• Computers and Concrete
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• v.33 no.2
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• pp.217-240
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• 2024

The purpose of this study is to propose new hysteretic characteristics of medium- to low-rise RC structures controlled by both shear and flexure. Through previous study, the dual lateral force-resisting system composed of shear and flexural failure members has a new failure mechanism that cooperates to enhance the flexural capacity of the flexural failure member even after the failure of the shear member, and the existing theoretical equation significantly underestimates the ultimate strength. In this study, the residual lateral strength mechanism of the dual lateral force-resisting system was analyzed, and, as a result, an equation for estimating the residual flexural strength of each shear-failure member was proposed. The residual flexural strength of each shear-failure member was verified in comparison with the structural testing results obtained in previous study, and the proposed residual flexural strength equation for shear-failure members was tested for reliability using FEA, and its applicable range was also determined. In addition, restoring-force characteristics for evaluating the seismic performance of the dual lateral force-resisting system (nonlinear dynamic analysis), reflecting the proposed residual flexural strength equation, were proposed. Finally, the validity of the restoring-force characteristics of RC buildings equipped with the dual lateral force-resisting system proposed in the present study was verified by performing pseudo-dynamic testing and nonlinear dynamic analysis based on the proposed restoring-force characteristics. Based on this comparative analysis, the applicability of the proposed restoring-force characteristics was verified.

• Journal of the Korean Society of Clothing and Textiles
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• v.13 no.4
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• pp.400-411
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• 1989

Moisture related properties of fabrics in dynamic modes are considered to be important in the judgement of the subjective comfort characteristics of clothing fabrics. In the current study, an attempt to improve the cobaltous chloride test method was made which has been known as a convenient screening test for dynamic surface wetness. The color changes of cobaltous chloride treated fabrics on the simulated sweating skin were calibrated against standard color strips. The standard color strips were made of all typs of test fabrics and installed inside of the test tubes containing a series of saturated salt solutions, which gives more quantitative informations on dynamic moisture transfer Influences of fiber types and finishes on dynamic moisture transfer in textiles were studied using a single layer of fabric samples. Fiber types included $100\%$ cotton, C/P 50/50, C/P 35/65. Durable press and soil release finished cotton and C/P 50/50 fabrics were also included. There were significant fiber effects on the dynamic moisture transfer. The order of time taken to reach to the specified $\%$ RH was C/P 35/65$100\%$ cotton fabrics. It was possible to detect significant finish effects by increasing the concentrations of cobaltous chloride solutions. The order of time taken to reach to the specified $\%$ R.H was durable press$100\%$ cotton, C/P 50/50, C/P 35/65 and $100\%$ PET were placed at the inner side of the outer layer and tested. It was shown that cobaltous chloride treated $100\%$ cotton fabirc was easier to detect color changes than C/P blend fabic in the double layer experiments. By placing test sample under the cobaltous chloride treated cotton fabrics, it was able to detect the differences among the test samples, some of which were known to be difficult in padding with cobaltous chloride solutions. Besides, the double layer method would provide with the broader application of the cobaltous chloride method in !uture, since it is possible to test the dynamic moisture transfer of clothing as worn.

• Journal of the Korean Society of Clothing and Textiles
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• v.24 no.6
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• pp.819-827
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• 2000

The purpose of this study is to produce cotton fabric having improved dyeability and colorfastness as well as retaining the desirable durable press property. When cotton fabric was treated with additives, nitrogen content was increased as the additive concentration was increased. DP ratings and wrinkle recovery properties of BTCA treated cotton fabrics were greatly increased. But DP rating was lowered slightly by adding additives and wrinkle recovery property was decreased with the increase of additive concentration. Tensile strength was decreased by BTCA treatment but increased as additive concentration was increased. Various BTCA/additive treatments produced great affinity for reactive and acid dyes when dyebaths were adjusted at pH 3. It was showed that dyeability was increased as additive concentration was increased. The most effective additive for improving the dyeing properties of the crosslinked cotton was TEAㆍHCl. In case of reactive dye, there was almost no improvement on the dyeability of finished cotton by adding salt. Color fastness to washing and light of finished and dyed cotton were low except for the washfastness of reactive dye. Dyeing the BTCA/additive treated cotton fabrics with reactive dye had no effect on the physical properties.

