• Title/Summary/Keyword: Strength of Concrete

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A Study on the Application of Color as Process of Symbolic Metaphor in the Game Storytelling (게임 스토리텔링에서 상징적 메타포로 작용하는 색채의 역할)

  • Cho, Yoon-Kyung;Han, Hye-Jeong;Kim, Kyu-Jung
    • Journal of Korea Game Society
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    • v.8 no.1
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    • pp.41-48
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    • 2008
  • If an association for a color develops and comes to form any kind of common idea, a symbolic meaning is given to the color. It is called' symbolism of color' that color builds up an abstract general idea, an emblem, feeling except things concrete. The color of game is the visual element that one can be immersed in the game, the image which act as important meaning, the attribute of light, and visual perceptional factor. With form, motion, light and shade, the color function importantly as media which express a person and person's circumstance. In game, the color is used symbolically to suggest not only mental change of character but also the situation, mood, attribute and strength of energy. These transmission of meaning express symbolism of the color iconically. So, the color for image express of game take on universality. This study research that focus on how the symbolical meaning of the color is reflected in game.

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Structural Performance of a New Truss Deckplate System with UHPC Infilled Top Chords in Construction Stage (UHPC 충전형 상현재를 활용한 트러스 데크플레이트 시스템 시공단계 구조성능 평가)

  • Son, Hong-Jun;Kim, Young-Ho;Kim, Dae-Jin
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.33 no.2
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    • pp.137-144
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    • 2020
  • In this study, we propose a new truss deckplate system, which does not require temporary floor supports during construction, with ultra-high-performance concrete (UHPC) infilled top bars. The increased stiffness and strength of the proposed system were well retained as compared to those of the existing truss deckplate systems, thereby resulting in the reduction of maximum deflection at the span center. Four-point bending tests were performed on five specimens with a net span of 4.6 m to evaluate the structural performance of proposed system in the construction stage. In addition, the load-deflection curve was plotted for each specimen, and the effects of test parameters were analyzed. Further, a rigorous nonlinear three-dimensional finite element analysis was performed, and its results were compared with the test results. From the results, it was observed that the test specimens of the proposed system exhibited superior performance as compared to those of the existing one and also satisfied the serviceability requirement during construction provided by the Korea Building Code 2016.

An Experimental Study on the Mechanical and Fire Resistance Properties of ECC Fire Resistance Panel (ECC내화패널의 역학 및 내화특성에 관한 실험적 연구)

  • Lee, Sang-Soo;Kang, Hoon
    • Journal of the Korea Institute of Building Construction
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    • v.10 no.2
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    • pp.89-96
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    • 2010
  • This study was based on an experiment that examines the manufacture and performance of fiber-reinforced cement composite panels. The conclusions were drawn after testing the mechanical properties and durability characteristics of fiber-reinforced mortar, and the mechanical properties and fire resistance of ECC fire resistant column panels. It was found that the fluidity of CEL fiber was lower than that of PVA and NY fiber. The amount of air increased slightly as the combination of fibers caused the number of fine pores to increase. It was found that the mechanical performance and deformability of high strength concrete could be improved through the confinement effect of ECC fire resistant column panels. Through continuous studies on the manufacturing and field construction methods of fire resistant column panels, a new PC method that eliminates weakness in the existing processes may be developed for skyscrapers.

Analysis of Chloride Content in Aqueous Solution and Mortar using Laser Induced Breakdown Spectroscopy (LIBS를 활용한 수용액과 모르타르 내 염화물량 분석)

  • Ryu, Hwa-Sung;Park, Won-Jun
    • Journal of the Korea Institute of Building Construction
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    • v.21 no.3
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    • pp.189-194
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    • 2021
  • LIBS has been attracting attention as an analytical method capable of real-time measurement without sample preparation. In this study, a Lab. scale LIBS device was fabricated to examine the applicability and reproducibility of LIBS in the analysis of chloride contents in mortar. The existing analysis method and LIBS analysis were performed simultaneously on the mortar test specimen with the chloride content adjusted. Compared to the chloride content condition of the mortar, the XRF and Potentiometric Titration results also showed a similar trend. As a result of LIBS analysis, chlorine ions were detected at a wavelength of 837.59 nm according to the chloride content condition. In order to improve the precision in various concentration ranges, the LIBS signal amplification of about 50 times through the electric field enhancement was implemented. Through the verification of the aqueous solution-based reproducibility, a high correlation between the LIBS signal strength and the Cl concentration was confirmed, and the possibility of applying LIBS to the durability diagnosis of concrete damage by chloride was confirmed.

