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Transverse opening in the plastic hinge region of reinforced concrete (RC) beam is generally not recommended due to increased risk of shear failure rather than flexure or flexure-shear failure. However, in recent years, the actual pipeline configuration requirements have posed challenges in arranging such opening in the plastic hinge region of an RC beam member. To address this issue and propose design guidelines, this work examines the mechanical behavior of nine specimens subjected to cyclic loading. The test results are compared with the design methods suggested in other guidelines and research. Additionally, a set of design guidelines and novel reinforcement methods, utilizing Double-square hoop and U-shaped stirrups, are proposed and compared with traditional reinforcement methods for RC beams with circular openings. Three distinct regions for reinforcing beams with transverse circular openings are proposed based on their distance from the column support. In the first region, extending from three times the opening diameter to one beam depth (1H), the opening is reinforced with two inclined U-shaped stirrups on each side and double-square hoops on both faces. The second region (1H to 2H) utilizes one inclined U-shaped stirrup on each side, along with double-square hoops on both faces. Beyond twice the beam depth (2H) in the third region, the opening is reinforced solely with double-square hoops on both faces. The sets of design methods provide valuable insights for future design considerations. [ABSTRACT FROM AUTHOR]

The reinforcing steel bars embedded in the concrete of a reinforced concrete (RC) structure in a region with high airborne chloride concentrations may corrode. To avoid overestimating the seismic capacity assessment, it is necessary to understand the residual shear strength of an RC frame with infilled wall and localized corrosion. This work investigates the residual shear strength of an RC frame with infilled wall and localized corrosion by designing five wall specimens with corroded reinforcing steel bars to obtain the residual shear strength of each RC frame with infilled wall with different corrosion zones. Additionally, a model based on the softened strut-and-tie model is proposed to determine the residual shear strength of an RC frame with infilled wall and localized corrosion. The experimental and calculation results are compared to verify the application of the proposed model for the shear strength of an RC frame infilled corroded RC wall. [ABSTRACT FROM AUTHOR]

This study tests ten full-size simple-supported beam specimens with the high-strength reinforcing steel bars (SD685 and SD785) using the four-point loading. The measured compressive strength of the concrete is in the range of 70-100 MPa. The main variable considered in the study is the shear-span to depth ratio. Based on the experimental data that include maximum shear crack width, residual shear crack width, angle of the main crack and shear drift ratio, a simplified equation are proposed to predict the shear deformation of the high-strength reinforced concrete (HSRC) beam member. Besides the post-earthquake damage assessment, these results can also be used to build the performance-based design for HSRC structures. And using the allowable shear stress at the peak maximum shear crack width of 0.4 and 1.0 mm to suggest the design formulas that can ensure serviceability (long-term loading) and reparability (short-term loading) for shear-critical HSRC beam members. [ABSTRACT FROM AUTHOR]

The purpose of this study is to investigate the flexural crack development of high-strength reinforced concrete (HSRC) beams and suggest the design equations of the flexural crack control for HSRC beams. This study conducts two full-size simply-supported beam specimens and seven full-size cantilever beam specimens, and collects the experimental data of twenty full-size simply-supported beams from the past researches. In addition to high-strength reinforced steel bars of specified yielding stresses of 685 and 785 MPa, these specimens are all designed with the high-strength concrete of a specified compressive stress of 70 or 100 MPa. The experimental data is used to verify the application of the flexural crack control equations recommended in ACI 318-14, as reported by AIJ 2010, as reported by JSCE 2007 and as reported by CEB-fib Model Code 2010 on HSRC beam members; then, this study concludes the design equations for the flexural crack control based on ACI 318-14. Additionally, according to the experimental data, to ensure the reparability of an HSRC beam member in a medium-magnitude earthquake, the allowable tensile stress of the main bars can be set at the specified yielding stress of 685 MPa. [ABSTRACT FROM AUTHOR]