Progressive collapse assessment of reinforced concrete (RC) buildings with high-performance fiber-reinforced cementitious composites (HPFRCC)

The susceptibility of concrete beam-column joints in reinforced concrete (RC) frame structures to progressive collapse can result in severe damage or collapse. High-performance fiber-reinforced cementitious composites (HPFRCCs), as a strain-hardening material, can be used instead of ordinary concrete to improve RC frame buildings' performance. This study evaluates the effects of using HPFRCC in beam-column joints on the behavior of RC frame structures subjected to progressive collapse. Five RC buildings with moment-resisting frame systems were studied for this purpose, one with ordinary concrete beam-column joints and the others with HPFRCC beam-column joints and varying quantities of reinforcement on beams and columns. The buildings were eval-uated using 3D modeling with OpenSees finite element software and removing a corner column using the alternative load path method (ALP) per GSA regulations. The results show that using HPFRCC in beam-column joints can improve the robustness of RC frame buildings to progressive collapse by increasing beam-column joint stiffness, load-bearing capacity, and the ability to withstand large deformations. Furthermore, damages caused by the sudden removal of corner columns in buildings reveal that the use of HPFRCC in beam-column joints results in a reduction in damages, even in buildings with a reduced quantity of reinforcements (buildings H1 and H2), even though a significant decrease in the number of longitudinal reinforcements of beams and columns in the building with HPFRCC beam-column joints (building H3) can result in severe damage to the connections.