• Computers and Concrete
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• v.32 no.4
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• pp.411-423
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• 2023

The rapid development of road transport has increased the number of bridges that require widening. A critical issue in the construction of bridge widening is the influence of vibrations of the old bridge on the casting of wet joint concrete between the old and new bridges owing to the running traffic. Typically, the bridge is closed to traffic during the pouring of wet joint concrete, which negatively affects the existing transportation network. In this study, a newly developed microscopic traffic load modeling approach and the vehicle-bridge interaction theory are incorporated to develop a refined numerical framework for the analysis of random traffic-bridge coupled dynamics. This framework was used to investigate traffic-induced vibrations at the wet joint of a widened bridge. Based on an experimental study on the vibration resistance of wet joint concrete, traffic control strategies were proposed to ensure the construction performance of cast-in-site wet joint concrete under random traffic without interruption. The results show that the vibration displacement and frequency of the old bridge, estimated by the proposed framework, were comparable with those obtained from field measurements. Based on the target peak particle velocity and vibration amplitude of the wet joint concrete, it was found that traffic control measures, such as limiting vehicle gross weight and limiting traffic volume by closing an additional traffic lane, could ensure the construction performance of the wet joint concrete.

• Journal of Korean Society of Steel Construction
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• v.25 no.4
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• pp.335-346
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• 2013

AASHTO LRFD and Korean Bridge Design Code (Limit State Design) specify to consider Truck and Lane load simultaneously determined from reliability-based live load model, and impact shall be applied to the truck load while it shall not be applied to the lane load. In this paper, vehicle-bridge interaction analysis under moving truck and lane loads were performed to estimate impact factor of the cables and girders for the selected multi-cable-stayed composite bridges with 230m, 400m and 540m main span. A 6-d.o.f. vehicle was used for truck load and a series of single-axle vehicles was applied to simulate equivalent lane load. The effect of damping ratio on the impact factor was estimated and then the essential parameters to impact factor, i.e., road surface roughness and vehicle speed were considered. The road surface roughness was randomly generated based on ISO 8608 and it was applied to the truck load only in the vehicle-bridge interaction analysis. The impact factors evaluated from dynamic interaction analysis were also compared with those by the influence line method that is currently used in design practice to estimate impact factor in cable-stayed bridge.

• Journal of Korean Society of Steel Construction
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• v.26 no.5
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• pp.485-498
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• 2014

In this paper, vehicle-bridge interaction analysis under a series of moving vehicles to simulate a lane load was performed to estimate impact factor of the main cable, hanger and girder for the selected suspension bridges with 404m and 1545m main span. Korea Bridge Design Code(Limit State Design) was selected for the live model in which KL-510 truck was modeled 6-d.o.f. vehicle and a lane load was simulated by a series of single-axle vehicles. For the 404m main span bridge, hinge-type and floating-type girders at the tower were considered to examine the impact factor according to the connection and supporting type of the girders. The parameters considered herein are the types of live load-a truck only and a truck plus lane load, eccentricity of moving vehicles, road surface roughness and vehicle speed. The road surface roughness was randomly generated based on ISO 8608 and it was applied to the truck only. The impact factors were also evaluated by using the influence line method that is commonly used in cable-supported bridges and compared with those from vehicle-bridge interaction analysis.

• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.6
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• pp.185-195
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• 2017

In recent years, unexpected bridge fire accidents have increased because of augmenting the number of traffic volumes and hazardous materials by the increment in traffics and distribution business. Furthermore, in accordance with the effort of using the under space of bridges, the ratio of occupied by combustible materials like oil tanker or lorry has been increased. As a result, the occurrence of bridge fire has been growing drastically. In order to mitigate the accident of bridge fire, risk assessment of bridge fire has been studied, however, practical risk models considering safety from users' viewpoints were scarce. This study represented quantitative risk assessment model applicable to national road bridges in Korea. The primary factors with significant impacts on bridge fire accidents was chosen such as clearance height, materials of bridges, arrival time of fire truck and fire intensity. The selected factors were used for Fire Dynamics Simulation (FDS) and the peak temperature calculated by FDS in accordance with the fire duration and fire intensity. The risk assessment model in bridge fire reflected the FDS analysis results, the fire damage criteria, and the grade of fire truck arrival time was established. Response plans for bridge fire accidents according to the risk assessment output has been discussed. Lastly, distances between bridges and fire stations were calculated by GIS network analysis. Based on the suggested assessment model and methodology, sample bridges were selected and graded for the risk assessment.

