• Title/Summary/Keyword: Concrete cover

Search Result 581, Processing Time 0.028 seconds

A study on the application and counter measures of IC tag in international marine container transport (국제해상컨테이너운송에서 보안강화를 위한 전자태그(IC tag)의 적용과 대응방안)

  • Han, Sang-Hyun;Choi, Jun-Ho
    • International Commerce and Information Review
    • /
    • v.12 no.2
    • /
    • pp.133-158
    • /
    • 2010
  • Since 11 September 2001, the awareness of terrorists' actions has clearly risen. The potential threat of terrorists using containers poses a large risk to our economies and to our societies. In order to protect cargo from damage and terrorist threats, business and government turn to RFID and IC tags, and tradition container is replaced by IC smart container. In this study, presented application of IC tag and future tasks to Container transport by sea in viewpoint of security strengthening. First, realization and international SCM realization structural order that cover container supply chain whole of international standardization and association between industry are certainly needed. Second, it may have to try in technical development for IC tag Ratio that can read elevation moment develop suitable IC tag or reader in International Standard. Third, Need to establish concrete use policy as soon as possible in national dimension at the same time effort for international standard normalization of frequency. Finally, it shows to uses jointly with electron sealing and must solve problem about usable plan and information leak.

  • PDF

Analysis on Thermal Environment of Marathon Course in 2011 Daegu World Championship in Athletics (대구 세계육상선수권대회 마라톤 구간의 열환경변화분석)

  • Baek, Sang-Hun;Oh, Sang-Hak;Jung, Yong-Hun;Jung, Eung-Ho
    • Journal of Environmental Science International
    • /
    • v.20 no.7
    • /
    • pp.881-890
    • /
    • 2011
  • In this study, thermal environment changes for a marathon course of IAAF World Championship, Daegu 2011 were modeled to provide improvements of thermal environment, so that runners could have the maximum condition and citizens pleasant streets. The three biggest size of intersections were selected for the study. Envi-met, 3G microclimate model, were used for a thermal environment analysis and three different cases - present status, planting roadside tree scenario, and roof-garden scenario - were compared. The followings are the results of the study. 1. The highest thermal distribution were shown at 1 p.m., but there was no significant difference between a thermal distribution at 1 p.m. and that at 5 p.m. since a heat flux from buildings affects thermal distributions rather than insolation does. 2. Tree planting or adding environmental friendly factors might lead a temperature drop effect, but the effect was not significant for areas covered with impermeability packing materials such as concrete or asphalt (especally, for Site case 2) 3. The combination of tree planting and adding environmental friendly factors also brought a temperature drop effect (Site 1 and 2) and this case showed even better result if green spaces (especially, parks) were closed.

Application of expert systems in prediction of flexural strength of cement mortars

  • Gulbandilar, Eyyup;Kocak, Yilmaz
    • Computers and Concrete
    • /
    • v.18 no.1
    • /
    • pp.1-16
    • /
    • 2016
  • In this study, an Artificial Neural Network (ANN) and Adaptive Network-based Fuzzy Inference Systems (ANFIS) prediction models for flexural strength of the cement mortars have been developed. For purpose of constructing this models, 12 different mixes with 144 specimens of the 2, 7, 28 and 90 days flexural strength experimental results of cement mortars containing pure Portland cement (PC), blast furnace slag (BFS), waste tire rubber powder (WTRP) and BFS+WTRP used in training and testing for ANN and ANFIS were gathered from the standard cement tests. The data used in the ANN and ANFIS models are arranged in a format of four input parameters that cover the Portland cement, BFS, WTRP and age of samples and an output parameter which is flexural strength of cement mortars. The ANN and ANFIS models have produced notable excellent outputs with higher coefficients of determination of $R^2$, RMS and MAPE. For the testing of dataset, the $R^2$, RMS and MAPE values for the ANN model were 0.9892, 0.1715 and 0.0212, respectively. Furthermore, the $R^2$, RMS and MAPE values for the ANFIS model were 0.9831, 0.1947 and 0.0270, respectively. As a result, in the models, the training and testing results indicated that experimental data can be estimated to a superior close extent by the ANN and ANFIS models.

