• Computational Structural Engineering
• /
• v.9 no.1
• /
• pp.125-132
• /
• 1996

This study is to propose a practical and realistic reliability analysis by ETCM (Expected Total Cost Minimization). One of the main objectives is intended to propose the safety assessment and capacity rating of existing reinforced concrete members by evaluation index, that is RF(Rating Factor) from the results of the field test and inspection for reinforced concrete bridge. ETCM method is used for the reliability analysis of the proposed models. The proposed reliability model and method are applied to the safety assessment and system factors of reinforced concrete members.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.20 no.3
• /
• pp.329-338
• /
• 2007

The PSC box bridge constructed of concrete, reinforcing bar and tendon is a complex structure that exhibits tension cracks, nonlinear behaviour of steel and time dependent behaviour of concrete. The frame element is commonly used for construction stage analysis PSC bridges. However, the frame element does not show sufficient information when in the curved PSC box bridges. For the case of curved PSC bridges, the deformations in the inner and outer web are different. In this case, different jacking forces are required in the inner and outer webs. However, it is impossible to calculate different jacking forces if we use the frame element for construction stage analysis. In order to overcome this problem, the use of the shell element is essential for a three-dimensional construction stage analysis of PSC bridges. In the following, the formulation of a Quasi-conforming shell element and its application of PSC box girder bridge analysis are presented.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2010.05a
• /
• pp.129-130
• /
• 2010

Lap splice of longitudinal reinforcing steels was located in the plastic hinge region of most bridge piers that had been designed and constructed before the adoption of the 1992 seismic design provision of Korea Highway Design Specification. This research aims at improving the seismic performance of reinforced concrete bridge piers with lap-spliced longitudinal steels, of which the plastic hinge region was wrapped by the shape memory alloy (SMA) wires. Quasi-static test was used to investigate the seismic behaviours of RC test specimens.

• The Journal of Engineering Research
• /
• v.6 no.1
• /
• pp.53-63
• /
• 2004

In this paper, influence of shear on the seismic performance and failure mode of reinforced concrete piers subjected to earthquake loading is investigated. Comparative study has been carried out for reinforced concrete column tests to verify the shear-axial interaction model presented in this paper. Comparison shows that predicted shear hysteretic response agrees well with the test results. Also conducted is a nonlinear time-history analysis of a reinforced concrete bridge damaged by the Kobe earthquake using the current development. Displacement response for piers reveals that maximum displacement is considerably increased due to the effect of shear coupled with axial force variation, which leads to overall stiffness degradation and period elongation. It is therefore concluded that the response considering both shear and axial force gives better explanation regarding the seismic damage evaluation of reinforced concrete bridge piers.

• Journal of the Korea Concrete Institute
• /
• v.16 no.5 s.83
• /
• pp.697-707
• /
• 2004

Most bridge piers were practically designed and constructed with lap spliced longitudinal reinforcing steels before the 1992 seismic design provisions of Korea Bridge Design Specification were implemented. It has been known that lap splice of longitudinal reinforcement in the plastic hinge region is not desirable for seismic performance of RC bridge piers. The objective of this research is to evaluate the seismic performance of existing circular reinforced concrete bridge piers by the Quasi-static test and to propose the need of seismic retrofit of existing bridge piers through the damage level. Test specimens were nonseismically designed with the aspect ratio 4.0 which could induce the flexural failure mode. It was confirmed from this experiment that significant reduction of seismic performance was observed for test specimens with lap spliced longitudinal reinforcing steels. Pertinent seismic retrofit was determined to be needed for existing RC bridge piers with the lap-spliced of $50\%$ longitudinal reinforcing steels.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.8 no.3
• /
• pp.217-224
• /
• 2004

In 1980's, the concrete bridge decks were constructed with 4cm wearing surface layer instead of asphalt concrete overlays. After about 15 year service periods, deteriorations were appeared on the surfaces of highway bridge decks. Various field NDTs and lab tests were done to analysis the cause of the deterioration on the concrete deck surface. The main cause was the corrosion of rebars with thinner concrete top cover than the design value. The rebars with thinner concrete top cover was earlier corroded by penetrated chloride ions. If the appropriate top cover could be achieved, the bare concrete bridge decks can be used without earlier deteriorations.

