• Journal of Korean Neurosurgical Society
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• v.53 no.6
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• pp.331-336
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• 2013

Objective : The offset connector can allow medial and lateral variability and facilitate intralaminar screw incorporation into the construct. The aim of this study was to compare the biomechanical characteristics of C7 intralaminar screw constructs with and without offset connector using a three dimensional finite element model of a C6-7 cervical spine segment. Methods : Finite element models representing C7 intralaminar screw constructs with and without the offset connector were developed. Range of motion (ROM) and maximum von Mises stresses in the vertebra for the two techniques were compared under pure moments in flexion, extension, lateral bending and axial rotation. Results : ROM for intralaminar screw construct with offset connector was less than the construct without the offset connector in the three principal directions. The maximum von Misses stress was observed in the C7 vertebra around the pedicle in both constructs. Maximum von Mises stress in the construct without offset connector was found to be 12-30% higher than the corresponding stresses in the construct with offset connector in the three principal directions. Conclusion : This study demonstrated that the intralaminar screw fixation with offset connector is better than the construct without offset connector in terms of biomechanical stability. Construct with the offset connector reduces the ROM of C6-7 segment more significantly compared to the construct without the offset connector and causes lower stresses around the C7 pedicle-vertebral body complex.

• The Journal of Korean Academy of Prosthodontics
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• v.30 no.4
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• pp.582-610
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• 1992

The long-term success of any dental implant is dependent upon the optimization of stresses which occur during oral function and parafunction. Especially, it has been suggested that there is an unique set of problems associated with joining an osseointegrated implant and a natural tooth with a fixed partial denture. For this particular case, although many literatures suggest different ways to avoid high stress concentrations on the bone surrounding the implant under static and dynamic loading conditions, but few studies on the biomechanical efficacy of each assertion have been reported. The purpose of this investigation was to evaluate the efficacies of clinically suggested methods on stress distribution under static load and shock absorption under dynamic load, using two dimensional finite element method. In FEM models of osseointegrated implant-natural tooth supported fixed partial dentures, calculations were made on the stresses in surrounding bone and on the deflections of abutments and superstructure, first, to compare the difference in stress distribution effects under static load by the flexure of fastening screw or prosthesis, or intramobile connector, and second, to compare the difference in the shock absorption effects under dynamic load by intramobile connector or occlusal veneering with composite resin. The results of this analysis suggest that : 1. Under static load condition, using an implant design with fastenign screw connecting implant abutment and prosthesis or increasing the flexibility of fastening screw, or increasing the flexibility of prosthesis led to the .increase in height of peak stresses in cortical bone surrounding the implant, and has little effect on stress change in bone around the natural tooth. 2. Under static load condition, intramobile connector caused the substantial decrease in stress concentration in cortical bone surrounding the implant and the slight increase in stress in bone around the natural tooth. 3. Under dynamic load condition, both intramobile connector and composite resin veneering showed shock absorption effect on bone surrounding the implant and composite resin veneering had a greater shock absorption effect than intramobile connector.

• Journal of Korean Association for Spatial Structures
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• v.21 no.3
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• pp.35-42
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• 2021

An experimental study was carried out to evaluate the shear performance at the interface composed of structural laminates and concrete. The main variables are the number of CLT layers and the shape of the shear connector. The number of CLT layers consisted of 3 and 5 layers. A total of 6 test specimens for shear performance evaluation were prepared in the form of a shear connector, a direct screw type and a vertically embedded type. As a result of the experiment, similar behavior was shown in all specimens, regardless of the number of layers, including direct screw type (SC series) and vertically embedded type (VE series). The behavior at the joint surface was damaged due to the occurrence of initial shear cracks, expansion of shear groove cracks, and splaying at the interface after the maximum load.After the maximum load, the shear strength decreased gradually due to the effect of the shear connector. It can be seen that the shear strength of all specimens is determined by shear and compression stress failure of concrete at the interface of the notch joint.

• Journal of the Korea institute for structural maintenance and inspection
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• v.11 no.2
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• pp.145-154
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• 2007

As buildings are built higher and their service life made longer, face brick walls are also required to be constructed in an easy and systematic manner, and to ensure their satisfying structural performance, inspectingly, against lateral load. Therefore this study aims to investigate the structural performance of face brick walls constructed by a new method using screwed stainless steel connectors and provide fundamental experiment data for field application of this method. The results of this study indicated that the face brick wall tied with screw connectors had better shear capacity against rocking motion than that of the wall constructed with ordinary tie bars when their tie spacing was the same. Based on the good performance of the wall tied with the screw connector, it is also expected that the spiral anchors developed in this study can possibly applied to high-rise by adjusting the spacing of the anchors considering the difference of dimensions.

• Steel and Composite Structures
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• v.9 no.3
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• pp.255-274
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• 2009

This paper presents an experimental study of a newly developed composite floor system, built up from thin-walled C-profiles and upper concrete deck. Trapezoidal sheeting provides the formwork and the fastening of the sheet transmits the shear forces between the C-profiles and the deck. The modified formation of the standard self-drilling screw in the beam-to-sheet connection is applied as shear connector. Push-out tests are completed to study the composite behaviour of the different connection arrangements. On the basis of the test results the behaviour is characterized by the observed failure modes. The design values of the connection stiffness and strength are calculated by the recommendation of Eurocode 4. In the next phase of the experimental study six full-scale composite beams are tested. The global geometry is based on the proposed geometry of the developed floor system. The applied shear connections are selected as the most efficient arrangements obtained from the push-out tests. The experimental behaviour of the composite beams are discussed and evaluated. As a conclusion of the experimental study the Eurocode 4 plastic design method is validated for the developed composite floor.

