Experimental study on bearing capacity of corroded high-strength bolt connections under shear force

Connection affects the whole behavior of a steel frame and its fracture will lead to the collapse of a structure. Corrosion, widely appeared in engineering, will change the mechanical behavior of members or connections, which seriously influences the safety of in-service steel structures. As such, safety assessment of in-service corroded connections has been concerned a lot in recent years. In this study, the structural behavior of corroded high-strength bolt under shear force is investigated using experimental method. The CopperAccelerated Acetic Acid-Salt Spray Testing is employed to obtain the high-strength bolt connections with different corrosion degree. The shear testing of corroded high-strength bolt connections is then performed to study the variation law of the anti-sliding load and the ultimate bearing capacity of corroded high-strength bolt connections. The anti-sliding load and the anti-sliding coefficient of corroded high-strength bolt connections shows a trend of first increase and then decrease as the mass loss ratio of steel plates increases. A model for estimating the anti-sliding coefficient of corroded high-strength bolt connections is suggested. GB50017-2017 is not good for predicting the anti-sliding load of corroded high-strength bolt connections as the maximum error estimated from GB50017-2017 approaches 35.94%. The effect of corrosion on the structural behavior of highstrength bolt connections is considered and a more accurate model is proposed for estimating the anti-sliding load of corroded high-strength bolt connections. GB50017-2017 is not accurate for predicting the ultimate bearing capacity of corroded high-strength bolt connections as the maximum error estimated from GB500172017 reaches 55.43%. This is mainly attributed to the ignorance of the residual friction force of steel plates. A more accurate model considering the effect of corrosion is developed for predicting the ultimate bearing capacity of corroded high-strength bolt connections. The conclusion based on the experiment of Q235 and Q345 high-strength bolt connections with Grade 10.9 twist-off tension-control bolts can provide a reference for the safety assessment of in-service corroded connections.