Papers by Author: Tae Soo Kim

Abstract: Experimental studies for single shear bolted connection of cold-formed ferritic stainless steel fastened with two bolts (2×1 bolt array) and 3.0 mm thick plate has been performed by T.S. Kim etc. End distances parallel to the direction of applied force were considered as the main variables of specimens. Curling (out of plane deformation) was observed in bolted connection with 60mm end distance and it caused abrupt strength reduction. The purpose of this paper is to compare the analysis results with test results and investigate the curling influence on ultimate strength through numerical modelling. FE models with restrained curling were also simulated for strength comparison with the curled specimen. Therefore, the validation of finite element(FE) analysis in predicting ultimate strength and curling behaviour was verified and the strength reduction ratio by the curling was estimated.

Abstract: Based on the existing test results of single shear bolted connection fabricated with cold-formed ferritic stainless steel, in this study, the experiment for double shear bolted connections with bolt arrangements(1×2, 2×2) and end distance parallel to the loading direction as main variables has been performed. Specimens were planed with a constant dimension of edge distance perpendicular to the loading direction, bolt diameter, pitch and gauge. Ultimate strength and fracture mode obtained from test results were compared with those predicted by current American and Japan design codes such as AISI and AIJ.

Abstract: Since stainless steel has significant characteristics such as its superior corrosion resistance, durability, aesthetic appeal etc., it has been utilized as structural members in buildings. Recently, ultimate behaviors and curling influence in austenitic stainless steel single shear bolted connections with thin-walled plane plates have been investigated by T.S. Kim. In this paper, finite element analysis (FEA) has been conducted based on the existing test results of angle bolted connections in fabricated with austenitic stainless steel. The validation of the numerical analysis prediction was verified through the comparison of test results for fracture mode, ultimate strength and curling occurrence. Curling (out-of- plane deformation) also observed in the connections with a long end distance. The curling caused the ultimate strength reduction and the ultimate strength reduction ratios (varied from 12% to 25%) caused by curling have been estimated quantitatively through the comparison of FEA results of FE models with free edge and restrained curling.

Abstract: Experiments have been carried out to investigate the ultimate behaviors of single shear bolted connections assembled with four bolts (2 rows×2 columns bolt arrangement) under shear and aluminum alloy plate. End distance parallel to the direction of applied load is considered as main variables. All specimens failed in block shear fracture and curling (out of plane deformation) in the direction parallel to plate thickness was also observed for some bolted connections with a long end distance. The curling led to sudden ultimate strength reduction and test strength was compared with the block shear strength predicted by current design specifications.

Abstract: The application of stainless steel in buildings has been increased gradually with excellent life cycle cost for ensuring the sustainability in structures for the reduction of green house gas emission. Especially, the purpose of this paper is to investigate the structural behaviors such as ultimate strength, fracture mode and out of plane deformation, i.e., curling of single shear bolted connection of cold-formed austenitic stainless steel with two bolts (2×1 bolt arrangement). Plate thickness and end distance parallel to the direction of applied force are considered as main variables. The curling was also observed in the bolted connections with a long end distance and edge distance as the previous researches. Curling occurrence resulted in the change of fracture modes in connections with same bolt arrangement and end distance and ultimate strength reduction.

Abstract: The experimental research for single shear bolted connection of cold-formed stainless steel fabricated with two bolts (2×1 bolt arrangement) has been conducted by T.S. Kim etc. Plate thickness and end distance parallel to the direction of loading was considered as main variables. It is found that the curling occurred easily in bolted connections with a long end distance and thinner plate. In this paper, finite element analysis study has been performed in order to compare test results with the predicted results and to investigate in detail the ultimate strength and curling influence. Finite element analysis(FEA) procedures also were introduced. FE models of connections with restrained out of plane deformation were also simulated for comparison with the curled models. Therefore, the validation of FEA in predicting ultimate strength and curling behavior was verified and the strength reduction ratio caused by curling was estimated.

Abstract: In recent years, the friction coefficient decline in the joints of steel structures caused by corrosion has drawn public attention. Therefore, this study investigated the friction coefficient and surface roughness of high tension bolt joints using a Zn/Al metal spraying corrosion resistance method to estimate the application possibility of the Zn/Al metal spraying corrosion resistance method on the joints of steel structures. According to results, the friction coefficient of Zn/Al metal spraying was 0.50 or more. In addition, the friction coefficient increased according to the decrease in surface roughness (Sm/Rz). Therefore, the Zn/Al metal spraying is applicable to a corrosion resistance method for high tension bolt joints.

Abstract: In this study, an Ohno's anti-symmetric shear loading test was conducted after strengthening reinforced concrete (RC) beams damaged by corrosion of stirrup, with carbon fiber sheets (CFS) with a view to reviewing the effect of CFS on shear strengthening. As a result, it was found that CFS like stirrups could take shear stress, and that shear strength could be increased by using more CFS for reinforcement. It was also revealed that shear strength could be calculated by an existing evaluation equation by properly evaluating the effect of CFS on shear strengthening, based on the quantity of reinforcing CFS, ways of fixing the sheets and anchorage length as the effect on shear strengthening varied depending on the fixing method while sheet anchorage increased deformability.