RESIDUAL LIFE OF REINFORCED CONCRETE SUPERSTRUCTURES OF RAILWAY BRIDGES

To date, there is no single methodology confirmed by the operational experience and approved at the federal level of estimating the residual life of reinforced concrete superstructures of railway bridges. The paper provides an overview of Russian and foreign regulatory documents to determine the durability of reinforced concrete bridge construction. The paper presents data on malfunctions of reinforced concrete superstructures which affect their capacity and durability. Over the past 30 years, Russian and foreign scientists have conducted extensive research into the residual life and proposed various methods. Shortcomings and advantages of these methods are analyzed. Based on the study of the operational experience and existing approaches, a methodology is proposed for estimating the residual life of construction, which considers malfunctions, operating history, climatic factor, and allows determining the probability of changing the technical state of the construction by several scenarios. The process of changing conditions is random. For predicting conditions and calculating indicators of the structural reliability of and its elements, a model based on the semi-Markov process is used. Data sources for reliability models are obtained from observations of the technical state of construction or mathematical models of the malfunction development. The residual life of reinforced concrete superstructures is determined in the event of the reinforcement corrosion. This methodology corresponds to the modern approach, as well as the Russian regulatory documents and implements the concept of operation and maintenance of artificial construction accepted by the Russian railway network.

1. Aktuganov I.Z. Metodika otsenki vliyaniya klimaticheskikh temperaturno-vlazhnostnykh vozdeistvii na ekspluatatsionnuyu nadezhnost' i dolgovechnost' betona stroitel'nykh konstruktsii [Climatic conditions effect on structural concrete durability]. Novosibirsk: SGUPS Publ., 2005. 76 p. (rus)

2. Bokarev S.A., Efimov S.V. O normirovanii vysoty prodol'nogo borta zhelezobetonnykh pro-letnykh stroenii s ezdoi na ballaste [Height normalizing of lengthwise side of reinforced concrete superstructures under moving load]. Vestnik Sibirskogo gosudarstvennogo universiteta putei soobshcheniya. 2016. No. 2. Pp. 10–19. (rus)

3. Vasil'ev A.I. Otsenka tekhnicheskogo sostoyaniya mostovykh sooruzhenii [Technical conditions of bridge structures]. Moscow: KNORUS, 2017. 256 p. (rus)

4. Instruktsiya po otsenke sostoyaniya i soderzhaniya iskusstvennykh sooruzhenii na zheleznykh dorogakh Rossiiskoi Federatsii [Estimation and maintenance of artificial railroad constructions in the Russian Federation]. Moscow: Departament puti i sooruzhenii OAO 'RZhD'. 2006. 120 p. (rus)

5. Iosilevskii L.I. Prakticheskie metody upravleniya nadezhnost'yu zhele-zobetonnykh mostov [Practical methods of reliability managing of steel bridges]. Moscow: ‗Inzhener‘ Publ., 1999. 295 p. (rus)

6. Iosilevskii L.I., Fedulov I.V. Prognozirovanie srokov sluzhby zhele-zobetonnykh proletnykh stroenii [Lifetime prediction of steel superstructures]. Put' i putevoe khozyaistvo. 1997. No. 8. Pp. 11–14. (rus)

7. Levin B.R. (Ed.). Spravochnik po nadezhnosti. Moscow: Mir, V. 1. 1969. 339 p. (rus)

8. Mamazhanov R.K. Osnovy teorii prognozirovaniya resursa zhelezobetonnykh mostov dlya Srednei Azii: avtoref. dis. … d-ra. tekh. nauk [Fundamentals of theory of predicting steel bridge service life in Central Asia. DSc Abstract]. Moscow: TsNIIS Publ., 1989. 41 p. (rus)

9. Orlov A.I. Matematika sluchaya. Veroyatnost' i statistika – osnovnye fakty [variation mathematics. Probability and statistics – main facts]. Moscow: MZ-Press, 2004. 110 p. (rus).

10. Chirkov V.P. Prikladnye metody teorii nadezhnosti v raschetakh stroi-tel'nykh konstruktsii [Applied methods of reliability theory in structural analysis]. Moscow: Marshrut Publ., 2006. 620 p. (rus)

11. Chirkov V.P., Klyukin V.I., Fedorov V.S., Shvidko Ya.I. Osnovy teorii proektirovaniya stroitel'nykh konstruktsii. Zhelezobetonnye konstruktsii [Design theory of reinforced concrete structures]. V.P. Chirkov, Ed. Moscow, 1999. 376 p. (rus)

12. Shesterikov V.I. Metodika raschetnogo prognozirovaniya sroka sluzhby zhelezobetonnykh pro-letnykh stroenii avtodorozhnykh mostov [Estimated prediction of steel bridge service life]. Moscow: Rosavtodor Publ., 2002. 140 p. (rus)

13. Muraleedharan G., Soares C.G. Characteristic and moment generating functions of generalised pareto (GP3) and weibull distributions. Journal of Scientific Research and Reports. 2014. V. 3. No. 14. Pp. 1861–1874.

14. Kristaps Gode. Predicting the service life of concrete bridges based on quantitative research. Construction Science. 2014 DOI: 10.2478/cons-2014-0002.

15. Rostam S. Service life design of concrete structures – a challenge to designers as well to owners. Asian Journal of Civil Engineering. 2005. V. 6.