• Proceedings of the Korean Institute of Building Construction Conference
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• 2013.11a
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• pp.13-14
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• 2013

Mechanical splices has been applied in nuclear power plant according to ASME(American Society of Mechanical Engineering) and ACI(American Concrete Institute) Code requirements. In particular sleeve with ferrous filler metal splices and cold roll formed parallel threaded splices have been used in domestic nuclear power plants. The objective of this study is to find out the constructability of the mechanical splices which had been used in Korea nuclear job site and to review the technical trends in the near future.

• Journal of the Korea institute for structural maintenance and inspection
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• v.4 no.1
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• pp.93-100
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• 2000

The purpose of this study is to investigate the shear behavior of reinforced concrete beams according to small shear span-depth ratio between a/d=1.5, 2.8, 3.6. In general, shear strength of reinforced concrete beams is dependent on the compressive strength of concrete the longitudinal steel ratio, the shear span-depth ratio and shear reinforcement. The static test was carried out to measure the ultimate load, the initial load of flexural and diagonal cracking, crack patterns, fracture modes. The load versus strain and load versus deflection relations were obtained from the static test. The test results on shear strength were compared with results obtained by the formulas of ACI code 318-95. The shear strength of reinforced concrete beams exceeded those predicted following present ACI code 318-95(11-6).

• Land and Housing Review
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• v.2 no.4
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• pp.471-477
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• 2011

This paper will describe the experimental results on the shear behaviors of reinforced concrete (RC) beam with recycled coarse aggregate (RCA). The primary objective of this research is to evaluate the influences of different RCA replacement percentage (i.e, 0%, 30%, 60%, and 100%) on the shear performance of reinforced concrete beams without shear reinforcement. Eight large-scale RC beams without shear reinforcement were manufactured and tested to shear failure. All had a rectangular cross-section with 400mm width ${\times}$ 600mm depth and 6000mm length, and were tested with a shear span-to-depth of 5.1. The results showed that the deflection and shear strength were little affected by the different RCA replacement percentage. Actual shear strength of each RCA beam was compared with the shear strength predicted using the provisions of ACI 318 code and Zsutty'e equation for shear design of RC beams. ACI 318 code predicted the shear strength of RCA reinforced concrete beams well.

• Computers and Concrete
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• v.24 no.1
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• pp.85-94
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• 2019

The ACI building code is allowing for higher strength reinforcement and concrete compressive strengths. The nominal strength of high-strength concrete columns is over predicted by the current ACI 318 rectangular stress block and is increasingly unconservative as higher strength materials are used. Calibration of a rectangular stress block to address this condition leads to increased computational complexity. A triangular stress block, derived from the general shape of the stress-strain curve for high-strength concrete, provides a superior solution. The nominal flexural and axial strengths of 150 high-strength concrete columns tests are calculated using the proposed stress distribution and compared with the predicted strength using various design codes and proposals of other researchers. The proposed triangular stress model provides similar level of accuracy and conservativeness and is easily incorporated into current codes.

• Advances in concrete construction
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• v.7 no.1
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• pp.1-9
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• 2019

The conventional ACI rectangular stress block is developed on the basis of normal-strength concrete column tests and it is still being used for the design of high-strength concrete members. Many research papers found in the literature indicate that the nominal strength of high-strength concrete members appears to be over-predicted by the ACI rectangular stress block. This is especially true for HSC columns. The general shape of the stress-strain curve of high-strength concrete becomes more likely as a triangle. A triangular stress block is, therefore, introduced in this paper. The proposed stress block is verified using a database which consists of 52 tested singly reinforced high-strength concrete beams having concrete strength above 55 MPa (8,000 psi). In addition, the proposed model is compared with models of various design codes and proposals of researchers found in the literature. The nominal flexural strengths computed using the proposed stress block are in a good agreement with the tested data as well as with that obtained from design codes models and proposals of researchers.