• Textile Coloration and Finishing
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• v.21 no.3
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• pp.1-9
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• 2009

Polycarboxylics acids are used as crosslinking agents for cotton cellulose to produce durable finished press cotton fabric. It has been observed that the strength of the cotton fabric treated with polycarboxylic acids showed significant reduction as a result of the crosslinking process. The effect of acid-catalyzed depolymerization on the tear strength of cotton fabric is investigated by evaluating the cotton fabric treated by succinic acid, which does not crosslink cotton cellulose and form little ester on the cotton fabric. We find that the tear strength of cotton fabric treated with succinic acid decreases at elevated temperature due to acid-catalyzed depolymerization of cellulose. The magnitude of fabric strength reduction increases as the acid concentration increases. At a constant acid concentration, it increases as the curing temperature and time increases. It decreases as the pH of the acid solution increases. We also find that the dissociation constant of an acid also has a significant effect on the fabric strength reduction. The magnitude of fabric tear strength reduction increases as the acid dissociation constant decreases.

• Textile Coloration and Finishing
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• v.20 no.3
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• pp.8-17
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• 2008

For the purpose of standardization and practicability of natural dyeing, the mordanting and dyeing properties of turmeric was studied. In this study, the colorants of turmeric were extracted with boiling water. Chitosan-crosslinked cotton fabrics was dyed with aqueous extract of turmeric and their dyeabilities on the fabrics were studied. Additionally the fastness to washing and light were also investigated. Cotton fabrics were treated with a crosslinking agent epichlorohydrin in the presence of chitosan to provide the cotton fabrics the dyeing properties of natural dye(turmeric) by the chemical linking of chitosan to the cellulose structure. The chitosan finishing and durable press finishing of the cotton fabrics occurred simultaneously in the mercerization bath. The dyeability(K/S), which was obtained by CCM observation, remarkably became increased when the crosslinked chitosan concentration was higher. Dyeability of turmeric was improved on chitosan-crosslinked cotton fabric rather than only cotton fabric, while the saturated dyeing time was 20minutes at $60^{\circ}C$. The hue value indicated greenish yellow with increasing the crosslinked chitosan concentration. And the color fastness to washing and light was almost the same.

• Fashion & Textile Research Journal
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• v.6 no.2
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• pp.229-233
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• 2004

Andongpo, 100% Korean hemp fabric was treated with the glyoxale resin type finishing agent and/or the soluble urethane type finishing agent to determine the optimum process condition of the crease resistant finish and the crease recovery of treated sample fabrics was evaluated for the study. The treatment conditions for the study were 6 conditions, such as, A-1~A-6, in which A-1 was the condition of treatment glyoxale resin type finishing agent only and A-2~A-6 were the condition of treatment both glyoxale resin type finishing agent and soluble urethane type finishing agent. Among the 6 conditions, the crease recovery of the sample treated with A-4 condition was $148^{\circ}$(angle of recovery method) and grade 3.2(appearance method) and so, these samples showed the excellent crease recovery. From the result, 15g/l of the catalyst conc., 50g/l of the glyoxale resin type finishing agent cone., and 40g/l of the softner were the optimum treatment condition for the crease resistant finish of the andongpo.

• Journal of the Korean Society of Clothing and Textiles
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• v.13 no.3 s.31
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• pp.242-251
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• 1989

