Cristian Sabau

Upgrading existing buildings to new functional requirements may require new openings that can weaken the structure, prompting the need for strengthening. In such cases traditional strengthening solutions, such as creating a reinforced concrete (RC) or steel frame around the opening, imply long-term restrictions in the use of the structure compared to solutions that use externally bonded composites. Two fabric-reinforced cementitious matrix (FRCM) composites were used in this study to restore the capacity of panels with newly created door type openings to that of a solid panel. Five half-scale RC panels acting as two-way action compression members were tested to failure. Two full-field optical deformation measurement systems were used to monitor and analyze the global structural response of each tested panel (i.e., crack pattern, failure mechanism, and displacement/strain fields). The performance of existing design methods for RC panels has been assessed in comparison with the experimental results. The capacity of strengthened panels with small openings ($450\times \mathrm{1,050}\mathrm{mm}$ ) was entirely restored to that of the solid panel. However, for panels with large openings ($900\times \mathrm{1,050}\mathrm{mm}$ ), only 75% of the solid panel’s capacity was restored. The capacity of the strengthened panels was about 175 and 150% higher compared to that of reference panels with small and large openings, respectively.