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

Document Type : Article

Authors

Department of Civil Engineering, Imam Khomeini International University, Qazvin, Iran.

Abstract

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. 

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References

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