• Ocean Systems Engineering
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• v.11 no.1
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• pp.43-58
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• 2021

In the present work, a 3D numerical model is proposed to study local scouring around single vertical piers with different cross-section shapes under steady-current flow. The model solves the flow field and sediment transport processes using a coupled approach. The flow field is obtained by solving the Unsteady Reynolds Averaged Navier-Stokes (URANS) equations in combination with the k-ω SST turbulence closure model and the sediment transport is considered using both bedload and suspended load models. The proposed model is validated against the empirical measurements of local scour around single vertical piers with circular, square, and diamond cross-section shapes obtained from the literature. The measurement of scour depth in equilibrium condition for the simulations reveal the differences of 4.6%, 6.7% and 13.1% from the experimental measurements for the circular, square, and diamond pier cases, respectively. The model displayed a remarkable performance in the prediction of scour around circular and square piers where horseshoe vortices (HSVs) have a leading impact on scour progression. On the other hand, the maximum deviation was found in the case of the diamond pier where HSVs are weak and have minimum impact on the formation of local scour. Overall, the results confirm that the prediction capability of the present model is almost independent of the strength of the formed HSVs and pier cross-section shapes.

• Journal of the Korea institute for structural maintenance and inspection
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• v.10 no.1
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• pp.216-222
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• 2006

This study is a simulative Paper on scour around piers. As materials on the river bed have been changing through erosion, transportation and accumulation, so does the waterway's section. Analyzing them through the BOSS SMS. this study deals with the local-scour characters with the change of shapes in row piers which have been built in the identical direction of water flow.

• 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 KIBIM
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• v.5 no.2
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• pp.12-18
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• 2015

Bridge piers typically have circular or rectangular shapes without decorative design. Prefabrication for accelerated construction has been widely adopted in bridge structures. Cost for steel formwork is a main restriction of creative irregular shapes. 3D modelling techniques allow creative design of columns and 3D printing provides possibility to minimize the fabrication cost. In this paper, 3D design process of bridge piers was suggested by converting 2D picture into 3D decorative shape. Formwork design using 3D printed panels was also proposed and mock-up tests were conducted. Precast columns need accurate geometry control from fabrication to assembly. Laser scanning and geometry control devices were adopted. Through the digitalized process of design, fabrication and assembly, creative design of structures can be realized in reasonable cost range.

• Journal of the Earthquake Engineering Society of Korea
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• v.9 no.1 s.41
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• pp.17-24
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• 2005

Response of reinforced concrete (RC) column-bent piers subjected to bidirectional seismic loadings was experimentally investigated. RC column-bent piers represent one of the most popular shapes of piers used in Korea highway bridges. Four column-bent piers were constructed in 400 mm diameter and 2,000 mm height. Each pier has two circular supporting columns. These piers were tested under bidirectional lateral load reversals with an axial load of $0.1f_{ck}A_g$. The test parameters included : different transverse reinforcement contents and lap-spliced longitudinal reinforcing steels. Test results indicate that the lap splice of longitudinal reinforcing steels have significantly influenced on hysteretic response of column-bent piers similar to previous test results for single columns with corresponding test parameters. Column capacity was changed with the level of transverse confinement. From the comparison of test result for single column under unidirectional loading, the damage of single column was concentrated on lower plastic hinge region but the damage of column-bent piers was scattered to upper and lower plastic hinge region.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.28 no.2
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• pp.207-212
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• 2015

Bridges are designed and constructed as infrastructures in order to overcome topographical obstructions for fast and smooth transfer of human/material resources. Therefore the shape and size of piers constructed along the longitudinal bridge axis should be restricted by topographical conditions. Action forces of connections and piers are affected by pier shapes and sizes together with connection arrangement which decides load carrying path under earthquakes. In this study a typical bridge is modelled with steel bearings and reinforced concrete piers and seismic analyses are performed with analysis models with different arrangement of steel bearings and piers. From analysis results ductile failure mechanisms for all analysis models are checked based on strength/action force ratios of steel bearings and pier columns. In this way the influences of arrangement of connections and piers on the earthquake resistant capacity of typical bridges are figured out in view of forming ductile failure mechanism.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2003.03a
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• pp.377-384
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• 2003