• Earthquakes and Structures
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• v.20 no.1
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• pp.29-38
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• 2021

According to ACI 224.3R-95 (ACI, 2013), construction joints (cold joint) in the column are to be provided at the top of floor slab for column continuing to the next floor and underside of floor slab and beam. A recent study reveals that providing cold joint of the mentioned location significantly reduced the seismic performance of the frame structures. Since, the construction joints in multi-story frame structures normally provided at the top of the floor slabs and at soffit of the beam in the column. This study investigated the effect of construction joint at various location in the column of beam-column joint such as at the top of floor slab, soffit level of the beam, half the depth of beam below the soffit of the beam and at a full depth of the beam below the soffit of the beam. The study revealed that there is an improvement in seismic capacity of the specimens as the location of cold joint is placed away from the soffit of the beam for lower story column.

• Earthquakes and Structures
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• v.21 no.6
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• pp.653-667
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• 2021

In this study, cyclic loading tests were conducted on the precast concrete (PC) wide beam (WB)-column joints. Two beam-column joint specimens were fabricated with the arrangement and anchorage details of the reinforcing bars penetrating the beam and column as variables. Through a cyclic loading test, the lateral load-story drift ratio responses, seismic performance characteristics (e.g., ductility, overstrength factor), energy dissipation, strength and stiffness degradations of each specimen were compared and analyzed based on the various indices and the current structural codes (ACI 318-19 and ACI 374.1-05 report). In addition, the shear lag effect was confirmed through the gauge values of the PC beam, and the differences in seismic performance between the specimens were identified on that basis.

• Journal of the Korea Concrete Institute
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• v.24 no.6
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• pp.685-693
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• 2012

The yield strength of shear reinforcement is restricted in the present design codes. In this study, the possibility of the yield strength increase in shear reinforcement is evaluated according to ACI318-08, EC2-02 and CSA-04 by comparing the experimental and calculated results. Three cases were used to analyze the shear strength of the beam. One had no limitation in the yield strength of shear reinforcement, another had restriction on the yield strength of shear reinforcement, and the other had a restriction on the yield strength of shear reinforcement and the shear reinforcement ratio. The study results showed that the case with unlimited shear reinforcement yield strength predicted the test result better than other two cases. Even though the rebar yield strength higher than the strength required in present code was applied to existing shear design equation, the result was reasonable. Therefore, the design equation seemed to be appropriate even if the high-strength shear reinforcement is used in practice based on the existing shear design method.

• Journal of the Earthquake Engineering Society of Korea
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• v.19 no.2
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• pp.55-62
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• 2015

Shear wall systems behave as individual wall because of openings like window and elevator cage. When coupling beams are installed in shear walls, they will have high strength and stiffness so that be less damaged by lateral loads like earthquake. However, coupling beam is difficult construction method. And arranging reinforcement of slender coupling beams are especially hard. It is because the details of coupling beam provided by ACI 318 are complex. In this paper, experiments were conducted using coupling beams with 3.5 aspect ratio to improve the details of slender coupling beams provided by ACI 318. Two specimens were proposed for this study. One specimen applied with bundled diagonally reinforcement only. Another specimen applied both bundled diagonally reinforcement and High-Performance Fiber Reinforced Cementitious Composite (HPFRCC) so that coupling beams have half of transverse reinforcement. All specimen were compared with a coupling beam designed according to ACI 318 and were evaluated with hysteretic behaviors. Test results showed that the performance of two specimen suggested in this study were similar to that of coupling beam designed according to current criteria. And it was considered that simplification of the details of reinforcement would be available if transverse reinforcement was reduced by using bundled diagonally reinforcement and HPFRCC.

• Magazine of the Korea Concrete Institute
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• v.6 no.5
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• pp.140-148
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• 1994

RCI 318-8!4 recommends that when the specified cornpresslve strength of concrete In a column is greater than 1.4 times thdt spec~f~ed for a floor svsttm. top surface of the colunm concrete shall extend 2ft(600mm) into the slab from the face of colurnn to avoid unexpected brittle failure. Six test specimens were cast arid tested on 2/3 scale frame specmiens havlng different extension distances and compressive strength of concrete as the major variables. The paper discusses the performance of the frames in terms of ductility and also presents the assessment of the ACI 318-89 provisions.The test results showed that the ductility index were incrrased with increasing of compressive strength of concrete and extension distance. And top surface of the column concrete should extend 2h(h overall depth of beam) into the beam from the face of the column to avoid unexpected brittle failure in frame.