• Proceedings of the Computational Structural Engineering Institute Conference
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• 2007.04a
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• pp.688-693
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• 2007

Nowadays various studies related with superstructure of bridges are developed and they pursuit more effective section of bridges superstructure, material and economical application of composite materials. CFT structure(Concrete Filled Steel Tubular Structure) is developed type of composite structure that concrete is filled with steel box, and the deformation of the member, stiffness and internal force will be improved by confinement effect of steel box and concrete. This paper introduces new type of girder, CFTA girder( Concrete- Filled and Tied Steel Tubular Arch Girder) which is combined with traditional CFT structure,arch effect and prestress through carrying out the structural analysis by computer programs. The computer programs which is used are ABAQCS and MIDAS, and the 12.2m girder which is applied same load and prestresses is analyzed and compared the results respectively.

• Structural Engineering and Mechanics
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• v.71 no.1
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• pp.13-22
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• 2019

In this paper, the static and dynamic responses of a tied-arch railway bridge under train load were studied through field tests. The deflection and stresses of the bridge were measured in different static loading scenarios. The dynamic load test of the bridge was carried out under the excitation of running train at different speeds. The dynamic properties of the bridge were investigated in terms of the free vibration characteristics, dynamic coefficients, accelerations, displacements and derailment coefficients. The results indicate that the tie of the measuring point has a significant effect on the vertical movement of the test section. The dynamic responses of arch bridge are insensitive to the number of trains. The derailment coefficients of locomotive and carriage increase with the train speed and symmetrically distributed double-line loads reduce the train derailment probability.

• Interaction and multiscale mechanics
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• v.3 no.4
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• pp.389-403
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• 2010

Based on the Model Coupled Method (MCM), a case study has been carried out on a Concrete-Filled Steel Tubular (CFST) tied arch bridge to investigate the vibration problem. The mathematical model assumed a finite element representation of the bridge together with beam, shell, and link elements, and the vehicle simulation employed a three dimensional linear vehicle model with seven independent degrees-of-freedom. A well-known power spectral density of road pavement profiles defined the road surface roughness for Perfect, Good and Poor roads respectively. In virtue of a home-code program, the dynamic interaction between the bridge and vehicle model was simulated, and the dynamic amplification factors were computed for displacement and internal force. The impact effects of the vehicle on different bridge members and the influencing factors were studied. Meanwhile the acceleration responses of some of the components were analyzed in the frequency domain. From the results some valuable conclusions have been drawn.

• Smart Structures and Systems
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• v.18 no.3
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• pp.389-403
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• 2016

Structural deflection can be identified from measured strains from long gague sensors, but the sensor layout scheme greatly influences on the accuracy of identified resutls. To determine the optimal sensor layout scheme for accurate deflection identification of the tied arch bridge, the method of optimal layout of long-gauge fiber optic sensors is studied, in which the characteristic curve is first developed by using the bending macro-strain curve under multiple target load conditions, then optimal sensor layout scheme with different number of sensors are determined. A tied arch bridge is studied as an example to verify the effectiveness and robustness of the proposed method for static and dynamic deflection identification.

• Steel and Composite Structures
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• v.47 no.1
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• pp.51-69
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• 2023

In tied-arch bridges, a properly designed connection between the arch and the deck may become crucial, since the forces in the structure may be significantly reduced. This implies substantial material savings and, consequently, cheaper constructions. The introduction of the Nielsen cable arrangement (composed of V-shaped inclined hangers) in the last century was a milestone because it was able to reduce deflections and bending moments both in the arch and in the deck. So far, the Nielsen cable arrangement has proven to be successful in traditional vertical arch bridges. However, despite its advantages, it has not been widely applied to spatial arch bridges. Thus, this article analyses the difference between the structural behavior of spatial arch bridges with Nielsen-type cable arrangements with respect to those with classical vertical hanger configurations. The main goal is to verify whether the known effectiveness of the Nielsen cable arrangement for classical arch bridges is still preserved when applied to spatial arch bridges. In order to achieve this objective, and as the first part of our study, a set of different all-steel bridges composed of vertical and inclined arches with straight decks have been compared for both cable arrangements. As a major conclusion, for planar vertical arch bridges, the Nielsen-type cable arrangement is always the most effective. In addition, it also seems that, for spatial arch bridges composed of a straight deck and an inclined arch, it still keeps most of its effectiveness as long as the arch is moderately inclined.