Recently, there are much concerns about new and innovative transverse materials which could be used instead of conventional transverse steel in reinforced concrete bridge piers. FRP materials could be substituted for conventional transverse steel because of their sufficient strength, light weight, easy fabrication, and useful applicability to any shapes of pier sections, such as rectangular or circular sections. The objective of this research is to evaluate the seismic performance of reinforced concrete bridge pier specimens with FRP transverse reinforcement by means of the Quasi-Static test. In the first task, test columns were made using FRP rope, but these specimens appeared to fail at low displacement ductility levels due to insufficient confinement of strand extension itself. Therefore, the second task was to evaluate the seismic performance of test specimens transversely confined with FRP band. Although FRP banded specimens showed lower seismic performance than the specimen with spiral reinforcing steel, it satisfied with the response modification factor, 3, required for the single column of Korea bridge roadway design code. It was concluded that FRP band could be efficiently substituted for conventional reinforcing steel.

• Structural Engineering and Mechanics
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• v.52 no.1
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• pp.51-73
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• 2014

A three-dimensional finite element model for the Jiashao Bridge, the longest multi-span cable-stayed bridge in the world, is established using the commercial software package ANSYS. Dynamic characteristics of the bridge are analyzed and the effects of structural system measures including the rigid hinge, auxiliary piers and longitudinal constraints between the girders and side towers on the dynamic properties including modal frequency, mode shape and effective mass are studied by referring to the Jiashao Bridge. The analysis results reveal that: (i) the installation of the rigid hinge significantly reduces the modal frequency of the first symmetric lateral bending mode of bridge deck. Moreover, the rigid hinge significantly changes the mode shape and effective mass of the first symmetric torsional mode of bridge deck; (ii) the layout of the auxiliary piers in the side-spans has a limited effect on changing the modal frequencies, mode shapes and effective masses of global vibration modes; (iii) the employment of the longitudinal constraints significantly increases the modal frequencies of the vertical bending modes and lateral bending modes of bridge deck and have significant effects on changing the mode shapes of vertical bending modes and lateral bending modes of bridge deck. Moreover, the effective mass of the first anti-symmetric vertical bending of bridge deck in the longitudinal direction of the fully floating system is significantly larger than that of the partially constrained system and fully constrained system. The results obtained indicate that the structural system measures of the multi-span cable-stayed bridge have a great effect on the dynamic properties, which deserves special attention for seismic design and wind-resistant design of the multi-span cable-stayed bridge.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.8
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• pp.5716-5720
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• 2015

This study has analyzed the backwater effect by the bridge pier on the basis of the result on hydraulic characteristics with pier shapes in study(I), using a two-dimensional model(RMA-2) and an one-dimensional model(HEC-RAS). The pier shapes are classified into total six types such as square, rhombus, octagon, oval, round, and no-piers. The result of the backwater effect analysis showed that the backwater length is about 150 and 50m from HEC-RAS and RMA-2, respectively for all pier types. Although it is difficult to directly compare between results from the two models, the oval shape pier has shown similar results to the no-pier situation before the bridge construction in hydraulic characteristics. This analysis can help to select pier types in the new bridge construction for the future.

• Structural Engineering and Mechanics
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• v.38 no.1
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• pp.65-79
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• 2011

Concrete hydraulic structures such as: Dams, Intake Towers, Piers and dock are usually recognized as" Vital and Special Structures" that must have sufficient safety margin at critical conditions like when earthquake occurred as same as normal servicing time. Hence, to evaluate hydrodynamic pressures generated due to seismic forces and Fluid-Structure Interaction (FSI); introduction to fluid-structure domains and interaction between them are inevitable. For this purpose, first step is exact modeling of water-structure and their interaction conditions. In this paper, the basic equation involved the water-structure-foundation interaction and the effective factors are explained briefly for concrete hydraulic structure types. The finite element modeling of two concrete gravity dams with 5 m, 150 m height, reservoir water and foundation bed rock is idealized and then the effects of fluid domain and bed rock have been investigated on modal characteristic of dams. The analytical results obtained from numerical studies and modal analysis show that the accurate modeling of dam-reservoir-foundation and their interaction considerably affects the modal periods, mode shapes and modal hydrodynamic pressure distribution. The results show that the foundation bed rock modeling increases modal periods about 80%, where reservoir modeling changes modal shapes and increases the period of all modes up to 30%. Reservoir-dam-foundation interaction increases modal period from 30% to 100% for different cases.