• Proceedings of the Korea Concrete Institute Conference
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• 2003.05a
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• pp.151-156
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• 2003

On the basis of the philosophy that "the compressive axial load capacity after spalling of shell concrete should be maintained as that before spalling" by applying the confinement model of high strength concrete proposed in the previous proceeding paper and equivalent lateral confining pressure considering configurations of transverse reinforcement, the amounts of transverse reinforcement from the compressive capacity design method about high strength reinforced concrete tied columns can be calculated through the formula proposed in this paper. The proposed design equation of transverse steel amounts for high strength reinforced concrete tied columns was quite agreeable with the test results of HSC tied columns conducted by other researchers as well as author.as author.

• Journal of the Korean Geosynthetics Society
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• v.6 no.3
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• pp.31-37
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• 2007

A steel strip reinforcement for the reinforced earth structures was recently developed to substitute the existing ribbed steel strip reinforcement. The developed reinforcement consists of the punched steel strip having dimension of 65mm width and 4.5mm thickness and the transverse steel bar for increasing bearing resistance. The punched steel strip has holes of 11mm diameter in every 50cm spacing with 2mm rising around perimeter of the holes. A series of shear friction tests and pull-out tests were carried out to evaluate the friction properties of the developed reinforcement. The results of these tests show that pull-out resistance of the developed reinforcement was significantly increased when the transverse steel bars are installed in the punched steel strip.

• Structural Engineering and Mechanics
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• v.82 no.2
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• pp.173-189
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• 2022

This study presents an experimental and numerically study about the effects of fiber reinforcement ratio on the behavior of concrete-filled steel tubes (CFST) under dynamic impact loading. In literature have examined the behavior of GFRP and FRP wrapped strengthened CFST elements impact loads. However, since the direction of potential impact force isn't too exact, there is always the probability of not being matched the impact force of the area where the reinforced. Therefore, instead of the fiber textile wrapping method which strengthens only a particular area of CFST element, we used fiber-added concrete-filled elements which allow strengthening the whole element. Thus, the effect of fiber-addition in concrete on the behavior of CFST elements under impact loads was examined. To do so, six simply supported CFST beams were constructed with none fiber, 2% fiber and 10% fiber reinforcement ratio on the concrete part of the CFST beam. CFST beams were examined under two different impact loads (75 kg and 225 kg). The impactors hit the beam from a 2000 mm free fall during the experimental study. Numerical models of the specimens were created using ABAQUS finite element software and validated with experimental data. The obtained results such as; mid-span displacement, acceleration, failure modes and energies from experimental and numerical studies were compared and discussed. Furthermore, the Von Misses stress distribution of the CFST beams with different ratio of fiber reinforcements were investigated numerically. To sum up, there is an optimum amount limit of the fiber reinforcement on CFST beams. Up to this limit, the fiber reinforcement increases the structural performances of the beam, beyond that limit the fiber reinforcement decreases the performances of the CFST beam under transverse impact loadings.

• KCI Concrete Journal
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• v.11 no.3
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• pp.201-210
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• 1999

An experimental study was carried out to determine pullout behavior of a new type of anchor bolt that used deformed reinforcement and a commercial adhesive. Concrete slabs and columns with about 20-MPa compressive strength were used for 136 pullout tests performed. Test variables included anchor diameter (10 mm ~ 32 mm). embedment depth (10$\Phi$ or 15$\Phi$), edge effect. and Presence of transverse reinforcement in existing concrete. In Tyre-S test. where the edge or reinforcing steel effect was not included, the anchor Pullout strengths increased with increasing anchor diameters. Anchors with 15$\Phi$ embedment depth had higher Pullout strengths than those with 100 embedment depth The largest average Pullout load of 208 kN was determined for anchors made with D25 reinforcement and with 15$\Phi$ embedment depth. In Type-E tests, where the anchors were installed close to the edge of existing concrete, there were reductions in pullout strengths when compared to those determined in Type-S tests. In Type-ER tests, influence of the reinforcement in existing concrete on the anchor pullout strengths was examined using reinforced concrete and plain concrete columns Test results indicated that existing transverse reinforcement (column ties) did not help increase the pullout strength. The overall pullout test results revealed that the new anchor bolt can develop large pullout strengths while the anchors can be made of materials that are readily available in the market.

