Appendix 2 – Calculations
A2.1 Reaction Forces
Page 1
Page 2
Page 3
A2.2 Buckling Load
A2.3 Rod Tension
A2.4 Clevis Pin
A2.5 Clevis Mount
A2.6 Mounting Brackets
A2.7 Welds
A2.7.1 Top and Bottom Plate
A2.7.2 Top of Tension Rods
A2.7.3 Clevis Mount
A2.7.4 Main Beam Joint
A2.7.5 Pin Brackets
A2.8 Bolts
A2.2 Buckling load
(Fix-free)
- S-8 @ 18.4, A36,
,
SR > Cc
will buckle
- S8 @ 23, A36
,
SR > Cc
-S10 beam @ 25.4, A36
,
,
SR > Cc
A2.3 Rod tension
Assume main beam pinned at one end
Wt of S-10 Beam
Rod tension due to weight of beam
Max Rod tension due to the load = 2700lb x 7.03* = 18981 lbs
ð Total Rod Tension
*Also see rod tension spreadsheet
A2.4 Clevis Pin
Rod tension = 21658 lb
Su = 58000 psi
N = 5
d = 1¾ in
Required pin size:
With 2 shear planes:
Stress on pins specified to fill clearance in clevis:
A2.5 Clevis Mount
See Drawing 2 for dimensions.
Su = 58000 psi
Sus = 33640 psi
F = 21658 lb
th = 2½ in
ro = 21/8 in
ri = 7/8 in
d = 1¾ in
Bearing stress:
Shear stress:
(This area is not perfectly accurate, but is conservative.)
Maximum shear stress:
A2.6 Mounting Brackets
Su = 58000 psi
Fh = 12636 lb
Fv = 3707 lb
th = 5/8 in
d = 57/8 in
Φb = ¾ in
Φp = 2½ in
Horizontal bearing stress:
Vertical bearing stress:
Von Mises equivalent stress:
A2.7 Welds
A2.7.1 Welds for top and bottom plate on vertical member
Use
UFWR= 184 MPa
Required
Available
Required throat size , leg size = 1mm
For load carrying member, use 5/16” welds (economical)
Weld pattern
A2.7.2 Welds on tension rods
Rod tension , Beam Wt
- Rod tension 1:
due to
Max due to
Total Rod tension 1
- Welds @ rod end:
Shear force for Rod 2 ®
Rod 1 ®
E60 electro Allowable shear stress
(based on t size , )
Assume
-Rod 1
-Rod 2
ð Welds @ rod end are OK
(Fill up clearances as shown)
A2.7.3 Clevis Mount and welds
Preliminary Shape of Clevis mount (2-1/2” A-36)
Final weld size
Stresses in welds are
-axial
-shear
-bending
= Axial
= Bending
Shear
Axial
Weld area (all around)
Shear
,
Bending
Where of E60
ð
ð
ð 5/16” weld (all around)
A2.7.4 Welds at main beam joint
Weld pattern
Required size
ð 5/16” welds (E60 electrode)
A2.7.5 Pin Brackets
E60 electro, allowable shear stress = 184 Mpa
- top (tension only)
Required
ð use 5/16” weld
Weld pattern from View A
- bottom
should be okay to use 5/16” welds
A2.8 Bolts
A-325, allowable Shear = 17.5 ksi
Tension = 44 ksi , use n = 4
- Top set (tension only @ 6400 lb)
6 bolts =>
=>
- Bottom set (shear only @ 3900 lb)
6 bolts =>
=>