Pullout Test of Headed Reinforcing Bar in RC or SFRC Members with Side-Face Blowout Failure

  • Lee, Chang-Yong;Kim, Seung-Hun;Lee, Yong-Taeg
    • Architectural research
    • /
    • v.22 no.1
    • /
    • pp.33-39
    • /
    • 2020
  • In this study, side-face blowout failure strength of high strength headed reinforcing bar, which is vertically anchoring between RC or SFRC members, is evaluated throughout pullout test. The major test parameters are content ratio of high strength steel fibers, strength of rebar, length of anchorage, presence of shear reinforcement, and the side concrete cover thickness planned to be 1.3 times of the rebar. In pullout test, tensile force was applied to the headed reinforcing bar with the hinged supports positioned 1.5 and 0.7 times the anchorage length on both sides of the headed reinforcing bar. As a result, the cone-shaped crack occurred where the headed reinforcing bar embedded and finally side-face blowout failure caused by bearing pressure of the headed reinforcing bar. The tensile strength of specimens increased by 13.0 ~26.2% with shear reinforcement. The pullout strength of the specimens increased by 3.6 ~15.4% according to steel fiber reinforcement. Increasing the anchoring length and shear reinforcement were evaluated to reduce the stress bearing ration of the total stress.

Monitoring of Corrosion Rates of Carbon Steel in Mortar under a Wet-Dry Cyclic Condition

  • Kim, Je-Kyoung;Kang, Tae-Young;Moon, Kyung-Man
    • Journal of the Korean Electrochemical Society
    • /
    • v.10 no.3
    • /
    • pp.179-183
    • /
    • 2007
  • The corrosion behavior of metal covered with mortar under a wet-dry cyclic condition were investigated to apply for the measurement of corrosion rates of reinforcing steel in concrete structure. The carbon steel in mortar having t=3 mm cover thickness was exposed to the alternate condition of 6 h immersion in chloride containing solution and 18 h drying at $25^{\circ}C$ and 50%RH. The electrochemical phenomena of a carbon steel and mortar interface was explained by an equivalent circuit consisting of a solution resistance, a charge transfer resistance and a CPE(Constant Phase Element). The corrosion rates were monitored continuously during exposure using an AC impedance technique. Simultaneously, the current distribution over the working electrode during impedance measurement was analyzed from the phase shift, $\theta$, in an intermediate frequency. The result showed that corrosion rate monitoring using an AC impedance method is suitable under the given exposure conditions even during the drying period when the metal is covered with the wetted mortar.

Seismic performance of RC frames retrofitted with haunch technique

  • Akbar, Junaid;Ahmad, Naveed;Alam, Bashir;Ashraf, Muhammad
    • Structural Engineering and Mechanics
    • /
    • v.67 no.1
    • /
    • pp.1-8
    • /
    • 2018
  • Shake table tests performed on five 1:3 reduced scale two story RC moment resisting frames having construction defects, have shown severe joint damageability in deficient RC frames, resulting in joint panels' cover spalling and core concrete crushing. Haunch retrofitting technique was adopted herein to upgrade the seismic resistance of the deficient RC frames. Additional four deficient RC frames were built and retrofitted with steel haunch; both axially stiffer and deformable with energy dissipation, fixed to the beam-column connections to reduce shear demand on joint panels. The as-built and retrofitted frames' seismic response parameters are calculated and compared to evaluate the viability of haunch retrofitting technique. The haunch retrofitting technique increased the lateral stiffness and strength of the structure, resulting in the increase of structure's overstrength. The retrofitting increased response modification factor R by 60% to 100%. Further, the input excitation PGA was correlated with the lateral roof displacement to derive structure response curve that have shown significant resistance of retrofitted models against input excitations. The technique can significantly enhance the seismic performance of deficient RC frames, particularly against the frequent and rare earthquake events, hence, promising for seismic risk mitigation.

A Domain Analysis on the Hybrid of Fashion Trends - Fashion Trends of 1995 S/S $\sim$ 2001/2002 A/W - (패션 트렌드의 다중화(多重化) 현상(現象)에 대(對)한 범주(範疇) 분석(分析) - 1995 S/S$\sim$2001/2002 A/W 시즌을 중심(中心)으로 -)

  • Yun, Su-Jeong;Lee, Joo-Hyeon
    • Journal of Fashion Business
    • /
    • v.6 no.2
    • /
    • pp.110-123
    • /
    • 2002
  • This study investigated the influence of cultural and general trend of the times on fashion trends and the hybridization of these trends. The objectives of this study were to suggest new approach method of the fashion forecasting and to find out the cultural meanings and values of fashion. Key words that explains fashion trend from spring/summer of 1995 to fall/winter of 2002 were collected from professional fashion trend journals. These terms were analysed with domain analysis based on the semantic relationship. The frequency of their appearance in each season and the aspect of their appearance in each season were analysed. The hybrids of the fashion trends were analysed longitudinally and cross-sectionally as well by investigating the cover terms that were found as a result of domain analysis. The method used in this study can be applied to future study of fashion trend in that it offers an objective view of fashion trend and can allow researchers to study fashion trend in a concrete way.

