"LIFTING_LUG" --- LIFTING LUG ANALYSIS Program Description: "LIFTING_LUG" is a spreadsheet program written in MS-Excel for the purpose of analysis of lifting lugs, used in rigging operations. The can enter a desired factor of safety (most applications, F.S. = 5.0). The program will determine the ultimate strength of the lifting lug based on several checks and will apply the desired factor of safety to the strengths to attain allowable loads for the lifting lug. This program is a workbook consisting of two (2) worksheets, described as follows:
Worksheet Name
Description
Doc Lifting Lug
This documentation sheet Analysis of lifting lugs per 13th Ed. AISC Manual (ASD) and Reference #1a & b
Program Assumptions and Limitations: 1. The following references were used in the development of this program: a. "Design and Construction of Lifting Beams" - David T. Ricker, originally published in American Institute of
Steel Construction (AISC) - Design Journal , 4th Quarter 1991. b. "Design of Below-the-Hook Lifting Devices" - ASME BTH-1-2008, American Society of Mechanical Engineers . c. American Institute of Steel Construction (AISC) 13th Edition Allowable Stress Design (ASD) Manual (2005) 2. This program contains “comment boxes” which contain a wide variety of information including explanations of input or output items, equations used, data tables, etc. (Note: presence of a “comment box” is denoted by a “red triangle” in the upper right-hand corner of a cell. Merely move the mouse pointer to the desired cell to view
"LIFTING_LUG.xls" Program Version 1.4
LIFTING LUG ANALYSIS Project Name: Project No.:
Per AISC 13th Edition ASD Manual, ASME BTH-1-2008, and "Design and Construction of Lifting Beams" by David T. Ricker Client: Prep. By: Date:
Input: Design Parameters: Lug Yield Strength, Fy = Lug Ult. Strength, Fu = Edge Dist., a = Edge Dist., e = Lug Width, b = Rounded Edge? = Will Pin Rotate Under Load? =
Hole Diameter, dh = Pin Diameter, dpin = Lug Thickness, t = AISC Factor of Safety, F.S.1 = AISC Factor of Safety, F.S.2 = ASME Factor of Safety, F.S.3 =
36 58 2.500 1.000 6.000 No No 1.000 0.750 0.750 5.0 3.1 3.0
ksi ksi in. in. in.
in. in. in. F.S.2 = max{3, Fy/(Fu/F.S.1)}
ASME Notation
Assuming Category B lifters
AISC Preferred Geometry
AISC Alternate Geometry
Results: Check Geometry: Check 1: Check 2: Check 3: Check 4: a,eff = a,max = a,use =
O.K. O.K. O.K. N.G. 0.75 2.13 0.75
in. in. in.
dh - dpin > 0, Pin fits in hole, O.K. a >= max(0.5*dh,2*t), Plate Proportions are O.K. e >= 0.67*dh, Plate Proportions are O.K. e < 1.33*a, Use a,eff = min(a, 3*e/4, 4*t, dh*1.25) in design 3*e/4 controls a,max = 2*t+.625 Use a,eff in design
(continued)
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"LIFTING_LUG.xls" Program Version 1.4
Tensile Strength of Lifting Lug (AISC Eqn. D5-1): P1 = 13.05 kips P1 = (2*a,use*t*Fu) / F.S.1 Bearing Capacity of Lifting Lug (AISC Eqn. J7-1): P2 = N/A kips P2 = (1.8*Fy*t*dpin) / F.S.2 Per Ricker, only check bearing capacity if pin is "snug" in hole
Tearing Tension Capacity of Lifting Lug (Ricker pg 152): P3 = 14.53 kips P3 = {(1.67*Fy*t*e^2)/dh} / F.S.2 Per Ricker pg. 152, Fb is used instead of Fy, but Fb = Fy/F.S.2
Shear Capacity (Shear Rupture) of Lifting Lug (AISC Eqn D5-2): P4 = 10.44 kips P4 = (0.6*Fu*2*t*e) / F.S.1 Per AISC Eqn. D5-2, Asf = 2*t*(e+dh/2), cons. to assume dh/2=0)
Gross Section Yielding of Lifting Lug (AISC Eqn D2-1): P5 = 52.20 kips P5 = (Fy*t*b) / F.S.2 Tensile Strength of Lifting Lug (ASME Eqn. 3-45): Cr = 1 - 0.275*sqrt{1 - (dpin^2 / dh^2)} Cr = 0.818 a, eff = min(a, 4*t, 0.6*a*(Fu/Fy)*sqrt(dh / a) a,eff = 1.53 in. P6 = 30.22 kips P6 = (Cr*Fu*2*t*a,eff) / (1.2*F.S.3) Single Plane Fracture Strength of Lifting Lug (ASME Eqn. 3-49): R = e+(dh/2) R= 1.500 in. P7 = 16.67 kips P7 = [(Cr*Fu)/(1.2*F.S.3)] * [1.13*(R-.5*dh)+(0.92*a,eff)/(1+a,eff/dh)] * t
Double Plane Fracture Strength of Lifting Lug (ASME Eqn. 3-50): f= 41.25 deg. f = 55*(dpin / dh) Z' = 0.000 in. Z' = R - sqrt{R^2 - [(dpin/2)*sin(f)]^2}, only applicable for rounded edges Av = 1.640 in.^2 Av = 2*{e+0.8*dpin*[1-cos(f)]-Z'}*t P8 = 18.49 kips P8 = (0.7*Fu*Av) / (1.2*F.S.3) Bearing Capacity of Lifting Lug (ASME Eqn. 3-53): P9 = 8.44 kips P9 = (1.25*Fy*dpin*t) / F.S.3
<============= Controls
Summary: Pallow =
8.44
kips
Pallow = min(P1, P2, P3, P4, P5, P6, P7, P8, P9)
Required Weld Strength for Vertical Load: Pdesign = 12.66 kips Assuming fillet weld and F.S. = 5.0 against Fexx. Use Pdesign to design welds using 0.3*Fexx*0.707*weld size. Could also use Pallow, but need to use 0.2*Fexx*0.707*weld size for F.S. = 5.0.
Comments:
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