• Korean Journal of Environment and Ecology
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• v.20 no.3
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• pp.340-344
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• 2006

The objective of this paper was to investigate the potential of road-crossing structures as biological corridors that can overcome wildlife habitat fragmentation caused by road construction. Snow tracking on animal trace adjacent to and under bridges, underpasses, and culverts of eight rural highways in Korea was carried out. A total 89 structures were monitored and the results follow. First, the probability of road crossing increases with the increasing cross sectional size of crossing structures. Second, small to medium sized carnivores such as raccoon dog, leopard cat, and Siberian weasel use all types of structures. Finally, water deer, or large herbivore crossed only under bridges. Consequently, further studies are necessary to identify suitable types of road crossing structures that can mitigate the probability of road-kills and habitat fragmentation of water deer.

• Journal of the Korean Society of Hazard Mitigation
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• v.6 no.2 s.21
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• pp.37-44
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• 2006

Any vehicle and equipment whose total weight is more than 40ton and its axle weight is 10ton or above is banned to cross any bridge in our country under section 54 in the Highway law. This restriction results from the accumulation and application of safety factors about which there is type specification in the "standard design vehicle". And in "standard design vehicle", Vehicle load to bridge is assumed concentrating one. Based on this restriction, there is an issue that military tank which has a total weight of 51ton (63ton in case of the US tank) can not cross any bridge. However, many research and practical examples concerned manifest that it is possible for military tanks to cross these bridges. The reasons of this issue in the current Highway law's provisions are analyzed in this paper. Correspondingly, feasibility of military tanks passing these bridges are discussed here. At last, considering economical efficiency and practicability for military, several suggestions and improving measures are put forward. This research has certain reality significance to guide bridge design considering the passage of military heavy vehicles.

• Journal of Korean Society of societal Security
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• v.3 no.1
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• pp.43-50
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• 2010

Sliding accidents on the road have a high percentage by road freezing, especially, they often have appeared at bridges and Tunnel of freezing areas. Thus, the stability of road operations is enhanced by preventing partial freezing phenomenon. According to the geothermal snow melting system analysis, a pattern of thermal conductivity is found out; pavement materials of concrete and asphalt where the system is buried. The heat transfer simulation is essential when the geothermal snow melting system is applied according to heating exchanger pipe placed in the lower pavements. The model tests are conducted on low temperature in freezer using the manufactured test model which is equal to pavement materials. Many variables are discovered from numerical analyses under the same conditions with model test.

• Journal of Korean Society of Transportation
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• v.14 no.1
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• pp.7-27
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• 1996

It is very costly to construct transportation facilities such as roads, bridges, tunnels, and public parking lots mainly because land price is very high in metropolis like Seoul. Private car oweners use these facilities more extensively than public transportation users. However, the government does not impose proper charges for using these facilities. Such improper charge causes traffic congestion and then decreases social welfare in efficiency and equity. To solve problem, many traffic demand management policies are used. Traffic management policies which are currently used or under consideration by the City Government of Seoul include the imposition of road tolls, increase of parking fees in public parking lots, increase of gasoline taxes, expanded implementation of bus only lanes, and shippujae, which requires one(1) non-driving day for 10 calendar days. This study examined the impacts of such policies on the different income classes using simulation analysis. We found that the impacts of market-oriented policies such as the imposition of road tolls and the increase of gasoline taxes is regressive. Also, we found that while the low and middle income private car users have incentive have incentive for public transportation use, the high income private car users have no incentive for public transportation use in many cases.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2006.04a
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• pp.772-777
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• 2006

An acoustic finite element model of a bridge is developed to evaluate the noise generated by the traffic-induced vibration of the bridge. The dynamic response of a multi-girder bridge, modeled by a 3-dimensional frame element model, is analyzed with a 3-axle(8DOF) truck model and a 5-axle(l3DOF) semi-trailer. The flat plate element is used to analyze the acoustic pressure due to the fluid-structure interactions between the vibrating surface and contiguous acoustic fluid medium. The radiation fields of noise with a specified distribution of vibrating velocity and pressure on the structural surface are also computed using the Kirchhoff-Helmholtz integral. In an attempt to illustrate the influence of the structural vibration noise of a bridge to total noise level around the bridge, the random function is used to generate the vehicle noise source including the engine noise and the rolling noise interacting between the road and tire. Among the diverse parameters affecting the dynamic response of bridge, the vehicle velocity, the vehicle weight, the spatial distribution of the road surface roughness, the stiffness degradation of the bridge and the variation of the air temperature changing the air density are found to be the main factors that increase the level of vibration noise. Consequently, The amplification rate of noise increases with the traveling speed and the vehicle weight.

• The KIPS Transactions:PartD
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• v.15D no.6
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• pp.873-878
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• 2008

The wild animal warning post and the echo-bridge on the road are widely used as a popular roadkill prevention system. The warning post shows a one way warning message to drivers and is not effective to prevent animals from being killed. In the case of echo-bridge, the construction cost is very high such that we could not build sufficient number of the echo bridges on the road. Therefore, we have proposed a new roadkill prevention system which is designed and implemented to warn both of drivers and animals. This system is composed with sensor, speaker, web server, and navigation system and the software is designed to use web services on the web under the. Net environment.