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7/16/2019 Lifting Lug
http://slidepdf.com/reader/full/lifting-lug-563388d62711a 1/5
LIFT LUG CALCULATION
DATA:
Vessel erection weight (lb) W = 38,025
Lift lug hole to tail lug hole (in) L1 = 759.00
COG to tail lug hole (in) L2 = 382.00Lift lug hole to COG (in) L3 = 377.00
Tail lug hole to vessel Axis L4 = 32
Impact factor (eg. 1.25, 1.50, 1.75, 2.0 etc.) for Lug Eye IF1 = 1.80
Tensile strength of lug material (psi) TSL = 70,000
Yield strength of lug material (psi) YSL = 38,000
Yield strength of shell material (psi) YSS = 38,000
Consumable Tensil Strength (psi) CST 70,000
Lug hole diameter (in) Dh = 1.750
Tearout radius (in) r = 4.000
Distance, center of lug hole to top of weld (in) L8 = 13.100
Distance, top of weld to bottom of lug (in) L9 = 6.750Length of inner welds (in) L10 = 0.000
Width of lift lug (in) B = 9.000
Width of inner weld (in) B2 = 0.000
Thickness of lift lug (in) TL = 1.250
Thickness of lug reinforcement washers (in) Tw = 0.000 OK
Fillet weld leg size, lug-to-shell (in) Lw = 0.375
Fillet weld leg size req'd, reinf. washer-lug =2Tw/3 (in) Lr = 0.000
Actual fillet weld leg size, washer-lug (in) Lp = 0.000 OK
Washer OD = 2(r - LP -.125) (in) Dw = 7.750
CALCULATE DESIGN LOAD @ EACH LUG (VERTICAL):
Design load @ lug = W/2 x IF1 (lb) Fv = 34,223Shackle rating (tons) Crosby G2130 = 17 OK
Shackle pin diameter (in) Dp = 1.630
CALCULATE DESIGN LOAD @ EACH LUG (HORIZONTAL):
Force @ lug in horiz position = W/2*L2/L1 (lb) fh = 9,569
Design load @ shell = fh x IF1 (lb) Fh = 17,224
Page 1 Lift Lug Rev 3.xls
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CALCULATE BENDING AND AXIAL STRESS IN LUG BODY:
Ft = ( W * L3 * COS(φ) ) / ( L1 * COS(φ) + L4 * SIN(φ) )
Fl = (W - Ft)/2 - Load per Lug with out impact Factor
Axial Stress Sa = FL / (TL * B) where FL = Fl * IF1 * SIN(φ)
Bending Stress Sb = (6 * FR * L8) / (TL * B2) where FR = Fl * IF1 * COS(φ)
Lift Angle Fl FL FR Sb Sa Sc
(deg) (Lbs) (Lbs) (Lbs) (psi) (psi) (psi)
0 9,569 0 17,224 13,371 0 13,371
5 9,604 1,507 17,221 13,368 134 13,502
10 9,639 3,013 17,086 13,264 268 13,531
15 9,674 4,507 16,820 13,058 401 13,458
20 9,712 5,979 16,427 12,752 531 13,283
25 9,751 7,418 15,907 12,349 659 13,008
30 9,793 8,814 15,266 11,851 783 12,635 35 9,840 10,159 14,508 11,263 903 12,166
40 9,892 11,445 13,639 10,588 1,017 11,605
45 9,951 12,665 12,665 9,832 1,126 10,958
50 10,021 13,817 11,594 9,000 1,228 10,229
55 10,105 14,900 10,433 8,099 1,324 9,424
60 10,212 15,918 9,190 7,134 1,415 8,549
65 10,352 16,888 7,875 6,113 1,501 7,614
70 10,549 17,843 6,494 5,042 1,586 6,628
