• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.3
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• pp.404-408
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• 2006

In this paper, connection strength between facing block and tie-bar was investigated through experimental study with varying in-fill material such as concrete, soil and crushed stone. Also, connection strength between anchor block and tie-bar was investigated with varying in-fill material. According to the experimental results, in case of using in-fill concrete, connection strength between facing block and tie-bar was larger than allowable tension load of tie-bar. Whereas in case of using in-fill soil or crushed stone, connection strength between facing block and tie-bar was less or similiar to allowable tension load of tie-bar. Connection strength between anchor block and tie-bar for which crushed stone was used as in-fill material, was larger than allowable tension load of tie-bar.

• Journal of Korean Society of Steel Construction
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• v.22 no.2
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• pp.151-160
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• 2010

The number of cases of collapsed plastic greenhouses in farmlands has increased due to the heavy local snowfall caused by extraordinary atmospheric phenomena. Consequently, the economic losses of farmers have also increased. However the government policy in relation to damage pretension is insufficient and collapse case is repeated every year. The main reason for frame collapse is that the moment capacity of a steel pipe is not sufficient to resist a heavy snowload. In this study, experiments were conducted on the current frame system of a greenhouse with a tension tie. The frame consisted of two sections(${\phi}25.4{\times}1.5$, ${\phi}31.8{\times}1.5$), and its span length was 6.5 m. A temporary tension tie using a steel wire and a fabric rope was connected to the two joints, to which a curved beam and a straight column were connected. The pretension force was applied at the tension tie, and a vertical force simulating snowfall was applied until failure. The fabric rope frame increased the load-carrying capacity by 10-45% compared to the normal frame without a tension tie, and the steel wire frame increased the load-carrying capacity by 58-73% compared to the normal frame without a tension tie. Steel wire was found to be more effective as far as strength is concerned, but its connection details and pretension application are more difficult and complicated than those of the fabric rope. The test results thus show that the fabric rope is more preferable.

• Ocean Systems Engineering
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• v.1 no.4
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• pp.263-283
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• 2011

The performance of a rig tie-down system on a TLP (Tension Leg Platform) is investigated for 10-year, 100-year, and 1000-year hurricane environments. The inertia loading on the derrick is obtained from the three-hour time histories of the platform motions and accelerations, and the dynamic wind forces as well as the time-dependent heel-induced gravitational forces are also applied. Then, the connection loads between the derrick and its substructure as well as the substructure and deck are obtained to assess the safety of the tie-down system. Both linear and nonlinear inertia loads on the derrick are included. The resultant external forces are subsequently used to calculate the loads on the tie-down clamps at every time step with the assumption of rigid derrick. The exact dynamic equations including nonlinear terms are used with all the linear and second-order wave forces considering that some dynamic contributions, such as rotational inertia, centripetal forces, and the nonlinear excitations, have not been accounted for in the conventional engineering practices. From the numerical simulations, it is seen that the contributions of the second-order sum-frequency (or springing) accelerations can be appreciable in certain hurricane conditions. Finally, the maximum reaction loads on the clamps are obtained and used to check the possibility of slip, shear, and tensile failure of the tie-down system for any given environment.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2009.11a
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• pp.31-34
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• 2009

Large outrigger elements tie the concrete core to perimeter columns, significantly increasing the building's lateral stiffness as well as its resistance to overturning due to wind. The outriggers are deep elements, and large tie forces are resisted by top and bottom heavy longitudinal reinforcing and vertical ties. To reduce construction costs, all primary reinforcing bars in outrigger levels are SD500. Further, concrete strengths of 80MPa have been specified for outrigger elements. However, the reductions in the amount of concrete and reinforcement steel are more increased in tall building. With these backgrounds, 80MPa high strength concrete outrigger system using post tension method is developed. Significant economic savings can be made by reducing the element sizes and material content. The developed outrigger system is designed using strut-and-tie models. In addition, four 1/4-scale test specimens were selected from the same prototype structure. The results from the tests are confirmed that the structural behaviors of the developed outrigger member have better capacities than those of a conventional method.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.05a
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• pp.391-396
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• 2003

The concrete corbels consist of various failure mechanisms such as the yielding of the tension reinforcement, the crushing or splitting from compression concrete struts, and localized bearing or shearing failure under the loading plate. However, predicting those failure mechanisms is very difficult. In this study, the ACI 318-02, the softened strut-tie model approach, and the nonlinear strut-tie model approach are applied to ultimate strength analysis of normal strength concrete corbels tested to failure. From the result of the analysis, an effective analysis and design method of normal strength concrete corbels is suggested.

