Experimental study on steel plate bolted tension members with staggered holes of two lines

In order to validate the equal-area method and the s2/(4g) rule, which are used commonly to compute tensile ultimate strength of bolted connections with staggered holes, an experimental study was conducted. The experimental study includes a testing of 16 full-scale steel plate bolted tension members with stagger holes of two lines. The parameters such as the gauge, the pitch and material properties were considered in tests. Test results indicate that 16 specimens fail in transverse section mode or stagger section mode. The failure mode of the specimens with the increase of pitch did not transform from the stagger section mode to transverse section mode, as the equal-area method and the s2/(4g) rule predicted. Neither of the methods can predict the failure mode accurately. Also the results present the ductility of steel has an obvious influence on the failure mode and the capacity of the specimens, for the fact that the lower ductility would lead to the premature fracture of bolt hole due to stress concentration. In addition when the pitch is large enough, the tensile ultimate strength predicted the two methods overestimate the loading capacity obtained from tests. Based on the test data and the theoritical analysis, a modified s2/(4g) rule is presented, and the predicted tensile ultimate strength agrees well with the test data.