-

Öz

Determination of Reliability Based New Load and Resistance Factors for Reinforced Concrete Structural Members In this study, a procedure for the determination of new load and resistance factors for reinforced concrete structural members is proposed in view of the fact that the design practice in Turkey has changed after the occurrence of major earthquakes. The implementation of the procedure is carried out for the shear failure mode of reinforced concrete beams subjected to dead and live load combination. First, the statistical parameters for the quantification of uncertainties involved in the design variables are assessed based on the available data. Then, the level of risk related with the current design practice is quantified in terms of the reliability index, β. Target reliability index, βT, is selected in view of the β values computed for the current design practice. By using the resulting target reliability index, βT, the load and resistance factors are computed based on the Advanced First Order Second Moment Method

Anahtar Kelimeler

• Reinforced concrete beams, load and resistance factors, uncertainty, earthquake load, reliability

Betonarme Yapı Elemanları için Güvenilirliğe Dayalı Yeni Yük ve Dayanım Katsayılarının Belirlenmesi

Öz

Bu çalışmada, yaşanan büyük depremlerden sonra Türkiye’de değişen tasarım ve uygulama koşullarına dayalı olarak, betonarme yapı elemanları için yeni yük ve dayanım katsayıları belirleme yöntemi sunulmuştur. Yöntemin uygulaması kesme göçme modundaki kirişlere etkiyen sabit ve hareketli yük kombinasyonu için gerçekleştirilmiştir. İlk önce güvenilirlik analizi yapmak için elde edilen veriler göz önünde bulundurularak, tasarım değişkenlerinin sahip olduğu belirsizlikler istatistiksel parametreler ile sayısallaştırılmıştır. Daha sonra, tasarım koşullarına dayalı risk düzeyleri güvenilirlik indeksi, β, cinsinden hesaplanmıştır. Hesaplanan bu β değerleri göz önünde tutularak hedef güvenilirlik indeksi, βT, uygun bir şekilde seçilmiştir. Son olarak, seçilen güvenilirlik indeksi kullanılarak yük ve dayanım katsayıları Geliştirilmiş Birinci Mertebe İkinci Moment yöntemine göre hesaplanmıştır

Anahtar Kelimeler

• Betonarme kiriş, yük ve dayanım katsayıları, belirsizlik, deprem yükü, güvenilirlik

Kaynakça

1. Doğangün, A., Ural, A., Sezen, H., Güney Y., Fırat, F.K., The 2011 earthquake in Simav, Turkey and seismic damage to reinforced concrete buildings, Buildings 2013, 3, 173-190, 2013. [4] İnel, M., Bilgin H., Özmen, H.B., Orta yükseklikli betonarme binaların Türkiye’de yaşanan son depremlerdeki performansı, İMO Teknik Dergi, Yazı 284, 4319-4331, 2008.
2. Dikmen, S.Ü., Özek, S., Deprem bölgelerinde zemin sınıfının sanayi yapılarının maliyetine etkisi, İMO Teknik Dergi,Yazı 357,5543-5558, 2011. [6] 2010
3. Yılı Hazır Beton Sektörü İstatistikleri, Türkiye Hazır Beton Birliği, Nisan 2010.
4. Fırat, F. K., Statistical evaluation of the quality of concrete used in Turkey, 7th International Congress on Advances in Civil Engineering, Yıldız Technical University, İstanbul, Türkiye, 2006.
5. Fırat, F.K., Yücemen M.S., The examination of the BC III(a) reinforcing steel bars according to earthquake codes, International Earthquake Symposium, August 17-19, Kocaeli, Turkey, 2009.
6. Ang, A.H.S., Tang, W.H., Probability Concepts in Engineering Planning and Design, Volume II, John Wiley and Sons Inc., New York, 1984.
7. Hasofer, A., Lind, N.C., Exact and invariant second-moment code format, Journal of Engineering Mechanics Division, ASCE, Vol. 100, No. EM. 1, 111-121, 1974
8. Yang, I. H., Uncertainty and sensitivity analysis of time-dependent effects in concrete structures, Engineering Structures, 29, 1366–1374, 2007.

9. Fırat, F. K., Yücemen M.S., Uncertainty analysis for reinforced concrete members constructed in Turkey, International Conference on Construction and Building Technology, ICCBT, Kuala Lumpur, Malaysia, 2008.
10. Mirza, S.A., Hatzinikolas, M., Mac Gregor, J.G., Statistical description of the strength of concrete, Journal of the Structural Division, ASCE, Vol. 105, No. ST6, 1021-1037, 1979.
11. Kömürcü, A.M., Yücemen, M.S., Load and resistance factors for reinforced concrete beams considering the design practice in Turkey, Concrete Technology for Developing Countries, Fourth International Conference, Eastern Mediterranean University, Gazi Magusa, North Cyprus, 1996.
12. Real, M.V., Filho, A.C., Sergio, R.M., Response variability in reinforced concrete structures with uncertain geometrical and material properties, Nuclear Engineering and Design, 205-220, 2003.
13. Celik, O.C., Ellingwood, B.R., Seismic fragilities for non-ductile reinforced concrete frames – Role of aleatoric and epistemic uncertainties Structural Safety, 32, 1–12, 2010.
14. Schlune, H., Plos, M., Safety formats for nonlinear analysis tested on concrete beams subjected to shear forces and bending moments, Engineering Structures, 33, 2350– 2356, 2011.
15. Fırat, F.K., Development of Load and Resistance Factors for Reinforced Concrete Structures in Turkey, The Graduate School of Natural and Applied Sciences, Middle East Technical University, Doctorate Thesis, Ankara, 2007.
16. TS-500; Betonarme Yapıların Hesap ve Yapım Kuralları, Türk Standartları Enstitüsü, Ankara, 2000.
17. Song, J., Kang, W.H., Kim, K.S., Jung, S., Probabilistic shear strength models for reinforced concrete beams without shear reinforcement, Structural Engineering and Mechanics, Vol. 34, No. 1, 15-38, 2010.
18. Ellingwood, B.R., Galambos, T.V., Mac Gregor, J.G., Cornell, C.A., Development of a Probability Based Load Criterion for American National Standards A58, NPS Special Publication 577, 1980.
19. Nowak, A.S., Szerszen, M.M., Calibration of design code for buildings (ACI 318): part 1- statistical models for resistance, ACI Structural Journal, May-June, 377-382, 2003.
20. Somo, S., Hong H.P., Gylltoft, K., “Modeling error analysis of shear predicting models for RC beams” Structural Safety, 28, 217–230, 2006.
21. Kumar, S., Live loads in office buildings: lifetime maximum load, building and environment, Vol. 37, 91-99, 2002a.
22. Kumar, S., Live loads in office buildings: point in time load intensity, building and environment, Vol. 37, 79-89, 2002b.
23. Choi, E.C.C., Live load in office buildings point-in-time load intensity of rooms. Proceedings of the Institution of Civil Engineers Structures and Buildings,94, 299- 306, 1992.
24. Kömürcü, A.M., A Probabilistic Assessment of Load and Resistance Factors for Reinforced Concrete Structures Considering the Design Practice in Turkey, M. Sc. Thesis, Department of Civil Engineering, METU, Ankara, 1995.
25. Türk Standartları, Yapı Elemanlarının Boyutlandırılmasında Alınacak Yüklerin Hesap Değerleri (TS 498), Türk Standartları Enstitüsü, Ankara, 1997.
26. Nowak, A.S., Szerszen, M.M., Calibration of design code for buildings (ACI 318): part 2- reliability analysis and resistance factors, ACI Structural Journal, May-June, 383-391, 2003b.