Shear-Friction Strength of Low-Rise Walls with 600 MPa (87 ksi) Reinforcing Bars

2019 ◽  
Vol 117 (1) ◽  
Author(s):  
Jang-Woon Baek ◽  
Sung-Hyun Kim ◽  
Hong-Gun Park ◽  
Byung-Soo Lee
2019 ◽  
Vol 46 (8) ◽  
pp. 742-758
Author(s):  
Tarek S. Sabra ◽  
Hatem Hassan Ibrahim

The shear friction capacity calculated using clauses 11.6.4 to 11.6.10 in ACI 318-14 or clauses 11.5.1 to 11.5.6 in CSA-A23.3-14 do not take into consideration the effect of edge distance on the shear friction capacity. The main objectives of this research are to study the effect of edge distance on the shear friction capacity by means of a specifically designed experimental program, to determine the minimum edge distance to develop the shear friction capacity, and to derive an expression for reduction of shear friction capacity for edge distances less than the minimum edge distance. The study involved testing eight specimens. In four specimens, a steel plate was anchored using welded reinforcing steel bars, and in the other four specimens the steel plate was anchored using headed concrete anchors (bolts) (HCA). The steel plates were tested under shear load at edge distances of 75, 150, 225, and 300 mm (3.0, 6.0, 9.0, and 12.0 in), for the two types of anchorage. The results were compared to design values according to ACI 318-14 and CAN/CSA-A23.3-14 standards. An equation is derived to compute the minimum edge distance after which the full shear friction capacity is developed. Another equation is derived to compute the proposed shear capacity for reinforcing bar anchors for edge distances less than the minimum edge distance.


2021 ◽  
Vol 13 (6) ◽  
pp. 3482
Author(s):  
Seoungho Cho ◽  
Myungkwan Lim ◽  
Changhee Lee

High-strength reinforcing bars have high yield strengths. It is possible to reduce the number of reinforcing bars placed in a building. Accordingly, as the amount of reinforcement decreases, the spacing of reinforcing bars increases, workability improves, and the construction period shortens. To evaluate the structural performance of high-strength reinforcing bars and the joint performance of high-strength threaded reinforcing bars, flexural performance tests were performed in this study on 12 beam members with the compressive strength of concrete, the yield strength of the tensile reinforcing bars, and the tensile reinforcing bar ratio as variables. The yield strengths of the tensile reinforcement and joint methods were used as variables, and joint performance tests were performed for six beam members. Based on this study, the foundation for using high-strength reinforcing bars with a design standard yield strength equal to 600 MPa was established. Accordingly, mechanical joints of high-strength threaded reinforcing bars (600 and 670 MPa) can be used. All six specimens were destroyed under more than the expected nominal strength. Lap splice caused brittle fractures because it was not reinforced in stirrup. Increases of 21% to 47% in the loads of specimens using a coupler and a lock nut were observed. Shape yield represents destruction—a section must ensure sufficient ductility after yielding. Therefore, a coupler and lock nut are effective.


Author(s):  
Keun-Hyeok Yang ◽  
Kyung-Ho Lee

Abstract The objective of this study is to assess the shear friction characteristics of lightweight aggregate concrete (LWAC) prepared using artificially expanded bottom ash and dredged soil granules. A total of 37 concrete mixtures were prepared under the classification of three series. In the first and second series, the natural sand content for replacing lightweight fine aggregates and the water-to-cement ratio varied to obtain different densities and compressive strengths of concrete. The third series was designed to estimate the effect of the maximum aggregate size on the friction resistance along the shear crack plane of the monolithic interfaces. The frictional angle of the LWAC tested was formulated as a function of the ratio of the effective tensile and compressive strengths of concrete through the expansion of the integrated mathematical models proposed by Kwon et al., based on the upper-bound theorem of concrete plasticity. When predicting the shear friction strength of LWAC, the present mathematical model exhibits relatively good accuracy, yielding the mean and standard deviation of the ratios between experiments and predictions of 1.06 and 0.14, respectively, whereas the empirical equations proposed by the AASHTO provision and Mattock underestimated the results. Ultimately, an advanced modification factor for shear design of LWAC is proposed as a function of the density and compressive strength of concrete and the maximum size of aggregates.


2021 ◽  
Vol 238 ◽  
pp. 112211
Author(s):  
Jin Xia ◽  
Kuang-yi Shan ◽  
Xiao-hui Wu ◽  
Run-li Gan ◽  
Wei-liang Jin

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