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Validation of Permanent Deformation Model for Flexible Pavement using Accelerated Pavement Testing (포장가속시험을 이용한 소성변형예측 모델의 검증)

  • Choi, Jeong Hoon;Seo, Youngguk;Suh, Young Chan
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.29 no.4D
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    • pp.491-497
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    • 2009
  • This paper presents the results of accelerated pavement tests (APT) that simulate permanent deformation (rutting) of asphalt concrete pavements under different temperatures and loading courses. Also, finite element (FE) analysis has been conducted to predict the test results. Test section for APT is the same as one of test sections at Korea Expressway Corporation test road and is subjected to a constant moving dual tire wheel load of APT at three different temperatures: 30, 40, $50^{\circ}C$. The moving wheel is applied at different loading courses within a 75cm wide wheel path to account for traffic wandering. Also, the effect of wandering on permanent deformation development is investigated numerically with three wandering schemes. In this study, ABAQUS is adopted to model APT pavement section with plain stain elements and creep strain rate model is used to take into account viscoplastic stain of asphalt concrete mixtures, and elastic layer properties are back-calculated from FWD measurements. Plus, the effect of boundary condition and subgrade on FE permanent deformation predictions is investigated. A full FE model that accounted for subgrade provided more realistic rut depth predictions, indicating subgrade has contributed to surface rutting.

A Development of Criteria for Evaluating School Zone by Utilizing Analytic Network Process (네트워크분석법(ANP)을 이용한 어린이보호구역 평가항목 개발)

  • Jeong, Kwang Seop;Kim, Tae Ho;Park, Je Jin;Won, Jai Mu
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.29 no.2D
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    • pp.191-197
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    • 2009
  • This study choose the Criteria by conducting survey questionnaire of expertise, ANP analysis, and reviewing literature to samples of School Zone in a synthetic and reasonable way. It draws the estimating factors including a variety of existing aspects (user, facility, operation and management, and education and institution) from the analyses and applies ANP to reflect the decision making process. The results show as follows: first, first level of weights presents proportion of 'facility' and 'user' takes 65% of total weights. It implies that the facility protects children from obstacles is the top priority of the settings. second, the second level of weights present similar importance with the first level. Facility management, road to school, surroundings, safety facility, decelerating facility hold approximately 72% of overall levels. This indicates that improving and repairing surroundings, and safety and decelerating facility are the first priority to consider. These estimating indicators will be properly utilized to rationally appoint prevention zone with reflecting various factors and social class.

Evaluation of Bursting Behavior in Anchorage Zone of PSC I Girders (PSC I 거더의 정착부 파열거동 평가)

  • Choi, Kyu Chon;Park, Young Ha;Paik, In Yeol
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.30 no.3A
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    • pp.329-336
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    • 2010
  • An experimental study to evaluate bursting behavior in anchorage zone of the standard PSC I girders (span length : 30 m) has been carried out. The arrangement of bursting reinforcement in anchorage zone of the standard PSC I girders is considered to be designed without accurately reflecting the stress flows in the end zone of the PSC I girders caused by presstressing forces of the tendons. Also, due to excessive arrangement of the bursting bars, the workability of the girder is decreased greatly. In this study, three specimens with the same dimensions as the end zone of the standard PSC I girder are prepared and the experiment is carried out by applying PS forces. The bursting reinforcement of each specimen consists of 100 mm, 200 mm, and 300mm spacings, respectively. The experimental results show that the range of the PS forces to cause crack in the anchorage zone of the specimen are more than 1.6 times of the design PS forces. The bursting cracks occur in the vertical direction on the inside of all specimens. After applying 2.7 times of the design PS force, some of the transverse bursting reinforcements only in the specimen reinforced by 300 mm spacing yielded. The experimental results show that the anchorage zone of the standard PSC I girders arranged by 300 mm spacing of the bursting reinforcements which is the maximum spacing allowed in the road bridge design specifications, can be considered safe enough.