• Journal of Korean Association for Spatial Structures
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• v.3 no.2 s.8
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• pp.91-99
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• 2003

The purpose of this study is to analyze the characteristics of the connector having an influence on the elasto-plastic buckling load of ball-jointed single layer latticed domes. As an analytic model, domes are composed of tubular member elements, balls and connectors. The joint system of members in single layer latticed domes has influence on the buckling load. Therefore, in this paper, the variation of the elasto-plastic buckling load by effects of the connectors characteristics is analyzed. The structural behavior of the connector is investigated by following points: (1) the length of rigid zone, (2) looseness of screw and (3) the diameter of connector. In addition, the elasto-plastic buckling analysis is carried out through the variation of the connectors section of yielding part, and then the buckling mode of the dome is examined. As a result, it is emphasized that the characteristics of the connector have significant effects on the buckling load of latticed domes.

• Steel and Composite Structures
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• v.35 no.2
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• pp.261-278
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• 2020

In steel-concrete composite beams, to improve the cracking resistance of the concrete slab in the hogging moment region, a new type of connector in the interface, named uplift-restricted and slip-permitted screw-type (URSP-S) connector has been proposed. This paper focuses on the behavior of steel-concrete composite beams with URSP-S connectors. A total of three beam specimens including a simply supported beam with URSP-S connectors and two continuous composite beams with different connectors arrangements were designed and tested. More specifically, one continuous composite beam was equipped with URSP-S connectors in negative moment region and traditional shear studs in other regions. For comparison, the other one was designed with only traditional shear studs. The failure modes, crack evolution process, ultimate capacities, strain responses at different locations as well as the interface slip of the three tested specimens were measured and evaluated in-depth. Based on the experimental study, the research findings indicate that the larger slip deformation is allowed while using URSP-S connectors. Meanwhile, the tensile stress reduces and the cracking resistance of the concrete slab improves accordingly. In addition, the overall stiffness and strength of the composite beam become slightly lower than those of the composite beam using traditional shear studs. Moreover, the arrangement suggestion of URSP-S connectors in the composite beam is discussed in this paper for its practical design and application.

• Journal of the Korean Wood Science and Technology
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• v.36 no.4
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• pp.26-36
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• 2008

As the height of the light-framed building increases, the lateral load and overturn-moment are increased and the possibility of the building overturn becomes larger. Because the shear wall resists lateral load in light-framed building, the reinforcement of shear wall is required. In order to reinforce the light-framed shear wall, using lag screw fastener type (B-HD) and using bolt type (S-HD) hold-down connectors were applied for test. And domestic larch lumbers, $38{\times}140mm$ and $89{\times}140mm$, KS 2nd grade, were used for the stud. The North American OSB panels were used for sheathing panel. Static loads, load speed 6 mm/min, were applied on top of the wall. As a result, shear strength of the wall that using hold-down connector was improved sufficiently. And when applying the S-HD type hold-down connector, stud should be reinforced against weakening by drilled hole. As increasing the number of lag screw, the number of bolt and the product allowable strength, the strength of shear wall that using hold-down connector was also increased. When applying hold-down connector to light-framed building using 38 mm stud, it must be reinforced by enlarging the thickness of stud like as 38 mm doubled column.

• Steel and Composite Structures
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• v.36 no.1
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• pp.1-16
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• 2020

In steel-concrete composite beams, to improve the cracking resistance of the concrete slab in the hogging moment region, a new type of connector in the interface, named uplift-restricted and slip-permitted screw-type (URSP-S) connector has been proposed. This paper focuses on the behavior of steel-concrete composite beams with URSP-S connectors. A total of three beam specimens including a simply supported beam with URSP-S connectors and two continuous composite beams with different connectors arrangements were designed and tested. More specifically, one continuous composite beam was equipped with URSP-S connectors in negative moment region and traditional shear studs in other regions. For comparison, the other one was designed with only traditional shear studs. The failure modes, crack evolution process, ultimate capacities, strain responses at different locations as well as the interface slip of the three tested specimens were measured and evaluated in-depth. Based on the experimental study, the research findings indicate that the larger slip deformation is allowed while using URSP-S connectors. Meanwhile, the tensile stress reduces and the cracking resistance of the concrete slab improves accordingly. In addition, the overall stiffness and strength of the composite beam become slightly lower than those of the composite beam using traditional shear studs. Moreover, the arrangement suggestion of URSP-S connectors in the composite beam is discussed in this paper for its practical design and application.

• Fire Science and Engineering
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• v.26 no.4
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• pp.82-88
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• 2012

To analyze the thermal characteristics of wire connection part that is connected to a screw-clamping terminal block depending on screw torque, the normal screw torque defined in KS C 2625 and the abnormal screw torque that can occur due to loosened screws resulting from defective work or aged deterioration were used as experimental variables. After the same load was applied to normal and abnormal screw torques, the thermal characteristics of the wire connector were measured and compared with a thermal imaging camera. The findings from this study will be used to detect heating due to defective screw torque at terminal block connections during electric safety inspection in the future and minimize the hazard of electric fire.