• Structural Engineering and Mechanics
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• v.83 no.1
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• pp.109-121
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• 2022

Twelve push-out test specimens were conducted with various parameters to study the static and fatigue performance of a new through-bolt shear connector transferring the shear forces of interface between prefabricated hybrid fiber reinforced concrete (HFRC) slabs and steel girders. It was found that the fibers could improve the fatigue life, capacity and initial stiffness of through-bolt shear connector. While the bolt-hole clearance reduced, the initial stiffness, capacity and slippage of through-bolt shear connector increased. After the steel-concrete interface properties were improved, the initial stiffness increased, and the capacity and slippage reduced. Base on the test results, the equation of the load-slip curve and capacity of through-bolt shear connector with prefabricated HFRC slab were obtained by the regression of test results, and the allowable range of shear force under fatigue load was recommended, which could provide the reference in the design of through-bolt shear connector with prefabricated HFRC slabs.

• 한국공간정보시스템학회:학술대회논문집
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• 2004.05a
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• pp.53-62
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• 2004

A single layer latticed dome is one of the most efficient structures because of its low specivic gravity. For easily analyzing of a single layer latticed dome, joint system is assumed to be pin or rigid joint. However, its joint uses ball whose system has intermediate properties of pin and rigid joint. Therefore this study has a grasp of bending rigidity, stress and mechanical properties through experimental and analyzing method of the bolt inserted ball joint. To analyze the stress of bolt and sleeve, this study uses through 3D elastic contact and cubic element, and then the ball and the bolt are perfectly connected for easily analyzing Compared experimental results to F.E.M, each specimen has an error of less than 12 percent. In the results of stress distribution through F.E.M, stress occurs from bottom of bolt to top of sleeve, and most of tension appears on the bolt, also compression occurs from upper parts of the bolt to the sleeve. The assumption of bending stiffness in ball joint is well known that bolt resists only tension and upper sleeve resiss compression. The results of experiment and analysis have $7{\sim}56%$ error, assuring that upper part of bolt occurs of partial compression. In the result of modified assumption have $4{\sim}20%$ error.

• Journal of Oriental Physiology
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• v.14 no.2 s.20
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• pp.157-178
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• 1999

In terms of the bolt-leaf-hanges in Three-yum and Three yang I referd to successive medical books and many recent literatures on the basis of Huangjenegeong Somun Treatise on the Darting and meeting of Yin and yang, thus considerd concept of successive commentators about the bolt-leaf-hanges in Three-yum and Three yang and reconstructed and systeamtically arranged the bolt-leaf-hanges's interrelationship, yum-yang's relation and movement of six chnnel, and then studied there trinciple in all the universe apply the body and the process is operated by the bolt-leaf-hanges in the trinciples followed in human make his life adaption environment. The process is operated by the bolt-leaf-hanges in Three-yum and Three yang. The trinciples followed in. Firstly, Three-yum and Three yang is not dirrerentiate by many, middle, little of yum-yanggi's different function & role. Secondly, Three-yum and Three yang is negatively related white showing that there is the bolt-leaf-hanges relationship through space of Three-yum and Three yang. Through internal relationship of Three yum channel & Three yang channel, it can be proven that Three-yum and Three yang is in negative relation and through achieving the bolt-leaf-hanges relation in dimensional concept, it can be proven that it can actually be applied to human. Thirdly, by showing Three-yum and Three yang's the bolt-leaf-hanges relation is relation between Three yum & Three yang as well as negative relation, it can be shown that Three-yum and Three yang's the bolt-leaf-hanges activity is circular, and that it maintains itself through appropriate transformation. Fourth, understanding of Three-yum and Three yang's the bolt-leaf-hanges relationship and yum-yang Concern & six channer's activity has been varied. It means that the understanding is affected by socity, philosophical & research culture of the various times. The purpose has been to systematically arrange and diagnosing Three-yum and Three yang's the bolt-leaf-hanges and thus make up a fundamental for recognition. But, further study should be carried out on medical explanation on the bolt-leaf-hanges and interpretation and operation of the bolt-leaf-hanges in O-UnYukKiron.

• Earthquakes and Structures
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• v.19 no.5
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• pp.315-329
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• 2020

Through bolt connections in Concrete Filled Steel Tubes (CFSTs) has been proved to be good in terms of seismic performance and constructability. Stiffened extended end plate connection with full through type bolt helps to avoid field weld altogether, and hence to improve the quality of joints. An experimental study was conducted on the hysteretic performance of square interior beam-column connections using flat extended end plates with through bolt. The study focuses on the effect of the bond between the tie rod and the core concrete on the cyclic performance of the joint. The study also quantifies how much the interior joint is getting strengthened due to the confinement effect induced by bi-directional bolting, which is widely used in 3D moment resisting frames. For a better understanding of the mechanism and for the prediction of shear capacity of the panel zone, a mathematical model was generated. The various parameters included in the model are the influence of axial load, amount of prestress induced by bolt tightening, anchorage, and the concrete strut action. The study investigates the strength, stiffness, ductility, and energy dissipation characteristics. The results indicate that the seismic resistance is at par with American Institute of Steel Construction (AISC) seismic recommendations. The bidirectional bolting and bond effect have got remarkable influence on the performance of joints.

