Mechanical properties of high-strength bolted connections with different bolt hole types under corrosion conditions

To reveal the changes in the mechanical properties of high-strength bolted connections with different hole types after corrosion, four groups of high-strength bolted connection specimens with steel plates assembled by highstrength bolts were subjected to neutral salt spray accelerated corrosion tests followed by shear tests. Based on the test results, the influence of corrosion duration on the slip coefficient, bolt pre-tension, initial slip load and ultimate bearing capacity of high-strength bolted connections with different hole types are discussed, followed by the presentation of simplified methods to determine the slip coefficient and bolt pre-tension with corrosion duration taken into account. It is found that one-day acceleration corrosion in the salt spray chamber of this paper can be roughly regarded as one-year exposure in the natural environment of Jiaodong Peninsula of China, especially for the long-term corrosion. Test results show that the corrosion has a more pronounced influence on the slip coefficient of high-strength bolted connections with enlarged bolt holes, while the pre-tension of the high-strength bolt is more sensitive to corrosion when standard hole is used. It is also observed that the initial slip load of high-strength bolted connections are significantly affected by corrosion while the corrosion hardly changes the ultimate bearing capacity regardless of bolt hole type. It is proved that the proposed simplified methods to determine the amplification factor of slip coefficient and bolt pre-tension can be used to evaluate the initial slip load of high-strength bolted connections in corrosive environments conservatively.