• Title/Summary/Keyword: DB-24

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Construction of Three Dimensional Soil Cadmium Pollution Map Using Geotechnical Information DB System (국토지반정보시스템을 이용한 3차원 토양오염지도 구축)

  • Hwang, Dae Young;Kang, In Joon;Jang, Yong Gu;Kim, Soo Kyum
    • Journal of Korean Society for Geospatial Information Science
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    • v.24 no.4
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    • pp.13-19
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    • 2016
  • This study presented the build-up of three-dimensional soil pollution map for precise analysis. To do this, survey on the existing pollutant region on Dongnae-gu, Busan that is the study subject, showed that it tended to produce 0.72 clusters. So, this study suggested to investigate center of $1km{\times}1km $ grid and, as the results of comparing the pollution map that input pollution figure values based on the actually investigation point showed precise results. And, it divided the standard of pollution into 5 levels in surface and underground space and the map was built up using IDW interpolation against the amount of polluted substance. The pollution of ground surface, flow of polluted substance, coefficient of permeability and ground water level that are 504 geotechnical informations were selected as the influential parameters in pollution analysis of underground space, and it calculated that to 0~20 points by dividing the characteristics. It enables the build-up of pollution map of ground surface-underground with depth that considers the characteristics of soil layers and it is considered that it is possible to analyze the general infiltration. And, it was considered that it enables more accurate forecast about influential analysis per depth and pollution of underground water.

Evaluation of Static and Fatigue Performances of Decks Reinforced with GFRP Rebar for Reinfocement Ratio (GFRP 보강근으로 보강된 바닥판의 보강비에 따른 정적 및 피로성능 평가)

  • You, Young-Jun;Park, Young-Hwan;Choi, Ji-Hun;Kim, Jang-Ho Jay
    • Journal of the Korea Concrete Institute
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    • v.26 no.4
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    • pp.491-497
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    • 2014
  • The corrosion of steel reinforcement in reinforced concrete bridge decks significantly affects the degradation of the capacity. Due to the advantageous characteristics such as high tensile strength and non-corrosive property, fiber reinforced polymer (FRP) has been gathering much interest from designers and engineers for possible usage as a alternative reinforcement for a steel reinforcing bar. However, its application has not been widespread, because there data for short- and long-term performance data of FRP reinforced concrete members are insufficient. In this paper, seven full-scale decks with dimensions of $4000{\times}3000{\times}240mm$ were prepared and tested to failure in the laboratory. The test parameter was the bottom reinforcement ratio in transverse direction. The decks were subjected to various levels of concentrated cyclic load with a contact area of $577{\times}231mm$ to simulate the vehicle loading of DB-24 truck wheel loads acting on the center span of the deck. It was observed that the glass FRP (GFRP) reinforced deck on a restraint girder is strongly effected to the level of the applied load rather than the bottom reinforcement ratio. The study results showed that the maximum load less than 58% of the maximum static load can be applied to the deck to resist a fatigue load of 2 million cycles. The fatigue life of the GFRP decks from this study showed the lower and higher fatigue performance than that of ordinary steel and CFRP rebar reinforced concrete deck. respectively.

Clinical Outcome and Arthroscopic Evaluation of Double-Bundle Anterior Cruciate Ligament Reconstruction (이중 다발 전방십자인대 재건술의 임상적 결과 및 이차적 관절경 소견)

  • Song, Eun-Kyoo;Seon, Jong-Keun;Lee, Kyoung-Jai;Kim, Hyung-Soon
    • Journal of Korean Orthopaedic Sports Medicine
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    • v.9 no.1
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    • pp.28-34
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    • 2010
  • Purpose: The aim of this study was to evaluate short-term clinical results and second-look arthroscopic findings after double-bundle anterior cruciate ligament (DB ACL) reconstruction. Materials and Methods: Forty-nine patients, who were followed up for at least 24 months after DB ACL reconstruction, were included. Clinical results, such as, Lysholm knee and Tegner activity scores, and manual laxity and instrumented anterior laxity test results were evaluated. In fifteen patients (15 knees), second-look arthroscopy with staple removal was performed. At second-look arthroscopy, the authors assessed about reconstructed ACL rupture, subjective graft tension and extent of synovial coverage. Results: Lysholm knee scores significantly improved from 67.4 preoperatively to 96.1 at last follow-up (p<0.01). Tegner activity scale improved from 2.0 to 6.1. The Lachman test, at last follow-up, showed normal laxity in 39 (of 49) patients, and the pivot-shift test showed normal laxity in 36 (of 49) patients. Mean side-to-side differences improved significantly from 10.8 mm to 3.3 mm (p<0.01). Second-look arthroscopic findings showed that all patients had a normal or a near normal anteromedial bundle. However, 8 patients (53.3%) were found to have partial or complete posterolateral bundle rupture. Conclusion: Even though double-bundle ACL reconstruction was clinically effective means of restoring knee rotational and anteroposterior stabilities, there were some ruptured posterolateral bundles observed in cases under arthroscopy after double-bundle ACL reconstruction.

