The reliability assessment of the method for calculating the strength of oblique sections in reinforced concrete elements with various cross-sectional shape

Introduction. The current standards for the design of concrete and reinforced concrete structures provide no methods for calculating the strength of the oblique sections in bending elements of various cross-sectional shape under the action of transverse forces. This prompts the designers to use simplifications in calculation of such elements, which, in some cases, may lead to excessive consumption of transverse reinforcement or the strength underestimation.

Aim. The performed study was aimed at assessing the reliability of a new method for calculating the strength of oblique sections in bending reinforced concrete structures with a non-rectangular cross-sectional shape.

Materials and methods. The reliability assessment of a new procedure for calculating oblique sections of a various cross-sectional shape was performed by the comparison between the calculated and experimental values of the transverse force received by the oblique section of reinforced concrete elements with various cross-sectional shape. The study considers the oblique bending tests of the samples with an annular, circular, and square cross-sectional shape, as well as T-shaped samples with a crossbar both in a stretched and compressed zone. The reliability assessment was performed using generally accepted methods of statistical analysis.

Results. The distributions of ratios of the experimental and calculated values of the destructive transverse force for various-section test samples were obtained to be close to normal ones. According to the results of the reliability assessment, the proposed procedure of calculating the strength of oblique sections in elements with various cross-sectional shape was established to be comparable with the procedure accepted in the SP 63.13330.2018 Rules and Regulations for calculating rectangular cross-section elements in terms of the accuracy and reliability indices.

Conclusions. The proposed procedure of calculating the strength of oblique sections in elements with various cross-sectional shape was determined to be comparable with the procedure accepted in the SP 63.13330.2018 Rules and Regulations for calculating rectangular cross-section elements in terms of the accuracy and reliability indices. 

1. Uffe G. Jensen, Linh C. Hoang, Henrik B. Joergensen, Lars S. Fabrin. Shear strength of heavily reinforced concrete members with circular cross section. Engineering Structures. 2010;32(3):617-626. https://doi.org/10.1016/j.engstruct.2009.11.008

2. Shivanov V.N., Yagodin V.K. Determination of the transverse force Qb in bending reinforced concrete elements of annular cross-section. Beton i Zhelezobeton. 1968;(1):37–43 (in Russian).

3. Izotov Yu.L. Strength of reinforced concrete beams. Kiev: Budivel’nik Publ.; 1978 (in Russian).

4. Sverdlov B.M. Improvement of methods for calculating the strength of girders of frame buildings [dissertation]. Moscow; 1989 (in Russian).

5. Thamrin R., Tanjung J., Aryanti R., Nur O.F., Devinus A. Shear strength of reinforced concrete T-beams without stirrups. Journal of Engineering Science and technology. 2016;11(4):548–562.

6. Thamrin R., Haris S., Dedi E., Dalmantias E. (2020). Shear Capacity of Reinforced Concrete Beams with Square Cross Section Subjected to Biaxial Bending. IOP Conference Series: Materials Science and Engineering. 2020;713(1):012029. https://doi.org/10.1088/1757-899X/713/1/012029

7. Rules and Regulations SP 63.13330.2018 Concrete and Reinforced Concrete Structures. General. Updated Edition of SNiP 52-01-2003. Moscow: Standartinform Publ.; 2019 (in Russian).