Influence of Joint Strengthening on the Seismic Performance of Non-Engineered Buildings

Non-engineered buildings (NEBs) are prone to earthquake damage. One type of damage that often occurs in NEBs is the separation of beam and column elements owing to joint failures. Strengthening joints with steel plates is expected to improve the seismic performance of this type of building. Strengthening with steel plates is cheap and easy to apply, so it will be a preferable choice in preventing damage to the NEB due to earthquake loads. This study investigated the seismic performance of reinforced concrete frames, representing an NEB whose beam–column joints were strengthened with L-shaped steel plates. Two widths of L-shaped steel plates were proposed: 75 mm (NEB-075) and 100 mm (NEB-100). An NEB without strengthening (NEB-000) was used as a control. Both experimental and numerical investigations were performed to determine the seismic performance of NEBs. The results showed that damage to the NEB-000 and NEB-075 models occurred at the joints, but less damage was observed in NEB-075 than in NEB-000. Furthermore, damage in the NEB-100 model occurred at the column. The undamaged limit levels of the NEB-000, NEB-075, and NEB-100 models were 56.49, 81.54, and 82.46%, respectively. These results show that strengthening the NEB with steel plates effectively improves its seismic performance. According to an analysis of the performance of the tested models, the NEB-100 model exhibited the best seismic performance.