting reinforced concrete beams (SCRCB). The experimental research consisted of two stages. The first stage used four types of concrete mixtures which were produced to indicate the effects of cement replaced with cement waste at 0%, 5%, 10%, and 15% by weight of cement content on fresh concrete properties of self-compacting concrete (SCC) such as, passing ability, filling ability, and segregation resistance. In addition, mechanical properties such as compressive, tensile, and flexural strength were also studied. The second stage selected the best mixture from the first stage and studied the effect of horizontal casting joints on the structural behavior of sustainable SCRCBs. The effect of horizontal casting joints on the mechanical properties and structural behavior were at the 25%, 50%, 75%, and 100% of sample height. Load deflection, failure mode, and theoretical analysis were studied. Results indicated that the incorporation of replacement with cement waste by 5% to 10% led to economic and environmental advantages, and the results were acceptable for fresh and mechanical properties. The results indicated that delaying the time for casting the second layer and increasing the cement waste in concrete mixtures had a great effect on the mechanical properties of SCC. The ultimate load capacity of horizontal casting joints reinforced concrete beams slightly decreased compared with the control beam. The maximum deflection of casting joint beams with 75% of samples height is similar with the control beam. The experimental results of reinforced concrete beams were substantially acceptable with the theoretical results. The failure modes obtained the best forced casting joint on the structural behavior at 50% height of casting in the beam.

• International Journal of Concrete Structures and Materials
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• 제10권2호
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• pp.125-142
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• 2016

An overall review of the structural behaviors of ultra-high-performance fiber-reinforced concrete (UHPFRC) elements subjected to various loading conditions needs to be conducted to prevent duplicate research and to promote its practical applications. Thus, in this study, the behavior of various UHPFRC structures under different loading conditions, such as flexure, shear, torsion, and high-rate loads (impacts and blasts), were synthetically reviewed. In addition, the bond performance between UHPFRC and reinforcements, which is fundamental information for the structural performance of reinforced concrete structures, was investigated. The most widely used international recommendations for structural design with UHPFRC throughout the world (AFGC-SETRA and JSCE) were specifically introduced in terms of material models and flexural and shear design. Lastly, examples of practical applications of UHPFRC for both architectural and civil structures were examined.

• 한국구조물진단유지관리공학회 논문집
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• 제5권4호
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• pp.139-146
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• 2001

Res system, with Reinforced Concrete columns and Steel beams, is defined as system in which both steel and concrete materials are efficiently combined to maximize the structural and economic advantages of each material. Tested in this study were 4 exterior beam-to-column joint specimens with variables that influence joint rigidity of RCS structure. The purpose of this study is to compare and analyze the structural behavior of exterior joints through the existing studies and tests, and offer basic data for practical use of RCS structure by studying flexible behavior(semi-rigid effect) of joints according to joint details.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2000년도 가을 학술발표회논문집
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• pp.151-158
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• 2000

Cable dome that consists of three component such as cable, strut and fabric membrane has complex structural characteristics. Main structural system of cable dome is cable-strut tensegric system and fabric membrane element is conceived as cladding roof material. One of the important problem of cable dome is to investigate the structural response from external load effect such as snow and wind. When cable dome is subjected to load each structural component has various special structural characteristics. One is that geometrical nonlinearity should be considered because large deformation is occurred from their flexible characteristic. The other is that wrinkling occurs occasionally because cable and membrane elements can not transmit compressive forces. So this paper researches the physical structural response of cable dome structure and the structural behavior when failure occurred at a part of structure.

• Steel and Composite Structures
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• 제34권4호
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• pp.487-497
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• 2020

During the last few decades, fluid viscous dampers have been significantly improved in terms of performance and reliability. Viscous dampers dissipate the input energy into heat and the increased temperature may damage internal seals of the damper. As a result, thermal compensation is crucial for almost all fluid viscous dampers. In this study, while referring to the main working principles of the recently developed bypass viscous damper in Iran, a comprehensive case study is conducted on a RC building having diagonal braces equipped with such viscous dampers. Experimental results of a small-scale bypass viscous damper is presented and it is shown that the currently available simplified Maxwell models can simulate behavior of the bypass viscous damper with good accuracy. Using a case study, contribution of bypass viscous dampers to seismic behavior of structural and non-structural elements are investigated. A designed procedure is adopted to increase damping ratio of the building from 3% to 15%. In this way, reductions of 25% and 13% in the required concrete and steel rebar materials have been achieved. From nonlinear time history analyses, it is observed that bypass viscous dampers can greatly improve seismic behavior of structural elements and non-structural elements.