• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2006년도 정기 학술대회 논문집
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• pp.749-756
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• 2006

Because of the orthotropic elastic properties and significant two-way bending action, orthotropic plate theory may be suitable for describing the behavior of concrete filled grid bridge decks. Current AASHTO LRFD Bridge Design Specification(2004) has live load moment equations considering flexural rigidity ratio between longitudinal and transverse direction, but the Korea highway bridge design specification(2005) doesn't. The Korea highway bridge standard specification LRFD(1996) considers an orthotropic plate model with a single load to estimate live load moments in concrete filled grid bridge decks, which may not be conservative. This paper presents live load moment equations for truck and passenger car, based on orthotropic plate theory. The equations of truck model use multiple presence factor, impact factor, design truck and design tandem of the Korea highway bridge standard specification LRFD(1996). The estimated moments are verified through finite-element analyses.

• 한국도로학회논문집
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• 제18권1호
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• pp.1-11
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• 2016

PURPOSES : This study estimated the load effect of a single heavy truck to develop a live load model for the design and assessment of bridges located on an expressway with a limited truck entry weight. METHODS : The statistical estimation methods for the live load effect acting on a bridge by a heavy vehicle are reviewed, and applications using the actual measurement data for trucks traveling on an expressway are presented. The weight estimation of a single vehicle and its effect on a bridge are fundamental elements in the construction of a live load model. Two statistical estimation methods for the application of extrapolation in a probabilistic study and an additional estimation method that adopts the extreme value theory are reviewed. RESULTS : The proposed methods are applied to the traffic data measured on an expressway. All of the estimation methods yield similar results using the data measured when the weight limit has been relatively well observed because of the rigid enforcement of the weight regulation. On the other hand, when the estimations are made using overweight traffic data, the resulting values differ with the estimation method. CONCLUSIONS : The estimation methods based on the extreme distribution theory and the modified procedure presented in this paper can yield reasonable values for the maximum weight of a single truck, which can be applied in both the design and evaluation of a bridge on an expressway.

• Structural Engineering and Mechanics
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• 제76권1호
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• pp.1-15
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• 2020

The aim of this paper is to simply present live load factor calculation methodology formulation with the addition of a simple new future load projection procedure to previously proposed two methods. For this purpose, Oregon Weigh-in-Motion (WIM) data were used to calculate live load factors by using WIM data. These factors were calculated with two different approaches and by presenting new simple modifications in these methods. A very simple future load projection method is presented in this paper. Using four different WIM sites with different average daily truck traffic (ADTT) volume, and all year data, live load factors were obtained. The live load factors, were proposed as a function of ADTT. ADTT values of these sites correspond to three different levels which are approximately ADTT= 5,000, ADTT = 1,500 and ADTT ≤ 500 cases. WIM data for a full year were used from each site in the calibration procedure. Load effects were projected into the future for the different span lengths considering five-year evaluation period and seventy-five-years design life. The live load factor for ADTT=5,000, AASHTO HS20 loading case and five-year evaluation period was obtained as 1.8. In the second approach, the methodology established in the Manual for Bridge Evaluation (MBE) was used to calibrate the live load factors. It was obtained that the calculated live load factors were smaller than those in the MBE specifications, and smaller than those used in the initial calibration which did not convert to the gross vehicle weight (GVW) into truck type 3S2 defined by AASHTO equivalents.

• 한국신뢰성학회지:신뢰성응용연구
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• 제16권2호
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• pp.90-97
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• 2016