The purpose of this study was to investigate the changes in easy-care and strength properties of the wet fixation processed viscose rayon fabrics. Rayon fabrics were treated with mixed resins of melamine formaldehyde (MF) and DMDHEU by one bath and two bath wet fixation processes. The MF/DMDHEU mixed resin concentrations were 50/100, 50/150, 100/100, 100/150 and 150/100(g/1). Magnasium chloride was used as a catalyst. Treated fabrics were evaluated by nitrogen content, DP rating, wrinkle recovery angle, breaking strength, tearing strength and abrasion resistance. The properties were compared to the fabrics treated by conventional Pad-Dry-Cure (PDC) method. Wet fixation processed fabrics showed DP ratings of higher than 3 and higher than 275 degrees of wrinkle recovery angles in all the mixed resin concentrations. Wet fixation processed fabrics showed increase in breaking strength and tearing strength but decrease in abrasion resistance. However, the decrease in abrasion resistance was much less than the conventional PDC treated fabrics. The one bath wet fixation processed fabrics showed better physical properties than the two bath processed fabrics in general. The optimum treatment condition was the mixed resin concentration of MF/DMDHEU, 100/100 g/l in one bath wet fixation process.

• Computers and Concrete
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• v.8 no.5
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• pp.511-524
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• 2011

Although concrete is believed to be a durable material, concrete structures have been degraded by severe environmental conditions such as the effects of chloride and chemical, abrasion, and other deterioration processes. Therefore, durability evaluation has been required to ensure the long term serviceability of structures located in chloride exposed environments. Recently, probability-based durability analysis and design have proven to be reliable for the service-life predictions of concrete structures. This approach has been successfully applied to durability estimation and design of concrete structures. However, currently it is difficult to find an appropriate method engineers can use to solve these probability-based diffusion problems. In this paper, computer software has been developed to facilitate probability-based durability analysis and design. This software predict the chloride diffusion using the Monte Carlo simulation method based on Fick's second law, and provides durability analysis and design solutions. A graphic user interface (GUI) is adapted for intuitive and easy use. The developed software is very useful not only for prediction of the service life but for the durability design of the concrete structures exposed to chloride environments.

• Computers and Concrete
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• v.12 no.6
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• pp.831-850
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• 2013

The high strength materials have been more widely used in reinforced concrete structures because of the benefits of the mechanical and durable properties. Generally, it is known that the ductility decreases with an increase in the strength of the materials. In the design of a reinforced concrete beam, both the flexural strength and ductility need to be considered. Especially, when a reinforced concrete structure may be subjected an earthquake, the members need to have a sufficient ductility. So, each design code has specified to provide a consistent level of minimum flexural ductility in seismic design of concrete structures. Therefore, it is necessary to assess accurately the ductility of the beam sections with high strength materials in order to ensure the ductility requirement in design. In this study, the effects of concrete strength, yield strength of reinforcement steel and amount of reinforcement including compression reinforcement on the complete moment-curvature behavior and the curvature ductility factor of doubly reinforcement concrete beam sections have been evaluated and a newly prediction formula for curvature ductility factor of doubly RC beam sections has been developed considering the stress of compression reinforcement at ultimate state. Based on the numerical analysis results, the proposed predictions for the curvature ductility factor are verified by comparisons with other prediction formulas. The proposed formula offers fairly accurate and consistent predictions for curvature ductility factor of doubly reinforced concrete beam sections.

• Structural Engineering and Mechanics
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• v.63 no.1
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• pp.55-64
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• 2017

The paper concerns concrete carbonation, the phenomena that occurs in every type of climate, especially in urban-industrial areas. In European Standards, including Eurocode (EC) for concrete structures the demanded durability of construction located in the conditions of the carbonation threat is mainly assured by the selection of suitable thickness of reinforcement cover. According to EC0 and EC2, the thickness of the cover in the particular class of exposure depends on the structural class/category and concrete compressive strength class which is determined by cement content and water-cement ratio (thus the quantitative composition) but it is not differentiated for various cements, nor additives (i.e., qualitative composition), nor technological types of concrete. As a consequence the selected thickness of concrete cover is in fact a far estimation - sometimes too exaggerated (too safe or too risky). The paper presents the elaborated "self-terminated carbonation model" that includes abovementioned factors and enables to indicate the maximal possible depth of carbonation. This is possible because presented model is a hyperbolic function of carbonation depth in time (the other models published in the literature use the parabolic function that theoretically assume the infinite increase of carbonation depth value). The paper discusses the presented model in comparison to other models published in the literature, moreover it contains the algorithm of concrete cover design with use of the model as well as an example of calculation of the cover thickness.