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Analysis of Moment Effect of Bridge Design Live Load KL-510 by Statistical Analysis of WIM Data of Expressway (고속도로 WIM 데이터의 통계분석을 통한 교량 설계활하중 KL-510의 모멘트 효과 분석)

  • Paik, Inyeol;Jeong, Kilhwan
    • Journal of Korean Society of Steel Construction
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    • v.29 no.6
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    • pp.467-477
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    • 2017
  • The live load effect of KL-510 of the current Korean bridge design code is examined by comparing with that of the multiple trucks of which the weights are statistically estimated from measured traffic data as well as with those of the related live load models. The truck weight data measured on the expressway before and after overweight enforcement are used to obtain the truck weights following the same procedures in deciding the live load model of the design codes and the results are compared with the load effect of KL-510. KL-510 yields a very uniform loading effect compared with the multiple truck effects when the weights are estimated from the data which contains some of the heavy trucks over the operational weight limit. KL-510 yields consistent results with the live load of AASHTO LRFD and shows less variation than the past load model DB-24 over the span lengths considered in this study. As a result of this research, the actual truck combinations equivalent to the notional KL-510 load model are constructed and it can be applied to the evaluation of the existing bridge and the calibration of the load factor of the permit vehicle.

Analysis of Carbon Emissions According to Combustion of Surface Fuels (지표연료의 연소에 따른 탄소배출량 분석)

  • Park, Young Ju;Lee, Hae Pyeong;Kim, Min Jung;Kim, Hae Rim
    • 한국방재학회:학술대회논문집
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    • 2011.02a
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    • pp.192-192
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    • 2011
  • 교토의정서에서 지구온난화의 원인이 되는 온실가스로 $CO_2$, $CH_4$, $N_2O$, HFCs, PFCs, $SF_6$를 규제하고 있다. 규제하는 6대 온실가스 가운데 $CO_2$가 가장 대표적이며, 우리나라의 연료연소에 의한 $CO_2$ 배출량은 세계 10위로 기후변화 진행속도는 세계 평균속도보다 빠르게 진행되고 있다. 이러한 기후변화에 대응하기 위하여는 온실가스 배출로 인한 DB구축 연구가 선행되어야 하며, 산림부분에 있어서는 연료의 열적특성 구명 연구가 극도로 미진한 국내현실에서 기초 data 확보를 위한 연구가 시급한 실정이다. 따라서, 본 연구에서는 산불발생 시 온실가스 배출량의 DB를 구축하기 위하여 산불발생 시 배출되는 탄소배출량을 예측하고자 산림 가연물의 연소실험을 수행 하였다. 연소실험은 산림 연료 가운데 지표연료 10가지(소나무낙엽, 굴참나무낙엽, 소나무솔방울, 밤나무밤송이껍질, 방아풀, 주름조개풀, 칡, 엉겅퀴, 김의털, 고비)를 대상으로 콘칼로리미터 장비를 이용하여 이산화탄소와 일산화탄소 배출량을 분석하였다. 탄소배출량 실험에 앞서 지표연료들의 함수율을 측정한 결과, 10가지 지표연료 가운데 고사한 연료(낙엽, 솔방울, 밤송이)는 9~24% 정도, 생연료인 초본류 6가지는 181~484% 정도인 것으로 나타났으며, 솔방울과 밤송이의 경우 9~10%로 가장 수분을 적게 함유하고 있음을 알 수 있었다. 탄소배출량 분석 결과, 50g 중량에 대한 10가지 지표연료들의 이산화탄소 총배출량은 28~98g 정도, 일산화탄소 총배출량은 0.76~4.08g 정도 배출하는 것으로 나타나 연료별 차이를 보였으며, 특히, 고사한 연료와 생연료의 탄소배출량 차이는 큰 것으로 나타났다. 일산화탄소 총배출량은 고사한 연료(소나무낙엽, 굴참나무 낙엽, 소나무 솔방울, 밤나무 밤송이)는 3.24~4.08g 정도, 생연료 초본류 6가지(방아풀, 주름조개풀, 칡, 엉겅퀴, 김의털, 고비)는 0.76~2.73g 정도 배출하는 것으로 나타났다. 이산화탄소 총배출량은 함수율이 현저히 낮은 4가지 연료(소나무 낙엽, 굴참나무 낙엽, 소나무 솔방울, 밤나무 밤송이 껍질)들은 52~98g 정도, 함수율이 높은 6가지 초본류는 28~48g 정도의 이산화탄소를 배출하는 것으로 나타났다. 따라서, 고사한 연료인 소나무 낙엽, 굴참나무 낙엽, 소나무 솔방울, 밤나무 밤송이는 초본류 보다 상대적으로 이산화탄소와 일산화탄소 배출량이 많은 것으로 나타났으며, 특히, 소나무 솔방울은 가장 많은 이산화탄소와 일산화탄소를 배출하는 것으로 나타났다. 상대적으로 방아풀과 주름조개풀은 각각 28g과 35g으로 이산화탄소 배출량이 작은 것으로 나타났다. 따라서, 산불발생 시, 소나무의 솔방울은 10가지 지표연료 가운데 상대적으로 많은 이산화탄소와 일산화탄소를 배출할 것으로 사료된다.

