• Earthquakes and Structures
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• v.17 no.3
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• pp.317-327
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• 2019

High-speed railway bridge piers in seismically active area may be subjected to multiple earthquakes and then produce cumulative residual deformation. To study the cumulative residual deformation of high-speed railway bridge piers under multiple earthquakes, a nonlinear numerical analytical model with multi-DOF (MDOF) system is presented and validated against two shaking table tests in this paper. Based on the presented model, a simple supported beam bridge pier model of high-speed railway is established and used to investigate the cumulative residual deformation of high-speed railway bridge pier under mainshock-aftershock sequences and swarm type seismic sequences. The results show that the cumulative residual deformation of the bridge pier increases with earthquake number, and the increasing rates are different under different earthquake number. The residual deformation of bridge pier subjected to multiple earthquakes is accumulated and may exceed the limit of code.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2006.11a
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• pp.99-104
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• 2006

There are several advantages to make use of a bridge pier for the tidal power generation. Current velocity increases near the pier, therefore the tidal power generation becomes more efficient because the power is proportional to the cubic of the current velocity. The pier is convenient for access and maintenance of the hydraulic turbine and the power unit. The project is now underway at the Ikitsuki Bridge in Tatsuno-Seto Strait of Nasasaki Prefecture, where the tidal current was measured by the bottom mount ADCP for almost one year. Model experiments for a Darrieus water turbine with two and three straight blades were carried out in the circulating water channel, in which the power coefficients of the turbine were obtained as a function of blade section and the attaching angle of a blade to the rotor. Those experimental results are discussed to obtain an optimum Darrieus turbine for tidal power generation.

• Steel and Composite Structures
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• v.21 no.3
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• pp.661-677
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• 2016

The quasi static test of the steel reinforced concrete (SRC) bridge piers and rigid frame arch bridge structure with SRC piers was conducted in the laboratory, and the seismic performance of SRC piers was compared with that of reinforced concrete (RC) bridge piers. In the test, the failure process, the failure mechanism, hysteretic curves, skeleton curves, ductility coefficient, stiffness degradation curves and the energy dissipation curves were analyzed. According to the $M-{\Phi}$ relationship of fiber section, the three-wire type theoretical skeleton curve of the lateral force and the pier top displacement was proposed, and the theoretical skeleton curves are well consistent with the experimental curves. Based on the theoretical model, the effects of the concrete strength, axial compression ratio, slenderness ratio, reinforcement ratio, and the stiffness ratio of arch to pier on the skeleton curve were analyzed.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.81-82
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• 2010

As a part of rapid construction technology of bridge pier caps, controversial issues for design and construction of precast pier caps were discussed. Three kinds of approaches of rapid bridge pier cap construction were proposed and discussed. Especially for an approach of precast shell type structures, experimental studies were performed to evaluate structural performance and compared with conventionally constructed reinforced concrete pier cap.

• Earthquakes and Structures
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• v.10 no.6
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• pp.1467-1486
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• 2016

This research focuses on seismic performance of a class of single pier skewed bridges with three different pier-deck connections; skew angles vary from $0^{\circ}$ to $60^{\circ}$. A well-documented four span continuous deck bridge has been modeled and verified. Seat-type connections with fixed and sliding bearings plus monolithic pier-deck connections are studied. Shear keys are considered either fully operational or ineffective. Seismic performances of the bridges and the structural components are investigated conducting bidirectional nonlinear time history analysis in OpenSees. Several global and intermediate engineering demand parameters (EDP) have been studied. On the basis of results, the values of demand parameters of skewed bridges, such as displacement and rotation of the deck plus plastic deformation and torsional demand of the piers, increase as the skew angle increases. In order to eliminate the deck collapse probability, the threshold skew angle is considered as $30^{\circ}$ in seat-type bridges. For bridges with skew angles greater than $30^{\circ}$, monolithic pier-deck connections should be applied. The functionality of shear keys is critical in preventing large displacements in the bearings. Pinned piers experience considerable ductility demand at the bottom.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.11a
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• pp.615-620
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• 2001

