• Proceedings of the Korea Concrete Institute Conference
• /
• 2005.11a
• /
• pp.303-306
• /
• 2005

For checking influence of load-position and system of stress-transmission in precast concrete bridge deck system, the test composite bridge was made a experiment by the wheel load machine. The result of experiment was the loop joint system of the precast decks has a difference which was the transmission system of longitudinal stress, comparing with general RC bridge deck system. The loop joint system has a behavior independently.

• Proceedings of the Korea Concrete Institute Conference
• /
• 1998.10b
• /
• pp.827-832
• /
• 1998

Recently, Carbon Fiber Sheets(CFS) have been used for strengthening the deteriorated RC beams and bridge decks because of its resistant capacity of corrosion and easy repairing works. In this study, the static test tare performed on RC bridge decks strengthened with CFS. Test results show that ultimate strength of specimens strengthened with CFS is increased as 15~26% comparing to the control specimen.

• Journal of Ocean Engineering and Technology
• /
• v.20 no.5 s.72
• /
• pp.63-69
• /
• 2006

An isolated bridge using a laminated rubber bearing provides an elastic support of continuous span and prevents the transmission of excessive seismic force from the substructure of the bridge, which uses a metal bearing, as this permits a relative displacement between the super-and substructure. Hawever, this kind of bridge is caused long periodic, as a result of enlargingtotal thickness of the rubber, since it corresponds to temperature change and increases the horizontal displacement of the superstructure. This paper uses a numerical study to describe the pounding problem between adjacent decks when subjected to a strong earthquake. Furthermore, numerical results are clarified for the buffer rubber used to mitigate the pounding force between adjacent decks.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2008.11a
• /
• pp.157-160
• /
• 2008

Bridge decks are directly exposed to traffic loads and environmental conditions like rainfall water and de-icing chemicals. In this reason, there are often observed the deteriorations of asphalt overlay and concrete deck. In this study, 32 concrete decks were evaluated by the road inspection vehicle and the GPR mounted on the vehicle. The GPR could detect the deteriorations of concrete decks under asphalt overlay, even though the asphalt overlay looks like soundness. Therefore, for the efficient maintenance of concrete bridge decks, GPR examination should be performed with visual inspection.

• Structural Engineering and Mechanics
• /
• v.12 no.4
• /
• pp.347-362
• /
• 2001

The paper deals with preventing the collapse of by the means of supporting the bridges by rubber bearings and pedeck structures of skew and curved bridges during earthquakes, rmitting pounding between the decks and the abutments. Seismic response during pounding is characterized by various phenomena, such as the caging of bridge decks between abutments during an earthquake or decks popping out. These behaviors depend on only a small difference in seismic intensity. Regarding the global characteristics of a seismic response, smaller clearance between a deck and its abutments results in smaller impact damage of the abutments as well as lesser deformation of the rubber bearings. Similarly, smaller clearance between a deck and the side blocks results in smaller damage. The stiffnesses of the bearings and the stiffness ratio between them control the deck displacement. In short to medium length bridges, zero clearance between a deck and the abutments or the deck and the side blocks is the most effective way in preventing the deck from falling and limits the damage to the abutments or the side blocks.

• Structural Engineering and Mechanics
• /
• v.76 no.6
• /
• pp.737-749
• /
• 2020

A hybrid bridge deck is proposed, which includes steel bars, concrete and glass-fiber-reinforced-polymer (GFRP) plates with channel sections. The steel bar in the negative moment region can increase the flexural stiffness, improve the ductility, and reduce the GFRP ratio. Three continuous decks with different steel bar ratios and a simply supported deck were fabricated and tested to study the mechanical performance. The failure mode, deflection, strain distribution, cracks and support reaction were tested and discussed. The steel bar improves the mechanical performance of continuous decks, and a theoretical method is proposed to predict the deformation and the shear capacity. The experimental results show that all specimens failed with shear failure in the positive moment region. The increase of steel bar ratio in the negative moment region can achieve an enhancement in the flexural stiffness and reduce the deflection without increasing GFRP. Moreover, the continuous deck can achieve a yield load, and the negative moment can be carried by GFRP plates after the steel bar yields. Finally, a nonlinear analytical method for the deflection calculation was proposed and verified, with considering the moment redistribution, non-cracked sections and nonlinearity of material. In addition, a simplified calculation method was proposed to predict the shear capacity of GFRP-concrete decks.

