• Proceedings of the Korea Concrete Institute Conference
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• 2004.11a
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• pp.281-284
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• 2004

The most important reason of using of ultra high strength concrete in super tall building is that ultra high strength concrete can reduce the section of members and control side sway effectively. However, the practical utilization of ultra high strength concrete is dependent not only on the production techniques, but also the overall preparation including proper code provisions, construction technique. The purpose of this study is to evaluate of mechanical properties of UHSC, such as modulus of elasticity, stress-strain behavior, modulus of rupture and tensile splitting strength. It is similar to normal or high strength concrete but necessary to discern the difference between normal or high strength concrete and ultra high strength concrete and modify existed equations. And in this study another important factor is to discern the difference according to member size, curing method in ultra high strength concrete experimentally.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.11a
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• pp.707-710
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• 2004

This paper reported the results of mock-up test on mass concrete for transfer girder using setting time difference of super retarding agent(SRA). According to test results, two mock-up structures were made. Plain concrete without placing layer reached maximum temperature after 24hours since placement and caused surface hydration cracks at top section. However, concrete with placing layer reached maximum temperature after 72hours and surface temperature was higher than center temperature, which did not cause surface crack. After form removing, no crack was observed at side surface of plain concrete, while concrete using SRA at mid section had surface scaling and settling crack. According to coring results, concrete with placing layer had a penetration crack from top section to bottom section. Therefore, the setting time difference method to reduce hydration heat will have difficulty in applying the mass concrete for transfer girder.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.10a
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• pp.837-843
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• 1999

A common hydraulic jack using brdige retrofit has a problem of increasing cost and time of construction to construct additionally temporary bent or concrete bracket, in case of insufficiency work space and release hydraulic pressure. To solve the problem, this technique is developed to alternate the bridge bearing in adequate inspection condition. After control maximum lift-height and minimum lift-force of no damage to super structure, the constructive technique is to alternate and repair the bridge bearing using the wedge jack with bridge bearing ability that is no release hydraulic pressure stopper, and able to reuse separable cylinder.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2008.11a
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• pp.106-111
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• 2008

Advanced concrete technology, which is the main construction technology of skyscraper, is dealt with in this paper. Advanced concrete technologies are classified into several types such as super high strength concrete(SHSC), low heat concrete(LHC), fire resistant concrete(FRC) and blast resistant concrete(BRC). The necessity, principal and application examples of advanced concrete technology are described respectively. In the last part of the paper, the introduction of HYUNDAI E&C's technology of Advanced concrete and future research trend are described.

• Proceedings of the Korea Concrete Institute Conference
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• 1996.04a
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• pp.211-215
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• 1996

This paper presents comparisons of pullout load of concrete with compressive strength of cylinders and cores, pulse velocity, and rebound number. A pullout test, which is a relatively new nondestructive technique, measures with a special tension ram the force required to pullout a specially shaped steel rod whose enlarged end has been cast into a concrete block. In this study 3 concrete mixes(normal strength, high-strength & super-high-strength) were made. From each mix, one 100$\times$70$\times$20 concrete block, 24 cylinders$(\phi10mm)$were casted. Each tests were performed on the concrete blocks at 3, 7, 28, and 91days. The test data shows that the pullout test is superior to the rebond hammer and the pulse velocity measurements on the evaluation of concrete strength. The pullout test is satisfactory for estimating the strength of in situ concrete at both early and late age, and its results can be reproduced with an acceptable degree of accuracy.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.109-110
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• 2010

A pedestrian UHPC cable-stayed bridge(Super Bridge I) of the KICT was completed as a test bed. A long-term monitoring system has been installed on the UHPC bridge in order to acquire all types of long-term data such as strain, acceleration, tension force, wind direction and speed, temperature, etc. This system will provide valuable database enabling to assess the long-term behavior of the UHPC pedestrian hybrid cable-stayed bridge. This database will be exploited for the evaluation of the mechanical characteristics and serviceability of the UHPC members so as to estimate the behavioral features of long-span hybrid cable stayed bridges.

• Earthquakes and Structures
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• v.6 no.3
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• pp.237-250
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• 2014

This paper experimentally investigates the seismic performance of RC columns retrofitted with Super Reinforcement with Flexibility (SRF), which is a polyester fiber reinforced polymer. A total of three specimens with a scale factor of 1/2 were constructed and tested in order to assess the structural behavior of the retrofitted RC columns. One specimen was a non-seismically designed column without any retrofit, while others were retrofitted with either one or two layers of the polyester belt with urethane as the adhesive. Static cyclic testing with a constant axial load was conducted to assess the seismic performance of the retrofitted RC columns. It is concluded that the SRF retrofitting method increases the strength and ductility of the RC columns and can also impact on the failure mode of the columns.

• International Journal of High-Rise Buildings
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• v.11 no.1
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• pp.61-68
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• 2022

The Address Jumeirah Resort is a mixed-use 77-story tower reaching a height of 301 meters with a slenderness ratio of 13.5:1. The development is situated in the Jumeirah Beach District and accommodates 217 key five-star hotel suites, 478 residential apartments, 444 serviced-branded apartments, retail shops, ballrooms and entertainment facilities around the premises. The building has over 242,000 m2 of usable area. The project is an award-winning development that broke multiple Guinness records. The focus of the paper is to present the challenges faced in the structural design and construction of the super tall tower and the highest occupiable skybridge in the world.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.05a
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• pp.183-188
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• 2002

When Concrete work during winter is placed, it has anxiety that concrete freeze at low temperature. As concrete's freezing cause reduction of durability, it is necessary for mixing to pay attention to Air content and W/C ratios. Accordingly, in this study, we set up three series and evaluate a frost-resistance of concrete with admixture, like fly-ash and blast-furnace slag, for early curing method and types of chemical admixture..The study is composed as; I series : Analysis for early curing method and types of chemical admixture in laboratory II series : Analysis for early curing method and types of chemical admixture in batcher plant and measured concrete' temperature. The result of this study, it was more effective the use of super-plasticizers than air entraining agent.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.11a
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• pp.735-738
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• 2004

In this study, it was founded to make the optimal mixture for producing concrete which is self-compacting, yet, and generates low heat of hydration by using fly ash, blast furnace slags and limestone powders as binders in addition to cement while using super-plasticizers and viscosity agents as admixture agents. The structural behaviors of the concrete produced with the selected mixture were compared with those of the concrete currently using for construction of nuclear power plants. The study shows that the blended high fluidity concrete including limestone is better in workability and durability than the concrete currently in use for nuclear power plants.