EXPERIMENTAL INVESTIGATION OF WIND LOADS ON 45° PITCHED GABLE AND HIP ROOFS

Öz

In this study, flow fields around a low-rise building model with 45º pitched gable and hip roofs have been investigated experimentally in order to search the wind loads that can damage the building roofs. The experiments were carried out in an atmospheric boundary layer that is modeled in the wind tunnel. Atmospheric boundary layer was simulated with combination of barrier, elliptic vortex generators and elements of roughness and a 150 mm height boundary layer was formed at 15 m/s wind velocity. The mean and fluctuating surface pressures were measured on the building models having gable and hip roofs immersed in boundary layer in detail for various wind directions to observe critical suction zones on the roof surfaces. It is found that suction effect on the hip roof is lower than suction effect on the gable roof.

Anahtar Kelimeler

• Atmospheric boundary layer,gable roof

45° EĞİME SAHİP BEŞİK VE KIRMA ÇATILAR ÜZERİNDEKİ RÜZGÂR YÜKLERİNİN DENEYSEL İNCELENMESİ

Öz

Bu çalışmada, bina çatılarını hasara uğratabilen rüzgâr yüklerinin araştırılması amacıyla, 45° eğime sahip beşik ve kırma çatılı bina modelleri yüzeylerindeki basınç dağılımları deneysel olarak incelenmiştir. Deneyler rüzgâr tünelinde modellenen atmosferik sınır tabaka akışında gerçekleştirilmiştir. Akışın modellenmesinde bariyer, eliptik girdap üreticiler ve pürüzlülük elemanları kombinasyonu kullanılmış ve 15 m/s’lik serbest akış hızında, 150 mm yüksekliğinde bir sınır tabaka oluşturulmuştur. Yüzey basınçlarının ortalama ve çalkantı değerlerinin ölçümü, sınır tabaka içerisine yerleştirilmiş, beşik ve kırma çatılı iki bina modeli üzerinde farklı rüzgâr geliş açılarına göre ayrıntılı bir şekilde gerçekleştirilerek emme etkilerinin kritik olduğu bölgeler belirlenmiştir. Kırma çatı üzerindeki emme etkisinin, beşik çatıya göre daha düşük olduğu bulunmuştur.

Anahtar Kelimeler

• Atmosferik sınır tabaka,beşik çatı

Kaynakça

1. 1. Davenport, A. G., Surry, D. J. 1974. “The Pressures on Low Rise Structures in Turbulent Wind,” Canadian Structural Engineering Conference, Ottowa, p. 1-39.
2. 2. Stathopouos, T. 1984. “Wind Loads on Low-Rise Buildings with Various-Sloped Roofs,” Engineering Structures, vol. 23, p. 813-824.
3. 3. Kind, R. J. 1988. “Worst Suctions Near Edges of Flat Rooftops with Parapets,” Journal of Wind Engineering and Industrial Aerodynamics, vol. 31, p. 251-264.
4. 4. Meecham, D., Surry, D., Davenport, A. G. 1991. “The Magnitude and Distribution of Wind-Induced Pressures on Hip and Gable Roofs,” Journal of Wind Engineering and Industrial Aerodynamics, vol. 38, p. 257-272.
5. 5. Kanda, M., Maruta, E. 1993. “Characteristics of Fluctuating Wind Pressure on Long Low-Rise Buildings with Gable Roofs,” Journal of Wind Engineering and Industrial Aerodynamics, vol. 50, p. 173-182.
6. 6. Case, P. C., Isyumov, N. 1998. “Wind Loads on Low Buildings with 4:12 Gable Roofs in Open Country and Suburban Exposures,” Journal of Wind Engineering and Industrial Aerodynamics, vol. 77-78, p. 107-118.
7. 7. Xu, Y. L., Reardon, G. F. 1998. “Variations of Wind Pressure on Hip Roofs with Roof Pitch,” Journal of Wind Engineering and Industrial Aerodynamics, vol. 73, p. 267-284.
8. 8. Uematsu, Y., Isyumov, N. 1999. “Wind Pressures Acting on Low-Rise Buildings,” J. Wind Eng. Ind., Aerodyn., vol. 82, p. 1-25.

9. 9. Ginger, J. D., Reardon, G. F., Whitbread, B. J. 2000. “Wind Load Effects and Equivalent Pressures on Low-Rise House Roofs,” Engineering Structures, vol. 22, p. 638-646.
10. 10. Ahmad, S., Kumar, K. 2002. “Effect of Geometry on Wind Pressures on Low-Rise Hip Roof Buildings,” Journal of Wind Engineering and Industrial Aerodynamics, vol. 90, p. 755–779.
11. 11. Ginger, J. D., Holmes J. D. 2003. “Effect of Building Length on Wind Loads on Low-Rise Buildings with a Steep Roof Pitch,” Journal of Wind Engineering and Industrial Aerodynamics, vol. 91, p. 1377–1400.
12. 12. Quan, Y., Tamura, Y., Matsui, M. 2007. “Mean Wind Pressure Coefficients on Surfaces of Gable-Roofed Low-Rise Buildings,” Advances in Structural Engineering, vol. 10 (3), 259-272.
13. 13. Prasad, D., Uliate, T., Ahmed, M. R. 2009. “Wind Loads on Low-Rise Building Models with Different Roof Configurations,” Fluid Mechanics Research, vol. 36 (3), p. 231-243.
14. 14. John, A. D., Singla, G., Shukla, S., Dua, R. 2011. “Interference Effect on Wind Loads on Gable Roof Building,” Procedia Engineering, vol. 14, p. 1776–1783.
15. 15. Hu, H., Yang, Z., Sarkar, P., Haan, F. “Characterization of the Wind Loads and Flow Fields around a Gable-Roof Building Model in Tornado-Like Winds,” Exp. Fluids, vol. 51, p. 835–851.
16. 16. Huang, P., Wang, X., Gu, M. 2012. “Field Experiments for Wind Loads on a Low-Rise Building with Adjustable Pitch,” International Journal of Distributed Sensor Networks, vol. 2012, p. 1-10.
17. 17. Gavanski, E., Kordi, B., Kopp, G. A., Vickery, P. J. 2013. “Wind Loads on Roof Sheathing of Houses,” J. Wind Eng. Ind. Aerodyn., vol. 114, p. 106–121.
18. 18. Holman, J. P. 1994. Experimental Methods for Engineers, McGraw-Hill Book Company, NewYork.
19. 19. Parmentier, B., Hoxey, R., Buchlin, J. M., Corieri, P. 2002 “The Assessment of Full- Scale Experimental Methods for Measuring Wind Effects on Low-Rise Buildings,” COST Action C14, Impact of Wind and Storm on City Life and Built Environment, 3-4 June 2002, Nantes, France.