Dynamic response of concrete filled steel tube column under lateral impact load: experimental study and calculation method

To reveal the failure mechanism of concrete filled steel tube column under lateral impact load, seven concrete filled tube columns, one partially concrete filled tube column and one empty steel tube column, subjected to lateral impact load, were investigated experimentally. The influences of impact speed, impact mass, impact energy and column end restraint on the dynamic response of concrete filled steel tube column under lateral impact load were taken into consideration. The test results indicate that the concrete filling can effectively improve the impact bearing resistance and deformation capability. The concrete filled steel tube columns with one fixed end and one simply supported end were susceptible to shear failure, whereas the cantilever columns were susceptible to flexural damage. The impact force and residual displacement increased obviously with the increase of impact speed and impact energy. Based on the current Chinese code, a calculation method was proposed by introducing the dynamic magnification coefficient R and energy absorption ratio k, and how to take the values of coefficients R and k was also clarified.