• Journal of the Korean Society of Safety
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• v.30 no.6
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• pp.70-77
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• 2015

In this study, the governing design factors of GFRP-reinforced concrete bridge deck are analyzed for typical bridges in Korea. The adopted bridge deck is a cast-in-situ concrete bridge deck for the prestressed concrete girder bridge with dimensions of 240 mm thickness and 2.75 m span length from center-to-center of supporting girders. The selected design variables are the diameters of GFRP rebar, spacings of GFRP rebars and concrete cover thicknesses, Considering the absence of the specification relating GFRP rebar in Korea, AASHTO specification is used to design the GFRP-reinforced concrete bridge deck. The GFRP-reinforced concrete bridge deck is proved to be governed by the criteria about serviceability, especially maximum crack width, while steel reinforced concrete bridge deck is governed by the criteria on ultimate limit state. In addition, GFRP rebars with diameter of 16 mm ~ 19 mm should be used for the main transverse direction of decks to assure appropriate rebar spacings.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.05a
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• pp.266-267
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• 2017

As apartment buildings defect lawsuits become socioeconomic problems, an objective basis system for the term of warranty liability of reinforced concrete constructions is urgent. This study was carried out as a basic study for developing a basis system for the term of warranty liability. To do this, defect data actual collected in apartment complexes were collected and analyzed. As the result of checking the cumulative rate of defect occurrence in reinforced concrete construction by year, the point of time of reaching the 90% level was the 5th years, which was similar with the provision of the Apartment Building Management Act. However, the current Supreme Court precedent has decided that the term of warranty liability for the main structural parts in reinforced concrete construction shall be 10 years and the dispute is expected to continue in the future in the defect lawsuit.

• Proceedings of the Korea Concrete Institute Conference
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• 1997.10a
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• pp.450-455
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• 1997

In recent years the research and development about the new material proceeds rapidly and actively in building industry. We are concerned with high-strength concrete as a new material. As the building structure becomes bigger, higher and more specialized, so does the demand of material and member with high strength for building expands greatly. In the future, we will quite need to research repair and rehabilitation to make high strength concrete structural building for our safe. So, I did an study on carbon fiber sheet rehabilitation(CFSR) of reinforced high strength concrete beams. The carbon fiber reinforced plastic(CFRP) bonding method is widely used for reinforcing the existing concrete structure among the various methods. The test results indicate that CFS is very effective for strengthening the damaged beams and controlling deflections of the repaired beams. When carbon fiber sheet rehabilitation of reinforced high strength concrete beams happened diagonal crack, the increase in the number of CFS layer didn't effect the increase in strength of beams. Also, by changing the CFS stick position gave diversified ultimate load in CFSR beams.

• Advances in concrete construction
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• v.4 no.2
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• pp.89-105
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• 2016

The post - fire investigation is conducted on a fire-affected reinforced concrete shear wall building to ascertain the level of its strength degradation due to the fire incident. Fire incident took place in a three-storey building made of reinforced concrete shear wall and roof with operating floors made of steel beams and chequered plates. The usage of the building is to handle explosives. Elevated temperature during the fire is estimated to be $350^{\circ}C$ based on visual inspection. Destructive (core extraction) and non-destructive (rebound hammer and ultrasonic pulse velocity) tests are conducted to evaluate the concrete strength. X-ray diffraction (XRD) and Field Emission Scanning Electron Microscopy (FESEM) are used for analyzing micro structural changes of the concrete due to fire. Tests are conducted for concrete walls and roof slab on both burnt and unburnt locations. The analysis of test results reveals no significant degradation of the building after the fire which signifies that the structure can be used with full expectancy of performance for the remaining service life. This document can be used as a reference for future forensic investigations of similar fire affected concrete structures.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.04a
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• pp.198-199
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• 2022

Reinforced concrete is the most widely used construction method for constructing structures. There is a lot of process for constructing Reinforced concrete structures such as installing rebars, molds and support, mixing and placing concrete, and curing. So the reinforced concrete work accounts for a large part of the total construction cost for constructing structure. For this reason a reasonable standard for estimating the cost of reinforced concrete construction has to be established and it will be possible to secure appropriate costs for construction work. In this study, we analyze the revision factors of the standard for estimating the cost of reinforced concrete construction and present them to secure reasonable construction costs.

