Static progressive collapse test on precast concrete frames with dry connections

The mechanical behavior of beam-column joints under large deformation is the key factor affecting the progressive collapse resistance of precast concrete frame structures with dry-connections. In this paper, a static progressive collapse test was conducted on three beam-column substructure specimens, including one bolted connection specimen, one unbonded prestressed connection specimen and one cast-in-situ specimen. The failure modes of joints and the static collapse resistance of substructures under different deformations were analyzed via test results. The dynamic collapse resistance of substructures was also investigated based on the energy conservation principle. Compared with the cast-in-situ specimen, the static and dynamic collapse resistances of the bolted connection specimen under the compression arch mechanism are reduced by 41% and 45%, respectively, due to the buckling of connection steel plate which has been exposed to the tensile force at beam ends. These resistances under the catenary mechanism are also reduced by 27% and 37%, respectively, owing to the fracture of connection angle steel and bolts. For the unbonded prestressed connection specimen, the static and dynamic collapse resistances under the compression arch mechanism are reduced by 39% and 45%, respectively, comparing with the cast-in-situ specimen due to the early crush of concrete. Although the static collapse resistance under the catenary mechanism is increased by 52%, which is contributed by the prestressed steel bars, the corresponding dynamic collapse resistance of the unbonded prestressed connection specimen is 17% lower than that of the cast-in-situ specimen due to the smaller accumulated dissipating energy under the compression arch mechanism. © 2020, Editorial Office of Journal of Building Structures. All right reserved.