A Barrier-free Design Assessment of Sidewalks for Improving Pedestrian Infrastructure (Barrier Free 인증 모의평가를 통한 보행자도로 개선 방안에 관한 연구 - 인덕원역, 석수역 주변 왕복 6차선 도로를 중심으로)

  • Kang, Jun Mo;Lee, Gun Rock
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.29 no.1D
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    • pp.101-110
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    • 2009
  • Urban Designers and Planners are interested in creating barrier-free (BF) environments as the demand for social equity increases. BF design consists of design strategies for modifying buildings or facilities to be used by the physically disadvantaged or disabled. To construct buildings or facilities to be "Barrier-free", design standards specifically modified for the physically disadvantaged or disabled should be applied. The purpose of this study is to analyze the BF design standard used in the national laws and provide suggestions for their future improvements. In the study national laws in four countries were reviewed and important BF standards to be used in the laws were identified using a frequency analysis. The results of the frequency analysis were applied to the BF assessment criteria for sidewalk design. Then a field assessment for two sidewalks located in Seoul metropolitan region was conducted using the refined BF criteria. The findings from the field assessments indicated that current regulations were not appropriately designed to provide sufficient convenience for the disabled. It is needed to enhance the BF standards in the domestic regulations to offer sufficient mobility to the physically disadvantaged or disabled.

Development of Task Planning System for Intelligent Excavating System Applying Heuristics (휴리스틱스(Heuristics)를 활용한 지능형 굴삭 시스템의 Task Planning System 개발)

  • Lee, Seung-Soo;Kim, Jeong-Hwan;Kang, Sang-Hyeok;Seo, Jong-Won
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.28 no.6D
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    • pp.859-869
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    • 2008
  • These days, almost every industry's production line has become automatic and this phenomenon brought a lot of benefits such as increase in productivity and economical effect, assurance in industrial safety, better quality and compatibility. However, unlike industrial production line, in construction industry, automation has number of barriers like uncertainty incidents and intellectual judgment to make ability to make solution out of it. Therefore construction industry is still demanding use of construction machine through labor. Due to this matter operational labor in construction industry is aging and fading. To solve these problem, in developed nations like Europe, US or Japan are keep researching for the automation in construction and road pavement, strengthening and some other simple operations have been worked through automation but in civil engineering site, automation research is still low despite of its importance in constructional site. For automating civil engineering operation, effective operational plan have to be set by analyzing ground information acquainted. If skillful worker apply heuristics, trial & error can be reduced with increased safety and the effective work plan can be established. Hence, this research will introduce Intellectual Task Planning System for Intelligent Excavating System's effective work plan and heuristics applied in each steps.

Detection of Steel Ribs in Tunnel GPR Images Based on YOLO Algorithm (YOLO 알고리즘을 활용한 터널 GPR 이미지 내 강지보재 탐지)

  • Bae, Byongkyu;Ahn, Jaehun;Jung, Hyunjun;Yoo, Chang Kyoon
    • Journal of the Korean Geotechnical Society
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    • v.39 no.7
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    • pp.31-37
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    • 2023
  • Since tunnels are built underground, it is impossible to check visually the location and degree of deterioration of steel ribs. Therefore, in tunnel maintenance, GPR images are generally used to detect steel ribs. While research on GPR image analysis employing artificial neural networks has primarily focused on detecting underground pipes and road damage, there have been limited applications for analyzing tunnel GPR data, specifically for steel rib detection, both internationally and domestically. In this study, a one-step object detection algorithm called YOLO, based on a convolutional neural network, was utilized to automate the localization of steel ribs using GPR data. The performance of the algorithm is then analyzed. Two datasets were employed for the analysis. A dataset comprising 512 original images and another dataset consisting of 2,048 augmented images. The omission rate, which represents the ratio of undetected steel ribs to the total number of steel ribs, was 0.38% for the model using the augmented data, whereas the omission rate for the model using only the original data was 7.18%. Thus, from an automation standpoint, it is more practical to employ an augmented dataset.

A study on the improvement of the protective shield construction method and explosion-proof tube performance for tunnel blasting (터널 발파에 대한 방호쉴드 공법 및 방폭튜브 성능 개선 연구)

  • Sang-Hwan Kim;Soo-Jin Lee;Jung-Nam Kwon;Dong-gyun Yoo;Yong-Woo Kim;Kwang-Eun Cho
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.25 no.4
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    • pp.285-303
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    • 2023
  • Interest in building underground spaces is increasing for the creation of downtown infrastructure and efficient space utilization. A representative method of utilizing underground space is a tunnel, and in addition to road tunnels, the construction of utility tunnels such as power conduits and utility conduits is gradually increasing. The current basic tunnel construction method can be divided into NATM (New Austrian Tunnelling Method) and TBM (Tunnel Boring Machine). The NATM is a reliable method, but it is accompanied by vibration and noise due to blasting. In the case of the TBM excavation method, there are disadvantages in terms of construction period and construction cost, but it is possible to improve economic feasibility by introducing appropriate complementary methods. In this study, a blasting method was develop using the NATM after TBM pre-excavation using the protective shield method. This is a method that compensates for the disadvantages of each tunnel construction method, and is expected to reduce construction costs, blasting vibration, and noise. In order to review the performance of the developed method, an experiment was conducted to evaluate the performance of explosion-proof tube to which a protective shield scale model was applied, and the impact of blasting vibration of the protective shield method was analyzed.

