• Geotechnical Engineering
• /
• v.10 no.3
• /
• pp.119-134
• /
• 1994

In order to assess the possibility of using steel fibers in the fissured ciays, uniaxial compression tests were performed on both unreinforced and reinforced clay samples containing a pre-existing crack. Test results showed that the steel fiber reinforcement increased resistance to cracks initiation and their propagation, and therefore increased both stress at crack growth initiation and peak stress at failure. The increase in resistance to cracks initiation and their propagation was related to the arresting or deflecting the crack propagation in clay samples by steel fibers. A theoretical interpretation of experimental results was made using fracture mechanics theory and pull-out mechanisms in fiber reinforced materials. It was revealed that the steel fibers had bridging effect through their pull-out action that caused an increased resistance to the propagation of the cracks in the samples. The predicted pull-out force based on theoretical analyses agreed reasonably well with the measured values obtained from pull-out tests.

• Transactions of the Korean Society of Pressure Vessels and Piping
• /
• v.15 no.1
• /
• pp.18-27
• /
• 2019

The Advanced Power Reactor 1400 (APR1400) Steam Generator (SG) uses alloy 690 as a tube material and SA-508 Grade 3 Class 1 as a tubesheet material to form tube-to-tubesheet joint through hydraulic expansion process. In this paper, the residual stresses in the SG tube-to-tubesheet contact area was investigated by applying Model-Based System Engineering (MBSE) methodology and the V-model. The use of MBSE transform system description into diagrams which clearly describe the logical interaction between functions hence minimizes the risk of ambiguity. A theoretical and Finite Element Methodology (FEM) was used to assess and compare the residual stresses in the tube-to-tubesheet contact area. Additionally, the axial strength of the tube to tubesheet joint based on the pull-out force against the contact joint force was evaluated and recommended optimum autofrettage pressure to minimize residual stresses in the transition zone given. A single U-tube hole and tubesheet with ligament thickness was taken as a single cylinder and plane strain condition was assumed. An iterative method was used in FEM simulation to find the limit autofrettage pressure at which pull-out force and contact force are of the same magnitude. The joint contact force was estimated to be 20 times more than the pull-out force and the limit autofrettage pressure was estimated to be 141.85MPa.

• Journal of the Korean Geosynthetics Society
• /
• v.20 no.4
• /
• pp.53-62
• /
• 2021

For the rational application of LRFD, which is actively applied in Korea, for the study of the pull-out load and the horizontal load, which are insufficient examples, a circular foundation based on the transmission tower foundation, which is a socially important structure, through field tests in single and mixed layer. Factors that can affect the design were studied by analyzing the resistance of each stratum to pull-out and horizontal loads.

• The Academic Congress of Korean Shoulder and Elbow Society
• /
• 2009.03a
• /
• pp.159-159
• /
• 2009

Repeated pulling-out of a suture anchor in the lateral row despite repeated attempts at insertion during a rotator cuff repair is not uncommon with the suture-bridge technique, especially in patients with osteoporosis. We describe a simple procedure for dealing with the pull-out of a PushLock anchor in the lateral row using a suture anchor with a suture eyelet during rotator cuff repair applying the suture-bridge technique.

• Geotechnical Engineering
• /
• v.12 no.3
• /
• pp.49-62
• /
• 1996

The pull-out test is a common test for detemining the strength and deformation parameters between reinforcement and soil inl the design of reinforced earth structures. It is often assumed in the interpretation of the results from the test that the mobilization of shear strength along the reinforcement is uniform. The progressive shearing at the soil-reinforcement interface during the pull-out test often leads to incorrect calculation of the shear displacement response between the reinforcement and the soil. To investigate the effect of progressive shearing during the calculation of the shear stiffness of the soil-reinforcement interface, the finite element method is used to simulate the pullout test. The reinforcement, soil and interface behaviors are modeled by rosing linear and non-linear constitutive models. Shear stiffnesses are calculated by uaiHg conventional methods. It is found that there are considerable discrepancies 13etween the calculated shear stiffnesses and the correct stiffnesses which are used in the finite element analysis. The amount of error depends on the relative stiffness between reinforcement and soil and the size of the specimen being analyzed. The finite element results are also compared with the observed response from laboratory experiments. A revised interpretation of the pull-out test results is discussed.

