بررسی آزمایشگاهی ظرفیت باربری دیوار بنایی مقاوم شده با پوشش پلی اوره سرد تحت بارگذاری خارج از صفحه‌‌

نوع مقاله : پژوهشی

نویسندگان

دانشکده‌ی فنی، دانشگاه بین‌المللی امام خمینی (ره)، قزوین، ایران.

چکیده

پس از زلزله‌ی کرمانشاه در سال 1396، نیاز به تقویت اعضاء غیرسازه‌ای ساختمان‌ها مشخص و پس از آن تغییرات آیین‌نامه‌ای به منظور ایمن‌ترساختن آن‌ها اعمال شده است. با وجود این، ساختمان‌هایی که پیش از اعمال تغییرات آیین‌نامه‌ای ساخته شده‌اند، نیاز به مقاوم‌سازی دارند، که استفاده از پوشش پلی‌اوره می‌تواند یکی از اقدام‌های مؤثر در این زمینه باشد. بارهای خارج از صفحه‌ای، نقش مهمی در تخریب دیوارها هنگام زلزله دارند، لذا برای بررسی تأثیر پوشش پلی‌اوره در برابر بارگذاری خارج از صفحه، از آزمایش خمشی چهارنقطه‌ای بر روی چهار نمونه‌ دیوار بنایی با مقیاس کوچک، به‌صورت  مقاوم‌نشده (دیوار مبنا) و مقاوم‌شده (با پوشش پلی‌اوره‌ی سرد به شکل کامل، ضربدری، و قابدار ضربدری) استفاده شده است. نتایج حاصل از اعمال بار استاتیکی خارج از صفحه‌ای نشان می‌دهد که ظرفیت باربری دیوارها تا بیشینه‌ی 45% افزایش یافته و جابجایی آن‌ها تا بیشینه‌ی 60% نسبت به حالت مبنا کاهش یافته است. همچنین از منظر مقاومت و اقتصاد، استفاده از پوشش با طرح قابدار ضربدری برای مقاوم‌سازی بارهای خارج از صفحه‌ای مناسب است.

کلیدواژه‌ها

موضوعات

عنوان مقاله [English]

Experimental Investigation of the Bearing Capacity of a Masonry Wall Strengthened with Cold Polyurea Coating Under Out-of-Plane Loading

نویسندگان [English]

  • Mohammad Ghajar
  • Ramezan Ali Izadifar
Department of Civil Engineering, Imam Khomeini International University, Qazvin, Iran.
چکیده [English]

One of the most vulnerable parts of a building during an earthquake, which can severely impact its functionality, is the non-structural walls or separating masonry walls. The 2016 Kermanshah earthquake highlighted that in some newly constructed buildings, while the primary structural elements, such as columns and beams remained intact, non-structural components, specifically walls, suffered significant damage, creating hazardous living conditions. These damages not only pose serious safety risks to occupants but also lead to substantial repair and reconstruction costs. Following the earthquake, modifications were made to building bylaws to enhance the reinforcement of non-structural elements, such as separating walls, aiming to improve overall structural stability. However, these regulations primarily apply to newly constructed buildings, and a large number of older structures, built before the implementation of these bylaws, still lack sufficient resistance in their non-structural elements, particularly walls. Thus, the need for strengthening these walls is evident, and the application of polyurea coating is one viable solution. In this research, the effectiveness of polyurea coating in enhancing wall resistance was evaluated through four four-point bending tests conducted on four different masonry walls with various forms of cold-applied polyurea coating. The experimental results demonstrated that walls coated with polyurea exhibited significantly higher load-bearing capacity compared to uncoated walls. Furthermore, displacement at the midpoint of the coated walls was considerably lower than in uncoated samples, confirming the effectiveness of polyurea in strengthening masonry structures. Specifically, walls treated with full polyurea coating and cross-framed polyurea coating showed a 45% and 39% increase in bearing capacity, respectively, compared to uncoated walls. Additionally, displacement in these coated walls decreased by 50%. Considering the optimal balance between structural resilience and cost-effectiveness, the application of polyurea coating in the form of a cross-frame or full coating is highly recommended to improve the resistance of masonry walls against out-of-plane loads, such as earthquakes and explosions. This method not only enhances the overall safety of buildings but also significantly mitigates damage risks during seismic events. 

