Question

Figure 1 shows a bolted truss connection used in the construction of a roof system for a large industrial building. The diagonal members of the truss are 150 x 150 x 12 Equal Angies (Grade 300). They are bolted to a 16 mm gusset plate using 8 M20 Grade 8.8/S bolts. a) What is the axial tension design capacity of the connection? (Assume that the 16 mm gusset plate is the strongest component and will not fail) (12 Marks) b) If the connection was to be welded rather than bolted, design the welds to carry a maximum tension force of 600 kN. (7 Marks) (Total 19 Marks) O 16 mm 50505050 PLATE 150X150X12 EA HO 8 M20 8-8/ X BOLTS ATE! LOAD AXIAL

Answer 1

since this is purely a numerical problem i have used handwritten presentation.

fu= 300 (ISA) 100 29 14 OM Load Load 1 40 Vash mub nu=1 connection p= pitch= 50mm gange length = 40mm capculty of the connection Mininuus value of s Shearing capacity of bott) Beaning capacity of bott Beaning capacity of plate) Bolt Grade 8.8 fub-800N/mm2 d=20 0 'Shean capauty of bolt Vasb = Vrsb, Imus- partial safety factor for bolt Vrso= fub xnn Anb 13 (No. of shear planes) And = area at bolt threads (Ymb= 1.25 -0.78% I d² 20-78 x 7 x20² = 245.06man? Vasb - bearing capauty of bolt Vapba Vapb Sub do= diameta of hole = d+2=20+2 = 22mm edge distance en 1.7x holedia=. tas soo xix 245.07 - 90.5kn

Vupb = 2.5 kų dtfu Kha Minge 40 -0.60 13 do 3x22 = 2.5x0.507x22x12 mm x 300 20.25.0.507 > 100-3kw .800 = 2.667 Vdpd = Unpb- 80.3kN It-thickness of small plate = 12 mm fu- ultimate strength of plate Bolt value = in of ou@ - 80.3kN Capauty of plate or angle section Tdu = 0-9 Anfu An- Min effectivarea smi P1 An= [b-ndu + { fe lat bi loro or of dn-dia of hole 1-4-6 or 2-5-7 n- no. of bolts in critical sertion on b= 150-12 I p- pitch g-gange length - 138mm An= [138 - 3x22 + 2x 50² x 12 o. - p² 19312gnant 1239 mus? o plug Ton=0.9x4owes x 300 &mi= 1.25 1-25 MARIN - 267.62KN 4x40) 1234

Bolt strength/putch - bolt value x2 = 80.3x2 = 160.6kN Capauty of the connection - Min of Bei Bolt value and plate beaning - 160.6kN b) Welded connection Assume fillet weld size of the weld = Thickness of plate - It - 3 (t) Circular edge for augle seation - 3 x 12 =qman i smo Designforce = bookN Assume strength of weld=250MPa fa fyxarea - 250x [Lwx th] to ww Lw-length of weld the throat thickness of weld = 0.75= 0·7x9=6.3mm Smw-partial safety factor for weld = 1.25 @ 600=250 x Lw x 6.3 1.25 Lw= 0.476m - 476 mm Actual length of weld on both sides of ange. 476 + 25 = 23 + 2x9 = 256 men.