• Advances in concrete construction
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• v.8 no.2
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• pp.145-154
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• 2019

The present experimental study addresses the structural response of reinforced concrete (RC) beams strengthened in shear. Thirteen RC beams were divided into four different sets to investigate the effect of transverse and longitudinal steel reinforcement ratios, concrete compressive strength change and orientation for installing carbon fiber-reinforced polymer (CFRP) laminates. Then, we employed a shear strengthening solution through externally bonded reinforcement in grooves (EBRIG) and externally bonded reinforcement (EBR) techniques. In this regard, rectangular beams of $200{\times}300{\times}2000mm$ dimensions were subjected to the 4-point static loading condition and their load-displacement curves, load-carrying capacity and ductility changes were compared. The results revealed that using EBRIG method, the gain percentage augmented with the increase in the longitudinal reinforcement ratio. Also, in the RC beams with stirrups, the gain in shear strength decreased as transverse reinforcement ratio increased. The results also revealed that the shear resistance obtained by the experimental tests were in acceptable agreement with the design equations. Besides, the results of this research indicated that using the EBRIG system through vertical grooves in RC beams with and without stirrups caused the energy absorption to increase about 85% and 97%, respectively, relative to the control.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2000.04a
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• pp.259-266
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• 2000

This study was conducted to investigate the seismic behavior assessment of circular reinforcement concrete bridge piers particularly with regard to assessing the displacement ductility curvature ductility response modification factor(R) and plastic hinge region etc, The experimental variables of bridge piers test consisted of transverse steel details amount and spacing different axial load levels etc. The test results indicated that reinforcement concrete bridge piers with confinement steel by the code specification exhibited suffcient ductile behavior and seismic performance. Also it is found that current seismic design code specification of confinement steel requirements may be revised.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.10a
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• pp.505-508
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• 1999

To evaluate the strength of square reinforced concrete shot columns, thirty specimens were manufactured and tested under monotonically increasing concentric compression. The test parameters included the volumetric ratio of transverse reinforcement($\rho$h = 0.49~2.65), and concrete compressive strength (234, 437, 704 kgf/$\textrm{cm}^2$). Test results are shown that : (1) Behavior of high -strength concrete column is improved by providing increased volumetric ratio; and (2) ACI, Eq. is not proper to evaluate HSC short column strength.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.11a
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• pp.1103-1108
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• 2001

ACI 318-99 predicts the torsional moment of reinforced concrete members by assuming that the angle of diagonal compressive concrete is equal to 45 degree. However, this angle depends on the difference of longitudinal and transverse steel ratios. This paper compares the torsional moments calculated by ACI 318-99 code and a truss model considering compatibility of strains. The comparison indicated that the torsion equation in ACI code underestimated the real torsional moment of reinforced concrete beam in which the ratio of longitudinal reinforcement was larger than that of transverse reinforcement.

• Journal of the Earthquake Engineering Society of Korea
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• v.2 no.4
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• pp.155-168
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• 1998

In this paper, the structural properties of the existing reinforced concrete(RC) piers are surveyed and the major factors influencing the member strength and deformation capacity are identified. Also a seismic evaluation procedure of RC piers is presented. The factors controlling the member strength are the applied axial load, the reinforcement ratio and yield strength of longitudinal rebar for flexural strength, and the transverse reinforcement for shear strength. Member deformation capacity largely depends on transverse reinforcement ratio and anchor detail, and splice location of longitudinal reinforcement. The above structural detail should be investigated for the detail seismic evaluation of RC piers. The most of existing RC piers have inadequate transverse reinforcement anchor details and the splices of longitudinal reinforcement in the pier bottom where plastic hinges are formed after yielding. Therefore the deformation capacity is not enough for the ductile flexural behavior of the RC piers. The presented evaluation procedure can be used for the rational decisions as to seismic retrofitting of the existing RC piers.

• Land and Housing Review
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• v.6 no.1
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• pp.11-19
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• 2015

This paper presents experimental results on detailing of boundary element transverse reinforcement, proposed to alleviate placement detailing of special shear wall experiencing difficulty in construction at the sites due to recently reinforced seismic regulations, according to the type and placement interval of transverse reinforcement. As a result of experiment, crack and destruction aspects of SSWR series specimen that employed the proposed detailing of transverse reinforcement showed similar trend as SSW series specimen that used closed hoop. Predicted maximum strength values were exceeded. Also as a result of comparing energy dissipation ability, SSWR2 specimen that follows alleviated placement detailing was found to have similar seismic performance as special shear wall SSW2 specimen based on the existing design standard. As it satisfies the deformation angle condition of 1.5% provided in the design standard, SSWR2 can be used as the main lateral force resistance element in structures.