Probabilistic seismic assessment of non-ductile RC buildings retrofitted using pre-tensioned aramid fiber reinforced polymer belts

摘要

The current manuscript presents a probabilistic seismic assessment of non-ductile RC structures retrofitted by pre-tensioned aramid fiber reinforced polymers (AFRP). Three RC buildings with different heights (4-, 6- and 8-stories) are designed according to older construction practice and the poorly detailed columns of each model are then retrofitted using pre-tensioned AFRP belts. The numerical finite element models are developed in OpenSees using concentrated plastic hinge models that can capture shear weakness of original columns and deterioration of beams' stiffness and strength. Incremental dynamic and nonlinear static analyses are performed to quantify structures' performance in terms of both global- and component-level metrics. The structures' global response is evaluated using fragility curves, mean annual frequency of collapse, and collapse margin ratios. Furthermore, statistical analyses are performed to obtain median inter-story drift distribution along the height of the structure, structural members' ductility and dissipated energy under three different seismic hazard levels. The results indicate that retrofitting by pre-tensioned AFRP improves the structure's global-level ductility and reduces the collapse probability significantly. Moreover, it can prevent weak story formation by engaging a larger number of stories in collapse mechanism. From a component-level perspective, pre-tensioned AFRP increases columns' ductility and dissipated energy and enhances their performance, particularly at near-collapse-limit states.