Çelik Lif Katkılı Alüminyum Tüp İçine Beton Doldurulmuş Kirişlerin Eğilme Dayanımlarının İncelenmesi

Öz

Çelik tüp içine beton doldurulmuş (ÇTBD) kirişlerin özellikle yüksek yapılarda ve köprü kirişlerinde kullanımı gün geçtikçe artmaktadır. Ancak, son yıllarda normal ve paslanmaz çelik yerine daha hafif ve ucuz olan alüminyum tüp içine beton doldurulmuş (ATBD) kirişler inşaat uygulamalarında yaygın bir şekilde kullanılmaktadır. Bu çalışmanın amacı çelik lif katkılı dikdörtgen en kesitli ATBD kirişlerin moment ve süneklik kapasitelerinin incelenmesidir. Çelik liflerin hacimsel lif oranları %0,5 ve %1,5 olarak, alüminyum tüp et kalınlıkları ise 2 ve 4 mm olarak seçilmiştir. Çalışma sonucunda, içi boş alüminyum tüplerin içine beton doldurulmasının ATBD kirişlerin dayanım ve süneklik kapasitelerini önemli oranda artırdığı belirlenmiştir. Çelik liflerin ATBD kirişlerin moment kapasitelerini arttırmada etkileri oldukça sınırlıyken, ATBD kirişlerin süneklik kapasitelerini arttırmada çok daha fazla etkili oldukları görülmüştür. Ayrıca, çelik lif hacimsel oranı %0,5’den %1,5’a çıkarıldığı zaman ATBD kirişlerin daha fazla elastik ötesi deformasyon yaptıkları ve bundan dolayı süneklik kapasitesindeki artışların daha belirgin olduğu belirlenmiştir

Anahtar Kelimeler

• Betonla doldurulmuş alüminyum tüp
• Çelik lif
• Eğilme dayanımı
• Süneklik

Flexural Behaviour of Steel Fiber Reinforced Concrete-Filled Aluminum Tube Beams

Öz

Nowadays, the use of concrete filled steel tube (CFST) beams is increasing especially in high structures and bridge beams. However, concrete filled aluminum tube (CFAT) beams that are lighter and cheaper than normal and stainless steel, are widely used in construction applications in recent years. The aim of this study is to examine the moment and ductility capacities of steel fiber reinforced rectangular CFAT beams. The volumetric ratios of steel fibers were selected as 0.5% and 1.5% and aluminum tube wall thicknesses were chosen as 2 and 4 mm. The results show that filling concrete into hollow aluminum tubes significantly increase the strength and ductility capacities of CFAT beams. While the effects of steel fibers in increasing the moment capacity of CFAT beams are quite limited, it has been observed that they are much more effective in enhancing the ductility capacity of CFAT beams. In addition, when the steel fiber ratio was increased from 0.5% to 1.5%, it was obtained that CFAT beams exhibit more inelastic deformation and therefore the increase in ductility capacity was more pronounced.

Anahtar Kelimeler

• Concrete filled aluminum tube
• Steel fiber
• Flexural strength
• Ductility

Kaynakça

1. 1. Cai, S.H., 1988. Ultimate Strength of Concrete- Filled Tube Columns. Composite Construction in Steel and Concrete. Proceedings of the Engineering Foundation Conference, 702-727.
2. 2. Gao, J., Sun, W., Morino, K., 1997. Mechanical Properties of Steel Fiberreinforced, High-strength, Lightweight Concrete, Cement Concrete Compos, 19(4), 307–13.
3. 3. Gardner, N.J., Jacobson, E.R., 1967. Structural Behavior of Concrete Filled Steel Tubes, Journal of the American Concrete Institute.64(11), 404-413.
4. 4. Lu, Y., Kennedy, D., 1994. Flexural Behavior of Concrete-Filled Hollow Structural Sections. Canadian Journal of Civil Engineering, 21(1),111-130.
5. 5. O’Shea, M.D., Bridge, R.Q., 1997. Local Buckling of Thin-Walled Circular Steel Sections With or Without Lateral Restraint, Research Report No. R740, School of Civil Engineering, University of Sydney, Sydney, Australia.
6. 6. Moon, J., Roeder, C.W., Lehman, D.E., Lee, H.E., 2012. Analytical Modeling of Bending of Circular Concrete-filled Steel Tubes. Engineering Structures, 42, 349–361.
7. 7. Nieuwoudt, P.D., Babafemi, A.J., Boshoff., W.P., 2017. The Response of Cracked Steel Fibre Reinforced Concrete Under Various Sustained Stress Levels on Both the Macro and Single Fibre Level, Constr. Build. Mater, 156, 828–843.
8. 8. Lu, Y., Liu, Z., Li, S., Hu., J., 2018. Axial Compression Behavior of Hybrid Fiber Reinforced Concrete Filled Steel Tube Stub Column, Constr. Build. Mater. 174, 96–107.

