• Steel and Composite Structures
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• v.49 no.4
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• pp.419-430
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• 2023

This paper is aimed at investigating the effect of multiple longitudinal stiffeners on the patch loading resistance of slender steel plate girders. Firstly, a numerical study is conducted through geometrically and materially nonlinear analysis with imperfections included (GMNIA), the model is validated with experimental results taken from the literature. The structural responses of girders with multiple longitudinal stiffeners are compared to the one of girders with a single longitudinal stiffener. Thereafter, a patch loading resistance model is developed through machine learning (ML) using symbolic regression (SR). An extensive numerical dataset covering a wide range of bridge girder geometries is employed to fit the resistance model using SR. Finally, the performance of the SR prediction model is evaluated by comparison of the resistances predicted using available formulae from the literature.

• Journal of the Korea institute for structural maintenance and inspection
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• v.15 no.2
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• pp.98-106
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• 2011

The deck of steel box girder bridges is composed of deck plate, longitudinal rib, and transverse ribs. The orthotropic steel decks have high possibility to fatigue damage due to numbers of welded connection part, the heavy contact loadings, and the increase of repeated loadings. Generally, the local stress by the repeated loadings of heavy vehicles causes the orthotropic steel deck bridge to fatigue cracks. The increase of traffic volume and heavy vehicle loadings are promoted the possibility of fatigue cracks. Thus, it is important to exactly evaluate the structural behavior of bridge considering the contact loading area of heavy vehicles and real load patterns of heavy trucks which have effects on the bridge. This study estimated the effect of contact area of design loads and real traffic vehicles through the finite element analysis considering the real loading conditions. The finite element analysis carried out 4 cases of loading patterns in the orthotropic steel deck bridge. Also, analysis estimated the influence of contact area of real truck loadings by the existence of diaphragm plate. The result of finite element analysis indicated that single tire loadings of real trucks occurred higher local stress than one of design loadings, and especially the deck plate got the most influence by the single tire loading. It was found that the diaphragm attachment at joint part of longitudinal ribs and transverse ribs had no effects on the improvement of structural performance against fatigue resistance in elastic analysis.

• Journal of Korean Society of Steel Construction
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• v.29 no.4
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• pp.281-289
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• 2017

The current AASHTO LRFD and Eurocode 3 specifications have been found to underestimate the flexural strength of longitudinally reinforced plate girders. This is because the web-flange interaction is not considered appropriately when a web is reinforced. The buckling strength of compression flange increases due to the improved rotational restraint to the compression flange. Also, the compression flange and the longitudinal stiffener could constrain the web rotation, so that a certain area of the web reaches yield strength. In this study, a model for evaluating the flexural strength is proposed for plate girders reinforced with one line of longitudinal stiffeners, considering the increase of the buckling strength of the compression flange and the actual stress distribution of the web. The flexural strengths of the conventional steel(SM490) and the high-strength steel(HSB800) plate girders were evaluated from the nonlinear analysis and the applicability of the proposed model was analyzed.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05a
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• pp.138-141
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• 2006

Shear wall-frame system is one of the most, if not the most, popular system for resisting lateral loads. The core is the primary lateral load-resisting systems, the perimeter frame is designed for gravity loads, and the connection between perimeter frame and core is generally a shear connection. Specially, single plate shear connection have gained considerable popularity in recent years due to their ease of fabrication and erection. Single plate shear connection should be designed to satisfy the dual criteria of shear strength and rotational ductility. An experimental program was undertaken to evaluate seismic behavior of single plate shear connection. The main test variable is the reinforcing detail of connection. Through the experimental program, the cyclic behavior of typical and reinforcing single plate shear connection was established.

• Journal of Korean Society of Steel Construction
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• v.19 no.3
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• pp.281-290
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• 2007

In this paper, the dynamic behavior of a 12m plate girder railway bridge is analyzed using the commercial FEM program. A time history load is applied to a standard train load via the shape function ofthe beam element. In addition, lateral behavior characteristics were simulated using the Klingel sine movement. A feasibility study of the FEM program and an analysis were performed by comparing the displacement and the acceleration, from the experimental data and the results of the FEM analysis. the time history of the lateral and vertical displacements are reflected in the experimental results. Six kinds of reinforcements were studied from the effects of the displacement and the acceleration. The RF-1 model that was applied to the upper lateral bracing system, and the RF-3 model that reinforced the plate, turned out to be the most effective reinforcement methods with respect to weight limits and construction simplification.

