• Korean Journal of Construction Engineering and Management
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• v.5 no.3 s.19
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• pp.146-152
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• 2004

Consideration of factors driving crew productivities is imperative for accurate construction time estimation. Their impacts need to be well understood by estimators. There have been, however, little studies that quantified relationships between crew productivities and factors. This paper quantifies impacts of $^{\circ}A$ECrew size $^{\circ}\phi$ on crew productivities, for three highway concrete bridge activities, namely Column, Cap, and Deck, based on data compiled from 17 on-going highway projects in Texas State, USA. It was found that, for Bridge Deck operation, an increase of one crew-worker of formwork and rebarwork by one, leads to an increase of the productivity (cy/crew day) by 2.5 and 2.9, respectively. For the other activities, larger crew sizes did not lead to better crew productivities.

• Proceedings of the Korea Information Processing Society Conference
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• 2012.11a
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• pp.1746-1749
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• 2012

국토해양부는 일반국도의 적정한 도로포장 유지보수를 통한 예산의 효율적사용을 위해 일반국도 포장관리시스템(PMS)을 운영하고 있으며, 일반국도 포장상태 조사 및 유지보수실적을 관리를 위하여 포장 자료 관리용 엑셀파일을 데이터베이스로 구축하였다. 본 연구에서는 기존 일반국도 포장관리시스템(PMS)운영의 한계를 분석하고 현장의 명확한 판단 기준을 제시 할 수 있는 시스템의 개선방안을 기술하고자 한다.

• International conference on construction engineering and project management
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• 2005.10a
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• pp.808-813
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• 2005

Effective cost management requires reliable cost estimates at every stage of project development. The primary purpose of this research is to develop systematic modeling procedures and an automatic computing program for infrastructure estimating in the Texas Department of Transportation (TxDOT). The computing system toggles between project input information and segregated district unit prices for highway work item quantity estimates associated with earthwork and landscape, subgrade treatments and base, surface courses and pavement, structures, miscellaneous construction, and lighting, signing, markings and signals. This quantity-based approach was chosen because of the conventional approach lacking of quantity information until primary design is complete.

• Structural Monitoring and Maintenance
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• v.10 no.3
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• pp.191-205
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• 2023

In this paper, through operational modal analysis and ambient vibration tests, the dynamic characteristics of a multi-span simply-supported reinforced concrete highway bridge deck was determined and the results were used to assess the quality of construction of the individual spans. Supporting finite element (FE) models were created and analyzed according to the design drawings. After carrying out the dynamic tests and extracting the modal properties of the deck, the quality of construction was relatively assessed by comparing the results obtained from all the tests from the individual spans and the FE results. A comparison of the test results among the different spans showed a maximum difference value of around 9.3 percent between the superstructure's natural frequencies. These minor differences besides the obtained values of modal damping ratios, in which the differences were not more than 5 percent, can be resulted from suitable performance, health, and acceptable construction quality of the bridge.

• Journal of the Korea Safety Management & Science
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• v.25 no.4
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• pp.57-65
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• 2023

The public safety management guidelines were introduced in 2019 and continue to be dedicated to advancing comprehensive measures for public safety management, with a primary focus on prioritizing the safety and well-being of the public within governmental institutions. To achieve this goal, our previous study developed a establishment procedure of risk assessment-based safety inspection system for public institutions that order construction projects and applied it to highway construction projects to evaluate its effectiveness. To enhance the practicality of the establishment procedure, it is essential to collect and analyze feedback from stakeholders regarding its performance and suitability. This study conducted a survey involving 200 participants who had experience with the establishment procedure, and performed statistical analyses to evaluate its performance and applicability. The survey results indicated that the participants reported a high level of satisfaction (scoring 4 and above on a 5-point Likert scale) in several areas: specialization of safety inspection items for different types of work (with a satisfaction rate of 65%), the evaluation process for safety ratings (64.5%), and their willingness to recommend the procedure to other institutions (75.5%). In the factor analysis with Varimax rotation, two factors emerged: (1) a specialization factor related to safety inspection items, and (2) a grading factor associated with safety evaluation results. Regression analyses of these factors unveiled significant positive relationships with improvements in safety and health performance, including the prevention of fatal accidents, heightened safety responsibility, and raised safety inspection standards. The establishment procedure of safety inspection system developed in our previous study can play a crucial role in reducing accidents resulting in fatalities and injuries at construction sites, ultimately contributing to a safer working environment for all involved parties.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1014-1019
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• 2005

In this paper, a neural network technique for automatic steering control of a four wheel drive autonomous highway snowplow vehicle is presented. Controllers are designed by the LQR method based on the vehicle model. Then, neural network is used as an auxiliary controller to minimize lateral tracking error under the presence of load. Simulation studies of LQR control and neural network control are conducted for the vehicle model under a virtual snowplowing situation. Tracking performances are also compared for two and four wheeled steering vehicles.

