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CRANE RUNWAY BEAM DESIGN - AISC ASD 1989          

Crane runway design based on           Code Abbreviation
AISC Manual of Steel Construction: Allowable Stress Design 9th Edition AISC ASD 1989
AISC Design Guide 7: Industrial Buildings-Roofs to Anchor Rods 2nd Edition AISC Design Guide 7
Crane runway beam section Label
Section Properties                  
Label                  
  A = Label [in2] dall = Label [in]  
  top y2 = Label [in] bott. y1 = Label [in]  
  Ix = Label [in4] Iy = Label [in4]  
  top S2 = Label [in3] bott. S1 = Label [in3]  
  Sy = Label [in3]          
  Zx = Label [in3] Zy = Label [in3]  
  rx = Label [in] ry = Label [in]  
  J = Label [in4]          
W Section                  
  d = Label [in] bf = Label [in]  
  tw = Label [in] tf = Label [in]  
  h = Label [in]          
Top Flange                  
  Af = Label [in2] dall / Af = Label [in-1]  
  rT = Label [in] ryt = Label [in]  
  It = Label [in4]          
  St = Label [in3] Zt = Label [in3]  
                   
W section yield strength Fwy = Label [ksi]          
Cap channel or plate yield strength Fcy = Label [ksi]          
Runway beam unbraced length Lb = Label [in]          
Design Forces                  
Bending moment x-x axis         Mx = Label [kip-ft]  
Bending moment y-y axis - top flange     My-t = Label [kip-ft]  
Bending moment y-y axis - bottom flange     My-b = Label [kip-ft]  
Shear along y-y axis         Vy = Label [kips]  

Conclusion                  
Overall         ratio = Label Label  

Local buckling               Label  
Bending about X-X Axis - max ratio of top flange compression
                                      and bottom flange tension
ratio = Label Label  
Bending about Y-Y axis in the top compression flange     ratio = Label Label  
Bending about the Y-Y axis in bottom flange -underhung crane      ratio = Label Label  
Biaxial bending in the top compression flange ratio = Label Label  
Shear along Y-Y Axis         ratio = Label Label  
Web sidesway buckling         ratio = Label Label  

Runway beam vertical deflection         ratio = Label Label  
Runway beam lateral deflection         ratio = Label Label  

Design Basis & Assumption                 Code Reference
1. The crane runway beam is designed as simple span beam. AISC Design Guide 7
2. The W section top flange and cap channel resist the hor. load and the combined section resists the ver.
    load. This assumption eliminates the need for an analysis of torsional effects on the combined section
    and simplifies the analysis.
Section 18.1 on Page 56
2. For underhung crane the hor. side thrust load is all taken by the W or S shape bottom flange.
    This assumption eliminates the need for an analysis of torsional effects on the combined section and
    simplifies the analysis.
Section 18.1 on Page 56
3. If A36 channel cap is used on A992 W section then lateral torsional buckling and weak axis flexure
    strength must be calculated based on A36 yield stress.
Section 18.1.4 on Page 57
4. For bending moment about the X axis, the moment caused by runway beam and rail self weight is
    calculated at beam midspan as maximum and added to the maximum moment caused by crane
    moving load. Even though the maximum moment caused by crane moving load may not be at the
    beam midspan, this conservative approach rarely makes a significant change in the final combined
    Mx value used in the runway beam design.
 

CALCULATION                  
Check Local Buckling                  
W Shape Classification                  
Flange of W shape                 AISC ASD 1989
Compact limit lp = 65 / sqrt (Fwy) = Label   Table B5.1
Noncompact limit lr = 95 / sqrt (Fwy) = Label    
  bf / 2tf = Label       Label  
Web of W shape                  
Compact limit lp = 640 / sqrt (Fwy) = Label   Table B5.1
Noncompact limit lr = 760 / sqrt (0.66Fwy) = Label    
  d / tw = Label   h / tw = Label  
              Label  
W shape classification             Label  
Channel Classification                  
Flange of Channel                 AISC ASD 1989
Compact limit lp = 65 / sqrt (Fcy) = Label   Table B5.1
Noncompact limit lr = 95 / sqrt (Fcy) = Label    
  bf / tf = Label       Label  
Web of Channel                  
Compact limit lp = 640 / sqrt (Fcy) = Label   Table B5.1
Noncompact limit lr = 760 / sqrt (0.66Fcy) = Label    
  d / tw = Label   h / tw = Label  
              Label  
Channel shape classification             Label  
Cap Plate Classification         AISC 360-10
Flange Cover Plate Between Lines of Welds          
Compact limit lp = 1.12 sqrt (E / Fpy) = Label   Table B4.1 Case 12
Noncompact limit lr = 1.40 sqrt (E / Fpy) = Label    
Cap plate classification bf / tp = Label       Label  
                   