• International Journal of Railway
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• v.5 no.1
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• pp.10-21
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• 2012

Open steel plate girder (OPSG) bridges are the most prevalent railroad bridge type in Korea, constituting about 40% of all railroad bridges. Solid steel bearings, known as line type bearings, are placed in most OSPG railway bridges. However, the line type rigid bearings generate several problems with the bridge's dynamic behavior and maintenance in service. To compare and investigate the dynamic behaviors of line type, spherical and disk bearings, the vertical displacements of each bearing, including fixed and expansion type, under running vehicles are measured and analyzed. The displacements of disk and spherical bearings are measured after replacing the line type bearings with spherical and disk bearings. This study also analyzed dynamic behaviors of bridges. Furthermore, the deformation of the PTFE (Polytetrafluoroethylene) plate that is placed inside of expansion type spherical and disk bearings is measured and its effect on the dynamic behavior of the bridges is discussed. The up-lift phenomenon at the bearings installed for the steel bridges is estimated. The vertical displacements at mid-span of the bridges are compared according to the bearing types. Finally, the 1st mode natural frequencies are estimated, and the relationship to the vertical displacement is discussed.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.36 no.6
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• pp.969-977
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• 2016

In this paper, the static load test of long span PSC deck used in the twin steel plate girder bridge was conducted. To evaluate the structural behavior of long span deck, longitudinally sufficient length of deck is needed, but it is difficult to test the full-scale long span deck due to limit of transportation, setting and laboratory space. Therefore, this study proposed a method to apply longitudinal stiffness of the full-scale deck to the test specimen of longitudinally short length, and it was reinforced with the steel beam. The failure behavior and structural performance of the long span deck were evaluated by the proposed test specimen deck.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.3 no.3
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• pp.39-51
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• 1983

Increasing of load on the highway bridge necessitate the strengthening of load capacity of bridge by some method. The method of strengthening is the usage of pre-stressing high tensile steel line. Having finished pre-stressing work, line is anchored both end, then it composed a member of bridge structure when loading. This paper includes the method and mechanism of strengthening of I-beam span(same originality of plate girder), could be summerized as following; (a) Simple girder, 2 span and 3 span continuous girder increasing the load capacity by more than 80 % for concentrated load. (b) For uniformly distributed load, when all span loaded, load capacity is increase more than 80% to 100% except 3 span continuous.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.6
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• pp.1731-1741
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• 2014

Recently, many overpasses, highway, and advanced transit systems have been constructed to distribute the traffic congestion, thus small size of curved bridges with small curvature such as ramp structures have been increasing. Many of early curved bridges had been constructed by using straight beams with curved slabs, but curved steel beams have replaced them due to the cost, aesthetic and the advantage in building the section form and manipulating the curvature of beams, thereby large portion of curved bridges were applied with steel box girders. However, steel box girder bridges needs comparatively high initial costs and continuous maintenance such as repainting, which is the one of the reason for increasing the cost. Moreover, I-type steel plate girder which is being studied by many researchers recently, seem to have problems in stability due to the low torsional stiffness, resulting from the section characteristics with thin plate used for web and open section forms. Therefore, in recent studies, researchers have proposed curved precast PSC girders with low cost and could secured safety which could replace the curved steel girder type bridges. Hence, this study developed a Smart Mold system to manufacture efficient curved precast PSC girders. And by using this mold system a 40 m 2-girder bridge was constructed for a static flexural test, to evaluate the safety and performance under ultimate load. At the manufacturing stage, each single girder showed problems in the stability due to the torsional moment, but after the girders were connected by cross beams and decks, the bridge successfully distributed the stress, thereby the stability was confirmed. The static loading test results show that the initial crack was observed at 1,400 kN when the design load was 450 kN, and the load at the allowable deflection by code was 1,800 kN, which shows that the safety and usability of the curved precast PSC bridge manufactured by Smart Mold system is secured.

• Steel and Composite Structures
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• v.26 no.2
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• pp.183-196
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• 2018

The traditional prestressed concrete composite box-girders with corrugated steel webs have several drawbacks such as large deflection and potential local buckling. In this study, two methods were investigated to optimize and improve the prestressed concrete composite box-girders with corrugated steel webs. The first method was to replace the concrete bottom slab with a steel plate and the second method was to support the concrete bottom slab on the steel flanges. The behavior of the prestressed concrete composite box-girders with corrugated steel webs with either method was studied by experiments on three specimens. The test results showed that behavior of the optimized and upgraded prestressed concrete composite box-girders with corrugated steel webs, including ultimate bearing capacity, flexural stiffness, and crack resistance, is greatly improved. In addition, the influence of different shear connectors, including perfobond leisten (PBL) and stud shear connectors, on the behavior of prestressed concrete composite box-girders with corrugated steel webs was studied. The results showed that PBL shear connectors can greatly improve the ultimate bearing capacity, flexural stiffness and crack resistance property of the prestressed concrete composite box-girders with corrugated steel webs. However, for the efficiency of prestressing introduced into the girder, the PBL shear connectors do not perform as well as the stud shear connectors.