75 10,853 18,869 5,056 3,925 1,677 5,602
80 11,391 20,193 3,561 2,764 1,795 4,559
85 12,640 22,665 1,983 1,539 2,015 3,554
90 19,013 34,223 0 0 3,042 3,042
Maximum Bending Stress = 13,371 psi
Maximum Axial Stress = 3,042 psi
Maximum Combined Stress = 13,531 psi
Allowable stress = 0.6*YSL = Sa = 22,800 Okay
CALCULATE SHEAR STRESS IN LUG BODY (HORIZONTAL):
Shear stress = Fh/(2TL*r) (psi) Ss = 1,722
Allowable shear stress = 0.5Sa (psi) Ssa = 11,400 OK
Page 2 Lift Lug Rev 3.xls
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CALCULATE STRESSES IN LUG-TO-SHELL WELDS:
Weld throat = 0.7071 x Lw (in) tw = 0.27
Locate N.A. of weld group:
(L9 + L10 + B2*L10)/(B + 2L9 + 2L10) (in) = X = 2.03
Distance to extreme weld point C:
SQRT((L9 - X) +(B/2) )) (in) = Y = 6.53
Eccentricity of weld group = L9+L8-X (in) E = 17.83
Polar moment of intertia (PMI) of weld group:
r1 = (.5L9 - X) + (.5B) (in ) r1 = 22.1
PMI of L9 welds = 2L9*tw*(L9 /12 + r1 ) (in ) J1 = 93
r2 = (.5L10 - X) + (.5B2) (in ) r2 = 4.1
PMI of L10 welds = 2L10*tw*(L10 /12 + r2 ) (in ) J2 = 0.0
B1 = .5(B - B2) (in) B1 = 5
r3 = (.5B1 + .5B2) + X (in ) r3 = 9.2
PMI of B1 welds = 2B1*tw*(B1 /12 + r3 ) (in ) J3 = 26
r4 = |(L10 - X) | (in ) r4 = 4.1
PMI of B2 weld = B2*tw*(B2 + r4 ) (in ) J4 = 0.0
Polar moment of inertia = J1+J2+J3+J4 (in ) J = 118
Torsional shear stress = Fh1 x E x Y/J (psi) St = 16,906
Angle of rotation for St = arctan (.5B/(L9-X) (rad) ø = 0.761
Horizontal component of St1 = St*sinø (psi) St1 = 11,659
Vertical component of St2 = St*cosø (psi) St2 = 12,242
Direct shear stress due to Fh1 = Fh1/(tw(B + 2L9 + 2L10)) (psi) Ssh = 2,887
Allow. shear stress = 0.3CST per AISC 9th Edition = 21,000 OK
Max. shear stress (torsional + direct) - horizontal @ point C:((Ssh
+St2) + St1 )
.(psi) Sm = 19,100
Allow. shear stress = 0.3*CST per AISC 9th Edition = 21,000 OK
Direct shear stress (vert) = Fv/(tw(B + 2L9 + 2L10)) (psi) Ssv = 5,736
Allow. shear stress = 0.3*CST - per AISC 9th Edition = 21,000 OK
Check weld size based on leg welded to shell or Lift Lug
Torsional shear stress Sts = St*tw/lw (psi) Sts = 11,954
Angle of rotation for Sts = arctan (.5B/(L9-X) (rad) ø = 0.761
Horizontal component of Sts1 = Sts*sinø (psi) Sts1 = 8,244
Vertical component of Sts2 = Sts*cosø (psi) Sts2 = 2,041
Weld Area based on weld Leg = Lw*(2*L9 + 2*L10 + B) in^2 = Warea = 8.4
Direct Shear stress (vert) = Fv/Warea = Ssv1 = 4,056
Allowable = .3*YSL or 0.3*YSS (smaller) = 11,400
Safety Factor = YSS*IF1/Ssv1 per ANSI B30.20 Safety Factor = 17
Page 3 Lift Lug Rev 3.xls
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Direct shear stress due to Fh1 = Fh1/(Lw(B + 2L9 + 2L10)) (psi) Ssh1 = 2,041
