• Journal of the Korea Institute of Military Science and Technology
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• v.12 no.2
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• pp.236-247
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• 2009

In Korea, the driving system restriction criteria is strictly applied(gross weight 400kN, axial load 100kN). Especially after the Seoungsu Bridge accident, safety factor has been strictly applied. The Safety factor is applied to the cumulative results for each steps like design, construction, maintenance of the Bridge. Because of it, the bridge is undervalued compared to its capacity. So, this generates loss for both private and military sector(eg. logistical delays, structural damage, etc.). But analyzing data from many existing researches we have confirmed that the military heavy vehicle may pass through the first class bridges. In consequence, this study have focused on determining whether HETS vehicles can pass over the first class bridge, without safety issues, using MIDAS structural analysis program. The results have confirmed that the military heavy vehicle may pass over the bridge.

• Computers and Concrete
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• v.23 no.5
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• pp.329-334
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• 2019

Traffic flow capacity of some old road bridges is insufficient due to limited deck width. In such cases bridge deck widening is a common solution. For multi-girder reinforced concrete (RC) bridges it is possible to add steel-concrete composite girders as the new outermost girders. The deck widening may be combined with bridge strengthening thanks to thickening of the existing deck slab. Joint action of the existing and the added parts of such bridge span must be ensured. It refers especially to the horizontal plane at the interface of the existing slab and the added concrete layer as well as to the vertical planes at the external surfaces of the initially outermost girders where the added girders are connected to the existing bridge span. Since the distribution of the added concrete is non-uniform in the span cross-section the structure is particularly sensitive to the added concrete shrinkage. The shrinkage induces shear forces in the aforementioned planes. Widening of a 12 m long RC multi-girder bridge span is numerically analysed to assess the influence of the added concrete shrinkage. The analysis results show that: a) in the vertical plane of the connection of the added and the existing deck slab the longitudinal shear due to the shrinkage of the added concrete is comparable with the effect of live load, b) it is necessary to provide appropriate longitudinal reinforcement in the deck slab over the added girders due to tension induced by the shrinkage of the added concrete.

• Journal of Korean Society of societal Security
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• v.1 no.4
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• pp.51-56
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• 2008

Because of our country's climate that has the 50% of the annual precipitation in summer, annually a lot of bridges on the roads are broken in this season. So, we need an accelerated bridge construction method that complete to repair the roads. This paper introduces the Hangae 2 bridge, prefabricated bridge using full depth precast deck panels and new types of PSC girders. The Hangae 2 bridge located in lnje-gun, kangwon-do. This is a good example of the accelerated bridge construction method for recovery of flood damaged road. The PSC girder bridge system introduced in this paper is a rapid construction method for bridge that can reduce the term of works over 50%.

• International Journal of High-Rise Buildings
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• v.4 no.3
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• pp.199-207
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• 2015

Abeno Harukas is the tallest building in Japan and is located in Abeno, which is one of the three main railway transport nodes in Osaka. This building has a height of 300 meters, and its lowest levels are 30 meters below ground. It contains a department store, museum, offices, a hotel, and an observatory. In this urban renewal project, a section of the department store that encloses the station was dismantled and replaced by a supertall building complex, while infrastructure was simultaneously constructed, including: upgrades to the station and the existing department store, improved connections to the subway and pedestrian bridges, and a new pedestrian walkway over the road. In this paper, the ingenious erection processes, newly developed technologies, and precise construction management techniques are introduced for Japan's tallest building.

• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.6
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• pp.177-184
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• 2021

In recent years, large-scale earthquake activity has occurred in Korea, and thus public interest in earthquakes is increasing. Accordingly, the importance of seismic performance management of structures is emerging. In particular, the collapse of a bridge, one of main road facilities, directly leads to many casualties. Therefore, engineers need to evaluate the seismic fragility of the bridge and prepare for the earthquake event. The service life of these bridges has been over 30 years, which requires a study on the aging effect on bridges. In this study, seismic analysis of the target RC slab bridge was performed considering the aging effects of each component of the bridge. Components of the bridge included pier and bearing, which dominate the seismic response of the bridge. The seismic performance of the bridge was evaluated using nonlinear static and dynamic analyses. In addition, the limit state and dynamic response of each component were used to evaluate the seismic fragility according to the aging of each component.

• Journal of Korean Society of societal Security
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• v.2 no.2
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• pp.63-68
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• 2009

Seismic design of newly built bridges can be considered and carried out during construction process according to the revised road bridge design standard issued recently. While for the existing reinforced concrete bridge priers under service before new standard implements, their resistance capacity against lateral seismic loading is inferior. In this research, seismic reinforcing for existing bridge piers by nickel-chrome alloy bar has been analyzed. Based on the established model by MIDAS program, the behaviors of bridge piers including deformation and stress with and without nickel-chrome alloy reinforcing bars have been compared and discussed under lateral seismic loading. And the advantages of using nickel-chrome alloy bar as seismic reinforcement over other materials, such as good performance, good economy etc. have been demonstrated by comparison with other researches. Also the anti-seismic efficiency of nickel-chrome alloy reinforcing bars has been confirmed by MIDAS modeling analysis.