Track-Structure Interaction Analysis of Fast Hardening Track on Railway Bridge Considering Effect of Anchor and Friction (앵커와 마찰의 영향을 고려한 교량상 급속경화궤도의 궤도-교량 상호작용해석)

  • Cho, Sang-Hyeon;Lee, Il-Wha;Chung, Won-Seok;Lee, Hee-Young;Lee, Kyoung-Chan
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.31 no.1
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    • pp.53-61
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    • 2018
  • Ballast track requires constant maintenance work due to progress of track irregularity. Fast Hardening Track(FHT) has been developed to reduce the maintenance effort done by injecting fast hardening mortar in aged ballast to convert slab track. For the application of FHT to a railway bridge, post-installed anchors should be placed at center of the track segment to fix it on bridge. This paper presents track-bridge interaction analysis results with FHT considering stiffness and strength of post-installed anchor, age of FHT concrete and friction between FHT and bridge deck surface. Based on the analysis results, this study suggests when is good to install the anchors and allow normal operation of passing train.

Seismic retrofitting by base-isolation of r.c. framed buildings exposed to different fire scenarios

  • Mazza, Fabio;Mazza, Mirko
    • Earthquakes and Structures
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    • v.13 no.3
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    • pp.267-277
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    • 2017
  • Base-isolation is now being adopted as a retrofitting strategy to improve seismic behaviour of reinforced concrete (r.c.) framed structures subjected to far-fault earthquakes. However, the increase in deformability of a base-isolated framed building may lead to amplification in the structural response under the long-duration horizontal pulses of high-magnitude near-fault earthquakes, which can become critical once the strength level of a fire-weakened r.c. superstructure is reduced. The aim of the present work is to investigate the nonlinear seismic response of fire-damaged r.c. framed structures retrofitted by base-isolation. For this purpose, a five-storey r.c. framed building primarily designed (as fixed-base) in compliance with a former Italian seismic code for a medium-risk zone, is to be retrofitted by the insertion of elastomeric bearings to meet the requirements of the current Italian code in a high-risk seismic zone. The nonlinear seismic response of the original (fixed-base) and retrofitted (base-isolated) test structures in a no fire situation are compared with those in the event of fire in the superstructure, where parametric temperature-time curves are defined at the first level, the first two and the upper levels. A lumped plasticity model describes the inelastic behaviour of the fire-damaged r.c. frame members, while a nonlinear force-displacement law is adopted for the elastomeric bearings. The average root-mean-square deviation of the observed spectrum from the target design spectrum together with a suitable intensity measure are chosen to select and scale near- and far-fault earthquakes on the basis of the design hypotheses adopted.

Durability of Ultrarapid-Hardening Polymer-Modified Concretes Using Metakaolin (메타카올린을 혼입한 초속경 폴리머 시멘트 콘크리트의 내구특성)

  • Yoo, Tae-Ho;Chang, Byung-Ha;Hong, Hyun-Pyo
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.22 no.5
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    • pp.31-38
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    • 2018
  • The effects of polymer-binder ratio and metakaolin content on the properties of ultrarapid-hardening polymer-modified concretes using metakaolin are examined. As a result, regardless of the metakaolin content, the flexural, compressive and adhesion in tension strength of the ultrarapid-hardening polymer-modified concretes tend to increase with increasing polymer-binder ratio. Regardless of the polymer-binder ratio, the strengths of the ultrarapid-hardening polymer-modified concretes increase with increasing metakaolin content, and reaches a maximum at metakaolin content of 5%. The water absorption, carbonation depth and resistance of chloride ion penetration of the ultrarapid-hardening polymer-modified concretes decrease with increasing polymer-binder ratio. The resistance of freezing and thawing improvement is attributed to the improved bond between cement hydrates and aggregates because of the incorporation of polymer dispersion.