A Study on the Real-time Recognition Methodology for IoT-based Traffic Accidents (IoT 기반 교통사고 실시간 인지방법론 연구)

  • Oh, Sung Hoon;Jeon, Young Jun;Kwon, Young Woo;Jeong, Seok Chan
    • The Journal of Bigdata
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    • v.7 no.1
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    • pp.15-27
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    • 2022
  • In the past five years, the fatality rate of single-vehicle accidents has been 4.7 times higher than that of all accidents, so it is necessary to establish a system that can detect and respond to single-vehicle accidents immediately. The IoT(Internet of Thing)-based real-time traffic accident recognition system proposed in this study is as following. By attaching an IoT sensor which detects the impact and vehicle ingress to the guardrail, when an impact occurs to the guardrail, the image of the accident site is analyzed through artificial intelligence technology and transmitted to a rescue organization to perform quick rescue operations to damage minimization. An IoT sensor module that recognizes vehicles entering the monitoring area and detects the impact of a guardrail and an AI-based object detection module based on vehicle image data learning were implemented. In addition, a monitoring and operation module that imanages sensor information and image data in integrate was also implemented. For the validation of the system, it was confirmed that the target values were all met by measuring the shock detection transmission speed, the object detection accuracy of vehicles and people, and the sensor failure detection accuracy. In the future, we plan to apply it to actual roads to verify the validity using real data and to commercialize it. This system will contribute to improving road safety.

The need for mechanization in todays canal building program in korea and overseas (수로의 기계화 시공의 필요성)

  • Ha, Gordon P.wkins
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.21 no.2
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    • pp.21-27
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    • 1979
  • Canal construction is not the only area in which mechanization has advanced with great strides. All phases of the construction industry, including earthmoving, land clearing and levelling, road construction, and drainage and water control projects, have benefited from today's technological advancements. Lasers, an excellant example of advanced technology, have been refined for use as guidance systems for construction machinery, increasing accuracy and the speed of operation. The use of explosives by contractors is becoming more commonplace. One of the most valuable modern tools available today is the two-way radio. On today's sophisticated projects a single machine being down can frequently stop the progress of the entire project, delaying hundreds of men and machines from completing their assigned work for the day. The use of two-way radios in all the pickups and cars being used on a project facilitates communication so that emergency repairs can be effected immediately, and costly down time on any project can be reduced to a minimum. Not every construction project is suitable to mechanization. However, on the majority of projects mechanization has a great deal to offer the Korean contractor, and all contractors, in savings of time and money. Each and every project being considered by a contractor, should be closely examined for the most effective and efficient machinery application available. The International Commission on Irrigation and Drainage (ICID) has formed a committee on construction techniques being used in canal construction today. Two publications are now available describing the advances made in recent years. Standards for construction have been established for mechanized systems and this information is being distributed worldwide.

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Condition Estimation of Facility Elements Using XGBoost (XGBoost를 활용한 시설물의 부재 상태 예측)

  • Chang, Taeyeon;Yoon, Sihoo;Chi, Seokho;Im, Seokbeen
    • Korean Journal of Construction Engineering and Management
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    • v.24 no.1
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    • pp.31-39
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    • 2023
  • To reduce facility management costs and safety concerns due to aging of facilities, it is important to estimate the future facilities' condition based on facility management data and utilize predictive information for management decision making. To this end, this study proposed a methodology to estimate facility elements' condition using XGBoost. To validate the proposed methodology, this study constructed sample data for road bridges and developed a model to estimate condition grades of major elements expected in the next inspection. As a result, the developed model showed satisfactory performance in estimating the condition grades of deck, girder, and abutment/pier (average F1 score 0.869). In addition, a testbed was established that provides data management function and element condition estimation function to demonstrate the practical applicability of the proposed methodology. It was confirmed that the facility management data and predictive information in this study could help managers in making facility management decisions.