• Journal of Korean Tunnelling and Underground Space Association
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• v.8 no.2
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• pp.141-149
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• 2006

For application of NATM, the self-supporting until installation of the supporting system must be satisfied. However, the face of a tunnel are always unsupported and therefore it is fairly vulnerable to tunnel collapses. Face blots are well known and widely used to prevent the deformation of the tunnel face and its circumference, which are installed horizontally toward the tunnel axis generally. To maximize the supporting effect of face bolts, this study has analysed the effective design patterns of face bolts by changing their installation angles. As the conclusion, it has been found that the axial displacement of the face increases slightly by installing the outermost bolts upward from the axis but surface settlement at 2.5D behind the face decreases up to 18%.

• Journal of Korean Society of Steel Construction
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• v.9 no.3 s.32
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• pp.301-307
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• 1997

In field fabrication of steel members, the oversize hole is frequently required due to reaming and mismatching. But, there are no provisions and investigations about oversize hole in the Korean specifications. So, in this study, the tension test of friction type high-tention bolted joints is performed with parameters of bolt hole size, surface treatment and tightening force, and investigate the effect of slip behavior with those parameters. From the results, the enough tightening force is needed to obtain some degree slip load in shot blast treatment case, although tightening force is reduced somewhat, it is no problem to guarantee slip load in zincrich primer case. The slip behavior of joints with oversize hole(26mm) is similar to the slip behavior of joints with hole of nominal size.

• Journal of Auto-vehicle Safety Association
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• v.7 no.1
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• pp.20-26
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• 2015

In vehicle development process, durability test should be carried out in field condition. Nowadays there are many customer live there multiple conditions. It makes change of the car's material. Such change causes to lose a bolt. Diversifications of climatic conditions are also a matter of loosening the bolt. To avoid this problem, to identify the cause of the problem, and the solution should be applied. To avoid problems during the durability development test should be measured by the clamping force. Ultrasonic instruments clamping force without affecting the torque can be measured. This instrument is part of the problem by monitoring the clamping force required to obtain objective data.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.1334-1340
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• 2004

Existing of angle assembly and angle beam joint examination with steel pole and steel beam of assembly existing anglerather then excellent enumerate, joint of beanding moment examination and economical existing show, in the futher, angle beam rather then steel I beam with all change.

• Journal of the korean Society of Automotive Engineers
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• v.10 no.3
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• pp.38-44
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• 1988

It is important to control the axial forces of high tension bolts such as the automobile, construction machine, aircraft, marine engine bolts. However, the direct method to measure the axial forces of bolts practically have not been found out. The ultrasonic techniques is based on the principles that the bolt tensile elongation and ultrasonic velocity changes are proportional to the axial force below the yield point of the materials. From the result of the experiment, the coefficient of acoustoelasticity k could be measured as - 11.18*10$_{-5}$m $m^{2}$k $g_{f}$./.

• Journal of Korean Society of Steel Construction
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• v.16 no.4 s.71
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• pp.407-414
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• 2004

Bridges in common use are expected to have more varieties of load in their connected members and bolts than in construction. Faults in connection members or bolts occur so often according to the time flow. One of the purposes of this study is to find out the behavior and structural features of high-tension bolted joints with faults that are very difficult and cost much to find out through experimentation with finite element analysis. Another purpose of this study is to provide sufficient data, estimated experimental results, and the scheme of the test plate for an economical experimental study in the future. Surveys of bridges with a variety of faults and statistical classifications of their faults were performed, as was a finite element analysis of the internal stress and the sliding behavior of standard and defective bridge models. The finite element analysis of the internal stress was performed according to the interval of the bolt, the thickness of the plate, the distance of the edge, the diameter of the bolt, and the expansion of the construction. Furthermore, the analysis explained the sliding behavior of high-tension bolt joints and showed the geometric non-linear against the large deformation, and the boundary non-linear against the non-linear in the contact surface, including the material non-linear, to best explain the exceeding of the yield stress by sliding. A normally bolted high-tension bolt joint and deduction of bolt tension were also analyzed with the finite element analysis of bridge-sliding behavior.

• Journal of Korean Tunnelling and Underground Space Association
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• v.7 no.3
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• pp.209-218
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• 2005

In a NATM tunnel, fully grouted bolts are widely used as part of supporting system. Grouted bolts play an important role not as to take some parts of load acting on the tunnel lining but as to reinforce the ground adjacent the tunnel. In conjunction with tunnel construction, the presence of groundwater may pose a number of difficulties. With respect to tunnel design, influences of groundwater on tunnel behavior have been considered in many aspects. However, the effect on grouted bolts has been rarely investigated. In this study, the behavior of grouted bolts, which are affected by the seepage forces, was examined. In order to investigate the effects of seepage forces, the theoretical solutions for a drained condition were proposed. Based on the theoretical solutions, ground reaction curves considering seepage forces were obtained. By comparing the ground reaction curves supported by grouted bolts with those for the unsupported cases, the effect of reinforcement was evaluated. Finally, through comparison between supported ground react ion curve s in the drained condition and those in the case of groundwater flow, it was observed that the grout ed bolts are more structurely beneficial when the seepage occurs towards the tunnel than when there is no groundwater flow.

• Journal of Korean Society of Steel Construction
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• v.17 no.2 s.75
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• pp.217-225
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• 2005

The purpose of this study is to investigate the behavior of H-shape column base plates subjected to axial loads and moments. In this study, the behavior of H-shape column base plates is investigated using finite element analysis method and an analytical modelingof the base plates is obtained. The variations of six test specimens include ratiosof axial load, sizes of anchor bolts, and thicknesses of base plates. The experimental results are compared with the results from the finite element analyses and those of the analytical modeling. Bearing pressures of base plates from the finite element analyses are compared with those that are assumed in the design of the base plates. From the results of the research, it is observed that the initial stiffness and yield strengths in the analytical study are very similar to the experimental results. And bearing pressures are concentrated under column section with thin base plates.

• Journal of Korean Society of Steel Construction
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• v.16 no.5 s.72
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• pp.599-607
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• 2004

As buildings become more high-rise and lightweight in recent years, steel has been utilized more frequently. Based on the American AISC standard, all axial loads could be carried through a bearing load in a column splice, but according to Korean codes, the bearing load has constrained the stress that could be carried by only 25% of all axial loads. Thus, new column splice methods that use metal touch have been examined. In this study, the stress path mechanism, as an intermediation parameter in the gap's magnitude, must be determined. Similarly, the behavioral aspect of the metal touch connection must be sought after comparing and analyzing the results of the test.

• Journal of the Korean Society for Advanced Composite Structures
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• v.5 no.3
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• pp.8-16
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• 2014

Torque control method and turn of nut method are specified as clamping method of high strength bolts in the steel construction specifications. Quality control of torque coefficient is essential activity because torque control method, which is presently adopted as clamping method in domestic construction sites, is affected by variation of torque coefficient. The clamping of torque shear bolt is based on KS B 2819. It was misunderstood that the tension force of the TS bolt was induced generally at the break of pin-tail specified. However, the clamping forces on slip critical connections do not often meet the intended tension, as it considerably varies due to torque coefficient dependent on the environmental factors and temperature variables despite the break of the pin tail.This study was focused to evaluate the effect of environmental factors and errors of installing bolts during tightening high strength bolts. The environmental parameters were composed of 'wet' condition, 'rust' condition, 'only exposure to air' condition. And the manufacture of trial product was planned to identify the induced force into the bolts. The algorithm for a trial product was composed of the relation between electricity energy taken from torque shear wrench and tension force from hydraulic tension meter.