• Journal of the Korea institute for structural maintenance and inspection
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• v.14 no.5
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• pp.161-168
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• 2010

Practicing engineers and researchers need computational tools that estimate accurately the cyclic response of RC walls, and in particular, force and deformation capacities and their materials strains. So this paper describes a nonlinear truss modeling approach for reinforced concrete walls, or in general, for plane stress reinforced concrete elements subjected to cyclic reversals. Nonlinear vertical, horizontal, and diagonal truss elements are used to represent concrete and steel reinforcement. The wall having aspect ratio of 1.2 was chosen to be compared with the experimental results. Here, four types of main diagonal member models and three types of diagonal members models were applied to find out more accurate results of analysis.

• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.6
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• pp.41-49
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• 2021

Cement-mixed polymer-based waterproofing materials are generally used in the form of application by mixing in the field, and it is necessary to supplement the construction ability for air bubbles and uneven coating thickness due to irregularities during construction. The final purpose of this study is to improve the waterproofing performance by adding a sheet attaching process to the composite construction rather than the single process of painting and applying the construction method when applying the polymer waterproofing material to the field. In this regard, the applicability was evaluated by examining the material, environment, and manufacturing method.

• Journal of the Korea institute for structural maintenance and inspection
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• v.10 no.6
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• pp.183-190
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• 2006

From the result of this research above, it may be summed up as follows. As a summary of results from each experiment, as the test body reinforced with the carbon rods was embedded inside the concrete section and made it possible uniform movement, this study has shown that it had excellent characteristics in improving the flexural strength and ductility. Also, it was considered as the carbon-steel sheet composite plate was to exert the strength more if it would complement the adherence with the concrete.

• Journal of the Korea institute for structural maintenance and inspection
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• v.10 no.5
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• pp.115-121
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• 2006

This paper deals with the influence of behavior of a variety of cable elements on the limit strength of steel cable-stayed bridges. The softening plastic-hinge model, which is represented in this study for the limit strength evaluation of the example bridge, considers both geometric and material nonlinearites. Geometric nonlinearity of beam-column members are accounted by using stability function, and material nonlinearity - by using CRC tangent modulus and parabolic function. Cable sag effect is considered for cable members. The result of this study shows that the limit strength of the example bridge using the equivalent of elasticity for truss straight elements is smaller than those using the cable or the catenary elements.

• Journal of the Korea institute for structural maintenance and inspection
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• v.10 no.5
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• pp.147-156
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• 2006

This study is purposed to improve the performance of concrete made of recycled coarse aggregate. For this, recycled aggregate concrete was produced with SBR latex, and fluidity, dynamic performance and drying shrinkage were examined. According to the result, with mixing 6% of SBR latex, fluidity having resistance against segregation can be insured and compressive and flexural strength was increased. Especially the increment in terms of flexures was remarkable. In addition to, with above mixing ratio, drying shrinkage was reduced. Therefore there is a strong inference that superior recycled aggregate concrete can be produced with using 6% of SBR latex.

• Journal of the Korea institute for structural maintenance and inspection
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• v.10 no.5
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• pp.203-211
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• 2006

In this paper, the optimization of direct design system of steel frames by genetic algorithm involving advanced analysis are performed. For the analysis of steel frames advanced analysis accounting for geometric nonlinearity and material nonlinearity are executed. The genetic algorithm was used as optimization technique. The weight of structures is treated as the objective function. The constraint functions are defined by load-carrying capacities, deflections, inter-story drifts, and ductility requirement. The effectiveness of the proposed method are verified by comparing the results of the proposed method with those of other method.

• Journal of the Korea institute for structural maintenance and inspection
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• v.10 no.1
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• pp.157-164
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• 2006

This paper presents the durability characteristics of commercially available CFRP rebars under various environmental conditions. Two types of GFRP rebars were tested by using an accelerated aging method. A total of 264 rebar specimens were conditioned up to 132 days in the moisture, chloride. alkaline, and freeze-thaw environmental conditions. The durability characteristics of conditioned rebars were obtained by comparing the tensile strength, horizontal shear strength, and elastic modulus between the unconditioned and conditioned GFRP rebars. The test results indicated that the mechanical properties of GFRP were significantly reduced after conditioning. Long-term degradation of GFRP rebars was also estimated using the results of a short-term durability test.

• Journal of the Korea institute for structural maintenance and inspection
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• v.11 no.2
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• pp.93-102
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• 2007

A large number of FRP decks are already in service worldwide because the lighter FRP-based bridge decks are ideal for rapid construction to reduce the dead load of superstructures. And the proper design process is demanded for the effective FRP deck application. In this paper, to get the basic prototype of FRP bridge decks, the ratio of individual parameters, which compose the specification of FRP bridge decks, are determined by a finite element analysis. In addition, optimum FRP deck shapes are determined considering complex constraints and material properties of bi-directional characteristics. Upon these results, the prototype of FRP bridge decks is validated.

• Journal of the Korea institute for structural maintenance and inspection
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• v.12 no.1
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• pp.65-72
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• 2008

The use of hybrid FRP-concrete structures with a dual purpose of both permanent formwork and reinforcement, has been considered in some studies recently. For the FRP plank and the concrete to act as a composite structural member a satisfactory bond at the interface between the smooth surface of the pultruded plank and the cast-in-place concrete must be developed. Sand was bonded to the pultruded FRP plank using a commercially available epoxy system. In applying general analysis techniques to evaluate the performance of composite structures with FRP stay-in-place forming, it is essential that characteristics of the bond stress-slip relation be identified. In this study I would like to propose a simplified bilinear bond stress-slip model for FRP composite structures.

• Journal of the Korea institute for structural maintenance and inspection
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• v.12 no.5
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• pp.169-178
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• 2008

Compressive flanges of steel box girder is designed based on the ultimate strength behavior of sub-panel which is enclosed with longitudinal stiffeners and transverse stiffeners on appropriate safety factor. However, it is rational that the ultimate strength is calculated considering the various factors such as number and stiffness of longitudinal stiffener, spacing of transverse stiffener, initial deformation and residual stress distribution. In this study, an analysis program based on Folded Plate theory is developed considering the geometric effects and the material nonlinearity. The analysis program is applicated to the steel box girder bridges which is really constructed in domestic.