• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.1A
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• pp.15-26
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• 2010

Quasi-static tests were conducted to evaluate structural performance of precast piers prestressed by bonded prestressing steels. Combinations of prestressing bars and normal reinforcing bars, embedded steel tubes and prestressing strands were used as continuous steels crossing the joints of a precast pier. Main design parameters were steel ratio, magnitude of prestress force, and section details. Flexural strength and energy dissipation capacity of precast columns with higher steel ratio showed better performance due to continuous steels after opening of the joints. Precast piers with embedded members showed stable behavior after reaching maximum loads resulting in higher displacement ductility and energy dissipation capacity increased as the introduced prestress increased. Self-centering behavior at early stages and stress increase of confining reinforcements were observed from highly prestressed columns. Combination of prestressing steels and normal reinforcing bars should be used in design to prevent rapid strength degradation after reaching the maximum load.

• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.6
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• pp.162-171
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• 2023

In this study, The details for a seismic adapter designed to easily connect concrete structures and reinforcement materials for the in-plane reinforcement of aged structures were proposed. Proposed seismic adapter was tested for performance using a dynamic simulation on a 2-story column-beam structure, scaled to half of the real size. The experimental results showed that the reinforced test specimens using the seismic adapter improved their energy dissipation capacity by 3.5 times compared to the non-reinforced specimens. It was confirmed that the seismic adapter experienced no damage within its general usage range, thus proving its effectiveness. Subsequently, upon loading until the limit of deformation (a deformation angle of 3.3%), it was observed that one of the M10 bolts connecting the adapter and the reinforcement at the lower part of the first floor broke. Considering this finding, when applying seismic retrofitting in real situations, emphasis should be placed on the design of the bolts and anchors connecting the seismic adapter. This aspect warrants further research for validation.

• Polymer(Korea)
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• v.29 no.6
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• pp.523-535
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• 2005

Linear aromatic polyesters are representative examples of thermotropic liquid crystalline polymers (TLCPs), which have been the subject of many researches. This article reviews the structure-LC properties relationship in wholly aromatic CLCPs mostly based on the results obtained for the past quarter of a century. Especially, this review deals with the structural details of aromatic polyester TLCPs that influence the liquid crystalline and thermal properties. In the last part of this article the liquid crystalline properties of combined type and hyperbranched polyester also are discussed. Introduction to various synthetic methods are included in the last section.

• Fashion & Textile Research Journal
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• v.9 no.6
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• pp.595-602
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• 2007

This study examined the aesthetic characteristics of Grecian style which is being considered as the representative classic of Western fashion and the transformations of those Grecian styles on the fashion of the twentieth century. This study used positive research method using literatures on art history and clothing history, fashion related publications, and magazines and websites to understand the trend of fashion designer's collections. The study results are as follows. The aesthetic characteristics of Grecian style was considered to be the ideal beauty combined with symmetry, the functional beauty combined with non-construction, and the sensual beauty combined with natural body. The ideal beauty combined with symmetry appears as a style that shows idealistic proportion of a body emphasizing high-waist based on the golden ratio and the body as a whole rather than details. The functional beauty combined with non-construction appears as perfect recreation a body in its original and natural form. The clothing takes a form that does not have any structural design and has simplified cutting and sewing. It uses pins and strings to fix up the form of clothing which is flexible and naturally draped. The sensual beauty combined with natural body is found in natural silhouette dress alluding naked body in connection with Rousseau' naturalism in neoclassic period. Throughout the twentieth century, the desire for Grecian style was conveyed by a single detail or through an array of allusive effects.

• Structural Engineering and Mechanics
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• v.18 no.3
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• pp.343-362
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• 2004

Rocking response of rigid bodies with rectangular footprint, freely standing on horizontal rigid plane is studied analytically. Bodies are subjected to simulated single component of horizontal earthquakes. The effect of baseline correction, applied to simulated excitations, on the rocking response is first examined. The sensitiveness of rocking motion to the details of earthquakes and geometric properties of rigid bodies is investigated. Due to the demonstrated sensitivity of rocking response to these factors, prediction of rocking stability must be made in the framework of probability theory. Therefore, using a large number of simulated earthquakes, the effects of duration and shape of intensity function of simulated earthquakes on overturning probability of rigid bodies are studied. In the case when a rigid body is placed on any floor of a building, the corresponding probability is compared to that of a body placed on the ground. For this purpose, several shear frames are employed. Finally, the viability of the energy balance equation, which was introduced by Housner in 1963 and widely used by nuclear power industry to estimate the rocking stability of bodies, is evaluated. It is found that the equation is robust. Examples are also given to show how this equation can be used.