Seismic performance evaluation of circular composite columns by shaking table test (진동대 실험을 통한 원형 합성 기둥의 내진 성능 평가)

  • Shim, Chang-Su;Chung, Young-Soo;Park, Ji-Ho;Park, Chang-Young
    • Journal of the Earthquake Engineering Society of Korea
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    • v.11 no.5
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    • pp.71-81
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    • 2007
  • For the design of composite bridge piers, detail requirements for the reinforcements is not clear to satisfy the required seismic performance. Composite bridge piers were suggested to reduce the sectional dimensions and to enhance the ductility of the columns under earthquake loadings. In this paper, five specimens of concrete encased composite columns of 400mm diameter with single core steel were fabricated to investigate the seismic performance of the composite columns. Shaking table tests and a Pseudo-Dynamic test were carried out and structural behavior of small-scaled models considering near-fault motions was evaluated. Test parameters were the pace of the transverse reinforcement, lap splice of longitudinal reinforcement and encased steel member sections. The displacement ductility from shaking table tests was lower than that from the pseudo-dynamic test. Limited ductile design and 50% lap splice of longitudinal reinforcement reduced the displacement ductility. Steel ratio showed significant effect on the ultimate strength. Lap splice and low transverse reinforcements reduced the displacement capacity. The energy dissipation capacity of composite columns did not show significant difference according to details.

Effects of Tie Details on Seismic Performance of RC Columns Subjected to Low Compression Loads (낮은 압축력을 받는 철근콘크리트 기둥의 내진성능에 대한 띠철근 상세의 영향)

  • Kim, Chul Goo;Park, Hong Gun;Eom, Tae Sung;Kim, Tae Wan
    • Journal of the Earthquake Engineering Society of Korea
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    • v.19 no.4
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    • pp.195-205
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    • 2015
  • Various non-seismic tie details are frequently used for one- and two-story small buildings because the seismic demand on their deformation capacities is not relatively significant. To evaluate the effects of the non-seismic tie details on the seismic performance of reinforced concrete columns, six square columns with a cross section of $400{\times}400mm$ and six rectangular columns with a cross section of $250{\times}640mm$ were tested. The anchorage details at both ends and spacing of tie hoops, along with the cross-sectional shape and the magnitude of axial load, were considered as the primary test parameters. Test results showed that square columns had higher stiffness and lower lateral deformation rather than rectangular columns. Both lap spliced tie and U-shaped tie provided comparable or improved seismic performance to $90^{\circ}$ hook tie in terms of maximum strength, ductility, and energy dissipation. The predicted curves with modeling parameters in ASCE41-13 were conservative for test results of lap spliced tie and U-shaped tie specimens since plastic behavior after flexural yielding could not be considered. For economical design, ASCE41-13 should be revised with various test results of tie details.

Verification of External Magnetization based EM Technique for Diagnosing Residual Tensile Stress in Aged PSC Structures (노후 PSC 구조물의 잔여 긴장 응력 진단을 위한 외부 자화 EM 기법 검증)

  • Soon-Jeon Park;Sehwan Park;Jaehoon Choi;Kyo-Young Jeon;Junkyeong Kim
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.36 no.4
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    • pp.251-257
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    • 2023
  • This study entailed an investigation of a tensile stress measurement method for prestressed concrete (PSC) tendons by utilizing external magnetization. The target of this study are PS structures that have been constructed and in use. An optimal external magnetization based elasto-magnetic (EM) sensor was designed using finite element analysis considering various factors, such as coil arrangement and size, that could influence the PS tendons inside the PSC girder. The residual tensile stress resulting from the external magnetization of the girder was then determined. Further, theoretical verification was performed using the numerical and material data used in the finite element analysis for sensor design. The calculated values of strength of magnetization at the target location were matched with the finite element analysis results. Thus, the designed sensor and the feasibility of magnetizing the tendons inside the PSC I-girder using an EM sensor were validated.