9. 9. Dong, M., Elchalakani, M., Karrech, A., Fawzia, S., Ali, M.S.M., Yang, B., Xu, S.Q., 2019. Circular Steel Tubes Filled with Rubberised Concrete Under Combined Loading. Journal of Constructional Steel Research, 162, 105613.
10. 10. Liu, Z., Lu, Y., Li, S., Liao, J., 2019. Axial Behavior of Slender Steel Tube Filled with Steel-fiber-reinforced Recycled Aggregate Concrete. Journal of Constructional Steel Research, 162, 105748.
11. 11. Xu, L., Lu, Q., Chi, Y., Yang, Y., Yu, M., Yan, Y., 2019. Axial Compressive Performance of UHPC Filled Steel Tube Stub Columns Containing Steel-polypropylene Hybrid Fiber. Construction and Building Materials, 204,754-767.
12. 12. Schneider, S.P., 1998. Axially Loaded Concrete-Filled Steel Tubes, Journal of Structural Engineering, ASCE, 124(10), 1125-1138.
13. 13. Shakir-Khalil, H., Mouli, M., 1990. Further Tests on Concrete-Filled Rectangular Hollow- Section Columns, The Structural Engineering, 68(20), 405-413.
14. 14. Saatcioglu., M., Razvi., S.R., 1992. Strength and Ductility of Confined Concrete, Journal of Structural Engineering, ASCE, 118(6), 1590-1607.
15. 15. Tomii, M., Sakino, K., 1979. Experimental Studies on the Ultimate Moment of Concrete Filled Square Steel Tubular Beam-Columns, Transactions of the Architectural Institute of Japan, no. 275, 55-63.
16. 16. Yu, Q., Tao, Z., Wu, Y.X., 2008. Experimental Behaviour of High Performance Concrete-Filled Steel Tubular Columns, Thin-Walled Structures, 46(4), 362–370.
17. 17. Zhang, S., Zhou, M., 2000. Stress-Strain Behavior of Concrete-Filled Square Steel Tubes, Composite and Hybrid Structures.Proceedings of the Sixth ASCCS International Conference on Steel-Concrete Composite Structures, March 22-24, Los Angeles, California, 403-409.
18. 18. Zhao, H.L, Zhao, Y.G., 2010. Suggested Empirical Models for The Axial Capacity of Circular CFT Stub Columns, Journal of Constructional Steel Research, 66(6), 850-62.
19. 19. Kim, Y.H., You, S.K., Jung, J.H., Yoon, S.J., 2006. Strengthening Effect of the Shear Key on the Flexural Behavior of Concrete Filled Circular Tube, Steel Struct, 6, 183–190.
20. 20. Alberti, M.G., Enfedaque, A., Galvez., J.C., 2018. A Review on the Assessment and Prediction of the Orientation and Distribution of Fibres for Concrete, Compos. B Eng. 151,274–290.
21. 21. TS EN 197-1, Çimento- Bölüm 1: Genel Çimentolar- Bileşim, Özellikler ve Uygunluk Kriterleri, TSE, Ankara, 2002.
22. 22. TS EN 12390-5, Beton – Sertleşmiş Beton Deneyleri Bölüm 5: Deney Numunelerinde Eğilme Dayanımının Tayini, TSE, Ankara, 2010.
23. 23. TS 706 EN 12620+A1, Beton Agregaları, TSE, Ankara, 2009.
24. 24. Meda, A., Minelli, F., Plizzari, G.A., 2012. Flexural Behaviour of RC Beams in Fibre Reinforced Concrete. Composites Part B: Engineering, 43(8), 2930–2937.