• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1997.04a
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• pp.173-181
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• 1997

To investigate the effects of haunch repair on the system seismic performance of steel moment-resisting frames (steel MRFs), a case study was conducted for a 13-story frame damaged during the 1994 Northridge earthquake. It was assumed that only those locations with reported damage would be repaired with haunches. A new analytical modeling technique for the dual panel zone developed by the author was incorporated in the analysis. Both the inelastic static and dynamic analyses did not indicate detrimental side effects resulting from the repair. As a result of the increased strength in dual panel zones, yielding in these locations were eliminated and larger plastic rotation demand occurred in the beams next to the shallow end of the haunches. Nevertheless, the beam plastic rotation demand produced by the Sylmar record of 1994 Northridge earthquake was still limited to 1.7% radians. The repair resulted in a minor increase in earthquake energy input. In the original structure, the panel zones should dissipate about 80%(for the Oxnard record) and 70%(for the Sylmar record) of the absorbed energy, assuming no brittle failure of moment connections. After repair, the energy dissipated in the panel zones and beams were about equal.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.34 no.9
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• pp.11-18
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• 2018

As the height of the modular buildings increases, their stability becomes more and more dependent on the core. All traditional construction methods in structural concrete and steel can be utilized for cores in modular buildings but a core system with dry connection is more desirable to complete a greater degree of factory finish and faster erection of modular buildings. In order to do that, the hybrid PC(precast concrete) panel, which has a pair of C-shaped steel beams combined at the top and bottom of a concrete wall, was developed, In this study the cyclic lateral loading test on the hybrid PC panel is carried out and the panel configurations are examined to enhance the structural performance in comparison with the RC wall. Experimental results show that the strength of hybrid PC panel is about 70% of thar ot RC wall and the anchorage of vertical reinforcing bar welded to C-shaped steel beam needs to be improved.

• Magazine of the Korea Concrete Institute
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• v.11 no.2
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• pp.209-220
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• 1999

This paper is aimed to evaluate the effectiveness of flexural toughness of slab panel structures($60{\times}60{\times}10$) reinforced by steel fiber instead of wire mesh. Steel fiber used in this study is double hooked Dramix type fiber. And the fiber length is 60mm, diameter is 0.8mm, Various assessment methods of toughness index are used to estimate the proper effectiveness. In this experimental study, we find that Johnston, JCI-SF4 and EFNARC method are more effective to assess the flexural toughness of slab panels than the others. And the steel fiber is very effective alternative material to reinforce slab panel structures instead of wire mesh. Fiber volume fraction of 0.5~0.75% is more useful than the others in enhancing the post-peak energy absorption and toughness index by Johnston's $I_{5.5}$ assessment method. And the slab panels reinforcing with steel fiber are more resistant to crack propagation than wire mesh reinforcing slabs.

• Journal of Korean Society of Steel Construction
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• v.9 no.2 s.31
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• pp.277-285
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• 1997

To investigate the shear strength and hysteretic behavior of SRC column to H steel beam joints, seven cruciform specimens were fabricated and tested. The test specimens showed stable hysteresis behavior with a little pinching. The strength decreased with increase in deflection after the speciemens reached at the maximum strength. The shear strength of panel zones increased with increased in the concrete amount of SRC column sections. The shear strength may conservatively be estimated by the sum of shear yielding strength of steel column web, plastic bending strength of steel column flange and ultimate shear strength of concrete in the panel zone.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1998.06a
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• pp.131-139
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• 1998

An aluminium sandwich sheet is the material fabricated by adhering two aluminum panels to one plastic core. If it has the same bending stiffness as an steel panel, it is 65% lighter than steel panel and 30% lighter than aluminum panel. Therefore it is marked exclusively as god substitutive materials of steel body for improving fuel efficiency. But an aluminium sandwich sheet has problem of the lower formability than steel for automotive application. In this paper we intend to develop application technologies of an aluminum sandwich sheet for auto body panels from the selecting composed materials of aluminium sandwich sheets to fabricating prototype. We selected aluminium sandwich panels fabricated by Hoogovens company. Through formability tests we have finished the design and fabricated a mould and a prototype.

• Steel and Composite Structures
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• v.30 no.3
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• pp.217-230
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• 2019

One of the most important design criteria in underground structure is to design lightweight protective layers to resist significant blast loads. Sandwich blast resistant panels are commonly used to protect underground structures. The front face of the sandwich panel is designed to resist the blast load and the core is designed to mitigate the blast energy from reaching the back panel. The design is to allow the sandwich panel to be repaired efficiently. Hence, the underground structure can be used under repeated blast loads. In this study, a novel sandwich panel, named RC panel - Helical springs- RC panel (RHR) sandwich panel, which consists of normal strength reinforced concrete (RC) panels at the front and the back and steel compression helical springs in the middle, is proposed. In this study, a detailed 3D nonlinear numerical analysis is proposed using the nonlinear finite element software, AUTODYN. The accuracy of the blast load and RHR Sandwich panel modelling are validated using available experimental results. The results show that the proposed finite element model can be used efficiently and effectively to simulate the nonlinear dynamic behaviour of the newly proposed RHR sandwich panels under different ranges of free air blast loads. Detailed parameter study is then conducted using the validated finite element model. The results show that the newly proposed RHR sandwich panel can be used as a reliable and effective lightweight protective layer for underground structures.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.10a
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• pp.307-310
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• 1999

In this panel test, the toughness and post-cracking tensile strength of SFRC(Steel Fiber Reinforced Concrete) measured on 24 panels(size; 60cm $\times$ 60cm $\times$ 10cm) which are the basic characteristics than can determine the load bearing capacity of SFRC are investigated. Those values are calculated using load-deflection curves and load-absorbed energy curves. Post-cracking tensile strength of SFRC in this study are determined by yield line theory. From the test results, it is seen that the higher the volume of steel fiber is, the higher the absorbed energy is.

• Journal of Welding and Joining
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• v.20 no.3
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• pp.46-53
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• 2002

The expolitation of substitute material and new manufacturing technology of the automobile body panel for next generation cars have been steadily professed by advanced automobile companies. High strength steel of TRIP (Transformation of Induced Plasticity) type is developed in response to demands about crash safety and high strength of automobile. In this study, basic technologies can fix up problems occurring on the mass production and applied to the other forming methods will be prepared through rasping a property of TRIP material.

• Journal of the Korean Society for Railway
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• v.13 no.5
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• pp.476-480
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• 2010

In the corrugated steel panels used for railway vehicles, sound insulation performance is significantly deteriorated by local resonance effect. In this study, as a countermeasure, polyurethane foam is filled in the corrugated steel panel and glass wool layer is inserted in the layered floor panel, and then improvement effect of the sound insulation performance is experimentally estimated. Based on ASTM E2249-02, intensity transmission loss is measured and estimated on the corrugated panel and floor structure. The aim of the study is to identify how the foam filling and inserting glass wool layer improve the sound insulation performance of the train body structure in aspect of the weight increment.

• Journal of the Society of Disaster Information
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• v.11 no.4
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• pp.607-614
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• 2015

This study evaluated the flexural performance of steel and PP fiber reinfroced shotcrete using round panel test according to ASTM that can consider the actual stress of fiber reinforced shotcrete in tunnel and under ground structures. The results of round panel test are converted to the square panel test results according to the EFNARC. The energy absorptions of each fiber reinforced shotcrete were classified according to the EFNARC toughness classification. Test results show that the PP fiber reinforced shotcrete has better flexural performance compared with the steel fiber reinforced shotcrete.