Tension Capacity For T-Shaped Tensile Connection Consideirng Bending Action

High strength bolted connections are widely used in steel structures. Theseconnections have advantages in quality stability, safety and high-efficiency. Scholars athome and abroad have studied a lot to build relative theories of mechanicscharacteristics when the high strength bolts are connected by tensile. Prying forces areconsidered as negative factors for the bolts’ internal forces. Relative stipulations can befound in standards of many countries. Because of the prying forces, moments on thecross section of bolts are unavoidable and affect the bolts’ internal forces, which are notmentioned both in research and designing. Based on that, the bearing capacity of highstrength bolted connections under tensile is studied deeply here.The typical T-stub connections are experimented by stretching26test-pieces,which can be divided into four groups to inquire into their affection on bolts’ internalforces by varying parameters, such as the thickness of flange plates, the positions ofbolt holes, bolt diameters and strength grades. According to the research, as thethickness of flange plate decreasing, there are four parameters changing thereupon.The ratio between the distance from bolt’s center to the T-stub’s flange edge and thedistance from bolt’s center to T-stub’s plate edge decreases, the bolt’s diameterdecreases, the strength grade of bolts reduces, while ratio between the bending stressand max tensile stress of bolt’ cross section increases. Also, the bending stress israther big and can’t be ignored when the outer force increase to a certain value. Afternumerical simulation analyzing on test-pieces with ANSYS software, it turns out thesimulation result fits experiment result quite well, which can be used for laterresearch.Finite element analysis and experiment research both indicate that: In the tensileconnection of T-stub, the cross section stress of the bolt is combined by axial tensilestress and bending stress. And the ratio of bending stress increases as the outer forceincreasing, which can be up to20%. After comparing with the experiment andsimulation results, the standard’s calculation results are slightly conservative.Therefore, after analyzing the forces of simplified model of T-stub tensile specimen and bolts, the calculating formula of bending moments on bolt’s cross section can begot. Besides, the calculating formula of bending moments and relative parameters isput forward, by researching the relationship between bolts’ bending moments andfour parameters mentioned above. Finally, a formula for bolts designing is got byconsidering prying control of bending stress.