• Resources Recycling
• /
• v.22 no.2
• /
• pp.62-70
• /
• 2013

Electric arc furnace slag is made in ironworks during steel refining, it is been increasing chemical and physical resistibility using ageing method of unstable state of melting steel slag for using concrete's fine aggregates. Which is been changing stable molecular structure of aggregates, it restrains moving of ion and molecule. In Korea, KS F 4571 has been prepared for using the electric arc furnace slag to concrete aggregates. In this study, Electric arc furnace slag is used in the PMC(Polymer Modified Concrete) which is applied a bridge pavement of rehabilitation, largely. In that case, this study evaluates the structural safety about increasing the specific weight. The 4-type bridges(RC slab bridge, RC rigid-frame bridge, PSC Beam bridge, Steel box girder bridge) pavement's increasing the total dead load is in 1 ~ 2%. Design moments in a load combination are increased less then 2%. safety factor is decreased less than 3%. Therefore, the structural safety has no problem for applying the electric arc furnace slag within PMC in bridge.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.27 no.4
• /
• pp.45-53
• /
• 2023

In this study, to analyze the correlation of surface chloride and corrosion amount level according to the installation location of steel members exposed to the marine environment, the surface chloride and mean corrosion depth were evaluated by member units for box girder members of the offshore steel bridge and box specimens. The surface chloride was measured monthly using the Bresle method for one year. The corrosion amount was evaluated by converting the weight loss due to corrosion products generated in the monitoring steel plate into mean corrosion depth. As a measurement result of the surface chloride and corrosion amount, relative differences in surface chloride and mean corrosion depth were appeared depending on the shape or installation location of the steel members. Moreover, even if members of the same shape were installed in the same bridge, it was confirmed that the corrosion amount was increased locally and rapidly. The tendency of corrosion amount depending on the surface chloride was evaluated to analyze the correlation between surface chloride and corrosion amount, and the relation equations that can asseses the corrosion amount depending on the surface chloride were analyzed. From the results of the correlation between surface chloride and corrosion amount, it was found that the corrosion amount of the steel member affected by the surface chloride was varied up to about 1.15 times depending on the structural detail.

• Journal of Korean Society of Steel Construction
• /
• v.24 no.5
• /
• pp.595-603
• /
• 2012

This study applied elastic supports in order to evaluate load carrying capacity using measurement data obtained from load tests actively and utilizing various evaluation methods. In order to confirm the adequacy of structural analysis based on elastic supports and to improve the reliability of experiment results, we conducted a deflection test with flexural beams prepared as overhanging beams and, based on the results, performed precision safety diagnosis for real bridges under public service for improving the load carrying capacity evaluation method for bridges under public service. In the results of the bending test, compared to deflection calculated by the existing method, deflection obtained by applying elastic supports was closer to the actually measured deflection. In the results of evaluating load carrying capacity for a 3 span continuous steel box girder bridge just after its completion, load carrying capacity by elastic supports was smaller by up to 39% than that by the existing method. When the load carrying capacity of bridges is evaluated by the existing method the results vary among engineers due to lack of guidelines for evaluation such as the application of stress modification factor. This study was conducted as an effort to solve this problem through active research.

• Journal of Korean Society of Steel Construction
• /
• v.28 no.5
• /
• pp.355-363
• /
• 2016

This study numerically investigates buckling behavior of press braked steel plates with a free edge that consists of the upper flange of U-shaped box girder. Since the press-braked plates include a rounded edge, the effective width to thickness ratio of the press-braked upper flange is obscure to determine the nominal compressive strength. This study performed 3D finite element analyses to evaluate an equivalent effective width of cold-formed plate with a free edge. Through the parametric numerical analyses, the elastic buckling stresses of the rounded corner plates were compared with those of general flat plates and then, the equivalent effective width has been estimated. A comparative study with Euler buckling formula speculated in the domestic design specifications has been conducted.

• Smart Structures and Systems
• /
• v.6 no.4
• /
• pp.373-388
• /
• 2010

The updated finite element model of K$\ddot{o}$m$\ddot{u}$rhan Highway Bridge on the Firat River located on the $51^{st}$ km of Elazi$\breve{g}$-Malatya highway is obtained by using analytical and experimental results. The 2D and 3D finite element model of the bridge is created by using SAP2000 structural analyses software, and the dynamic characteristics of the bridge are determined analytically. The experimental measurements are carried out by Operational Modal Analysis Method under traffic induced vibrations and the dynamic characteristics are obtained experimentally. The vibration data are gathered from the both box girder and the deck of the bridge, separately. Due to the expansion joint in the middle of the bridge, special measurement points are selected when experimental test setups constitute. Measurement duration, frequency span and effective mode number are determined by considering similar studies in literature. The Peak Picking method in the frequency domain is used in the modal identification. At the end of the study, analytical and experimental dynamic characteristic are compared with each other and the finite element model of the bridge is updated by changing some uncertain parameters such as material properties and boundary conditions. Maximum differences between the natural frequencies are reduced from 10% to 2%, and a good agreement is found between natural frequencies and mode shapes after model updating.

