• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2004.11a
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• pp.233-238
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• 2004

In this study, speed survey has been conducted on Pusan Freeway to identify actual running speed. therefore, suggest that Highway Design Regulations and Highway Design Standard from Ministry of Construction and Transportation, which requires stopping sight distance for 20% less speed when rainy condition in accordance with Highway Safety Act, is not coincident with driver's characteristics. Consequently, it is prudent to compute stopping sight distance with 85th percentile running speed, considering driver's actual behavior and mountainous terrain.

• Wind and Structures
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• v.7 no.6
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• pp.393-404
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• 2004

The design of truss type sign support structures is based on the guidelines provided by the American Association of State Highway and Transportation Officials Standard Specifications for Highway Signs, Luminaries and Traffic Signals and the American Institute of Steel Construction Design Specifications. Using these specifications, the column design strength is normally determined using the effective length approach. This approach does not always accurately address all issues associated with frame stability, including the actual end conditions of the individual members, variations of the loads in the members, and the resulting sidesway buckling for truss type sign support structures. This paper provides insight into the problems with the simplified design approach for determining the effective lengths and discusses different approaches for overcoming these simplifications. A system buckling approach, also known as a rational buckling analysis, is used in this study to determine improved predictions for design strength of truss type sign support structures.

• Wind and Structures
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• v.35 no.4
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• pp.229-242
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• 2022

Wind tunnel test is often adopted to assess the site-specific wind characteristics for the design of bridges as suggested by current design standards. To investigate the wind characteristics of flat and mountainous terrain, two topographic models are tested in a boundary layer wind tunnel. The wind characteristics, including the vertical and horizontal mean wind speed distributions, the turbulence intensity, and the wind power spectra, are presented. They are investigated intensively in present study with the discussions on the effect of wind direction and the effect of topography. It is indicated that for flat terrain, the wind direction has negligible effect on the wind characteristics, however, the assumption of a homogenous wind field for the mountainous terrain is not applicable. Further, the non-homogeneous wind field can be defined based on a proposed approach if the wind tunnel test or on-site measurement is performed. The calculated turbulence intensities and wind power spectra by using the measured wind speeds are also given. It is shown that for the mountainous terrain, engineers should take into account the variability of the wind characteristics for design considerations.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2006.04a
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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.

• Journal of Korean Society of Steel Construction
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• v.21 no.6
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• pp.553-561
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• 2009

Risk analysis of highway sign supporting structures and sound barriers was done. Stochastic wind load was modeled by using extreme value distribution from site measurement and the variability of structural parameters was considered. Limit state functions were defined to assess structural stability by wind and risk of highway facilities was analyzed by combining wind hazard. According to the numerical analysis results, sound barrier post shows significantly higher risk than highway sign supporting structures. This is caused by the fact that the design codes of the structures are different. To distribute wind induced risk in highway structures, unification and improvement of design codes are required based on risk assessment.

• International Journal of Highway Engineering
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• v.8 no.2 s.28
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• pp.75-85
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• 2006

Currently, cross-section design can not reflect highway function and traffic volume, various construction. This research paper provides analysis of traffic accident type, improvement of traffic operation and safety, assessment for new cross-section standards of two-lane highway. Research show higher accident rate on 6$\sim$8.9m road than 9$\sim$12.9m road width in two-lane highway. Typical improvement is widening on lane and shoulder width. Simulation show large increase on 6$\sim$7m road delay-time in 1,200vph. In contrast 10$\sim$11.5m road shows slight change on delay-time. This research paper provides various cross-section construction by traffic volume in minor arterial and distributor two-lane highway. The new cross-section design provides adopting highway volume, various construction and flexibility.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.1A
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• pp.59-67
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• 2008

Acceleration time history used in the seismic analysis of nuclear power plant structures should envelop a target power spectral density (PSD) function in addition to the design response spectrum in order to have sufficient energy at each frequency for the purpose of ensuring adequate load. The safety for complex long-span highway bridges cannot be over-emphasize. An alternative method to improve the seismic capacity is to ensure the minimum PSD function of the applied seismic load. This study proposes a technical scheme to obtain the reference power spectral density function by using artificial earthquakes which are compatible with the highway bridge design spectrum.

• International conference on construction engineering and project management
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• 2022.06a
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• pp.74-82
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• 2022

Improving long-term performance in highway projects is an imperative goal for public administrations. Project delivery and procurement methods might provide an opportunity to align design and construction processes with this goal. Previous studies have explored whether project delivery methods impact the long-term performance of highway projects. However, these studies did not focus specifically on how core elements within the procurement might relate to long-term performance. Thus, this research aims to fill this gap by exploring to what extent and how long-term evaluation criteria are considered in design-build best-value procurement of highway projects. To this end, content analysis was conducted on 100 projects procured between 2009 and 2019 by 19 DOTs across the U.S. The analysis of 365 evaluation criteria found that (1) roughly 11% of them related to long-term performance. (2) The weight given to these criteria in the overall technical proposal was lower than 30%. (3) Sixty-five percent (65%) of long-term evaluation criteria focused on design while 15% related to materials and technology, respectively. The results of this study are a first steppingstone to initiate a deep exploration of the relationship between procurement practices and actual project performance. Currently, with sustainability and life cycle assessments being top concerns in infrastructure projects, this line of research might be of particular interest to DOTs and highway agencies across the U.S. and worldwide.

• International Journal of Highway Engineering
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• v.18 no.4
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• pp.77-82
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• 2016

PURPOSES : This paper proposes a reliability index for the safety evaluation of freeway sections. It establishes a reliability index as a safety surrogate on freeways considering speeds and speed dispersions. METHODS : We collated values of design elements including radii, curve lengths, vertical slopes (absolute values), superelevations, and vertical slopes from seven freeway sections in Korea. We also collected data about driving speeds, traffic accidents, and their deviations. We established a reliability index using these variables. RESULTS : The average radii, curve lengths, and superelevations are highly correlated with the incidence of traffic accidents. Deviations in radius and curve lengths show an especially high correlation. The reliability index, derived from speed and speed dispersions of the seven freeway sections, also correlated highly with accidents with a correlation index of 0.63. CONCLUSIONS : Since the reliability index obtained from speed and speed dispersions are highly correlated with traffic accidents, we conclude that a reliability index can be a safety surrogate on freeways considering speeds and speed dispersions together in terms of design and operational levels.

• International conference on construction engineering and project management
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• 2005.10a
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• pp.974-979
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• 2005

Effective communication flow is a fundamental for the success of any construction projects. The key role of communications among project parties is even more critical in the case of Design-Build (DB) projects. Previous research has shown that these projects have an environment where integration between different project team members and schedule constraints increase channels of communication, and require faster communication flows. This paper summarizes the findings from research analyzing organizational structures and communication flow of the Texas State Highway 130 (SH130) project. Awarded in 2002, the SH130 project, totaling $1.3 billion USD, constitutes the "pilot" application for the DB approach in the state of Texas. A set of observations pertaining to team organization and communication issues in the design-build environment is included.