http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
도로 포장의 초기상태에 따른 공사비 차등지급규정의 시험적용
서영국 한국도로학회 2009 한국도로학회논문집 Vol.11 No.3
Recently, pay adjustment regulation (PAR) has been developed to induce better performing road pavements around the country. This regulation was successfully applied during rehabilitation of highway flexible pavements for the first time, and their results are the focus of this paper. For highway pavements, a lot has been defined by typical amount of works a day. This lot was further divided into several sublots depending on field conditions. According to AASHTO Quality Assurance Guide Specification, pay factors for each lot were statistically determined with field measurements of five performance indicators. And composite pay factors were calculated by accounting for the impact of individual performance indicators on a long-term performance of pavement. In 2008, the PAR was tested with asphalt overlays conducted at all six local headquarters of Korea Expressway Corporation. Also, concerns raised during implementation are discussed in this paper. Limited data used in this study showed that if all performance indicators fall within the construction limits with less variances final construction costs may increase by 50%, whereas 10% reduction in construction costs could be necessary if key performance indicators such as density do not meet the construction quality requirements. 본 논문에서는 도로포장의 성능개선을 유도하기 위한 제도적 수단인 공사비 차등지급규정(지불규정)을 제시하고 이를 고속도로 아스팔트 포장 공사에 처음으로 적용한 결과를 다루고 있다. 지불규정을 적용하기 위한 단위구간(lot)은 덧씌우기 포장의 일평균 시공연장으로 정의하였다. 단위구간은 다시 포장의 초기상태 평가를 위한 최소 단위인 세부단위구간(sublot)으로 나누었으며, 세부단위구간에서 측정한 품질항목의 평균과 표준편차를 이용하여 단위구간을 대표하는 품질항목별 지불계수(pay factor)를 산정하였다. 마지막으로, 각각의 품질항목이 포장의 중장기 공용성에 미치는 상대적 영향을 고려하여 합성지불계수를 결정하였다. 본 연구에서 제시한 지불규정은 2008년에 한국도로공사 6개 지역본부(충청, 호남, 경북, 경남, 경인, 강원)에서 시행된 아스팔트 덧씌우기 포장공사에 적용하였으며, 이 과정에서 제기된 고려사항 및 문제점을 정리하였다. 결론적으로, 품질항목에 대한 평가결과가 품질관리한계를 만족하는 경우에는 기존 공사비 대비 최대 50% 가까이 인센티브 지급이 가능함을 알 수 있었다. 반면에, 다짐도와 같은 주요 성능관련 품질이 낮을 경우 기존 공사비 대비 최대 10% 가까이 공사비 감액도 있을 수 있음을 확인하였다.
서영국,김성민,이재훈 대한토목학회 2013 KSCE JOURNAL OF CIVIL ENGINEERING Vol.17 No.5
This paper presents an operation scheme developed and implemented for Korea Expressway Corporation Test Road (KECTR), the first full scale road test facility in Korea. Several key elements such as field testing, data acquisition system, database, budget,schedule, and staff were identified as either technical or administrative aspect of operation. Some issues related to those elements were discussed based on operation at KECTR from 2002 to 2010. During this period, asphalt sections with thin layers were prematurely damaged under heavy highway traffic and high temperature, whereas most of data acquisition systems functioned properly. It was found that the lack of supporting staffs and a decreasing number of researchers have caused frequent delays during operation. Findings of this study may serve as practical guidelines for subsequent road test facilities.
Longitudinal Cracking at Transverse Joints Caused by Dowel Bars in Jointed Concrete Pavements
서영국,김성민 대한토목학회 2013 KSCE Journal of Civil Engineering Vol.17 No.2
Longitudinal cracking at transverse joints in the Jointed Concrete Pavement (JCP) was investigated and causes were discovered by performing field observation and numerical analyses. Finite element models of JCP were developed considering very detailed modeling of dowel bars and their contact characteristic to concrete. Using the models, transverse stresses at joints that could induce longitudinal cracking were comprehensively analyzed. The results showed that primary causes of longitudinal cracks at joints were found to be related to the vertical translation of dowel bar and the curling of the JCP slab due to environmental loading. Other factors affecting those cracks included concrete elastic modulus, concrete thermal expansion coefficient, foundation stiffness, vertical temperature gradient, and bond characteristic between concrete and dowel bar. To mitigate longitudinal cracking at joints, dowel bars should be installed at the mid-depth of the slab and cares must be taken when installing dowel bars to prevent their vertical translation.
서영국,정운용,조준상 대한토목학회 2010 KSCE Journal of Civil Engineering Vol.14 No.4
This paper presents a simplified dynamic analysis of a suspension bridge subjected to a ground motion representing a seismic event. A Finite Element (FE) model developed here is found on the conditions that meet the design requirements for initial equilibrium state of a suspension bridge. Geometry and materials are assumed to be linear and elastic, respectively. Therefore, time consuming nonlinear iterations are not necessary to obtain key structural responses. First, a fundamental vibration behavior of a suspension cable was verified with an exact solution, and a stiffening girder-pylon structure modeled with three dimensional frame elements was validated with both free and forced vibration analyses. To simulate a seismic motion, a horizontal ground force was applied in longitudinal and transverse directions of a cable-stiffening girder-pylon system and the response spectrum analysis was conducted with two mode combination methods: Square Root of Sum of Square (SRSS) and Complete Quadratic Combination (CQC). Finally, a FE model of in-situ Nam-hae grand bridge was developed and its dynamic responses after complete erection were simulated under virtual ground motions, and diagrams of member forces were visualized by a DACS-POST, a web-based post-processing program.