• Computers and Concrete
• /
• v.15 no.4
• /
• pp.563-588
• /
• 2015

Piers are the most vulnerable part of a bridge structure during an earthquake event. During Kobe earthquake in 1995, several bridge piers of the Hanshin Expressway collapsed for more than 600m of the bridge length. In this paper, the most important results of an experimental and analytical investigation of ten reinforced concrete bridge piers specimens with the same cross section subjected to constant axial (or variable) load and reversed (or one direction) cycling loading are presented. The objective was to investigate the main parameters influencing the seismic performance of reinforced concrete bridge piers. It was found that loading history and axial load intensity had a great influence on the performance of piers, especially concerning strength and stiffness degradation as well as the energy dissipation. Controlling these parameters is one of the keys for an ideal seismic performance for a given structure during an eventual seismic event. Numerical models for the tested specimens were developed and analyzed using SeismoStruct software. The analytical results show reasonable agreement with the experimental ones. The analysis not only correctly predicted the stiffness, load, and deformation at the peak, but also captured the post-peak softening as well. The analytical results showed that, in all cases, the ratio, experimental peak strength to the analytical one, was greater than 0.95.

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

• Composites Research
• /
• v.23 no.1
• /
• pp.23-30
• /
• 2010

Most of the bridge systems, including the girders, cross-beams, and concrete decks behave as specially orthotropic plates. In general, the analytical solution for such complex system is very difficult to obtain. In this paper presented, a design method of slab bridge of simple supported made by composite materials. For the design of bridge made by the composite materials, cross-section was used the form-core shape because of this shape is economical and profitable, and for output of the stress value used finite difference method. In this paper, the rate of tensile strength reduction due to increased size was considered. Strength-failure analysis procedure, using the reduced tensile strength, was presented. And also numerical study was made for these cases.

• Journal of the Korean Society for Railway
• /
• v.14 no.3
• /
• pp.234-239
• /
• 2011

Installing the temporary bridge after excavating the railway requires installing movable cross beam, but as it doesn't requires isolating the catenary or cutting the rail, it's applicable to double-track with frequent operation. In this study, a displacement meter was placed on temporary bridge to monitor the displacement pattern in curve section (R400) completed using temporary bridge method, and wheel load, lateral pressure and derailment coefficient were measured to evaluate the load imposed on track and the stability in curve section (R400) for quantitative evaluation of training running safety. As a result of the measurement, when trains passing over a temporary bridge, the maximum value of Wheel load and Lateral Force is analyzed as the 51% and 81% of standard level according to foreign country's performance tests, There is no trouble with stability analysis in Wheel load and Lateral Force occurring. Additionally, Wheel load and Lateral Force considered as the safety standard are tested 49% of limiting value regardless of trains, which the norm value quite well, there is no problem with train running.

• Journal of Korean Society of Steel Construction
• /
• v.19 no.5
• /
• pp.527-537
• /
• 2007

The main girders and cross-beams of an H-beam bridge consisted of factory-made H-beams, providing better conditions for quality control. Also, on-site fabrication works can be minimized and most of the stiffeners can be omitted, enabling simple and economic construction. In this study, the effect of the Multi-Stepwise TPSM (M-TPSM) on improving the maximum span length and section efficiency is analyzed. Compared to a 30-m-long, five-girder conventional plate girder bridge, structural analysis results showed that 50.7~55.1% of the girder height and 24.1~26.2% of the self-weight may be reduced by the application of M-TPSM to a five-girder H-beam bridge constructed with H-$900{\times}300$beams. In case of conventional H-beam bridges without M-TPSM, it was found that seven girders are required for a similar level of load-carrying capacity. Therefore, it is concluded that by the application of the M-TPSM, the H-beam bridge would become one of most cost-competitive options for short- and medium-span bridges.

• Structural Engineering and Mechanics
• /
• v.61 no.4
• /
• pp.453-461
• /
• 2017

This paper presents the series multiple tuned mass dampers (STMDs) to suppress the resonant vibrations of railway bridges under the passage of high-speed trains (HSTs). A STMD device consisting of two spring-mass-damper units connected each other in series is installed on the bridge. In solution, bridge is modeled as a simply-supported Euler-Bernoulli beam with constant cross-section, and vehicle is simulated as a series of moving forces with constant speed. By the assumed mode method, the governing equations of motion of the beam-TMD device coupled system traversed by a moving train are obtained. The optimum values for the parameters of the STMD device are obtained for the criterion based on the minimization of the maximum dynamic displacement of the beam at its midspan. Single TMD and multiple TMDs in parallel are also considered for demonstration of the STMD device's performance. The results show that STMDs are effective in bridge vibration suppression and robust to parameters' change in the main system and the absorber itself.

