Progressive Collapse Resistance of Axially-Restrained Frame Beams

Twelve specimens representing reinforced concrete frame beams were tested to investigate their gravity load-carrying capacity against progressive collapse. In these tests, the beams within the frame subassemblies were restrained longitudinally against axial deformation. The tests indicated that the compressive arch action due to longitudinal restraint can significantly enhance the flexural strength of a beam subjected to vertical loads. The compressive arch action was observed to be a function of flexural reinforcement ratio and ratio of beam span to depth. The test results validated an analytical model that has considered the axial restraining effects on beam loading capacity. The application of compressive arch effect to the prevention of progressive collapse is discussed.