Purpose: Majority of bridges and roads in Gangwon Province have been carrying loads associated with heavy materials such as rocks, mining products, and cement. This location-specific live loads have contributed to the present situation of overloading, compared to other provinces in Korea. However, the bridges in Gangwon province are designed by national bridge design specification, without considering the location-specific live load characteristics. Therefore, this study focuses on the real traffic data accumulated on regional weighing station to verify the live load characteristics, including actual live load gross vehicle weight, axle weight axle spacings, and number of trucks. Methods: In order to take into account the location specific live load, a governmental weigh station (38th national highway Miro) have been selected and the passing truck data are processed. Based on the truck survey, trucks are categorized into 3 different shapes, and each shape has been idealized into normal distribution. Then, the resulting survey data are processed to predict the target maximum live load values, including the axle loads and gross vehicle weights in 75 years service life span. Results: The results are compared to the nationally used DB-24 live loads, and the results show that nationally recognized DB-24 live load does not sufficiently represent real traffic in mountaineous region in Gangwon province. Conclusion: The comparison results in the recommendation of location-specific live load that should be taken into account for bridge design and evaluation.

• 대한토목학회논문집
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• 제26권1A호
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• pp.143-153
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• 2006

교량의 설계에 있어서 정확한 하중의 산정은 교량의 안전성 확보에 가장 핵심적인 사항이며 향후 유지 관리 측면에서도 매우 중요하다. 일반적으로 교량에서 차량에 의한 하중효과는 주로 활하중(충격하중 포함) 및 피로하중으로 나타나는데 이들 하중의 정형화를 위해서는 실제 교량 상을 주행하는 중 차량의 중량 및 통행특성을 정확히 파악하는 것이 중요하다. 이를 위해서 주행 중인 차량을 정지시키지 않고 중량을 계측할 수 있는 시스템(Bridge Weigh-In-Motion, BWIM)의 개발이 선행되어야 한다. 본 연구에서는 다양한 기능을 갖는 BWIM시스템을 개발하고 이를 고속도로 교량에 적용하여 차량정보를 수집한 후 교량 설계를 위한 활하중 및 피로하중의 정형화를 수행하였다. 본 연구의 목적은 주행 중인 차량의 중량을 산정하는 BWIM시스템을 개발하여 시험 교량에 설치 한 후 교량거동의 계측을 통하여 최종적으로 고속도로 교통량 특성을 반영하는 활하중의 정형화 및 합리적인 피로하중산정 방안을 도출하는데 있다.

• 한국강구조학회 논문집
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• 제29권6호
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• pp.467-477
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• 2017

현행 국내 교량 설계기준의 활하중 모형인 KL-510의 하중 효과를 실측된 통행자료로부터 통계적으로 추정한 트럭의 연행효과 및 국내외 관련 설계기준이 하중모형과 비교한다. 과적단속 전후에 고속도로에서 측정된 트럭의 중량 자료를 이용하여 설계기준의 활하중 모형 결정과 동일한 과정을 따라서 트럭 중량을 산정하여 그 하중효과를 KL-510과 비교하였다. KL-510은 운행제한중량을 초과하는 트럭을 일부 포함하는 자료로부터 추정한 트럭의 연행에 의한 하중효과와 매우 부합하는 결과를 보였다. KL-510은 미국 AASHTO LRFD의 활하중 모형과 일관성 있는 결과를 주며, 기존 하중 모형인 DB-24보다 하중효과의 비율이 균일하였다. 이 연구의 결과로 가상의 하중 모형인 KL-510에 해당하는 실제 트럭의 조합을 구성하였으며, 향후 공용중인 교량의 평가와 허가차량의 하중계수 보정에 적용할 수 있다.

• 한국강구조학회 논문집
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• 제25권4호
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• pp.335-346
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• 2013

AASHTO LRFD 및 도로교한계상태설계기준에서는 신뢰도 기반 활하중 모델로부터 결정된 트럭하중과 차로하중을 동시에 재하하도록 하고 있으며, 트럭하중은 충격계수를 고려하되 차로하중은 충격계수를 적용하지 않도록 규정하고 있다. 본 연구에서는 중앙경간 230m, 400m 및 540m의 멀티케이블 강합성 사장교를 대상으로 트럭하중과 차로하중이 동시에 주행하는 경우에 대해 차량-교량 상호작용 해석을 수행하고 케이블과 보강거더의 충격계수를 평가하였다. 트럭하중은 6-자유도의 차량 모델을 사용하였으며, 차로하중은 일련의 1축 차량이 연행해서 주행하는 것으로 모사하였다. 교량의 감쇠비가 충격계수에 미치는 영향을 평가하였으며, 충격에 영향을 미치는 주요 인자인 노면조도와 주행속도를 해석변수로 고려하였다. 노면조도는 ISO 8608 규정에 근거하여 랜덤 생성하였으며, 차량-교량 상호작용해석 시 노면조도는 트럭하중에만 적용하였다. 한편, 사장교의 충격계수 평가를 위해 실무에서 사용되고 있는 영향선 기법에 의한 충격계수를 동적 상호작용 해석에 의한 결과와 비교하였다.