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Effects of Post-Tensioning Tendons and Vehicle Speeds on Dynamic Response of Concrete-Filled Steel Tubular Tied Arch Girder (긴장재 및 차량속도 변화에 따른 콘크리트 충전 타이드 아치형 거더의 동적거동)

  • Roh, Hwasung;Hong, Sanghyun;Park, Kyunghoon;Lee, Jong Seh
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.31 no.3A
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    • pp.163-172
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    • 2011
  • The CFTA girder developed is a concrete filled steel tubular system with arched shape and external post-tensioning (PT) tendons which control the initial camber and the bending stress of the girder. In the present study the effects of the PT tendons on the dynamic behavior of the girder subjected to a moving vehicle load are numerically investigated. Various levels for the tendon quantity and the tendon forces are considered, using the existing FE model of the girder. The vehicle considered is a DB-24 truck and is modeled with two tracks-three axles. Equivalent-load pulse time histories are applied to each node to simulate the moving vehicle, depending on the time of arrival and the discretization. The vehicle speeds are varied from 40 km/hr to 100 km/hr with increment of 20 km/hr. The analysis results show that the tendon forces do not produce any influences on the dynamic responses of the girder. However the dymamic deflection of the girder increases when a smaller amount of tendons is used. The Dynamic Amplification Factors (DAF) are evaluated based on the static and dynamic responses. Much lower values of the DAF are obtained, even no tendons applied, than those provided by the design criteria of the AASHTO LRFD and the Korea Highway Standard Specification.

Shape Optimum Design of Pultruded FRP Bridge Decks (인발성형된 FRP 바닥판의 형상 최적설계)

  • 조효남;최영민;김희성;김형열;이종순
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.17 no.3
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    • pp.319-332
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    • 2004
  • Due to their high strength to weight ratios and excellent durability, fiber reinforced polymer(FRP) is widely used in construction industries. In this paper, a shape optimum design of FRP bridge decks haying pultruded cellular cross-section is presented. In the problem formulation, an objective function is selected to minimize the volumes. The cross-sectional dimensions and material properties of the deck of FRP bridges are used as the design variables. On the other hand, deflection limits in the design code, material failure criteria, buckling load, minimum height, and stress are selected as the design constraints to enhance the structural performance of FRP decks. In order to efficiently treat the optimization process, the cross-sectional shape of bridge decks is assumed to be a tube shape. The optimization process utilizes an improved Genetic Algorithms incorporating indexing technique. For the structural analysis using a three-dimensional finite element, a commercial package(ABAQUS) is used. Using a computer program coded for this study, an example problem is solved and the results are presented with sensitivity analysis. The bridge consists of a deck width of 12.14m and is supported by five 40m long steel girders spaced at 2.5m. The bridge is designed to carry a standard DB-24 truck loading according to the Standard Specifications for Highway Bridges in Korea. Based on the optimum design, viable cross-sectional dimensions for FRP decks, suitable for pultrusion process are proposed.