• Journal of Korean Society of Steel Construction
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• v.18 no.6
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• pp.697-706
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• 2006

Tower crane's wall tie is generally used for extending of mast height according to rising of lifting height. In order to get wall tie member force this problem, this study concerning wall tie is based on load data described in manual book of 290HC model. This study made the equation of wall tie member force and computer programming for calculating wall tie member force and then get ${\theta}-P$ curves(angle-wall tie force). After considering the ${\theta}-P$ curves, optimum angle range ($48.4^{\circ}{\sim}77.2^{\circ}$) about wall ties (A), (C) members was obtained. Member force of wall tie (B) was changed from tension to compression or from compression to tension at $74^{\circ}$ in service and $54^{\circ}$ in out of service. When both horizontal force($H_A$) and torsional moment ($M_D$) were varied from (+) to (-), wall tie force(A, B, C) were changed almost symmetrically about ${\theta}$-axis. Because this study was based on wall tie analysis conditions, wall tie members in symmetric and ideal geometry shape used for analizing wall tie of tower crane, it is necessary to have more careful verification in order to apply generally the results of this study.

• Journal of the Korea institute for structural maintenance and inspection
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• v.19 no.1
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• pp.62-71
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• 2015

KCI 2012 and ACI318-11 contains development length provisions for the use of headed deformed bars in tension and does not allow their tension lap splices. In ACI318-11, the confinement factor, such as transverse reinforcement factor, is not used to calculate the development length of headed bars. The purpose of this experimental study is to evaluate the effect of confinement details to the lap splice performance of headed deformed reinforcing bars in grade SD400 and SD500. The confinement details are stirrups and tie-down bars in lap zone. Test results showed that specimens with only stirrups had the brittle failure and could not increase lap strengths, and that specimens with composite confinements by stirrups and tie-down bars had the flexural strengths over than nominal flexural strengths. Stirrups with tie-down bars can have an effect on improvement in lap splice of headed bars in grade SD400 and SD500.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.11a
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• pp.271-274
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• 2005

Existing strut-and-tie model cannot be applied to analysis of slender beams without shear reinforcement because shear transfer mechanism is not formed. In the present study, a new strut-and-tie model with rigid joint was developed. Basically, concrete strut is modeled as a frame element which can transfer shear force (or moment) as well as axial force. Employing Rankine failure criterion, failure strength due to shear-tension and shear-compression developed in compressive concrete strut was defined. For verification, various test specimens were analyzed and the results were compared with tests. The proposed strut-and-tie model predicted shear strength and failure displacement with reasonable precision, addressing the design parameters such as shear reinforcement, concrete compressive strength, and shear span ratio.

• Structural Engineering and Mechanics
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• v.34 no.2
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• pp.189-211
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• 2010

The behaviour of a reinforced concrete tension member is governed by the contribution of concrete between cracks, tension stiffening effect. Under highly repeated loading, this contribution is progressively reduced and the member response approximates that given by the fully cracked member. When focusing on the unloaded state, experiments show deformations larger than those of the naked reinforcement. This has been referred to as negative tension stiffening and is due to the fact that concrete carries compressive stresses along the crack spacing, even thought the tie is subjected to an external tensile force. In this paper a cycle-dependent approach is presented to reproduce the behaviour of the axially loaded tension member, paying attention to the negative tension stiffening contribution. The interaction of cyclic bond degradation and time-dependent effects of concrete is investigated. Finally, some practical diagrams are given to account for the negative tension stiffening effect in reinforced concrete elements.

• Journal of Veterinary Clinics
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• v.35 no.2
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• pp.46-49
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• 2018

A common kestrel was admitted to Chungnam wild animal rescue center, having been unable to fly. On the physical examination, the bird was presented with contusion and swelling on its right humerus closed fraction and had pain response. Radiographic examination was explicitly revealed closed fracture on right proximal humerus. Its closed fracture was reduced with tie-in fixator and figure-of-eight tension band, and inserted pins on its right humerus surgery were removed on the $14^{th}$ day after the surgery. As Falco tinnunculus was able to move its wings from Day $21^{st}$ day, its rehabilitation was done at outdoor facility and it was successfully released. Proximal humerus reduction with tie-in fixator and the wire was a success, and this treatment with reference to this study will be surely effective to support the other wildbird's reduction stability.