Experimental Investigation on Friction Coefficient between Sawtooth Steel Plate and Concrete

It is easy to think of using sawtooth steel plate on the surface of column to increase the interfacial friction in the temporary RC column underpinning structure. However, there is little research on the friction properties between sawtooth steel plate and concrete. 108 working condition of double interface shear tests were conducted for measuring the friction coefficient between the sawtooth steel plate and the concrete, and the effects of concrete strength, sawtooth size, interface contact method and interface normal pressure on the friction coefficient were also analyzed. The results show that concrete strength on the friction coefficient is not significant when the interface normal pressure is less than 6MPa. After the use of sawtooth steel, the coefficient of friction is greatly improved, and the friction coefficient is approximately linearly related to the aspect ratio of the sawtooth. Damage on the concrete surface will be reduced after adding a flexible material at the contacting interface, but at the same time, it will reduce the friction coefficient. When the sawtooth steel is in direct contact with the concrete, the friction coefficient increases with increasing normal pressure at the interface, however, when the interface is added with flexible material, the friction coefficient is almost irrelevant to the normal pressure.