• Structural Engineering and Mechanics
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• v.25 no.5
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• pp.519-540
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• 2007

In this paper, the energy-based plastic-damage model previously proposed by the authors [International Journal of Solids and Structures, 43(3-4): 583-612] is first simplified with an empirically defined evolution law for the irreversible strains, and then it is extended to its rate-dependent version to account for the strain rate effect. Regarding the energy dissipation by the motion of the structure under dynamic loadings, within the framework of continuum damage mechanics a new damping model is proposed and incorporated into the developed rate-dependent plastic-damage mode, leading to a unified constitutive model which is capable of directly considering the damping on the material scale. Pertinent computational aspects concerning the numerical implementation and the algorithmic consistent modulus for the unified model are also discussed in details, through which the dynamic nonlinear analysis of damping structures can be coped with by the same procedures as those without damping. The proposed unified plastic-damage model is verfied by the simulations of concrete specimens under different quasistatic and high rate straining loading conditions, and is then applied to the Koyna dam under earthquake motions. The numerical predictions agree fairly well with the results obtained from experimental tests and/or reported by other investigators, demonstrating its capability for reproducing most of the typical nonlinear performances of concrete under quasi-static and dynamic loading conditions.

• Structural Engineering and Mechanics
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• v.49 no.5
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• pp.597-618
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• 2014

For the structures containing multiple discontinuities (voids, inclusions, and cracks), the simulation technologies in the framework of extended finite element method (XFEM) are discussed in details. The level set method is used for representing the location of inner discontinuous interfaces so that the mesh does not need to align with these discontinuities. Several illustrations have been given to verify that the implemented XFEM program is effective. Then, the implemented XFEM program is used to investigate the effects of the voids, inclusions, and minor cracks on the path of major crack propagation. For a plate containing cracks and voids, two possibly crack path can be observed: i) the crack propagates into the void; ii) the crack initially curves towards the void, then, the crack reorients itself and propagates along its original orientation. For a plate with a soft inclusion, the final predicted crack paths tend to close with the inclusion, and an evident difference of crack paths can be observed with different inclusion material properties. However, for a plate with a hard inclusion, the paths tend to away from the inclusion, and a slightly difference of crack paths can only be seen with different inclusion material properties. For a plate with several minor cracks, the trend of crack paths can still be described as that the crack initially curves towards these minor cracks, and then, the crack reorients itself and propagates almost horizontally along its original orientation.

• Bulletin of the Korean Chemical Society
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• v.32 no.5
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• pp.1640-1644
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• 2011

Water-soluble mutant of intrinsically insoluble protein, crambin, was produced by mutagenesis based on the sequence analysis with homologous proteins. Thr1, Phe13, and Lys33 of crambin were substituted for Lys, Tyr, and Lys, respectively. The resultant mutant was soluble in aqueous buffer as well as in dodecylphosphocholine (DPC) micelle solution. The $^1H-^{15}N$ spectrum of the mutant crambin showed spectral similarity to that of the wild-type protein except for local regions proximal to the sites of mutation. Solution structure of water-soluble mutant crambin was determined in aqueous buffer by NMR spectroscopy. The structure was almost identical to the wild-type structure determined in non-aqueous solvent. Subtle difference in structure was very local and related to the change of the intra- and inter-protein hydrophobic interaction of crambin. The structural details for the enhanced solubility of crambin in aqueous solvent by the mutation were provided and discussed.

• Steel and Composite Structures
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• v.3 no.2
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• pp.123-140
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• 2003

The importance of the research on moment-resistant properties of unstiffened tubular joints and the research background are introduced. The performed experimental research on the bending rigidity and capacity of the joints is reported. The emphasis is put on the discussion of the flexural behavior of the joints including sets of geometrical parameters of the joints and several loading combinations. Procedures and results of loading tests on four full size joints in planar KK and X configuration are described in details at first. Mechanical models are proposed to analyze the joint specimens. Three-dimensional nonlinear FE models are established and verified with the experimental results. By comparing the experimental data with the results of the analysis, it is reported reasonable to carry out the structural analysis under the assumption that the joint is fully rigidly connected, and their bending capacities can assure the strength of the members connected under certain limitation. Furthermore, a parametric formula for inplane bengding rigidity of T and Y type tubular joints is proposed on the basis of FE calculation and regression analysis. Compared with test results, it is shown that the parametric formula developed in this paper has good applicability.

• Structural Engineering and Mechanics
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• v.65 no.5
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• pp.601-609
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• 2018

Steel bolts are used in the construction industry for a large variety of applications that range from fixing permanent installations to temporary fixtures. In the past much research has been focused on developing destructive testing techniques to estimate their pull-out load carrying capacity with very little attention to develop non-destructive techniques. In this regards the presented research work details the combined use of ultrasonic pulse velocity and Schmidt hammer tests to identify anchor bolts with faculty installation and to estimate their pull-out strength by relating it to the Schmidt hammer rebound value. From experimentation, it was observed that the load capacity of bolt depends on its embedment length, diameter, bond quality/concrete strength and alignment. Ultrasonic pulse velocity test is used to judge the quality of bond of embedded anchor bolt by relating the increase in ultrasonic pulse transit time to the presence of internal pours and cracks in the vicinity of steel bolt and the surrounding concrete. This information combined with the Schmidt hammer rebound number, R, can be used to accurately identify defective bolts which resulted in lower pull-out strength. 12 mm diameter bolts with embedment length of 70 mm and 50 mm were investigated using constant strength concrete. Pull-out load capacity versus the Schmidt hammer rebound number for each embedment length is presented.