Mechanical behaviors of T-shaped concrete-filled steel tubular columns under axial impact

In order to study the bearing capacity of T-shaped concrete-filled steel tubular columns under axial impact and the stress distribution characteristics of concrete inside, the PVDF piezoelectric film is fabricated as an implantable piezoelectric stress transducer and put it inside of the steel tube to carry out the axial drop weight impact test of T-shaped concrete-filled steel tubular columns. Through the transformation of PVDF monitoring data, the stress variation law of concrete in the steel tube is obtained, the impact force-time history curve and the impact bearing capacity of the concrete-filled steel tubular column under impact height are obtained at the same time. The test results show that the T-shaped concrete filled steel tubular column has good anti-impact performance. The specimen with a thicker steel wall has greater peak value of impact force, less vertical deformation and shorter impact duration. Increasing the wall thickness of the steel tube can improve the restraint effect on the concrete and increase the impact bearing capacity of the specimen.