Shear friction between the steel base plate and base mortar contributes to the shear resistance of standard column bases. A value of 0.5 is adopted as the coefficient of shear friction in AIJ's design specifications, but the associated background data are limited. To investigate the dynamic shear resistance behavior between the base plate and mortar, a shake table study is undertaken using a large rigid mass supported by steel contact elements that rest on mortar surfaces fixed on the shake table. Horizontal input accelerations are considered for various magnitudes and frequencies. The results provide a constant friction coefficient during sliding with an average value of 0.78. Comparisons with previous test and numerical analysis are also carried out, and good correlation among them is noticed.
