In order to research the damage evolution rules of three typical details of bolt and weld steel bridges(lap joints,non-load-bearing fillet weld joints and high-strength bolted friction-type joints),the relations between damage degree and cycle ratio of the three details were investigated by MTS(mechanical testing and simulation)fatigue testing machines with sinusoidal loadings.

In this paper,the feasibility and rationality of a rigid flange connection with friction type connection of high-strength bolt is proved with analyzing and scale model test.

In order to make sure that the design calculation of friction_type high_strength bolt connection is more reasonable, a method of assessing the reliability of friction-type high strength bolt connection when achieving the maximum design allowable bearing power by analyzing many main factors and with a lot of experiments data of friction-type high strength bolts.