• Journal of Korean Society of Steel Construction
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• v.15 no.6 s.67
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• pp.673-681
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• 2003

This paper describes the experiment that determines the ultimate strength of new uniplanar T-joints made of cold-formed square hollow sections. The new T-joint focused on the configuration of a branch member that is oriented 45 degrees to the plane of the truss and welded to the chord member whose web is stiffened with plate. The strength and failure mode are examined using the existing strength formula for the branch-rotated T-joint $(16.7{\leq}2{\gamma}(B/T){\leq}33.3$ and $0.63{\leq}{\beta}(b1/B){\leq}0.7)$. The test result shows that the capacity of the stiffened joint increases with thicker stiffening plate. The failure mode of the specimen $(2{\gamma}=33.3)$ is stiffened with plate changes from M2 (flange failure) to M3 (combined failure). On the other hand, the failure mode of the specimen $(2{\gamma}=16.7)$ is stiffened with plate changes from M1 ( web failure) to M2 (flange failure)

• Journal of Korean Society of Steel Construction
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• v.21 no.3
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• pp.211-219
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• 2009

The purpose of the study described in this paper was to experimentally investigate branch squared T joints with cold formed hollow structural sections under the in plane moment in a Vierendeel Truss. The branch in the T joints was welded to the upper flange of the chord. The main experimental parameters were the ratio of the width to the thickness of the chord ($2{\gamma}$), with ${16.7{\leq}2{\gamma}{\leq}33.3}$, and the width ratio of the branch to the chord ($\beta$), with ${0.40{\leq}{\beta}{\leq}0.71}$. Nine specimens were tested and manufactured in joints under the in plane bending moment. Based on the results of the test, the in plane moment strength of the branch squared T joints was determined according to the bending deformation of the chord flange yielding, regardless of the ratio of the width to the thickness of the chord and the ratio of the width of the branch to the width of the chord. Also, the in plane moment strength of the branch squared T joints in the hollow structural sections can be defined as 1.5 times the moment load at M1%B the strength of the joints that governed the serviceability in the control group. Finally, the experimental results with the branch squared T joints show that the in lane moment strength of the joint increased as $2{\gamma}$ decreased and $\beta$ increased.

• Journal of the Korea Concrete Institute
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• v.24 no.2
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• pp.185-193
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• 2012

In this study, an estimation equation was proposed to predict the shear strength of RC interior beam-column connections. The proposed equation considered the effect of both truss and arch mechanisms, while the existing equations in the ACI and AIJ design codes consider only arch mechanism. In addition, the proposed equation estimates the shear strength of RC joints by considering the contribution of the vertical and horizontal steel bars on the effective compressive strength of concrete. The shear strength of RC joints calculated by the proposed equation was compared with the test results of 54 RC joints, which failed in shear before plastic hinges developed at the end of the adjacent beams. The comparison study showed that the proposed equation estimated the strength of the 54 specimens with a mean value of 1.14 and the coefficient of variation of 20%. The proposed equation provides improved prediction compared to those obtained from the equations in the ACI and AIJ design codes.

• KEPCO Journal on Electric Power and Energy
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• v.5 no.4
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• pp.257-262
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• 2019

Lattice steel towers for overhead transmission lines have been replaced by tubular steel poles due to the visual impact of large and complex shape of truss type. Demand for tubular steel poles consisting of a single frame member continues to grow because of its advantages such as visual minimization, architectural appeal and minimal site consumptions. However, there are some constraints on the transportation and construction. As the diameter of tower base has been enlarged, it may exceed minimum height limit required to pass the tunnel in case of land transportation. Also, in a narrow place where it is not easy to secure the installation areas such as mountainous places, there might be some areas wherein it must secure a wide working space so that large vehicles and working cranes will be allowed to enter. In this paper, we presented a vertical separated tubular steel pole, which is a new type of support that can be implemented for general purpose such as mountainous areas or narrow areas to improve the issues raised by breaking away from the conventional design and fabrication methods. Technical approaches for overcoming the limit of the cross-sectional size is to separate and modularize the cross-section of the tubular steel pole designed with a size that cannot be carried or assembled, and to lighten it with a weight capable of being transported and assembled in a narrow space or mountainous area. As a result of this research, it will be possible to enter small and medium sized vehicles in locations where it is restricted to transport by large-sized vehicles. In the case of mountainous areas, it will be possible to divide it into a weight capable of being carried by a helicopter and it will be easy to adjust and fabricate it with individual modules. Furthermore, in order to break away from the traditional construction method, we proposed the equipment that can be applied to the assembly of Tubular Steel Pole without using a large crane in locations where there is no accessible road or in locations wherein large cranes cannot enter. In particular, this paper shows the movable assembling equipment and some methods that are specialized for vertical separated tubular steel pole consisting of members with reduced weight. The proposed assembly equipment is a device for assembling the body of the Tubular Steel Poles. It will be installed inside the support and the modules can be lifted by using the support itself.