Asad Mohammad, Zahra Tatheer, Thamboo Julian
School of Civil and Environmental Engineering, Queensland University of Technology, Brisbane 4000, Australia.
Department of Civil Engineering, South Eastern University of Sri Lanka, Oluvil 32360, Sri Lanka.
Polymers (Basel). 2022 Apr 28;14(9):1800. doi: 10.3390/polym14091800.
Bonded brickwork used for loadbearing walls is widely found in heritage structures worldwide. The evaluation of bonded masonry structures and their strengthening strategies against dynamic actions require appropriate understanding under cyclic loading. Subsequently, a simplified 3D microscale numerical model is developed in this paper to analyse bonded brickwork under cyclic compression. A plasticity-based damage constitutive model to represent damage in masonry bricks under cyclic compression loading was employed, and zero-thickness interfaces were considered with non-linear damage properties to simulate the mechanical behaviour of masonry. A threshold strain level was used to enact the element deletion technique for initiating brittle crack opening in the masonry units. The developed model was validated against the experimental results published by the authors in the past. The models were able to accurately predict the experimental results with an error limit of 10% maximum. Mainly, two types of strengthening materials, possessing (1) high energy absorption characteristics (auxetic fabric) and (2) high strength properties (carbon fibre reinforced polymer composites/CFRP) were employed for damage mitigation under cyclic compression. Results show that the CFRP-strengthened masonry failure was mainly attributed to de-bonding of the CFRP and crushing under compression. However, the auxetic strengthening is shown to significantly minimise the de-bonding phenomenon. Enhanced energy dissipation characteristics with relatively higher ductility (up to ~50%) and reduced damages on the bonded brickwork were observed as compared to the CFRP-strengthened brickwork under cyclic compression loading. Additionally, the auxetic fabric application also increased the compressive resistance of brickwork by 38-60% under monotonic loading, which is comparably higher than with the CFRP strengthening technique.
用于承重墙的粘结砖砌结构在世界各地的历史建筑中广泛存在。对粘结砌体结构及其抗动态作用的加固策略进行评估，需要在循环加载下有适当的理解。随后，本文建立了一个简化的三维微观数值模型，以分析循环压缩下的粘结砖砌结构。采用了基于塑性的损伤本构模型来表示循环压缩荷载下砌体砖的损伤，并考虑了具有非线性损伤特性的零厚度界面来模拟砌体的力学行为。使用阈值应变水平来实施单元删除技术，以引发砌体单元中的脆性裂纹张开。所开发的模型根据作者过去发表的实验结果进行了验证。这些模型能够准确预测实验结果，最大误差限制为10%。主要采用了两种类型的增强材料，即（1）具有高能量吸收特性的（拉胀织物）和（2）具有高强度特性的（碳纤维增强聚合物复合材料/CFRP），用于减轻循环压缩下的损伤。结果表明，CFRP加固砌体的破坏主要归因于CFRP的脱粘和受压破碎。然而，拉胀加固显示出能显著减少脱粘现象。与循环压缩荷载下的CFRP加固砖砌结构相比，观察到拉胀加固具有更高的延性（高达约50%）和增强的能量耗散特性，并且粘结砖砌结构的损伤减少。此外，在单调加载下，拉胀织物的应用还使砖砌结构的抗压强度提高了38 - 60%，这比CFRP加固技术要高得多。