• International Journal of Safety
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• v.9 no.2
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• pp.16-21
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• 2010

In this study, the variations of transformed impact factors and load carrying capacity of highway bridges measured from the state of expansion joint are evaluated. the field loading tests were performed on the highway bridge with damaged expansion joint to investigate the variation of the load carrying capacity. From the field loading tests in case that damaged expansion joint exist or do not exist, the static displacements and dynamic displacements were measured, and TIF were calculated, respectively. dynamic test is performed in order to estimate dynamic displacement and TIF according to the level of damage of expansion joint. From the results of TIF, the load carrying capacity of highway bridges with damaged expansion joint were estimated.

• International Journal of Concrete Structures and Materials
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• v.1 no.1
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• pp.75-81
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• 2007

The concrete pavement of the Seohae Highway in Korea has suffered from serious distress, only four to seven years after construction. Deterioration due to Alkali-Silica Reaction (ASR) has seldom been reported per se in Korea, because the aggregate used for the cement concrete has been considered safe against alkali-silica reaction so far. The purpose of this study is to examine the deterioration caused by an alkali-silica reaction of concrete pavement in Korea. The investigation methods included visual inspection and Automatic Road Analyzer (ARAN) analysis of surface cracks, coring for internal cracks, stereo microscopic analysis, scanning electronic microscope (SEM) analysis, and electron dispersive X-ray spectrometer (EDX) analysis. The results are presented as follows: the crack pattern of the concrete pavement in Korea was longitudinal cracking, map cracking or D-cracking. Local areas of damage were noticed four to five years after construction. The cracks started from edges or joints and spread out to slabs. The most intensive cracking was observed at the intersection of the transverse and longitudinal joints. Where cracking was the most intense, pieces of concrete and aggregate had spalled away from top surface and joint interface area. The progress of deterioration was very fast. The reaction product of alkali-silica gel was clearly identified by its generally colorless, white, or very pale yellow hue seen through a stereo optical microscopy. The typical locations of the reaction product were at the interface between aggregate and cement paste in a shape of a rim, within aggregate particles in the cracks, and in the large void in the cement paste. Most of the white products were found at interface or internal aggregates. SEM and EDX analysis confirmed that the white gel was a typical reaction product of ASR. The ASR gel in Korea mainly consisted of Silicate (Si) and Potassium (K) from the cement. The crack in the concrete pavement was caused by ASR. It seems that Korea is no longer safe from alkali-silica reaction.

• Korean Journal of Construction Engineering and Management
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• v.10 no.1
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• pp.126-135
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• 2009

Recently, operation of highway is the complex digital Infrastructure based on complicated IT. The application of IT is increasing more and more in digital Infrastructure. Though IT is very convenient, if unpredicted operating risk of highway occurs, widespread damage can be large. When operating risk of highway occurs, road users are out of smoothly-run service because of the operating interruption. This risk causes unpredicted operating management cost and additional maintenance cost. It will excess over the planned operating cost, which may leads to users's unsafety and operator's insolvency because of income loss. Until now, related studies to find out the risk are not sufficient. The purpose of this study is to suggest risk cost items and to estimate the reasonable risk cost by using simulation method in case of occurring the huge power failure at the operating digitalized highway. This study indicates the several plans to hedge against risk cost and the management of highway project. From now on, it will be used as basic data to confirm the soundness of operating system in Digital Infrastructure.

• Journal of the Earthquake Engineering Society of Korea
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• v.10 no.3 s.49
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• pp.135-147
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• 2006

The essential information elements for the Earthquake Damage Evaluation System (EDES) of highway bridges are defined in this study, and a database construction method, which fits the circumstances of Korea, is proposed. The information elements for the EDES of highway bridges are categorized in two groups: structure related information, location related information. The structure related information is composed of the fragility curve information which is necessary for earthquake damage evaluation of highway bridges. The data structure of road network, which represents the location related information, is defined in more detail than the existing GIS-based data structure of road network for modeling of junctions. A pilot GIS-based EDES subjected to 110 bridges on expressway in Korea is developed, and it is verified that the proposed database construction method for the EDES can be used to develop a decision making system for quick retrofitting of the seismic damages of highway bridges and road network.