• Computers and Concrete
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• v.7 no.3
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• pp.203-220
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• 2010

In the present study, exterior beam-column sub-assemblage from a regular reinforced concrete (RC) building has been considered. Two different types of beam-column sub-assemblages from existing RC building have been considered, i.e., gravity load designed ('GLD'), and seismically designed but without any ductile detailing ('NonDuctile'). Hence, both the cases represent the under-designed structure at different time frame span before the introduction of ductile detailing. For designing 'NonDuctile' structure, Eurocode and Indian Standard were considered. Non-linear finite element (FE) program has been employed for analysing the sub-assemblages under cyclic loading. FE models were developed using quadratic concrete brick elements with embedded truss elements to represent reinforcements. It has been found that the results obtained from the numerical analysis are well corroborated with that of experimental results. Using the validated numerical models, it was proposed to correlate the energy dissipation from numerical analysis to that from experimental analysis. Numerical models would be helpful in practice to evaluate the seismic performance of the critical sub-assemblages prior to design decisions. Further, using the numerical studies, performance of the sub-assemblages with variation of axial load ratios (ratio is defined by applied axial load divided by axial strength) has been studied since many researchers have brought out inconsistent observations on role of axial load in changing strength and energy dissipation under cyclic load.

• Journal of the Korea institute for structural maintenance and inspection
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• v.16 no.1
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• pp.9-17
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• 2012

This study is dealt with the experimental seam strength of deep corrugated steel plate which is used as underpasses, storm sewers and other buried applications. The soil-metal structure using deep corrugated plate should be sufficient to ensure safety for compressive loading. The experimental and theoretical results on the seam strength are accumulated enough to take the design guideline, even if the seam strength at the bolt connected lap joint in construction site can be varied depending on the connection detailing and the thickness of plate. In this study, compressive behavior of bolted lap jointed plates using various connection detail such as gasket, slot hole, washer was experimentally analyzed. From the test, failure pattern with an increases in the thickness of specimens was changed from plate bearing to bolt shearing. In case of thicker plates than 6.0mm, the structural performance of lap joint using gasket and slot hole is more effective than it of the plate adopted washer.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2000.04a
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• pp.327-334
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• 2000

The seismic performance evaluation of the existing non-seismic detailed RC piers has risen as urgent task for rational and cost-effective seismic retrofitting works as well as development of new seismic design concept. The scale model test has been conducted to investigate nonlinear behavior characteristics and the seismic performance of existing piers with lap-spliced longitudinal reinforcements in the plastic hinge zone which are of the solid circular and the hollow rectangular section. The lap splice in this zone is found to cause premature bond failure. The experimental results show very poor seismic performance of circular section pier but relatively large ductility of the rectangular one.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2000.04a
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• pp.202-212
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• 2000

This study investigates the ductility capacity of slender-wide reinforced concrete walls under predominant flexural moment loading. The experimental work for this study aims to provide design guidelines for bar detailing in critical regions under compressive stress in particular in case of slender-wide RC walls. According to the experimental observation the Bernoulli hypothesis of linear strain distribution is no longer valid and the ultimate compressive strain of concrete is significantly reduced, It is postulated that the nonlinear strain distribution causes the concentrated compressive stressed region and hence the premature crushing failure at the toe of walls. The reduced ultimate strain and nonlinear strain distribution need transverse reinforcement for confinement and more realistic models for the strength and displacement estimation of slender-wide RC wall.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2008.04a
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• pp.596-601
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• 2008

This paper presents how to develop visual design tools for construction of strut-and-tie models(S (STM). STMs have shown internal force flows for dimensioning and proportioning of D-regions of reinforced concrete structures. In order to select an appropriate strut-and-tie model some interactive graphic tools are necessary to help designers compare alternatives by changing the geometry of initial STM. This study proposes to use force polygons representing the equilibrium state of STM. The change of STM dynamically shows change of force magnitudes by force polygon. Once the geometry of STM is determined the detailing design process is required in the next procedure.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2002.03a
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• pp.195-202
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• 2002

