Elevated temperature and hole-type effects on sliding behaviour of bolted connections

Abstract

This article experimentally studied the sliding behaviour of high-strength bolted connections. A total of 14 specimens varying in types of hole and bolt diameters were designed and tested under ambient temperature and target temperature of 130°C and 200°C, respectively. The experimental results show that the pretension in the bolts increases with the increase in temperature below 200°C. After 200°C, the pretension reverses and starts to decrease. It was found that the reverse temperature depended on the relative thermal expansion of the steel plates and bolts. The model of temperature-dependent thermal expansion coefficients given by Australian standard AS 4100 is in good agreement with the test results. The friction coefficient increases with the increase in temperature. The friction coefficients of connections with slot holes increase by 12% at 200°C compared with that at ambient temperature. At the same temperature, the friction coefficients of connections with slot holes are found to be 12% lower than that of connections with standard holes.