• Journal of the Earthquake Engineering Society of Korea
• /
• v.26 no.4
• /
• pp.165-172
• /
• 2022

This study is conducted to verify the seismic reinforcement effects of internally inserted buckling-restrained braces supported laterally by buckling-restrained rings for the seismic reinforcement of existing reinforced concrete buildings with non-seismic details. First, to evaluate the performance of KDS, the hysteretic characteristics of buckling-restrained braces are verified, and it is discovered that they satisfy the conformance criteria of the displacement-dependent damping device. Three full-scale, two-story reinforced concrete framework specimens are prepared to verify the seismic reinforcement effects, and the proposed buckling-restrained braces are bolstered with single diagonal and V-shaped braces to be compared with non-reinforced specimens. By performing a comparison with non-reinforced specimens that present intensive shear cracks at the bottom of first-floor columns, it is revealed that the maximum load and energy dissipation of specimens reinforced with the proposed buckling restrained braces, in which the structural damage extends evenly throughout the system, are approximately 4 and 6.2 times higher, respectively, which proves the effectiveness of the proposed seismic reinforcement method.

• Bulletin of the Society of Naval Architects of Korea
• /
• v.20 no.4
• /
• pp.9-16
• /
• 1983

When the perforated panels are under in-plane shear loads, shear buckling analysis is also necessary because of the presence of stress concentration around holes. To constrain it, we need some reinforcement. The methods of reinforcement are attaching doubler around hole and stiffeners in the arbitary directions. In this paper, two kinds of methods mentioned above are investigated, it is also clarified that which of the two is the more effective reinforcement. For the sake of convenience those arbitary directions were selected parallel ($90^{\circ}$) and oblique ($135^{\circ}$) to the edge. From the results of the above investigation, following conclusion was obtained. In case of parallel stiffeners, doubler reinforcement gives higher buckling strength than stiffener, however, in case of oblique stiffeners, doubler reinforcement gives higher buckling strength than doubler when the external load direction is known.

• Journal of Korean Association for Spatial Structures
• /
• v.16 no.4
• /
• pp.45-52
• /
• 2016

The single layer latticed domes have attracted many designers and researchers's attention all of the world, because these structures as spatial structure are of great advantage in not only mechanical rationality but also function, fabrication, construction and economic aspect. But single layer latticed domes are apt to occur the unstable phenomena that are called "buckling" because of the lack of strength of members, instability of structural shape, etc. In the case of latticed dome, there are several types of buckling mode such as overall buckling, local buckling, and member buckling according to the shape of dome, section type of member, the size of member, junction's condition of member and so on. There are many methods to increase the buckling strength of the single layer latticed dome, that is, with the change of geometrical shape of dome, the reinforcement of buckled member, etc. Therefore, the purpose of this study is to verify the reinforcement effect of buckled member when designers reinforce the buckled member to increase the buckling strength of single layer latticed dome with 3-way grid.

• Bulletin of the Society of Naval Architects of Korea
• /
• v.19 no.4
• /
• pp.11-18
• /
• 1982

When the perforated plate is under in-plane load of compression, buckling analysis becomes to be necessary because of the presence of stress concentration around holes. To constraint it, we need reinforcement. The methods of reinforcement are attaching doubler around hole and attaching stiffener in the direction of initial stress. In this paper, two methods are investigated mentioned above, which of the two better effective reinforcement. In the consequence of the above investigation, following conclusion was obtained. The method of doubler reinforcement was less buckling stress than that of stiffener because the former had large compressive stress. So, effective method of reinforcement is stiffener reinforcement.

• Bulletin of the Society of Naval Architects of Korea
• /
• v.22 no.1
• /
• pp.9-20
• /
• 1985

Generally the stiffened plate in the ship structure is subjected to not only axial load but shear load. With respect to those combined loads buckling analysis in necessary. In this paper, buckling strength is analyzed by using Finite Element Method when the stiffened plate with hole is under loading conditions mentioned above. To obtain the higher buckling strength, we need some reinforcement. The methods of reinforcement are attaching doubler around hole and stiffeners in the arbitrary directions For the sake of convenience those arbitrary directions were selected paralleled($0^{\circ}C$), vertical($90^{\circ}C$)and oblique($45^{\circ}C$) to the edge. Two kinds of method mentioned above are investigated, it is clarified that which of the two is more effective reinforcement. From the viewpoint of buckling strength, following conclusions were obtained. When external load direction is unknown, doubler reinforcement is more effective than those of parallel and vertical stiffener. And oblique stiffener reinforcement is more effective than that of doubler when external load direction is know.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2005.10a
• /
• pp.1008-1011
• /
• 2005

