Friction anomaly alarm for bridge sliding bearings under operating environmental conditions

•A temperature-displacement hysteresis model was proposed by considering the friction of bridge bearings.•An anomaly alarm approach was established using the extracted sliding friction indicator from the hysteresis model.•The friction of sliding bearings fluctuates at the same temperature and slightly decreases with an increase in the temperature.•The anomaly alarm approach can effectively detect the mild increase in sliding friction of bridge bearings under operating environmental conditions.