• The Journal of the Convergence on Culture Technology
• /
• v.6 no.4
• /
• pp.753-760
• /
• 2020

In this study, the structural safety of the bearing support was analysed by applying the vertical load (bearing design load) and horizontal load (horizontal force generated during an earthquake) using a precise three-dimensional numerical model. The results of stress and displacement of newly-poured concrete and welded rebars were confirmed numerically. Numerical results show that the increase in the horizontal force and the height of the beam causes the concrete cracking and the stress increase of the rebar connections due to the increase of the stress at the new concrete interface. Therefore, it was analyzed that the increase in the height of bearing support is directly related to the horizontal force and it is necessary to apply the bearing support height appropriate for the bearing support capacity. It was proposed that a method of setting the height of the bearing support suitable for the bearing capacity and determining the reinforcement by presenting the guideline with the correlation between the horizontal force acting on the bearing support and its height.

• Journal of the Korean GEO-environmental Society
• /
• v.22 no.3
• /
• pp.31-35
• /
• 2021

The expansion joints installed on the bridge for the accommodation of expansion and contraction of the supper structure are essential members of the bridge. However, the expansion joints are deteriorated over time and the waterproof function weakens, causing rainwater to penetrate and deteriorate the structure. In order to solve the traffic congestion caused by frequent replacement of the old expansion joints along with the deterioration of the structure, a post-integrated abutment bridge in which the existing expansion joints are removed and replaced with reinforced concrete link connection has been applied to highway bridges since 2016. After the post-integrated abutment method was applied, it was partially applied to bridges in which the superstructure and abutment were jammed. In this study, the causes of problems that may occur when the post-integrated abutment method is applied to the jammed bridge were analyzed numerically. It was analyzed that damage occurred in the link connection part. Based on the results of this study, the application condition for the post-integrated abutment method is reinforced as it is not possible to apply the post-integrated abutment method to bridges are already jammed.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.14 no.4
• /
• pp.126-132
• /
• 2010

Carbonation is the results of the interaction of carbon dioxide gas in the atmosphere with the alkaline hydroxides in the concrete. Reinforced steel corrosion due to concrete carbonation is one of main factors on the decrease in durability of RC structure. This study investigates the influence of carbonation on the bridges under various environment condition and quantifies the effect of carbonation various domestic field data. The failure probability of durability is evaluated on the basis of reliability concept. In addition, service life of the structures is predicted based on the intended probability of durable failure in domestic concrete specification. According to experimental results of the carbonation depth, the carbonation depth increased with structural age. It is analyzed that carbonation velocity of the structures under urban area and sea condition is 1.6-1.9 times faster than the river condition. Service life of the bridges under urban area and sea condition is decreased about 2.4-3.3 times than river condition.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.28 no.2A
• /
• pp.187-196
• /
• 2008

The punching shear strength of RC slabs is estimated analytically by the simple truss model. To avoid intrinsic difficulties in punching shear analysis of reinforced concrete slabs, the slabs were divided into three sub-structures as the punching cone and the remaining parts. The strength of the punching cone was evaluated by the stiffness of inclined strut. The stiffness of springs which control lateral displacement of the roller supports consists of the steel reinforcement which passed through the punching cone. Initial angle of struts was determined by curve fitting method of the experimental data with variable reinforcement ratio in order to compensate for uncertainties in the slab's punching shear, the simplification errors and the stiffness of the remaining sub-structures. The validity of computed punching shear strength by simple truss model was shown by comparing with experimental results. The punching shear strength, which was determined by snap-through critical load of shallow truss, can be used effectively to examine punching shear strength of RC slabs.