It is necessary for the design of lead frame punches in blanking to consider buckling because inner lead pitch of lead frame has been narrowed by miniaturization and high accumulation of semiconductor. In addition, if process variables change in press stamping process, the lift of punches is no longer influenced in wear and punches can be broken suddenly. To prevent the fracture of fine pitch lead frame punches, having considered applying reinforcement to it, this paper verified the design with buckling analysis. This study presents the optimal position and number of reinforcement to be attached to punches. Finally this study presents design rules of attaching reinforcement.

• Earthquakes and Structures
• /
• v.25 no.1
• /
• pp.57-67
• /
• 2023

The buckling of longitudinal reinforcements under seismic loading accelerates the degradation of the bearing capacity of reinforced concrete columns. The traditional hysteretic constitutive model of reinforcement, which does not consider buckling, usually overestimates the seismic performance of pier columns. Subsequent researchers have also proposed many models including the buckling effects. However, the accuracy of these hysteretic constitutive models proposed for simulating the buckling behavior is inadequate. In this study, based on their works, the influence of historical events on buckling is considered, the path of the re-tensioning phase is corrected by adjusting the boundary lines, and the positions of the onset buckling point and compressive buckling path during each buckling deformation are corrected by introducing correction parameters and a boundary line. A modified hysteretic constitutive model is obtained, that can more accurately reflect the buckling behavior of reinforcements. Finally, a series of hysteresis tests of reinforcements with different slenderness ratios were then conducted. The experimental results verify the effectiveness of the proposed modified model. Indicating that the modified model can more accurately simulate the equivalent stress-strain relationship of the buckling reinforcement segment.

• Structural Engineering and Mechanics
• /
• v.5 no.5
• /
• pp.565-576
• /
• 1997

The material-based homogenization design method generates arbitrary topologies of initial structural design as well as reinforcement structural design by controlling the amount of material available. However, if a small volume constraint is specified in the design of Lightweight structures, thin and slender structures are usually obtained. For these structures stability becomes one of the most important requirements. Thus, to prevent overall buckling (that is, to increase stability), the objective of the design is to maximize the buckling load of a structure. In this paper, the buckling analysis is restricted to the linear buckling behavior of a structure. The global stability requirement is defined as a stiffness constraint, and determined by solving the eigenvalue problem. The optimality conditions to update the design variables are derived based on the sequential convex approximation method and the dual method. Illustrated examples are presented to validate the feasibility of this method in the design of structures.

• Structural Engineering and Mechanics
• /
• v.23 no.4
• /
• pp.369-386
• /
• 2006

The influence of reinforcement buckling on the flexural response of reinforced concrete members is studied. The stress-strain response of compression reinforcement is determined computationally using a large-strain finite element model for bars of varied diameter, length, and initial eccentricity, and a mathematical expression is fitted to the simulation results. This relationship is used to represent the response of bars in compression in a moment-curvature analysis of a reinforced concrete cross section. The compression bar may carry more or less force than a tension bar at a corresponding strain, depending on the relative influence of Poisson effects and bar slenderness. Several cross-section analyses indicate that, for the distances between stirrups prescribed in modern concrete codes, the influence of inelastic buckling of the longitudinal reinforcement on the monotonic moment capacity is very small and can be neglected in many circumstances.

• Structural Engineering and Mechanics
• /
• v.73 no.2
• /
• pp.209-223
• /
• 2020

This paper investigates the buckling behavior of carbon nanotube-reinforced composite plates supported by Kerr foundation model. In this foundation elastic of Kerr consisting of two spring layers interconnected by a shearing layer. The plates are reinforced by single-walled carbon nanotubes with four types of distributions of uniaxially aligned reinforcement material. The analytical equations are derived and the exact solutions for buckling analyses of such type's plates are obtained. The mathematical models provided, and the present solutions are numerically validated by comparison with some available results in the literature. Effect of various reinforced plates parameters such as aspect ratios, volume fraction, types of reinforcement, parameters constant factors of Kerr foundation and plate thickness on the buckling analyses of carbon nanotube-reinforced composite plates are studied and discussed.