• Journal of Korean Society of Steel Construction
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• v.19 no.4
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• pp.357-366
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• 2007

This paper is a pilot study regarding an experimental and parametric study to investigate the structural behavior of slimfloor beam(ASB) in fire. The objective of this research is to obtain the rational fire resistance design method through understanding the structural behavior of composite members in fire. The flexural capacity of slimfloor section under various thermal conditions is examined on a basis of the strength retention of the materials at elevated temperatures and full bonding assumption. The effect of web thickness and ASB depth to the moment capacity in fire is also examined.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.21-22
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• 2009

This paper presents the results of an experimental study on flexural behavior and cracking process of concrete beams subjected to cycles of freezing and thawing after patch-repaired with strain-hardening cement composites (SHCCs). The SHCCs were reinforced with hybrid 0.75% PVA and 0.75% PE fibers. Experimental testing of concrete beams patch-repaired with SHCCs revealed that the SHCC patch-repair system without freeze thaw (FT) exposure showed average 3.31 times increased load carrying capacity and for beams exposed to 300 FT cycles, load carrying capacity increased up to 2.42 times. Cracking damage of SHCC patch-repaired beams mitigated compared to plain concrete beams but this trend decreased under FT exposure.

• Journal of the Korea institute for structural maintenance and inspection
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• v.16 no.1
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• pp.18-26
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• 2012

Recently, research about Near-Surface-Mounted Rertofit (NSMR) method has been being widely performed as a method for retrofit of RC structure using FRP. This method requires additional work to make grooves during retrofit but makes it possible to improve retrofit effect and reduce the attack by environment. In this paper, the retrofit effect of NSMR method, especially the method using FRP plate instead of bar is investigated through experiment. Six RC beams were made and retrofitted using by FRP plate following the planned methods; Surface-Bonding Retrofit (SBR), NSMR without debonding region and NSMR with debonding region. Flexural capacity of all specimens was evaluated by beam test with simple support condition. As a result, NSMR method with FRP plate had more improved structural capacity than SBR method. The calculation process of ACI 440-2R can be used to predict the member retrofitted by NSMR with FRP plate with consideration on the three anchorage failure mechanism.

• Journal of Korean Society of Steel Construction
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• v.13 no.3
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• pp.265-277
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• 2001

This paper present a study on the flexural behavior of composite slabs using the flat-type profiled(ACE-DECK) steel deck plate which are developed recently. Forty eight composite slabs with different thickness, span, shear span and deck profile were tested to evaluate the flexural capacity and compared to the existing traperzodial deck profiles (KEM, ALPHA-DECK) According to the experiment results, flat-type profiled steel deck plate indicates more excellent capacity than existing traperzodial deck profiles in strength, stiffness, and ductility. The equation proposed by ASCE code for the effective moment of inertia are more acceptable than the equation proposed by ACI code. Thus, in this paper, test results are summarized by strength, stiffness, and deformation capacity for the specimens.

• Journal of the Korean Wood Science and Technology
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• v.41 no.3
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• pp.211-220
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• 2013

The nailed joints in wood construction are commonly designed to resist and carry the lateral load but also subject to withdrawal force like uplift load due to the wind. This research was conducted to evaluate the performance of nailed joint composed of dimension lumber and sheathing materials through the nail withdrawal and unsymmetric double shear joint test, and then compared to current design values. The withdrawal strength was greatly dependant on wood specific gravity, and the withdrawal strength of I-joist with OSB showed higher value in spite of low specific gravity. The maximum withdrawal loads were greater than that of derived current design values about 5 times. The lateral resistance of Japanese larch/OSB nailed joints was higher than that of SPF/OSB nailed joint, and derived allowable lateral strength of nailed joints in this study exceeded the current design values. The failure mode of nailed joints was primarily due to the nail bending and this tendency was notable in SPF/OSB nailed joint.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.111-112
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• 2010

This study proposes a new methodology of earthquake damage evaluation for R/C Buildings combined with shear and flexural failure systems, based on non-linear required strength spectrum. Part I shows a concept of methodology of earthquake damage evaluation, which is estimated on the basis of system ductility, non-linear required strength spectrum and remaining seismic capacity ratio.

• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.2
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• pp.130-137
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• 2017

Due to the economic growth and development of construction technology, a role of foundation to resist heavy loads has been increased. In this present study to improve the structural performance of reinforced concrete pile, the precast HPC pile reinforced with rebar and filling concrete was developed and the strength of pile was predicted based on the limit state design method. The safety of HPC pile strength was evaluated by comparing with the design values. The geometry of HPC pile is a decagon cross section with a maximum width of 500 mm and a minimum width of 475 mm, and the hollow head of pile thickness is 70 mm. The inner area of the hollow head part was made as the square ribbed shape presented in the limit state design code in order to achieve horizontal shear strength between pile concrete and filling concrete. From the shear test results, it was found that the stable shear strength were secured without abrupt failure until maximum load stage despite the shear cracks was found. Shear strength is 135% and 119% higher than that of design value calculated from limit state design code. The driving test results of HPC pile according to the presence of additional reinforcement showed the outstanding crack resistance against impact loads condition. From the bending test results the flexural load between PHC pile and HPC pile was 1.51 times and 1.48 times higher than that of the design flexural load of conventional PHC pile.

• Journal of Korean Society of Steel Construction
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• v.23 no.3
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• pp.317-326
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• 2011

Today there is a growing range of applications for Concrete-Filled Steel Tube (CFT) member because of its superior performance. Ductility estimation test of concrete-filled seismic resistant steel tubular columns, subjected to axial and cyclic lateral load, was carried out in this study. Seismic resistant steel tubes are manufactured using SN400B plates by a two-seam welding at center of the column width for cold press-formed shape plates of two pieces. A total of eight specimens were manufactured and tested with the parameters of width-thickness ratio of steel tubular column, axial load ratio, and loading conditions to act axial and cyclic lateral load two dynamic actuators were used. From test results, flexural strength, deformation capacity, energy dissipation capacity, and ductility behavior of columns were analyzed.

• Journal of the Korea institute for structural maintenance and inspection
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• v.14 no.1
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• pp.125-132
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• 2010

In the recent construction industry, an external strengthening method using fiber reinforced polymers has been widely used. Since reinforced concrete structures strengthened with fiber reinforced polymers are always under sustained loads, influence of creep and shrinkage on the structures is inevitable. Due to the creep and shrinkage, behaviors of the structures, such as deflection, deformation, recovery capability, strength and so on are also under the influence of creep and shrinkage. Thus, in order to estimate efficacy, creep recovery and residual strength of FRP strengthened RC beams, long-term flexural experiments and static flexural experiments were carried out. As the result of the experiments, FRP strengthened RC beams were very effective in terms of deflection control. Furthermore, the strengthened beams had higher immediate deformation recovery than immediate deformation. Through the static flexural experiments, it was shown that the CFRP strengthened beam had high residual strength. It seems that the sustained loads did not affect bond and residual strength of the beams.

• Journal of the Korea institute for structural maintenance and inspection
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• v.13 no.2 s.54
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• pp.199-205
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• 2009

Recently, as the concern for the development of a construction method for an environmental protection and for tall building is increasing, the use of the half precast concrete(PC) slab that has the solution of environmental problems and the advantage such as reduction of construction period is being demanded. However, there is shortcoming that the crack can occur easily while constructing, and these cracks can have a bad influence upon the structural performance of PC composite slab. However, there is little studies on the influence of these cracks on the structural performance of composite PC slab. In this study, the specimen caused the crack before pouring topping concrete in the half PC slab and the PC composite slab without the cracks were produced to investigate the structural performance of PC composite slab with crack.