Experimental study on dynamic performance of concrete filled steel tubular piles under impact loads

A kind of concrete filled steel tubular pile is proposed to resist the impact of boulders. In order to study the dynamic performance of the structure under impact loads, the tests considering impact loads of multi working conditions are carried out. The response modes of the structure are summarized and compared with the numerical simulations by analyzing the strain, displacement and acceleration of the structure. The results show that the typical response modes of the structure can be summarized as follows: slight damage, local damage and joint failure. The strain and displacement of structure increase with the enlarging impact energy and height. The acceleration of structure increases with the raising impact height, while decreases with the raising impact mass. The impact process from the response of impact zone to that of whole structure takes a very short time, about 0.6 ms. The whole structure plays a great role in energy dissipation when the pile tube is subjected to impact loads, and it is not obvious when the bracing tube subjected to impact loads. The experimental results are in good agreement with the numerical simulations. The concrete filled steel tubular pile is of good impact resistance.