Lap splices of longitudinal reinforcement steels were practically located in the potential plastic hinge region of most bridge columns that were constructed before the 1992 seismic design provision of Roadway Bridge Design Specification in Korea. The objective of this research is to evaluate the seismic performance of shear-critical reinforced concrete(RC) bridge piers with poor detailing of the starter bars in the plastic hinge region, and to develop the enhancement scheme of their seismic capacity by retrofitting with fiber composites. Seven test specimens in the aspect ratio of 2.5 were made with three confinement ratios and two types of lap splices. Quasi-static test was conducted in a displacement-controlled test mode. A significant reduction of displacement ductility ratios were observed for test columns with lap splices of longitudinal steels.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2002.03a
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• pp.258-265
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• 2002

The recent earthquakes in worldwide have caused extensive damage to highway bridge structures. In particular, it has been demonstrated that concrete columns with inadequate lateral reinforcement contributed to the catastrophic collapse of many bridges. The poor detailing of the starter bars in these columns compounded the problem of seismic deficiency. Therefore, this study has been performed to verify the effect of lap spliced longitudinal steel and confinement steel type for the seismic behavior of reinforced concrete bridge piers. Eight concrete columns were constructed with existing scale as diameter, 1.2m and height, 4.8m. 4 confinement steel types were adopted for seismic performance evaluation. All specimens were rested under inelastic cyclic loading while simultaneously subjected to a constant axial load. The longitudinal steel lap-splice is highly effective in seismic performance deterioration of reinforced concrete bridge piers.

• Steel and Composite Structures
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• v.5 no.2_3
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• pp.141-158
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• 2005

The new version of Code for Design of Steel Structures (GB50017-2003) and other design standards in China were released over the last two years. Comparing with the previous version (GBJ17-88), many clauses covering the connection design have been revised. A number of additional provisions are supplemented to specify the design requirements for beam-column moment connections, as well as gusset plates for truss joints. In this paper, a summary on the design rules on connections specified in the current Chinese code is presented, and relevant commentary and background information is provided whenever appropriate. The design criteria governing weld and bolt resistance is examined and reviewed. Moreover, several issues such as detailing requirements for stiffeners and end-plate connections are discussed.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.10a
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• pp.345-348
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• 1999

Since the cement-water reaction is exothermic by nature, the temperature rise within a large concrete mass. Significant tensile stresses may develop from the volumn change associated with the increase and decrease of the temperature with the mass concrete. These thermal stresses will cause temperature-related cracking in mass concrete structures. These typical type of mass concrete include mat foundation, bridge piers, thich walls, box type walls, tunnel linings, etc. Crack control methods can be considered at such stages as designing, selecting the materials, and detailing the construction method. In this paper, the effect of placing of crack control joint or construction joint was analysed by a three dimensional finite element method. As a result, using this method, crack control can be easily performed for structures such as wall-type structures.

• Imaging Science in Dentistry
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• v.50 no.1
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• pp.65-71
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• 2020

Ossifying fibroma is a slow-growing benign neoplasm that occurs most often in the jaws, especially the mandible. The tumor is composed of bone that develops within fibrous connective tissue. Some ossifying fibromas consist of cementum-like calcifications, while others contain only bony material; however, a mixture of these calcification types is commonly seen in a single lesion. Of the craniofacial bones, the mandible is the most commonly involved site, with the lesion typically inferior to the premolars and molars. Ossifying fibroma of the jaw shows a female predominance. Some reports of ossifying fibroma have been published in the literature; however, this report continues the research on this topic by detailing 3 types of ossifying fibroma findings on panoramic radiographs and cone-beam computed tomographic images of 4 patients. The radiographs of the presented cases could help clinicians understand the variations in the radiographic appearance of this lesion.