• The Korean Journal of Zoology
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• v.39 no.1
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• pp.98-105
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• 1996

Studies on thermal adaptation postulate that optimal temperature of physiological properties matches a usually experienced body temperature (Tb) of organisms. Hibernating bats maintain Tb's that are slighdy higher than ambient temperatures (9$^{\circ}$-12$^{\circ}$C) of their wintering sites. To test the hypothesis that muscle function is adjusted to the Tb range of the hibernating animals, we examined contractile function of the biceps brachil muscle of Korean greater horseshoe bats, Rhinolophus ferrumequlnum korai (n = 5) at tissue temperatures between 1O$^{\circ}$ and 35$^{\circ}$C. Relative tetanic force (% of maximum force) was highest at temperatures of 1O$^{\circ}$-15$^{\circ}$C, which match well their Tb's during hibernation. Because non-hibernating endotherms with Tb of around 37$^{\circ}$C show the optimal temperature for muscle force over 30$^{\circ}$-40$^{\circ}$C, our results strongly suggest that the flight muscle of the bats may exhibit thermal adjustments according to their seasonal Tb's. The capacity to generate strong force at such low body temperatures may be adaptive, because bats must have muscles functioning to fly for occasional watering or excretion, or to move away from potential predators during hibernation.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.34 no.12
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• pp.11-20
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• 2018

The purpose of this study is to investigate the seismic performance of exposed column-base plate strong-axis connections for small-sized steel buildings. Even though the seismic design for small-sized buildings became mandatory since Dec.2017, the arbitrary connection details in steel structure have been applied at the construction site, which is considered to be very insufficient to secure structural safety and stability considering the increased seismic risk. Therefore, a series of experimental test programs had been carried out to develop enhanced connection details in order to ensue the adequate seismic safety of small buildings. The hysteretic behavior of the exposed column-base plate connections commonly used in Korea seem to be very pure poor due to the "Rocking" phenomena between anchor plate and concrete by the residual plastic deformation of anchor bolts. A series of hysteretic tests were conducted to find the solution to overcome the "Rocking" phenomena of the exposed column-base plate connections, finally the stable seismic behavior was obtained by uisng at least 8 anchor bolts with good bonding strength to the protptype specimen.

• Journal of Korean Society of Steel Construction
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• v.28 no.5
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• pp.365-371
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• 2016

In the case of the superstructure which is consist of two I girders and slab, the section can behave as II section, so that the neutral axis with respect to out of plane direction flexure can be regarded as major axis. Therefore in-plane flexural mode might govern the free vibration mode. Meanwhile, horizontally curved girders always experience not only bending moments but also torsional moments although the primary load is usually supposed to be gravitational load. The interaction due to bending and torsional moments make the behavior complicated and torsional mode may govern the free vibration mode. In other words, structure can have different dynamic characteristic due to its initial curvature. In this research, using 3-dimensional sell elements, free-vibration analyses are carried out due to initial curvature. The analysis models are assumed to be composite and non-composite and finally natural frequency and eigen mode are discussed.

• Journal of Korean Society of Steel Construction
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• v.24 no.6
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• pp.725-734
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• 2012

A new modular pier system using concrete filled circular steel tubes was suggested to realize modular bridge substructures for accelerated bridge construction. Structural details and connection details were proposed by connection multiple concrete filled tubes (CFT) for standardized products of fabrication, delivery and erection. Static tests were performed for the modular pier with suggested details under lateral load conditions for weak and strong axes. Due to the eccentricity by the bracing system, the modular pier showed 5.23 times higher flexural stiffness and 6 times greater flexural strength from the test. It is proper for the rational design to evaluate stress and deformation by frame modeling of the modular CFT pier. Structural capacity of the pier can be obtained by adjusting the spacing of the CFT columns. Design recommendations were derived from the test.

• Journal of the Korean Society for Advanced Composite Structures
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• v.3 no.2
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• pp.19-27
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• 2012

Structural insulated panels, which are structurally performed panels consisting of a plastic insulation bonded between two structural panel facings are one of emerging products with a viewpoint of its energy and construction efficiencies. These components are applicable to fabricated wood structures. By now, there are few technical documents regulated structural performance and engineering criteria in domestic market. This study was conducted to suggest fundamental reports such as racking resistance, axial capacity, transverse load capacity, and lintel load capacity for SIPs. Test results showed that maximum load was 44.3kN, allowable load was 14.7kN for racking resistance, and that maximum load was 137.6kN, allowable load was 37.4kN/m for axial compression capacity. For transverse load capacity, test results showed $10.3kN/m^2$ of maximum load, $3.4kN/m^2$ of allowable load. For lintel load capacity for SIPs dependent to lengths, allowable loads were 20.4kN for 600mm long lintel, 23.9kN for 1,200mm long lintel, 19.3kN for 1,800mm long lintel, and 2,400mm long lintel had 14.1kN of allowable load. In the near future, when the allowable load for wall application is established, SIPs is considered to substitute the existent post-and-lintel construction to bearing wall structure.