• Journal of Environmental Impact Assessment
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• v.16 no.1
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• pp.59-68
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• 2007

Urban streams have been severely degraded with wastewater and concrete structure over a prolonged period. The Chonggyecheon Restoration Project recovered a stream in the downtown Seoul with landscaping, plantings and bridges after the cover concrete and elevated asphalt road were removed. The project has been criticized partly because it is not an ecological restoration but rather the development of an urban park with an unnaturally straight flowing stream, artificial building structures, and artificial water pumping from the Han River. Nevertheless, the public have praised the project and almost 100,000 visitors per day come to see the reeds, catfish, and ducks. The stream restoration project is attractive to central and regional government decision makers because it increases the public concern of landscape amenity. Several projects such as Sanjichon and Kaeumjungchon are on going and proposed. These projects have a common and different respect in scope and procedure. The Chonggyecheon project in the process of environmental impact assessment (EIA) and prior environmental review system (PERS) reviewed the environmental impacts before development. Kaeumjungchon in the PERS and Sanjichon without EIA and PERS are reviewed. EIA and PERS systems contribute to checking the ecological sustainability of the restoration projects. A stream restoration project is a very complex task, so an integrated approach from plan to project is needed for ecologically sound restoration. Ecological stream restoration requires 1) an assessment of the entire stream ecosystem 2) establishing an ecologically sound management system of the stream reflecting not only benefits for people but also flora and fauna; 3) developing the site-specific design criteria and construction techniques including habitat restoration, flood plains conservation, and fluvial management; 4) considering the stream watershed in land use plan, EIA, PERS, and strategic environmental assessment (SEA). Additionally the process needs to develop the methodologies to enhance stakeholder's participation during planning, construction, and monitoring.

• International Journal of Highway Engineering
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• v.13 no.4
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• pp.71-79
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• 2011

Korean national highway has been increased 2 times more for the past ten years because of many highway geometric improvements and new routes since 2000. According to the reasons, maintenance cost has been increased continuously. Deterioration of concrete bridge decks caused by asphalt pavement deformation occupies a high proportion of overall bridge management budget. The number of current highway bridges has reached over 7,800 in 2011, and It is difficult to determine to some future budget. This study predicted the remaining life of concrete bridge decks using the reliability analysis based on Weibull distribution. and The expected future maintenance cost was estimated.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.30 no.2
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• pp.163-171
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• 2012

High resolution satellite images have been used for building and road system analysis, landscape analysis, and ecological assessment for several years. However, in high resolution satellite images, shadows are necessarily cast by manmade objects such as buildings and over-pass bridges. This paper develops the shadow extraction procedures in urban area including various land-use classes, and the extracted shadow areas are evaluated by a manually digitized shadow map. For the shadow extraction, the Canny edge operator and the dilation filter are applied to make building edge buffer area. Also, the object-based segmentation was performed using Gram-Schmitt fusion image, and spectral and spatial parameters are calculated from the segmentation results. Finally, we proposed appropriate parameters and extraction rules for the shadow extraction. The accuracy of the shadow extraction results from the various assessment indices is 80% to 90%.

• Smart Structures and Systems
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• v.32 no.3
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• pp.153-166
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• 2023

Health monitoring of civil infrastructures, in particular, old bridges that are still in service, has become more than necessary, given the risk that a possible degradation or failure of these infrastructures can induce on the safety of users in addition to the resulting commercial and economic impact. Bridge integrity assessment has attracted significant research efforts over the past forty years with the aim of developing new damage identification methods applicable to real structures. The bridge of Ouled Mimoun (Tlemcen, Algeria) is one of the oldest railway structure in the country. It was built in 1889. This bridge, which is too low with respect to the level of the road, has suffered multiple shocks from various machines that caused considerable damage to its central part. The present work aims to analyze the stability of this bridge by identifying damages and evaluating the damage rate in different parts of the structure on the basis of a finite element model. The applied method is based on an inverse analysis of the normal stress responses that were calculated from the corresponding recorded strains, during the passage of a real train, by means of a set of strain gauges placed on certain elements of the bridge. The results obtained from the inverse analysis made it possible to successfully locate areas that were really damaged and to estimate the damage rate. These results were also used to detect an excessive rigidity in certain elements due to the presence of plates, which were neglected in the numerical reference model. In the case of the continuous bridge monitoring, this developed method will be a very powerful tool as a smart health monitoring system, allowing engineers to take in time decisions in the event of bridge damage.