• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.27 no.6
• /
• pp.533-542
• /
• 2014

In design standards such as AASHTO LRFD and Korea Highway Bridge Design, the dynamic behaviors under the impact loading has not been considered and it recommends of using a static force for designing bridge column against vehicle collisions. Accordingly, in this study, models of vehicle collisions to concrete bridge column were developed with various boundary conditions in order to take into account dynamic behaviour of the column. Cargo trucks of 10tons, 16tons and 38tons were selected and a typical type of concrete bridge pier column along the Kyungbu highway in Korea was selected for this study. Results from this study indicate that the static load specified in the design standards are too small compared to results obtained in this study. It was also found that a consideration of the bridge superstructure allowed smaller damages of concrete bridge pier column under truck impact loadings. Furthermore, a comparison study of direct impact analysis of vehicle to bridge-column with in-direct impact analysis using load-time history functions was performed. The in-direct impact analysis shows that the use of load-time history graph improves the computational cost up to 92% and predict the behaviors of the bridge column under the impact loadings well. The obtained load-time history graph could be easily applied to several existing models.

• Journal of the Korea Institute of Building Construction
• /
• v.16 no.3
• /
• pp.271-278
• /
• 2016

In the case of South Korea, steel girder bridge (steel box or H-steel) and PSC (Pre-Stressed Concrete) girder bridge are the representative upper structures of railroad and road bridges. These structures account for 75% of the total bridge constructions and 80% of the total construction cost. Since the form work for concreting bridge slab is difficult, various construction methods developed and applied. However, several problems in those methods did not solve partially, including cost increase by material loss and rise of labor costs, quality deterioration by unskilled workers, increased construction time by complicated method, reduced productivity, safety accident by high place work, difficult transportation by big member, and rise of maintenance cost by material characteristic. Alternative method is needed to solve problems of as-is methods. Therefore, the purpose of this study is development of the purlin hanging system form for the girder bridge slab and its economic analysis. Through the findings of this study, it was verified that the purlin hanging system form is possible 60% reduction in cost and 80% reduction in time as comparison with conventional method.

• Journal of Korean Society of Disaster and Security
• /
• v.15 no.4
• /
• pp.31-38
• /
• 2022

In the case of special bridges whose superstructure is supported by cables, there are many blind spots that are difficult to access without special equipment and personnel. As a result, there are difficulties in the safety inspection of special bridges. The purpose of this study is to review the inspection blind spots of cable-supported bridges such as cable-stayed bridges and suspension bridges, and to study ways to eliminate blind spots using drones. To this end, the cables, stiffened girder, and pylons of the cable-stayed bridge located in the sea were inspected using drones. Through this study, it was confirmed that external safety inspection of special bridges that are difficult for inspectors to access is possible using drones. In particular, drone inspection to check the external condition and damage of the pylon, which is a blind spot for inspection of special bridges, is a very effective safety inspection method.

• Journal of the Earthquake Engineering Society of Korea
• /
• v.6 no.5
• /
• pp.19-27
• /
• 2002

Dynamic responses of a multi-span simply supported bridge are investigated to examine the effect of bearing damage under seismic excitations. The damaged bearings are modeled as sliding elements with friction between the superstructure and the top of the pier. Various values of the friction coefficients are examined to figure out the effect of damaged bearings with various levels of peak ground accelerations. It is found that the global seismic behaviors are significantly influenced by the occurrence of bearing damage. It should be noticed that the most possible location of unseating failure of superstructures differs from that in the bridge model without considering the bearing damage. It can be concluded that the bearing damage may play the major role in the unseating failure of a bridge system, so that the damage of bearings should be included to achieve more rational seismic safety evaluation.

• Journal of Korean Society of Steel Construction
• /
• v.10 no.1 s.34
• /
• pp.1-10
• /
• 1998

The temporary steel bridges which are constructed for detour and constructional expediency are consisted of H-beams(as superstructure) and H-piles(as substructure). Because these members are fastened by high-tension bolts, there are no expansion joints in these bridges. So, these kinds of bridges have no system which can relieve the excessive thermal stress. In this investigation, monitoring system was set up at temporary steel bridge and stress and temperature changes of H-beam are monitored. From these measured data, it is analyzed that the relationship between ambient and main-girder temperature change, between temperature and stress change. With these analyses, it is resulted that the thermal stress take main part of stress variation in this bridge and the restrain of thermal longitudinal displacement of H-pile. In addition, because the connection part of H-beam to H-beam is weak in the continuous spans, the sub-modelling is well apt to reflect the effect of thermal stress.

