Robustness of Post-Tensioned Concrete Beam-Column Subassemblies under Various Column Removal Scenarios

To fully recognize the load-resisting mechanisms of post-tensioned concrete (PC) structures with realistic boundary conditions against disproportionate collapse, four beam-column subassemblies were extracted from a prototype building and side columns joints reproduced to reflect actual condition. The parametric analysis was conducted, including location removed column (middle or penultimate) strand profile (straight parabolic). In addition, two RC counterparts tested as control group. Test results indicate that unbonded post-tensioning (UPS) able enhance structural robustness by increasing compressive arch action capacity beams developing catenary action. Compared specimens, both PC specimens achieved much higher load resistance; herein, specimen straight obtained highest resistance due strands used, while parabolic had deformation capacity. However, existence UPS increased tensile force demand column, leading flexural tension failure when loss penultimate considered. Finally, an analytical study carried out quantify each dominant mechanism.