• Proceedings of the Korea Concrete Institute Conference
• /
• 1999.10a
• /
• pp.627-630
• /
• 1999

In this study, the usefulness of Radar method by means of assessing deck data-layer properties-was tested on the highway bridge. The obtained GPR data were compared with values measured from drilled cores and damage mapping by the visual survey. It is shown that GPR can provide the highly accurate measurements of layer properties of concrete decks and can map areas of deterioration in bridge by dielectric constants.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2002.05a
• /
• pp.463-468
• /
• 2002

Transverse prestressing of bridge decks is an attractive concept with substantial benefits in both economy and crack control in slabs. To evaluate the necessary information for the prestressed long span bridge slab design, a series of static and fatigue tests were peformed. It is shown that the minimum thickness recommendation in Korean Highway Bridge Design Code is too conservative.

• Wind and Structures
• /
• v.30 no.6
• /
• pp.633-648
• /
• 2020

The objective of this work was to investigate the interference effects of two-parallel bridge decks on aerodynamic coefficients, vortex-induced vibration, flutter instability and flutter derivatives. The two bridges have significant difference in cross-sections, dynamic properties, and flutter speeds of each isolate bridge. The aerodynamic static tests and aeroelastic tests were performed in TU-AIT boundary layer wind tunnel in Thammasat University (Thailand) with sectional models in a 1:90 scale. Three configuration cases, including the new bridge stand-alone (case 1), the upstream new bridge and downstream existing bridge (case 2), and the downstream new bridge and the upstream existing bridge (case 3), were selected in this study. The covariance-driven stochastic subspace identification technique (SSI-COV) was applied to identify aerodynamic parameters (i.e., natural frequency, structural damping and state space matrix) of the decks. The results showed that, interference effects of two bridges decks on aerodynamic coefficients result in the slightly reduction of the drag coefficient of case 2 and 3 when compared with case 1. The two parallel configurations of the bridge result in vortex-induced vibrations (VIV) and significantly lower the flutter speed compared with the new bridge alone. The huge torsional motion from upstream new bridge (case 2) generated turbulent wakes flow and resulted in vertical aerodynamic damping H1^* of existing bridge becomes zero at wind speed of 72.01 m/s. In this case, the downstream existing bridge was subjected to galloping oscillation induced by the turbulent wake of upstream new bridge. The new bridge also results in significant reduction of the flutter speed of existing bridge from the 128.29 m/s flutter speed of the isolated existing bridge to the 75.35 m/s flutter speed of downstream existing bridge.

• Structural Monitoring and Maintenance
• /
• v.2 no.1
• /
• pp.19-34
• /
• 2015

One of the main causes of a limited use of nondestructive evaluation (NDE) technologies in bridge deck assessment is the speed of data collection and analysis. The paper describes development and implementation of the RABIT (Robotics Assisted Bridge Inspection Tool) for data collection using multiple NDE technologies. The system is designed to characterize three most common deterioration types in concrete bridge decks: rebar corrosion, delamination, and concrete degradation. It implements four NDE technologies: electrical resistivity (ER), impact echo (IE), ground-penetrating radar (GPR), and ultrasonic surface waves (USW) method. The technologies are used in a complementary way to enhance the interpretation. In addition, the system utilizes advanced vision to complement traditional visual inspection. Finally, the RABIT collects data at a significantly higher speed than it is done using traditional NDE equipment. The robotic system is complemented by an advanced data interpretation. The associated platform for the enhanced interpretation of condition assessment in concrete bridge decks utilizes data integration, fusion, and deterioration and defect visualization. This paper concentrates on the validation and field implementation of two NDE technologies. The first one is IE used in the delamination detection and characterization, while the second one is the USW method used in the assessment of concrete quality. The validation of performance of the two methods was conducted on a 9 m long and 3.6 m wide fabricated bridge structure with numerous artificial defects embedded in the deck.