کلیدواژه‌ها [English]

  • Reinforcement of masonry wall
  • cold polyurea coating
  • four-point bending test
  • out-of-plane loading

مراجع

1. Shojaei, B., Najafi, M., Yazdanbakhsh, A., Abtahi, M. and Zhang, C., 2021. A review on the applications of polyurea in the construction industry. Polymers For Advanced Technologies, 32(8), 2797-2812. https://doi.org/10.1002/pat.5277
2. Eftekhar, M. and Emami, M., 2018. Investigation the different methods of connecting gfrp sheets to ductility and in-plane behavor of masonry walls. Ferdowsi Civil Engineering. 31, pp. 57-73  [In Persian]. DOI: 10.22067/civil.v31i2.56881
3. Shabdin, M., Zargaran, M. and Attari, N.K., 2018. Experimental diagonal tension (shear) test of un-reinforced masonry (urm) walls strengthened with textile reinforced mortar (trm). Construction and Building Materials, 164, pp.704-715. https://doi.org/10.1016/j.conbuildmat.2017.12.234.
4. Son, S.H., An, J.H., Song, J.H., Hong, Y.S., Jang, H.S. and Eun, H.C., 2021. In-plane strengthening of unreinforced masonry walls by glass fiber-reinforced polyurea. of Civil Engineering, 7(12), pp.2119-2129.      https://doi.org/10.28991/cej-2021-03091782
5. Bagheri, B., Lee, J.H., Kim, H.G. and Oh, S.H., 2020. Experimental evaluation of the seismic performance of retrofitted masonry walls. Composite Structures, 240,111997. https://doi.org/10.1016/j.compstruct.2020.111997
6. Yu, P., Silva, P. and Nanni, A., 2007. In-plane response of urm walls strengthened with gfrp grid reinforced polyurea. In 10th North American Masonry Conference. 466-77. https://hdl.handle.net/11588/120096.
7. Cuong, N.H., Luat, N.V., Gayoon, L., An, H., Han, S.W. and Lee, K., 2023. Experimental and dem numerical analyses of the flexural and diagonal compression behavior of masonry reinforced with polyurea coating. In Structures 54, pp. 1578-1592. Elsevier. https://doi.org/10.1016/j.istruc.2023.05.051
8. Jang, H.S., An, J.H., Song, J.H., Son, S.H., Hong, Y.S. and Eun, H.C., 2022. Out-of-plane strengthening of unreinforced masonry walls by glass fiber-reinforced polyurea. Of Civil Engineering, 8(1), pp.145-154. https://10.28991/CEJ-2022-08-01-011.
9. Myers, J.J. and Hrynyk, T.D., 2006. Out of plane behavior of masonry infill walls retrofitted with a reinforced polymer grid and polyurea system. Structural Faults and Repairs. https://scholarsmine.mst.edu/civarc_enveng_facwork/197/.
10. Cassol, D., Giongo, I., Ingham, J. and Dizhur, D., 2021. Seismic out-of-plane retrofit of urm walls using timber strong-backs. Construction and Building Materials, 269, p.121237. https://doi.org/10.1016/j.conbuildmat.2020.121237
11. Dong, Z., Deng, M., Zhang, Y., Zhang, C. and Ma, P., 2020. Out-of-plane strengthening of unreinforced masonry walls using textile reinforced mortar added short polyvinyl alcohol fibers. Construction and Building Materials, 260, 119910. https://doi.org/10.1016/j.conbuildmat.2020.119910
12. Tan, K.H. and Patoary, M.K.H., 2004. Strengthening of masonry walls against out-of-plane loads using fiber-reinforced polymer reinforcement. of Composites for Construction, 8(1), pp.79-87. https://doi.org/10.1061/(ASCE)1090-0268(2004)8:1(79)
13. Gu, M., Ling, X., Wang, H., Yu, A. and Chen, G., 2019. Experimental and numerical study of polymer-retrofitted masonry walls under gas explosions. Processes, 7(12), p.863. https://doi.org/10.3390/pr7120863
14. Shojaei, B., Najafi, M., Yazdanbakhsh, A., Abtahi, M. and Zhang, C., 2021. A review on the applications of polyurea in the construction industry. Polymers for Advanced Technologies, 32(8),2797-2812. https://doi.org/10.1002/pat.5277
15. Chen, D., Wu, H., Fang, Q., Wei, J.S. and Xu, S.L.. 2023. Out-of-plane behaviors of unreinforced and spray polyurea retrofitted one-way masonry infilled walls. of Building Engineering, 67, p.106006. https://doi.org/10.1016/j.jobe.2023.106006
16. Cuong, N.H., Luat, N.V., Gayoon, L., An, H., Han, S.W. and Lee, K., 2023. Experimental and dem numerical analyses of the flexural and diagonal compression behavior of masonry reinforced with polyurea coating. In Structures, 54, pp. 1578-1592. https://doi.org/10.1016/j.istruc.2023.05.051
17. Chang, L.Z., Messali, F. and Esposito, R., 2020. Capacity of unreinforced masonry walls in out-of-plane two-way bending: a review of analytical formulations. In Structures, 28, pp. 2431-447.https://doi.org/10.1016/j.istruc.2020.10.060 

فایل ها

هم رسانی

ارجاع به این مقاله

آمار