• Journal of Korean Society of Steel Construction
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• v.16 no.5 s.72
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• pp.641-652
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• 2004

The strong beam-to-column axis connections in steel structures have been studied for a long time to develop the strength and resistance of the connections. There have been very few studies, however, related to weak axis connections. Domestically, the bracket-type connection is commonly used in weak axis connections to elevate the efficiency of the constructions when the steel structures are constructed. The bracket-type connection detail has been applied moderately to weak axis connections. Therefore, the bracket-type connection in weak axis connections might be brittle and over-designed. The results of this study showed that the welding on the web of the column and the beam was unnecessary. In addition, this study confirmed that the new weak axis connection proposed in this study was superior to the previous connection in terms of strength and ductility.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.19 no.1 s.71
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• pp.73-83
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• 2006

The failure mechanism of a hollow bridge deck which is made of fiber reinforced polymer (FRP) to improve its durability and life time significantly is investigated using both experiments and analyses. While the Load-displacement behavior of the deck in the longitudinal direction is almost linear just before the failure, the behavior in the transverse direction shows a strong nonlinearity even in its initial response with relatively small magnitude of loads. We found that the nonlinearity is due to the imperfection of the connection between the flange and the web; a plastic deformation can t라e place in the connection. The argument is demonstrated using a simple structural model in which a rigid plastic hinge is introduced to the connection. We also checked the contribution of the delamination mechanism to the failure. But the delamination is not the main mechanism which initiates and causes the failure of the bridge deck. In order to improved the structural behavior of the deck in the transverse direction, we suggested that the empty space of the bridge deck is filled with a foam and confirmed the improved behavior by a numerical analysis.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.3
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• pp.1467-1473
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• 2013

In construction project, it is important to exchange and share the digital information generated by their own professional softwares. So this paper analyzed the information delivery requirements of steel structure according the structural design stages using IDM methodology. For schematic design stage and detailed design stage, the structural design information to share in each design stages is abstracted by defining the PM, ER, and FP. The new ERs and FPs are proposed by defining the new property sets(Psets), suchlike bolt gauge line, weld, scallop, and cope, to complement the structural design information of $IFC2{\times}3$. Finally, the reasonability of the proposed new ERs, FPs are verified by applying them to represent the standard steel connection sample in detailed design stage. As a result, the structural design information of standard steel connection could be stored and managed sufficiently by using the proposed new ERs and FPs.

• Journal of Korean Society of Steel Construction
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• v.17 no.4 s.77
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• pp.431-438
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• 2005

A steel-concrete composite column is a recently developed composite system in which the two opposite flanges of the H-shape section are connected by welded links, and the vacant space enclosed by the flanges, web, and links is filled with concrete. Previous experiments on the SC composite column were performed to evaluate its compression and bending and shear strengths, respectively, and they showed fairly good results. In addition to thesestudies, it may be necessary to evaluate the flexural-axial capacity of an SC composite column, because itscolumn members are generally subjected to axial force and bending moment at the same time. In this study, the bending strength of an SC composite column subjected to axial compression force was investigated experimentally. The results of the study showed that the AISC-LRFD provisions representedexcessively low values compared with those of the ACI, Eurocode-4, and Japan Code provisions. The Eurocode-4 provisions represented reasonable evaluations of the strength of the SC composite column composed of a non-compact section.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.4 no.1
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• pp.1-10
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• 1984

This dissertation presents an exact solution for the shearing and normal stresses of an orthotropic plane body loaded by a pairtial-uniform shear load. The solution satisfies the equilibrium and compatibility equations concurrently. An Airy stress function is introduced to solve the problem related to an orthotropic half-infinite plane under a partial-uniform shear load. All the equations for orthotropy must be degenerated into the expressions for isotropy when orthotropic constants are replaced by isotropic ones. The author has evaluated all the equations of orthotropy and succeeded in obtaining exactly identical expressions to the equations of isotropy which were derived independently by means of L'hospital's rule. The analytical results of, isotropy ate compared with the simple results of other investigator. Since a concentrated shear load is a particular case of partial-uniform shear load, all the equations of partial-uniform shear load case are degenerated into the expressions for concentrated load case of isotropy and orthotropy. The formal solution is expressed in terms of closed form. The numerical results for orthotropy are evaluated for two kinds and two different orientations of the grain of wood. The type of wood considered are three-layered plywood and laminated delta wood. The distribution of normal and shearing stresses are shown in figures. It is noted that the distribution of stresses of orthctropic materials dependson the type of materials and orientations of the grain.