Seasonal Changes in Structure and Landscape of Urban Stream Corridor - In the Case of Gongji Stream in Chuncheon- (도시하천 하도구조와 경관의 계절변화 - 춘천시 공지천을 중심으로 -)

  • Jo Hyun-Kil;Han Gab-Soo
    • Journal of Environmental Science International
    • /
    • v.14 no.8
    • /
    • pp.739-748
    • /
    • 2005
  • The purpose of this study is to analyze seasonal changes in structure and landscape of Gongji stream corridor in Chuncheon, and to suggest some guidelines to contribute to creating a desirable close-to- nature stream. The study seasonally surveyed floodplain and revetment conditions, channel micro-topography, streamflow level and velocity, and vegetational cover. Flooding, water level, and vegetation were major factors of affecting seasonal changes in streambed structure and stream landscape. Small sand bars and islands were considerably disturbed by flooding and water level change. However, large islands and sand bars in the upper and middle section of the study stream remained or reappeared even after flooding. Flooding also tended to repeat channel sedimentation at the same spot. Controlling water volume of the Euiam Lake, which is adjacent to the study stream, caused higher water level downstream in the dry seasons. The majority of vegetation in sand bars and islands was washed away by the floods. Vehicle passing, crop cultivation, and ball game were other elements which disturbed vegetation in the floodplain. Creating a close-to-nature stream should reflect micro-topographical changes of channel by flooding, prevent improper vehicle entry and human use, and remove concrete material in the revetment and floodplain.

Cyclic shear test on a dowel beam-to-column connection of precast buildings

  • Magliulo, Gennaro;Ercolino, Marianna;Cimmino, Maddalena;Capozzi, Vittorio;Manfredi, Gaetano
    • Earthquakes and Structures
    • /
    • v.9 no.3
    • /
    • pp.541-562
    • /
    • 2015
  • This paper aims at developing the knowledge on the seismic behavior of dowel beam-to-column connections, typically employed in precast buildings in Europe. Despite the large diffusion of the industrial buildings, a high seismic vulnerability was exhibited by these structures, mostly due to the connection systems deficiencies, during some recent earthquakes (Emilia 2012, Turkey 2011). An experimental campaign was conducted on a typical dowel connection between an external column and a roof beam. In this paper, the performed cyclic shear test is described. According to the experimental results, the seismic response of the system is evaluated in terms of strength, stiffness and failure mechanism. Moreover, the complete damage pattern of the test is described by means of the instrumentations records. The connection failure occurred due to the concrete cover failure in the column (splitting failure). Such a mechanism corresponds to a negligible energy dissipation capacity of the connection, compared to the overall seismic response of the structure. The experimental results are also compared with the results of a similar monotonic shear test, as well as with some literature relationships for predicting the strength of dowel connections under horizontal (seismic) loads.

Bond Splitting Strength and Behavior of GFRP Reinforcement with Roughened Surface (거친표면 GFRP 보강근의 쪼갬부착파괴강도 및 거동 고찰)

  • Moon, Do-Young
    • Journal of the Korean Society of Hazard Mitigation
    • /
    • v.11 no.2
    • /
    • pp.23-29
    • /
    • 2011
  • In this experimental study, bond splitting strength and behavior were evaluated through pull-out tests. The tests were conducted on a GFRP rebar with roughened surface which was produced by Canadian manufacturer. The used variables in this study were rebar diameter, cover depth and compressive strength of concrete. For each variable, five specimens were made and tested to obtain good results. The bond splitting behavior was investigated from the relationship of pull-out force and slip. The experimental bond splitting strength was compared with the predicted strength obtained from the equations presented by some researchers. The results of the comparison demonstrated that the strength could be predicted well by using the Harajli et al's equation.