• Journal of Korean Society of Steel Construction
• /
• v.25 no.5
• /
• pp.531-541
• /
• 2013

This paper investigated the structural capacity of the CT shear connectors, which is a kind of the perfobond rib and functions as an anchor transferring the tension force in the joint between a composite PHC wall pile and a bottom slab. The direct pull-out test was performed for various specimens. From failure modes and load-displacement curves, it was found that transverse rebars should be placed to holes in a web to restrict pull-out failure of CT shear connectors. The results of additional tests for specimens with transverse rebars and various support lengths indicated that all specimens were failed by the tension failure of PHC pile before pull-out failure of CT shear connector and concrete pull-out failure. Thus, the CT shear connector could endure the tension force between the PHC wall pile and the bottom slab.

• Journal of Biomedical Engineering Research
• /
• v.29 no.2
• /
• pp.132-138
• /
• 2008

We investigated the biomechanical properties of a newly designed self-expansion type anterior cruciate ligament (ACL) anchor. The ACL anchor consists of the ring section giving the elastic force, the wedge for maintaining in contact with the femur tunnel wall and the link suspending hamstring graft or artificial ligament. The main design parameters that determine the performance of this device were the expansion angle (${\theta}$) and the thickness ($t_R$). The Ti6Al4V anchors were heated after inserting in a jig for 1 hour at $800^{\circ}C$ in a protective argon gas atmosphere and allowed to cool to room temperature in the furnace. In order to investigate the influence of the expansion angle and the thickness of the ring on the biomechanical properties of the anchor, the maximum pull-out load, stiffness and slippage of the ACL anchor were measured using the pull-out tester, and statistical analyses were also executed. The present results showed that the design parameters gave a significant effect on the performance of the self- expansion type of anchor. The pull-out load of the ACL anchors significantly increased as the thickness of the ring section was increased, having a similar trend for both expansion angles. The ACL anchor showed about 2.5 times higher values of the pull-out load than that of the minimum load (500N)required for the "accelerated rehabilitation". The optimum ${\theta}$ and $t_R$ values of this ACL anchor were suggested to have sufficient resistance against the pull-out force, high stiffness and relatively low slippage after ACL reconstruction.

• Journal of Korean Society of Steel Construction
• /
• v.28 no.3
• /
• pp.139-149
• /
• 2016

Roof cladding of buildings are required for the measures about the 'screw pull-out' which causes the casualties and the property damage by typhoons. In this study, the pull-out resistance was increased by increasing the penetration depth of the screw installing a ironware called 'insert nut' on the roof cladding frame. Tensile tests were conducted to compare the pull-out strengths of a general screw-joint and a nut insert joint. Roof cladding that is actually being used in the field was produced using the 'solid work' and then the roof claddings using a general screw-joint and a nut insert joint were compared by a static test and dynamic test.

• Journal of Korean Society of Steel Construction
• /
• v.30 no.2
• /
• pp.105-114
• /
• 2018

The use of post installed anchors with bond type has lately been increasing when it is necessary to repair, reinforce, or remodel structures. This method provides flexibility and simplicity for construction of structural members that require adhering or fixing. Meanwhile, strength evaluation of anchors with expansion type among post-installed anchors systems has nearly reached setting up stage like design code through continual experimental studies for the last ten years, but analyses or experimental studies on anchor system with bond type are not yet sufficient. Accordingly, the designers and builders of korea depend on foreign design codes since there are no exact domestic design code they could credit. In this study, the objectives are investigating the effects on pull-out strength of resin anchors embedded into plain concrete by pull-out experiment of resin anchors with variables such as anchor diameter, anchor interval, embedment depth and edge distance.

• Journal of the Korea Institute of Building Construction
• /
• v.22 no.2
• /
• pp.149-160
• /
• 2022

In this study, a pull-out test considering the adhesive type, embedded length, and direction of re-bar was conducted to evaluate the pull-out performance of glued-in rod joints using timber and adhesive produced in Korea. In the test, the specimens using liquid adhesive showed better pull-out performance, and the longer the embedded length of the re-bar, the higher the maximum tensile load by inducing the yield of the re-bar first. Through the test results, a glued-in rod joints design, which is advantageous to design the adhesive strength stronger than the yield strength of re-bar, was proposed, and a correction factor of 0.75 for the adhesive strength considering construction error was also suggested.