• Structural Engineering and Mechanics
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• v.89 no.1
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• pp.61-75
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• 2024

Strengthening of hollow structural sections using through-bolts is a cost-effective and straightforward approach. It's a versatile method that can be applied during both design and service phases, serving as a non-disruptive and budget-friendly retrofitting solution. Existing research on axially loaded hollow sections T-joints has demonstrated that this technique can amplify the joint strength by 50%, where single bolt could enhance the strength of the joint by 35%. However, there's a gap in understanding their use for K-joints. As the behavior of K-joints is more complex, and they are widely existent in structures, this study aims to bridge that gap by conducting comprehensive parametric study using finite element analysis. Numerical investigation was conducted to evaluate the effect of through bolts on K-joints focusing on using single through bolt to achieve most of the strengthening effect. A full-scale parametric model was developed to investigate the effect of various geometric parameters of the joint. This study concluded the existence of optimal bolt location to achieve the highest strength gain for the joint. Moreover, a rigorous statistical analysis was conducted on the data to propose design equations to predict optimal bolt location and the corresponding strength gain implementing the verified by finite element models.

• Geomechanics and Engineering
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• v.15 no.3
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• pp.841-849
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• 2018

The purpose of a rock bolt is to improve the mechanical performance of a jointed-rock mass. The performance of a rock bolt is generally evaluated by conducting a field pullout test, as the analytical or numerical evaluation of the rock bolt behavior still remains difficult. In this study, wide range of field test was performed to investigate the pullout resistance of rock bolts considering influencing factors such as the rock type, water bearing conditions, rock bolt type and length. The test results showed that the fully grouted rock bolt (FGR) in water-bearing rocks can be inadequate to provide the required pullout resistance, meanwhile the inflated steel tube rock bolt (ISR) satisfied required pullout resistance, even immediately after installation in water-bearing conditions. The ISR was particularly effective when the water inflow into a drill hole is greater than 1.0 l/min. The effect of the rock bolt failure on the tunnel stability was investigated through numerical analysis. The results show that the contribution of the rock bolt to the overall stability of the tunnel was not significant. However, it is found that the rock bolt can effectively reinforce the jointed-rock mass and reduce the possibility of local collapses of rocks, thus the importance of the rock bolt should not be overlooked, regardless of the overall stability.

• Proceedings of the KSR Conference
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• 2006.11b
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• pp.508-513
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• 2006

Anchor bolt in baseplate fastenings on the slab track is an important component to conform placing and safety of fastenings. Due to the way of load transmission control of fastenings, sometimes anchor bolt has to be applied lateral load. So we have to take care for it when we design. Especially, in the case of anchor bolt which is applied loads repeatedly, we have to consider fatigue failure. If parts of machine are damaged in static loads, stress will exceed the yield strength. So parts could be transformed largely. Therefore because they are visible to the naked eyes, we can replace parts before failure. However, because fatigue failure that are invisible to the naked eyes happen unexpectedly, it's very dangerous. To make a reasonable design of anchor bolts, we will analyze them by changing diameters of anchor bolt, quality of insert, initial gap between anchor bolt and insert, the presence of insert, etc. which affect the stresses of anchor bolts. We can get the maximum and minimum amplitude of stress through the modified Goodman diagram or Smith diagram which represents limit of all strengths and stress components to the average stress. We also tried to show the way of examining the expected th life of anchor bolt briefly through considering above.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.3
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• pp.495-501
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• 2001

In this paper, a new technique which models the joints characteristics through reduction of DOFs of structures with joints using component mode synthesis (CMS) method is proposed. Bolt joints are modeled by mass-spring systems. Also generalized mass and stiffness matrices for this models are introduced. Because bolt joints have influence on eigenvalues of structures, exact eigenvalues from modal test are used. The results show that the behaviors of structures with bolt joints depend to a large extent on the translational DOFs and not on rotational DOFs of mass and stiffness matrices of bolts. Furthermore it is confirmed that lumped mass-spring systems as models of bolt joints are effective models considering the facts that joint characteristics converged to constant values in some iterations and eignevalues from proposed method are in good agreement with ones from modal test.

• Journal of the Korean Society of Safety
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• v.28 no.3
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• pp.29-32
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• 2013

An aircraft made an emergency landing through the loss of capability controlling steering. A torsion link which is a part of steering apparatus has been adrift from the steering system and the bolt connected to the steering link has fractured. At the same time, the FLIR(Forward Looking Infrared Radar) mounted in front of the steering link has been also damaged. In the early of this investigation, we considered the failure of the FLIR had occurred first, that FLIR hit the steering link and finally the bolt fractured. The fractured section of the bolt has shown a beach mark and a dimple mark as well. The outside of the bolt has shown a large deformation by a heavy load. As a result, we have found out what the cause of the heavy load and the fractures for bolt, link and FLIR have occurred in what order.

• Explosives and Blasting
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• v.29 no.1
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• pp.10-16
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• 2011

To make large slopes or rock structures stable, supporting systems, such as anchor bolt, rock bolt and spiral bolt which are developed recently, are commonly used. In this study, in-situ pull-out tests were carried out to compare the characteristics of rock bolt that is most widely used with ones of spiral bolt that is newly developed. Re-pull-out test for the spiral bolt in which loading and unloading cycles are repeated three times showed that the maximum pull-out load is almost constant irrespective of the number of loading cycles, which may be due to no failure between spiral bolt and filler. On the other hand, the maximum pull-out load for the conventional rock bolt decreases with the number of loading cycles due to the partial failure between rock bolt and filler.