• Computers and Concrete
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• 제6권1호
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• pp.59-78
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• 2009

Reliability analysis for a proposed limit state bridge design code is performed. In order to introduce reliability concept to design code, the proposed live load model is based on truck weight survey. Test data of domestic material strengths are collected to model statistical properties of member strengths. Sample RC and PSC girder sections are designed following the safety factor format of the proposed code and compared with the current design practice. Reliability indexes are calculated and examined for material and member resistance factor formats and sample calibrations of safety factors are presented. It is concluded that the proposed code provides reasonable level of reliability compared to the international design standards.

• Computers and Concrete
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• 제24권4호
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• pp.303-311
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• 2019

The depth of superstructure is the summation of the height of girders and the thickness of the deck floor. In this study, it is aim to determine the maximum span length of girders and minimum depth of the superstructure of prestressed concrete I-girder bridge. For this purpose the superstructure of the bridge with the width of 10m and the thickness of the deck floor of 0.175m, which the girders length was changed by two meter increments between 15m and 35m, was taken into account. Twelve different girders with heights of 60, 75, 90, 100, 110, 120, 130, 140, 150, 160, 170 and 180 cm, which are frequently used in Turkey, were chosen as girder type. The analyses of the superstructure of prestressed concrete I girder bridge was conducted with I-CAD software. In the analyses AASHTO LRFD (2012) conditions were taken into account a great extent. The dead loads of the structural and non-structural elements forming the bridge superstructure, prestressing force, standard truck load, equivalent lane load and pedestrian load were taken into consideration. HL93, design truck of AASHTO and also H30S24 design truck of Turkish Code were selected as vehicular live load. The allowable concrete stress limit, the number of prestressed strands, the number of debonded strands and the deflection parameters obtained from analyses were compared with the limit values found in AASHTO LRFD (2012) to determine the suitability of the girders. At the end of the study maximum span length of girders and equation using for calculation for minimum depth of the superstructure of prestressed concrete I-girder bridge were proposed.

• 대한토목학회논문집
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• 제29권3A호
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• pp.199-207
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• 2009

본 논문에서는 신뢰도기반 도로교설계기준을 위한 새로운 활하중모형을 개발하였다. 합리적 하중모형과 함께 하중의 통계적 특성의 구축은 신뢰도기반 설계기준의 개발에 매우 중요하다. 이전 논문에서는 WIM 또는 BWIM시스템을 이용하여 수집된 국내 8개 지역의 자료를 분석하여 교량수명기간동안의 예상최대중량을 구하였다. 차종별 총중량의 확률분포는 상위 20%의 자료를 이용하여 극한분포(Gumbel분포)로 가정되었으며 이 확률분포를 사용하여 교량수명기간동안의 최대중량을 예측하였다. 이 논문에서는 교량상에 두 대 이상의 차량이 동시에 재하되는 경우를 분석하였다. 여러 자료를 이용하여 동시재하의 확률을 구하였으며 이에 따른 동시재하차량의 총중량을 이전 논문과 같은 확률분포를 이용하여 구하였다. 10-200 m까지의 지간별로 예측된 하중효과를 모사할 수 있는 공칭하중모형이 제안되었다. 제안된 하중모형은 기존의 하중모형 뿐만 아니라 국외의 여러 기준들과 비교분석되었다.