WORLD FOR CIVIL

Statics & Strength of Materials

Topic 6.8b - Problem Assignment - Rivets/Welds

Allowable stresses [ksi(MPa)]

		Allowable Bearing Stress		Allowable Tensile Stress
Structural steels	St(ult)	Sp(all) = (1.5)St(ult)	Sy	(Gross) St(all) = (0.60)Sy	(Net) St(all) = (0.50)St(ult)
A36 carbon	58 (400)	87 (600)	36 (250)	22 (152)	29*(200)

Allowable shear stress on steel fasteners.

Description of Fastener	Allowable Shear Stress (Ss(all))[ksi MPa)]
	Slip-Critical Connection	Bearing-Type Connection
A307 low-carbon bolts	-	10.0(68.9)
A325 bolts --- threads in shear plane	17.0(117)	21.0(145)
A325 bolts --- threads excluded from shear plane	17.0(117)	30.0(207)
A490 bolts --- threads in shear plane	21.0(145)	28.0(193)
A490 bolts --- threads excludes from shear plane	21.0(145)	40.0(276)
A502 Grade 1 hot-driven rivets	-	17.5(121)
A502 Grade 2 hot-driven rivets	-	22.0(152)

1. Determine the allowable tensile load for the single shear lap joint shown. Assume that the threads are excluded from the shear plane. The plates are ASTM A36 steel and the bolts are A325. The Diameter of the Rivets is 1 inch.
[Use gross allowable tensile stress for ASTM A36]
[ For Joint use Bearing Type connection]
(Rivet Shear = 212,000 lb., Plate Bearing = 391,500 lb., Plate Tearing= 77,000 lb)

2. Determine the allowable tensile load for the double shear butt joint shown. Assume that the threads are excluded from the shear plane. The plates are ASTM A36 steel and the bolts are A325. The Diameter of Rivets is 1 inch.
[Use gross allowable tensile stress for ASTM A36]
[ For Joint use Bearing Type connection]
(Rivet Shear = 188,500 lb., Plate Bearing = 174,000 lb., Plate Tearing= 68,750 lb)

3. Determine the number of 3/4 inch bolts needed for a maximum efficiency lap joint of two 8" x 1/2" plates. The plates are ASTM A36 steel and the bolts are A325.
[Use gross allowable tensile stress for ASTM A36]
[ For Joint use Bearing Type connection, and A325 bolts --- threads excluded from shear plane] (6 rivets)

4. Determine the number of 3/4 inch bolts needed for a maximum efficiency butt joint of two 8" x 1/2" plates. The cover plates are 8" x 9/16". The plates are ASTM A36 steel and the bolts are A325.
[Use gross allowable tensile stress for ASTM A36]
[ For Joint use Bearing Type connection, and A325 bolts --- threads excluded from shear plane] (3 rivets)

5. Calculate the allowable tensile load for the connection in the diagram shown. The plates are ASTM A36 steel and the weld is a 3/4 in. fillet weld, which is made using an E70 electrode.
[E70 electrode has allowable tensile stress of 70,000 psi.; and allowable shear stress of 30% of tensile stress]
[Use gross allowable tensile stress for ASTM A36]
(Weld strength (shear) = 178,160 lb.; Plate strength (tension) = 99,000 lb. ]

6. In the connection in the diagram shown, 1/4 in. side and end fillet welds are used to connect the 2.0 in. by 1.0 in tension member to the plate. The applied load is 65,000 lb. Find the required dimension L. The steel is ASTM A36 and the electrode used is an E70.
[E70 electrode has allowable tensile stress of 70,000 psi.; and allowable shear stress of 30% of tensile stress]
[Use gross allowable tensile stress for ASTM A36]
(L = 7.76"; however joint fails in plate tearing at 44,000 lb)

7. Design the fillet welds parallel to the applied load to develop the full allowable tensile load of the 6 in. by 3/8 in. ASTM A36 steel plate in the diagram shown. The electrode is an E70. The Plate is welded along the far end in addition to the sides.
[E70 electrode has allowable tensile stress of 70,000 psi.; and allowable shear stress of 30% of tensile stress]
[Use gross allowable tensile stress for ASTM A36]
(L = 1.45")

8.A fillet weld between two steel plates intersecting at right angles was made with one 3/8 in. leg and one 1/2 in leg using an E70 electrode. Determine the strength of the weld in kips/in.
[E70 electrode has allowable tensile stress of 70,000 psi.; and allowable shear stress of 30% of tensile stress]
(5570 lb/in = 5.57kips/in.)