A Study on the Stability of Embankment Due to the Construction of Embankment Combined Use Road (제방겸용도로 건설에 따른 제방 안정성 해석에 관한 연구)

  • Kim, Sung-Nam;Lee, Young-Woo
    • International Journal of Highway Engineering
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    • v.10 no.3
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    • pp.109-118
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    • 2008
  • This study analyzes the change of stability of embankment due to the construction of embankment combined used road with two different construction phases. The stabilities have been checked both in the phase of earth banking for a road construction and in the phase of the application of the traffic roads(DB-24). In both cases the factor of safety has been found higher than 1.3 which is the general criterion of the safety of an embankment. The results indicate that the safety of an embankment due to the construction of embankment combined use road is assured, and thus, it is thought that the construction of embankment combined use road can be considered for cutting down on expenses of construction sites for a road construction. However, the pre-examination of stability due to the construction should be carried out because it decreases the factor of safety of an embankment. From this study, it has been found that the factor of safety was dropped most when the water level rose in the transient flow. The result indicates that the stability analysis of a river embankment where the water level changes frequently should be carried out in the condition of transient flow. It is recommended that the inner side of an embankment should have a slope of 1:2 which is identical with the slope of the existing embankment. In addition, the factor of safety also can be decreased due to the traffic loads, and therefore, the effect should also be considered after the construction of embankment combined used road limiting the traffic loads.

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Design and Implementation of Indoor Air Hazardous Substance Detection Mobile System based on IoT Platform (IoT platform 기반 실내 대기 위험 물질 감지 모바일 시스템 설계 및 구현)

  • Yang, Oh-Seok;Kim, Yeong-Uk;Lee, Hong-Lo
    • Journal of Korea Society of Industrial Information Systems
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    • v.24 no.6
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    • pp.43-53
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    • 2019
  • In recent years, there have been many cases of damage to indoor air hazardous materials, and major damage due to the lack of quick action. In this regard, the system is intended to establish for sending push messages to the user's mobile when the concentration of hazardous substances is exceeded. This system extracts data with IoT system such as Arduino and Raspberry Pi and then constructs database through MongoDB and MySQL in cloud computing system. The database is imported through the application server using NodeJS and sent to the application for visualization. Also, when receiving signals about a dangerous situation in IoT system, push message is sent using Google FCM library. Mobile application is developed using Android Web view, and page to enter Web view is developed using HTML5 (HTML, Javascript CSS). The application of this system enables real-time monitoring of indoor air-dangerous substances. In addition, real-time information on indoor/outdoor detection location and concentration can be sent to the user's mobile in case of a risk situation, which can be expected to help the user respond quickly.

Comparison of reaction force and contact pressure on design truck load of slab bridge supported by MSEW abutment (보강토교대로 지지된 슬래브교의 설계 활하중에 대한 반력 및 접지압 검토)

  • Kim, Hong-Bae;Han, Heui-Soo
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.5
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    • pp.510-519
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    • 2019
  • In this study, the structural analysis was conducted to the comparison of reaction force and contact pressure on the design truck load (DB-24 and KL-510) of slab bridge supported by MSEW abutment. As a result of the structural analysis, the reaction force acting on the abutment at the continuous bridge was reduced rather than the simple span bridge. The reaction force due to the dead load was estimated to be about twice as large as that of the live load, and the influence of the live load on the total reaction force was relatively small. The contact pressure of the MSEW abutment was estimated to be the largest in the simple span bridge. The influence of contact pressure on the type of live load was relatively small. Therefore, it is considered to be more advantageous to apply the MSEW abutment to the continuous bridge than to the simple span bridge because the contact pressure acting on the abutment on the continuous bridge is estimated to be small. Since the reaction force and the load sharing ratio acting on the MSEW abutment depending on various conditions, it is necessary to examine the contact pressure in various types of bridges and specifications.