Issue 41

S.M.J. Razavi et alii, Frattura ed Integrità Strutturale, 41 (2017) 432-439; DOI: 10.3221/IGF-ESIS.41.54 434 illustrates hot-dip galvanized bolted connection before the test. A comparison before and after sweep blasting procedure has been shown in Fig. 3. According to prescriptions of UNI EN 1090-2 the assembly of the joints were carried out: the high strength bolts, class 10.9, system HR (UNI EN 14399-3) were tightened by the torque control method in two steps. The final torque applied to the fasteners (equal to 1.1 Mr.2) corresponded to 91 Nm as defined and declared by the fastener manufacturer in the box label. Before the fatigue tests all the joint bolt torques were checked. Adopted values Suggested values (*) Abrasive garnet garnet or ilmenite Mesh 80 80-100 Venturi nozzle Orifice diameter (mm) 10 10÷13 Distance from the surface (mm) 400 350÷400 Angle to the surface 45° ≤45° Blast pressure(kPa) 200 ≤275 Table 1: Sweep blasting procedure. (*) with reference to well established international specifications relating to surface treatment for paintings (ISO 8503). Figure 2: Hot-dip galvanized bolted connection before the test. Figure 3: Comparison between specimens before and after sweep blasting.