Diagrams of reinforcement deformation under the combined action of loads and elevated temperatures up to +500 °С

Real nonlinear diagrams of reinforcement and concrete deformation form the basis of the modern diagrammatic method for calculating reinforced concrete structures. This method allows for the most accurate consideration of the physico-mechanical and rheological properties of reinforced concrete under various modes of force loading of constructions. To extend the diagrammatic method to the calculation of reinforced concrete structures under the combined action of loads and elevated temperatures, a significant adjustment of the deformation diagrams of reinforcement and concrete is necessary. This article discusses the transition from reinforcement deformation diagrams at normal temperature to deformation diagrams under the combined action of force and temperature influences up to +500°C. At the same time, the basic physical and mechanical characteristics of the diagrams change depending on the values of the heating temperature. Changes in these characteristics are considered for two types of reinforcement – without yield point and with yield point. The results obtained provide the basis for constructing a method for calculating reinforced concrete structures under the combined action of loads and various heating modes.

1. Korsun V.I. Development of methods for calculating reinforced concrete structures of buildings and structures for temperature and humidity effects. Modern industrial and civil engineering. 2021. Vol. 17. No. 1. Pp. 29- 40.

2. Korsun V.I., Khon Khemarak, Ha Van Quynh. Temperature moments in statically indeterminate beams made of high-strength concrete with one-sided heating. [In the collection: Science Week of ISI. Proceedings of the All-Russian Conference in 3 parts.] Civil Engineering Institute of Peter the Great St. Petersburg Polytechnic University. Saint Petersburg, 2021. P. 382-384.

3. Rehman A., Masood A., Akhtar S., Ibrahim S.M., Shariq M. Experimental and numerical investigation into flexural bond strength of RC beams exposed to elevated temperature. Construction and Building Materials. 2021. (282). C. 122630.

4. Liu Jin, Renbo Zhang, Liang Li, Xiuli Du, Yunlong Yao. Impact behavior of SFRC beams at elevated temperatures: Experimental and analytical studies. Engineering Structures. 2019. (197). P. 109401. DOI: 10.1016/j.engstruct.2019.109401.

5. Khon Khemarak, Korsun V.I., Ha Van Quynh, Volkov A.S. Effect of Short-Term Heating up to +90°C on Deformation and Strength 137 of High-Strength Concrete. Ed. B. Anatolijs, V. Nikolai, S. Vitalii, Springer Nature Switzerland AG, 2020. P. 585-592. DOI: 10.1007/978-3-030-42351-3_51

6. Korsun V.I., Baranov A.O., Khon Khemarak, Ha Van Quynh. [Vladimir Korsun, Aleksey Baranov, Khemarak Khon, and Quynh Ha. The Influence of Temperature and Duration of Heating on the Properties of High-Strength Concrete Modified by Organo-Mineral Components .Ed. N. Vatin, A. Borodinecs, B. Teltayev, Cham: Springer Nature Switzerland AG, 2021. P. 515-524. https://doi.org/10.1007/978-3-030-72404-7_50

7. Korsun V.I., Khon Khemarak, Ha Van Quynh, Baranov A.O. Strength and deformations of highstrength concrete under short-term heating conditions up to + 90°C. IOP Conference Series: Materials Science and Engineering. 2020. (896). P. 012035. DOI: 10.1088/1757-899X/896/1/012035

8. Korsun V., Korsun A., Volkov A. Characteristics of mechanical and rheological properties of concrete under heating conditions up to 200°C. MATEC Web of Conferences. 2013. (6). P. 1-8.

9. Korsun V., Shvets G. The calculation of creep deformation of high-strength concrete in relation to the conditions of exposure to elevated temperatures. IOP Conference Series: Materials Science and Engineering. 2020. (896). C. 012039. DOI: 10.1088/1757-899X/896/1/012039

10. Mustafa M.A., Yusof K.M. Mechanical properties of hardened concrete in hot humid climate. Cement and Concrete Research. 1991. No. 4 (21). C. 601-613.

11. Mohd Zain M.F., Radin S.S. Physical properties of high-performance concrete with admixtures exposed to a medium temperature range of 20℃ to 50℃. Cement and Concrete Research. 2000. (30). C. 1283-1287.

12. Samir N.S. [and etc.]. Effect of moisture and temperature on the mechanical properties of concrete. Construction and Building Materials. 2011. (25). C. 688-696.

13. Korsun V.I., Baranov A.O. Calculation of temperature-shrinkage deformations of high-strength concretes in relation to conditions of exposure to elevated temperatures [Fundamental, exploratory and applied research of the Russian Academy of Architecture and Construction Sciences on scientific support for the development of architecture, urban planning and the construction industry of the Russian Federation in 2019: Coll. scientific. tr. RAASN. Moscow]: ASV Publishing House, 2020. Pp. 314-321.

14. Krichevsky A.P. Calculation of reinforced concrete engineering structures for temperature effects. Moscow, Stroyizdat USSR, 1984.

15. Madatyan S.A. Reinforcement of reinforced concrete structures. OOO Voentekhmet, Moscow, 2000.

16. Milovanov A.F., Tupov N.I. Creep and stress relaxation in mature concrete under long-term exposure to elevated temperatures up to 90 °C. Creep and shrinkage of concrete. Proceedings of the meeting prepared by the Research Institute of Reinforced Concrete of the USSR Gosstroy. TSINIS, Moscow, 1969.

17. .SP 63.13330.2018. Concrete and reinforced concrete structures. Basic provisions. Moscow, Standartinform, 2019.

18. Karpenko N.I. General models of reinforced concrete mechanics / N.I. Karpenko. - Moscow: Stroyizdat, 1996. - 416 p.

19. Karpenko N.I. Methodological manual "Statically indeterminate reinforced concrete structures. Diagrammatic methods of automated calculation and design" FAU "Federal Center for Normation, Standardization and Conformity Assessment in Construction". Moscow, 2017, supervised by N.I. Karpenko.

20. Karpenko N.I. Methodological manual "Automated methods for calculating massive reinforced concrete structures under volumetric stress state" FAU "Federal Center for Normation, Standardization and Conformity Assessment in Construction". Moscow, 2019, supervised by N.I. Karpenko, pp. 29-36.

21. SP 27.13330.2017. Concrete and reinforced concrete structures designed to work under conditions of elevated and high temperatures. M., 2017.