• Journal of the Korean Society for Railway
• /
• v.19 no.3
• /
• pp.341-350
• /
• 2016

Concrete track on railway bridges should be designed to effectively respond to the movement of the superstructure of the bridge. In the design procedure, shear keys are generally placed on the protection concrete layer (PCL) before casting the concrete track so the shear force due to slip between the concrete track and the bridge super-structure can be transferred. In this paper, a nonlinear structural analysis procedure that considers the construction joint has been developed to predict the shear behavior of a shear key. With the developed analysis procedure, it was possible to predict the shear force-shear slip response at the construction joint in a shear key by considering the friction of concrete surface and the dowel action of the rebars. The analysis results showed good agreement with the test results for 4 specimens.

• Journal of the Society of Naval Architects of Korea
• /
• v.38 no.1
• /
• pp.108-115
• /
• 2001

The noise level of the navigation bridge as well as topside of the superstructure is dominated by the exhaust gas noise of the high-powered main engine and generator engine of special purpose vessels. In the case of the noise radiated from the top of the funnel. the exhaust pipe can be fitted with a silencer to reduce the propagated noise level. This paper is prepared based on an experimental performance test results of the silencers for generator-engine exhaust gas noise with consideration of air velocity. Two silencers were examined to check the performance of noise reduction in cases of air velocity 0m/s and 32m/s. In the sound reduction test, 400mm and 600mm diameter pipe ducts equipped with an axial fan were used as exhaust gas pipe system in the actual ship. The test procedure and results are presented in detail.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 2001.10a
• /
• pp.385-392
• /
• 2001

The stiffness of pavement is scarcely considered in structural analysis of the superstructure bridge. It will be reasonable in the case of asphalt concrete pavement over concrete deck plate because stiffness of the pavement compared with concrete deck plate can be ignored. Additionally, it is considered correct to do a design with a safety. However, various pavement materials which have even value reaching to the elastic modulus of concrete are applied to the orthotropic steel deck plate which has a relatively less stiffness comparing with the concrete deck plate. In this paper, the steel plate deck of the bridge of real project was modeled considering the pavement stiffness for the FEM analysis and the linear elastic analysis was performed. It was assumed to be perfectly bonded between the steel plate deck and the pavement and the temperature effect was ignored. It was analyzed on the vertical deflection of steel deck plate influencing to the serviceability of pavement and the bending stress of steel deck plate related to the fatigue life. As a result, It was indicated that the structural behavior of the orthotropic steel deck plate could be affected by the stiffness of pavement in some cases.

• Journal of the Earthquake Engineering Society of Korea
• /
• v.21 no.3
• /
• pp.125-135
• /
• 2017

Various seismic isolation methods are being applied to bridges and buildings to improve their seismic performance. Most seismic isolation systems are the structural seismic isolation systems. In this study, the seismic performance of geotechnical seismic isolation system capable of isolating the lower foundation of the bridge structure from ground was evaluated. The geotechnical seismic isolation system was built with teflon, and the model structure was made by adopting the similitude law. The response acceleration for sinusoidal waves of various amplitudes and frequencies and seismic waves were analyzed by performing 1-G shaking table experiments. Fixed foundation, Sliding foundation, and Rocking foundation were evaluated. The results of this study indicated that the Teflon-type seismic foundation isolation system is effective in reducing the acceleration transmitted to the superstructure subject to large input ground motion. Response spectrum of the Rocking and Sliding foundation structures moves to the long period, while that of Fixed foundation moves to short period.

• International Journal of Ocean Engineering and Technology Speciallssue:Selected Papers
• /
• v.6 no.1
• /
• pp.44-50
• /
• 2003

If the accelerometers are used in measuring the response, the absolute values of the velocity and displacement are not usually obtainable because their initial values are not accounted for in the integration of the acceleration response. A new dynamic response conversion algorithm of both the time domain and the frequency domain is proposed for the problem in estimating the displacement data by defining the transformed responses. In this algorithm, the displacement response can be obtained from the measured acceleration records by integration without requiring the knowledge of the initial velocity and displacement information. The applicability of the technique is tested by an example problem using the real bridge's superstructure under several cases of moving load. In the response conversion procedure of the frequency domain, the identified response according to the frequency can be estimated by changing over the limits of integration. If the reliability of the identified responses is ensured, it is expected that the proposed method for estimating the impact factor can be useful in the bridge's dynamic test. This method can be useful in those practical cases when the direct measurement of the displacement is difficult as in the dynamic studies of huge structure.