Evaluation of Electromagnetic Shielding and Impact Resistance Effectiveness for Metallic Grid Strengthening Concrete Walls

The need for electromagnetic interference (EMI) shielding and structural design against external loading has increasing to secure social safety. Therefore, sixteen concrete walls were fabricated and tested to determine optimum strengthening methods, which show high shielding effectiveness (SE) and impact resistance. Four types of metallic grid were considered as strengthening method in this research. Furthermore, the relationship between SE and damaged area ratio was analyzed via drop weight impact testing. SE was increased with reduction of grid size, regardless of number of layers. The SE of specimen singly strengthened by smaller than 140 % of free space area ratio, exhibit more than 30 dB. It was found that strengthening method by double layer of grid is effective in improving shielding performance, rather than simply increasing the size of grid. The specimen strengthened by metallic grid exhibited higher impact resistance than the unreinforced specimen, and the smallest metallic grid exhibited great SE after impact loading.