• Journal of the Korea Institute of Building Construction
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• v.8 no.1
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• pp.43-48
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• 2008

Fifteen concrete specimens were mixed and tested to explore the significance and limitation of appling the polyvinyl alcohol (PVA) fiber and steel fiber with end hook to concrete. Main parameters investigated were volume fraction and length of the fibers. The measured mechanical properties of fiber reinforced concrete are analyzed according to the equivalent fiber amount index explaining the adding amount and length of fibers. Test results showed that compressive strength of fiber reinforced concrete was higher than that of concrete with no fiber by $10{\sim}20%$. The normalized splitting tensile strength and flexural strength of PVA fiber reinforced concrete were similar to those of concrete with no fiber, whereas those of steel fiber reinforced concrete increased with the increase of the equivalent fiber amount index. In particular, much higher ductile behavior was observed in steel fiber reinforced concrete than in PVA reinforced concrete, indicating that the slope of descending branch of load-displacement relationship of steel fiber reinforced concrete decreased with the increase of the volume fraction and length of the fiber.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.11a
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• pp.15-16
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• 2017

In this study, the flexural behavior of fiber-reinforced concrete by fiber type were evaluated. As a result, the flexural strength of the hooked steel fiber-reinforced concrete(HSFRC) was lower than that of the amorphous metallic fiber reinforced concrete(AFRC), however it was shown strain-softening behavior by the pull-out of fiber. The flexural strength and the equivalent flexural strength of polyamide fiber-reinforced concrete(PAFRC) were lower than other specimens, but the equivalent flexural strength ratio was similar to that of AFRC. The flexural behavior of the fiber-reinforced concrete was associated with the bonding and pull-out properties of the fiber and matrix depending on the fiber type.

• Advances in concrete construction
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• v.5 no.1
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• pp.49-63
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• 2017

Traditional reinforced concrete slabs and beams are widely used for building. The use of flat slab structures gives advantages over traditional reinforced concrete building in terms of design flexibility, easier formwork and use of space and shorter building time. Deflection of the slab plays a critical role on the design and service life of building components; however, there is no recent research to explore actual deformation of concrete slab despite various advancements within the design codes and construction technology. This experimental study adopts the Hydrostatic Levelling Cells method for monitoring the deformation of a multi-storey building with flat slabs. In addition, this research presents and discusses the experimental results for the vertical deformation.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.05a
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• pp.38-39
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• 2015

This study reviewed slump and air content as pre-hardening characteristics depending on B/P production of amorphous steel fiber-reinforced concrete and evaluated compressive strength, flexural strength and tensile strength as post-hardening characteristics depending on B/P production of amorphous steel fiber-reinforced concrete.

• Computers and Concrete
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• v.21 no.1
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• pp.95-102
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• 2018

Reinforced concrete corbel beams (span to depth ratio of a corbel is less than one) are designed with primary reinforcement bars to account for bending moment and with the secondary reinforcement placed parallel to the primary reinforcement (shear stirrups) to resist shear force. It is interesting to note that most of the available analytical procedures employ empirical formulas for the analysis of reinforced concrete corbels. In the present work, a generalized and a simple strut and tie models were employed for the analysis of reinforced corbel beams. The models were benchmarked against experimental results available in the literature. It was shown here that increase of shear stirrups increases the load carrying capacity of reinforced concrete corbel beams. The effect of horizontal load on the load carrying capacity of the corbel beams has also been examined in the present paper. It is observed from the strut and tie models that the resistance of the corbel beam subjected to combined horizontal and vertical load did not change with increase in shear stirrups if the failure of the corbel is limited by concrete crushing. In other words, the load carrying capacity was independent of the horizontal load when failure of the beam occurred due to concrete crushing.