Static progressive collapse test on prefabricated concrete #br#
frames with wet connections
Yuan Xinjie1Li Yi1Lu Xinzheng2Ren Peiqi3An Yi1
1. Beijing Key Laboratory of Earthquake Engineering and Structural Retrofit，Beijing University of Technology，Beijing 100124，China;
2. Key Laboratory of Civil Engineering Safety and Durability of the Ministry of Education，Tsinghua University，Beijing 100084，China;
3. China Institute of Building Standard Design & Research Co. ，Ltd. ，Beijing 100048，China
Abstract：The loading and deformation capacities of beam-column joints under large deformation have a significant impact on the progressive collapse performance of prefabricated concrete frame structures. A static progressive collapse test was conducted on four prefabricated concrete frame specimens with different wet connections and one castinsitu specimen. Mechanical sleeves，bent-up steel bar anchorage and prestressing tendon were used as the connections of beam reinforcement，while rebar splicing by grout-filled coupling sleeve and rebar lapping in grout-filled hole were used as the connections of column reinforcement. It is found that all bottom reinforcing bars in the beam fractured simultaneously at the same location of one sleeve when the mechanical sleeves were used，which significantly reduced the collapse resistance of the specimen under the compression arch mechanism and the catenary mechanismWhen the beam reinforcement was bent up and anchored in concrete，the mechanical behavior and collapse resistance of the specimen were very similar with those of the cast-in-situ specimen. The prestressing tendon significantly improved the collapse resistance of the specimen under the two mechanisms，but local splitting failure of concrete in the joint was induced by the concentrated load transferred from the prestressed anchors under the ultimate deformationThe rebar splicing by groutfilled coupling sleeve and the rebar lapping in grout-filled hole of the column steel bars were capable to withstand the horizontal shear force under large deformation in progressive collapse，but shear-slip of the column jointgrouting layer was found when exposed to the significant horizontal shear force，which in turn weakened the constraint of the column to the beam. When the collapse-resisting mechanism was transformed from the compression arch mechanism to the catenary mechanism，the axial compressive force of the compressive arch mechanism negatively contributed to the collapse resistance of the specimen. The contribution of axial force to collapse resistance of the specimens connected by mechanical sleeves and prestressing tendon were respectively higher and lower than that of the cast-in-situ concrete specimen.