The aim of this paper is to open up a relatively new type in bridge engineering by introducing plan and design of extradosed bridge which is implemented in Sungnam-Janghowon T/K project. The topic encompasses parametric study including the behavior of the bridge relevant to the cable layout, the distance from pier table to the first cable's location, the height of pylon, the stiffness of cross section and wind vibration to ascertain sectional type of bridge and span length. For the purpose of the knowledge base presented here, the important feature of design is recommended such as modeling method, camber control, finite element analysis and heat hydration of pier table. We can verify the issue related to the characteristics of extradosed bridge as a result of study and design endeavor.

• Structural Engineering and Mechanics
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• v.77 no.3
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• pp.343-354
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• 2021

The frequencies formulas of the bridge are of great importance in the design process since these formulas provide insight dynamic characteristics of the structure, which guides the designers to parametric analyses and the layout of the bridge in conceptual or preliminary design. Continuous rigid frame bridge is popular in the mountainous area. Mostly, this type of bridge was simplified either as a girder or cantilever when calculating the frequency, however, studies showed that the different configuration of the bridge made the problem more complex, and there is no unified fundamental calculation pattern for this kind of bridge. In this study, an empirical frequency equation is proposed as a function of pier's height, stiffness of pier and the weight of the structure. A unified fundamental frequency formula is presented based on the energy principle, then the typical continuous rigid frame bridge is investigated by finite element method (FEM) to study the dynamic characteristics of the structure, and then several key parameters are investigated on the effect of structural frequency. These parameters include the number, position and stiffness of the tie beam. Nonlinear regression analyses are conducted with a comprehensive statistical study from plenty of engineering structures. Finally, the proposed frequency equation is validated by field test results. The results show that the fundamental frequency of the continuous rigid frame bridge increases more than 15% when the tie beams are set, and it increases with the stiffness ratio of tie beam to pier. The results also show that the presented unified fundamental frequency has an error of 4.6% compared with the measured results. The investigation can predicate the approximate longitudinal fundamental frequency of continuous ridged frame bridge, which can provide reference for the seismic response and dynamic impact factor design of the pier.

• Journal of Korea Water Resources Association
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• v.32 no.1
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• pp.49-59
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• 1999

In order to understand the present situation of bridge scouring and to provide the fundamental information for bridge design, in-situ measured data is analyzed for bridge scours at small and medium streams in the heartland of Korea. The physical parameters affecting the bridge scouring such as flow depth, velocity, pier length and width, scouring depth, and the angle between flow and pier are extensively surveyed and measured. According to the locality and the pier type data are classified to analyze. With these data, some important factors for the scour depth such as flow depth, angle and Froude number are investigated and applied to existing formulas proposed by many researchers. In addition, the computational results are compared with the measured and some of the applicable formulas in this region are recommended.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.7
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• pp.4936-4941
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• 2015

This study(I) has analyzed hydraulic characteristics with pier shapes by the bridge construction. The pier shapes are classified into total six types such as square, rhombus, octagon, oval, round, and no-piers. One-dimensional model(HEC-RAS) and two-dimensional model (RMA-2) were employed to analyze hydraulic characteristics around bridge piers. Square and rhombus shapes of piers showed velocity vectors in the upstream direction, which has a significant impact on the river bed changes by erosion and sediment transport around the piers. The flow characteristics of the oval type pier was most similar to that of no-pier situation almost without disrupting the river flow. This analysis can help to select pier types in the new bridge construction for the future.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.23 no.6
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• pp.422-428
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• 2011

Optimal reliability indices were found by optimizing life cycle cost(LCC) of pier type quay walls. Failure probability of pier and shore bridge were calculated by response surface method. Then, they were used to obtain recovery cost after damage. Costs for initial construction and maintenance were also considered in finding optimal reliability indices. Target reliability indices which may be used in reliability based design were suggested by numerical examples under seismic load and ship load.