• Structural Engineering and Mechanics
• /
• v.46 no.4
• /
• pp.519-531
• /
• 2013

To have a better understanding of the torsional mechanism and influencing factors of PC composite box-girder with corrugated steel webs, ultimate torsional strength of four specimens under pure torsion were analyzed with Model Test Method. Monotonic pure torsion acts on specimens by eccentric concentrated loading. The experimental results show that cracks form at an angle of $45^{\circ}$ to the member's longitudinal axis in the top and bottom concrete slabs. Longitudinal reinforcement located in the center of cross section contributes little to torsional capacity of the specimens. Torsional rigidity is proportional to shape parameter ${\eta}$ of corrugation and there is an increase in yielding torque and ultimate torque of specimens as the thickness of corrugated steel webs increases.

• Journal of the Earthquake Engineering Society of Korea
• /
• v.18 no.4
• /
• pp.201-212
• /
• 2014

The plastic hinge region of RC pier ensures its nonlinear behavior during strong earthquake events. It is assumed that the piers secure sufficient strength and ductility in order to prevent the collapse of the bridge during strong earthquake. However, the presence of a lap-splice of longitudinal bars in the plastic hinge region may lead to the occurrence of early bond failure in the lap-splice zone and result in significant loss of the seismic performance. The current regulations for seismic performance evaluation limit the ultimate strain and displacement ductility considering the eventual presence of lap-splice, but do not consider the lap-splice length. In this study, seismic performance test and analysis are performed according to the cross-sectional size and the lap-splice length in the case of longitudinal bars with lap-splice located in the plastic hinge region of existing RC bridge columns with circular cross-section. The seismic behavioral characteristics of the piers are also analyzed. Based upon the results, this paper presents a more reasonable seismic performance evaluation method considering the lap-splice length and the cross-sectional size of the column.

• Steel and Composite Structures
• /
• v.52 no.2
• /
• pp.199-215
• /
• 2024

The Caynarachi Bridge is a 130 m long posttensioned steel-concrete composite bridge built in Peru. The structural performance of this bridge under construction loads is reviewed in this paper using numerical simulation. Hence, a numerical model using shell finite elements to trace its deformational behavior at service conditions is proposed. The geometry and boundary conditions of the superstructure are updated according to the construction schedule. Firstly, the adequacy of the proposed model is validated with the field measurements obtained from the static truck load test. Secondly, the study of other scenarios less explored in research are performed to investigate the effect of some variables on bridge performance such as time effects, sequence of execution of concrete slabs and type of supports conditions at the abutments. The obtained results show that the original sequence of execution of the superstructure better behaves mechanically in relation to the other studied scenarios, yielding smaller stresses at critical cross sections with staging. It is also demonstrated that an improper slab staging may lead to more critical stresses at the studied cross sections and that casting the concrete slab at the negative moment regions first can lead to an optimal design. Also, the long-term displacements can be accurately predicted using an equivalent composite resistance cross section defined by a steel to concrete modulus ratio equal to three. This article gives some insights into the potential shortcomings or advantages of the original design through high-fidelity finite element simulations and reinforces the understating of posttensioned composite bridges with staging.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.26 no.5A
• /
• pp.887-899
• /
• 2006

The aim of this study is to investigate a correlation between fundamental data on aerodynamic characteristics of bridge girder cross-sections, such as aerodynamic force coefficients and flutter derivatives, and their aerodynamic behaviour. The section model tests were carried out in three stages. In the first stage, seven deck configurations were studied, namely; Six 2-edge girders and one box girder. In this stage, changes in aerodynamic force coefficients due to geometrical shape of girders, incidence angle of flow, wind directions and turbulence intensities were studied by static section model tests. In the second stage, the dynamic section model tests were carried out to investigate the relativity of static coefficients to dynamic responses. And finally, the two-dimensional (lift-torsion) aerodynamic derivatives of three bridge deck configurations were investigated by dynamic section model tests. The aerodynamic derivatives can be best described as a representation of the aerodynamic damping and the aerodynamic stiffness provided by the wind for a given deck geometry. The method employed here to extract these unsteady aerodynamic properties is known as the initial displacement technique. It involves the measurement of the decay in amplitude with time of an initial displacement of the deck in heave and torsion, for various wind speeds, in smooth flow. It is suggested that the proposed aerodynamic force coefficients and flutter derivatives of bridge girder sections will be potentially useful for the aeroelastic analysis and buffeting analysis.