• Steel and Composite Structures
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• v.32 no.4
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• pp.479-495
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• 2019

In tied-arch bridges, the way the arch and the deck are connected may become crucial. The deck is usually suspended from hangers made out of steel pinned cables capable of resisting axial forces only. However, a proper structural response may be ensured by fixing and stiffening the hangers in order to resist, additionally, shear forces and bending moments. Thus, this paper studies the effect of different pinned and stiffened hanger arrangements on the structural behavior of the tied-arch bridges, with the intention of providing designers with useful tools at the early steps of design. Longitudinally and transversally stiffened hangers (and the effect of hinges at the hangers and their locations) are studied separately because the in-plane and the out-of-plane behavior of the bridge are uncoupled due to its symmetry. As a major conclusion, regarding the in-plane behavior, hangers composed of cables (either with vertical, $Nielsen-L\ddot{o}hse$ or network arrangements) are recommended due to its low cost and ease of erection. Alternatively, longitudinally stiffened hangers, fixed at both ends, can be used. Regarding the out-of-plane behavior, and in addition to three-dimensional arrangements of cables, of limited effectiveness, transversally stiffened hangers fixed at both ends are the most efficient arrangement. A configuration almost as efficient and, additionally, cheaper and easier to build can be achieved by locating a hinge at the end corresponding to the most flexible structural element (normally the arch). Its efficiency is further improved if the cross-section tapers from the fixed end to the pinned end.

• Steel and Composite Structures
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• v.27 no.2
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• pp.161-175
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• 2018

In this study, in-situ dynamic tests of the world's longest steel box tied-arch bridge over the Yangtze River, China, are reported. The double deck bridge supports highway and monorail systems at upper and lower levels, respectively. Strain, displacement, and acceleration responses were measured and used to investigate the vibration characteristics of the bridge when excited by running trains and/or trucks at a speed of 5-60 km/h, train braking, and truck bouncing. Impact factors were correlated with the running speed of trains and trucks. A three-dimensional finite element model of the coupled monorail-train-bridge vibration system accounting for track irregularities was established to understand the system behavior and validated by the experimental results. Truck bouncing was the dominant impact factor on bridge responses. The running speed of vehicles determined the riding comfort of traveling trains.

• Smart Structures and Systems
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• v.23 no.5
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• pp.507-520
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• 2019

In the structural health monitoring field, damage detection has been commonly carried out based on the structural model and the engineering features related to the model. However, the extracted features are often subjected to various errors, which makes the pattern recognition for damage detection still challenging. In this study, an automated damage identification method is presented for hanger cables in a tied-arch bridge using a convolutional neural network (CNN). Raw measurement data for Fourier amplitude spectra (FAS) of acceleration responses are used without a complex data pre-processing for modal identification. A CNN is a kind of deep neural network that typically consists of convolution, pooling, and fully-connected layers. A numerical simulation study was performed for multiple damage detection in the hangers using ambient wind vibration data on the bridge deck. The results show that the current CNN using FAS data performs better under various damage states than the CNN using time-history data and the traditional neural network using FAS. Robustness of the present CNN has been proven under various observational noise levels and wind speeds.

• Journal of the Korean Society of Hazard Mitigation
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• v.11 no.1
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• pp.15-22
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• 2011

In this research, static load test is performed to verify the arch effect and structural performance of CFTA(Concrete-Filled and Tied steel tubular Arch) girder, and FE(Finite Element) analysis is performed to investigate validity of the test result. CFTA girder is designed to maximize the benefit of each material, such as steel plate, filled concrete and PS tendon. Static load test is performed based on the frame-analysis result of 12m sample miniature model. The result of static load test is that structural performance and safety of CFTA girder are confirmed and there is different deflection mode with other structural form result from arch effect. FE analysis with ABAQUS is also performed to show the validity of the truck collision safety and static load test.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.05a
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• pp.912-917
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• 2003

In this paper a new truss modeling technique for describing the beam shear resistance mechanism is proposed based on the reinterpretation of the well-known relationship between shear and the rate of change of bending moment in a reinforced concrete beam subjected to combined shear and moment loads. The core of the model is that a new perspective on the shear resistance can be gained by viewing the internal stress filed in terms of the superposition of two base components of shear resistance; arch action and beam action. The arch action can be described as a simple tied-arch which is consisted of a curved compression chord and a tension tie of the longitudinal steel, while the beam action between the two chords can be modeled as a membrane shearing element with forming a smeared truss action. The compatibility of deformation associated to the two action is taken into account by employing an experimental factor or internal state force factor a. Then the base equation of V=dM/dx is numerically duplicated. The new model was examined by the 362 experimental results. The shear strength predicted by the internal force state factor a show better correlation with the tested values than the present shear design.