ABSTRACT
As shown in Figure 1, six vertical Linear Variable Displacement Transducers (LDVT), including LVDT1 to LVDT6, were used to monitor the rotation of the two beam segments (θb = δb/Lb2, where δb is the vertical displacement of the beam measured by the vertical LVDT; and Lb2 is the distance from the face of the steel tube to the location of the vertical LVDT2); Two horizontal LVDTs (HVDT4 and HVDT5) were used to monitor the rotation of the column [θc = (δc4-δc5)/h45, where δc4 and δc5 are the horizontal displacements of the column measured by HVDT4 and HVDT5, respectively; and h45 is the distance between HVDT4 and HVDT5]. The relative rotation between the column and beam can be calculated by the following equation:
θ = θb−θc (1)
3 TEST RESULTS AND DISCUSSION
3.1 Failure modes
The joint specimen SB1-0 without composite slab was tested under monotonic loading. The failure of this joint was dominated by the local outward deformation of the square steel tube as shown in Figure 2(a). This was due to the pull-out force of the top row of blind bolts resulting from the bending moment. As a result, a gap between the end plate and steel tube was formed, and the gap size increased significantly towards the end of the testing period and reached 14.6 mm. After the test, it was found that weld fracture had occurred between the steel tube and the top binding bars, and the observation is similar to that reported by Wang et al. (2016). All other components in specimen SB1-0 remained in a good condition.