Allow shear stress = 0.3*YSL or 0.3*YSS = 11,400
Safety Factor = (YSS * IF1)/Ssh1 per ANSI B30.20 Safety Factor = 34
Max. shear stress (torsional + direct) - horizontal @ point C:
((Ssh1 + Sts2)) + (Sts1)̂ 2) . (psi) = 13,506
Allow Shear Stress = 0.4*YSL or 0.4*YSS = 15,200
Safety Factor = (YSS * IF1)/(Max shear stress compared to yield) = 5.1
per ANSI B30.20
CALCULATE STRESSES IN LUG (Curved beam analysis):
Minimum radius of lug = 1.5 x hole dia. (in) rmin = 2.625
Actual radius (in) r = 4.000 OK
H1 = r - Dh/2 (in) H1 = 3.125
H2 = 0.5(Dw - Dh) (in) H2 = 3.000
C = H1/2 (in) C = 1.563
R = (H1 + Dh)/2 (in) R = 2.438
z = -1 + (R/H1) x LN ((R + C)/(R-C)) z = 0.18546409
Moment = 0.5Fv x R(2/((π x (1+z)) -1) (in.lb.) MA = -19,310
Calculate stress A @ Y = -H1/2 (in) Y = -1.563
SA*A = Fv/2 + MA/R(1+Y/(z(R+Y))) ((lbf) SA*A = 85,466
Min section area = SA*A/Sa (in ) Amin = 3.75
Required washer thickness = 0.5(Amin-(TL x H1))/H2 (in) Twr = -0.026
Actual washer thickness (in) Tw = 0.000 OK
Stress A = SA*A/(TL x H1 + 2Tw x H2) (psi) SA = 21,879
Allowable stress (psi) Sa = 22,800 OK
Safety Factor compared to yield per ANSI B30.20 = YSL*IF1/SA Safety Factor = 3.13
Calculate stress B @ Y = -H/2 (in) Y = -1.563
Stress B = | (MA+.5Fv*R)/((TL*H1+2Tw*H2)*R) * (1+(Y/(z(R+Y)))) | (psi) SB = 20,297
Allowable stress (psi) Sa = 22,800 OK
Safety Factor compared to yield per ANSI B30.20 = YSL*IF1/SB 3.4
Combined section thickness = TL + 2Tw (in) Tc = 1.25
Tearout stress = Fv/(2H2 x Tc) (psi) ST = 4,563
Allowable Tearout stress (psi) = Sa/2 Sta = 11,400 OK
Bearing stress = Fv/(Tc*Dp) (psi) Sbr = 16,796
Allowable bearing stress = 0.85YSL (psi) Sba = 32,300 OK
CALCULATE STRESSES IN REINFORCEMENT WASHER FILLET WELDS:
Load on washer = Tw/Tc x Fv (lb) Fw = 0
Shear stress = Fw/(Dw x ¶ x Lp) (psi) Ssw = #DIV/0!
Allowable shear stress = Sa/2 (psi) = 11,400 #DIV/0!
Page 4 Lift Lug Rev 3.xls
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SUMMARY OF STRESSES
LOCATION DESCRIPTION CALC'D ALLOWABLE
Lug body Bending stress (psi) (horiz.) 13,371 22,800 OK
Axial Stress (psi) (vert.) 3,042 22,800 OK
Combined Bending and Axial Stress (psi) 13,531 22,800 OK
Shear stress (psi) (horiz) 1,722 11,400 OK
Lug-shell welds Direct shear (horiz) (psi) 2,887 21,000 OK
Maximum shear (horiz) (psi) 19,100 21,000 OK
Direct shear (vert) (psi) 5,736 21,000 OK
Lug Circ stress SA (psi) 21,879 22,800 OK
Circ stress SB (psi) 20,297 22,800 OK
Tearout stress (psi) 4,563 11,400 OK
Bearing stress (psi) 16,796 32,300 OK
Washer filletwelds Shear stress (psi) #DIV/0! 11,400 #DIV/0!
Page 5 Lift Lug Rev 3.xls