• Computers and Concrete
• /
• v.12 no.2
• /
• pp.169-186
• /
• 2013

The aim of this paper is to determine the effect of soil-structure interaction and time dependent material properties on behavior of concrete box-girder highway bridges. Two different finite element analyses, one stage and construction stage, have been carried out on Komurhan Bridge between Elazi$\breve{g}$ and Malatya province of Turkey, over Fırat River. The one stage analysis assume that structure was built in a second and material properties of structure not change under different loads and site conditions during time. However, construction stage analysis considers that construction time and time dependent material properties. The main and side spans of bridge are 135 m and 76 m, respectively. The bridge had been constructed in 3 years between 1983 and 1986 by balanced cantilever construction method. The parameters of soil-structure interaction (SSI), time dependent material properties and construction method are taken into consideration in the construction stage analysis while SSI is single parameter taking into consideration in the one stage analysis. The 3D finite element model of bridge is created the commercial program of SAP2000. Time dependent material properties are elasticity modulus, creep and shrinkage for concrete and relaxation for steel. Soft, medium, and firm soils are selected for evaluating SSI in both analyses. The results of two different finite element analyses are compared with each other. It is seen that both construction stage and SSI have a remarkable effect on the structural behavior of the bridge.

• Smart Structures and Systems
• /
• v.4 no.5
• /
• pp.605-628
• /
• 2008

In bridge structures, damage may induce an additional deflection which may naturally contain essential information about the damage. However, inverse mapping from the damage-induced deflection to the actual damage location and severity is generally complex, particularly for statically indeterminate systems. In this paper, a new load concept, called the positive-bending-inspection-load (PBIL) is proposed to construct a simple inverse mapping from the damage-induced deflection to the actual damage location. A PBIL for an inspection region is defined as a load or a system of loads which guarantees the bending moment to be positive in the inspection region. From the theoretical investigations, it was proven that the damage-induced chord-wise deflection (DI-CD) has the maximum value with the abrupt change in its slope at the damage location under a PBIL. Hence, a novel damage localization method is proposed based on the DI-CD under a PBIL. The procedure may be summarized as: (1) identification of the modal flexibility matrices from acceleration measurements, (2) design for a PBIL for an inspection region of interest in a structure, (3) calculation of the chord-wise deflections for the PBIL using the modal flexibility matrices, and (4) damage localization by finding the location with the maximum DI-CD with the abrupt change in its slope within the inspection region. Procedures from (2)-(4) can be repeated for several inspection regions to cover the whole structure complementarily. Numerical verification studies were carried out on a simply supported beam and a three-span continuous beam model. Experimental verification study was also carried out on a two-span continuous beam structure with a steel box-girder. It was found that the proposed method can identify the damage existence and damage location for small damage cases with narrow cuts at the bottom flange.

• Proceedings of the Korea Contents Association Conference
• /
• 2006.05a
• /
• pp.541-544
• /
• 2006

Currently the bolt joint defect occurs from the steel bridge which is in the process of using but that investigation about each kind defect is lacking state. Research to see consequently the high strength bolt joint sliding conduct bring the model it used a structural analysis program LUSAS numerical analysis execution and a plan for Steel Box Girder Bridge copying full-size H-Beam and plan pretensioned bolt force 100%. 75%, 50% and 25% pretensioned force it acted in standard. And a hold an examination, against the sliding loads which it follows in the pretensioned force it will analysis.

• Journal of Korean Society of Steel Construction
• /
• v.15 no.4 s.65
• /
• pp.341-358
• /
• 2003

This paper proposed a general formulation of Life-Cycle Cost (LCC) models and LCC effective design system models of steel bridges suitable for practical implementation. An LCC model for the optimum design of steel bridges included initial cost and direct/indirect rehabilitation costs of a steel bridge as well as repair/replacement costs, loss of contents or fatality and injury losses, road user costs, and indirect socioeconomic losses. The new road user cost model and regional socioeconomic losses model were especially considered because of the traffic network. Illustrative design examples of an actual steel box girder and an orthotropic steel deck bridge were discussed to demonstrate the LCC effectiveness of the design of steel bridges. Based on the results of the numerical investigation, the LCC-effective optimum design of steel bridges based on the proposed LCC model was found to lead to a more rational, economical, and safer design compared with the initial cost-optimum design and the conventional code-based design.

• Journal of Welding and Joining
• /
• v.16 no.5
• /
• pp.134-141
• /
• 1998

In this study, a fillet size for bending fatigue strength of one side fillet welded T-joint, used in box type girder and other welding structure, was investigated by bending fatigue test with or without edge preparation and burn through, with variation of joint shape. As a result, the following conclusions were obtained. (1) In one side fillet welded T-joint, the larger the leg length, the greater the bending fatigue strength. The increase in bending fatigue strength. (2) One side filet welded T-joint with edge preparation showed higher bending fatigue strength than that with twofold-large leg length and without edge preparation. (3) In one side fillet welded T-joint without edge preparation, both manual welding and automatic welding were carried out with same condition. In this case, automatic welding shoed deeper penetration and more increased horizontal leg length than manual welding, so that automatic welding offers grater bending fatigue strength. (4) For one side fillet welded T-joint without edge preparation, the ratio(h/t) of the leg length (h) and the main plate thickness (t) in which toe crack can occur was 1.2 over. (5) In one side fillet welded T-joint with edge preparation, the burn through led to reduced bending fatigue strength. However, this bending fatigue strength was higher than that of one side fillet welded T-joint without edge preparation and with a larger leg length.