Label     Label       Label  
                   
Check Bending about X-X Axis                  
Tension                  
Allowable tension stress Fbx t = 0.6 x Fwy   = Label [ksi]  
Actual tension stress fbx t = Mx / S1   = Label [ksi]  
  ratio = fbx t / Fbx t   = Label Label  
Compression                  
Label Fy = Label [ksi] Label
Label bf = Label [in] Label
                  AISC ASD 1989
Critical length Lc = = Label [in] Eq F1-2
76 bf / sqrt( Fy ) =       = Label [in]  
When Lb <= Lc                 AISC ASD 1989
      For compact sect                  
  Fbx = 0.66 x Fy   = Label [ksi] Eq F1-1
      For non-compact sect                  
  bf / 2tf = Label = Label    
  Fbx = = Label [ksi] Eq F1-3
  Fbx = 0.6 x Fy = Label [ksi] Eq F1-5
When Lb > Lc                 AISC ASD 1989
  Lb / rT =       = Label    
Bending coefficient Cb = 1.0 to be conservative        
  x = = Label   AISC ASD 1989
      For ( Lb / rT ) <= x                  
  Fbx = = Label [ksi] Eq F1-6
      For ( Lb / rT ) > x                  
  Fbx = = Label [ksi] Eq F1-7
      For any value of ( Lb / rT )                  
  Fbx = = Label [ksi] Eq F1-8
                   
Allowable compression stress Fbx c =       = Label [ksi]  
Actual compression stress fbx c = Mx / S2 = Label [ksi]  
  ratio = fbx c / Fbx c = Label Label  
                   
Check Bending about Y-Y Axis on Top Flange           AISC ASD 1989
For compact top flange                  
  Fby = 0.75 x Fy   = Label [ksi] Eq F2-1
For non-compact top flange                  
  Fby = 0.60 x Fy   = Label [ksi] Eq F2-2
Allowable compression stress Fby c =       = Label [ksi]  
Actual compression stress fby c = My-t / St = Label [ksi]  
  ratio = fby c / Fby c = Label Label  
Check Bending about Y-Y Axis on Bottom Flange           AISC ASD 1989
For compact bottom flange                  
  Fby = 0.75 x Fy   = Label [ksi] Eq F2-1
For non-compact bottom flange                  
  Fby = 0.60 x Fy   = Label [ksi] Eq F2-2
Allowable compression stress Fby c =       = Label [ksi]  
Actual compression stress fby c = My-b / Sb = Label [ksi]  
  ratio = fby c / Fby c = Label Label  
                   
Check Biaxial Bending on Top Flange           AISC ASD 1989
Combined bending stress     fbx / Fbx + fby / Fby = Label Label Eq H1-3
Combined bending stress     fbx / Fbx  = Label Label Eq H1-3
                   
Check Shear along Y-Y Axis           AISC ASD 1989
Clear dist between trans. stiffeners a = Lb     = Label [in]  
W sect clear dist between flange h = Label [in] a / h = Label    
  kv = 4.00 + 5.34 / (a / h)2 if a / h <=1 = Label   F4
      5.34 + 4.00 / (a / h)2 if a / h >1        
  h / tw = Label   Cv = Label   AISC ASD 1989
For h / tw <= 380 / sqrt ( Fy )                  
  Fv = 0.40 x Fy   = Label [ksi] Eq F4-1
For h / tw > 380 / sqrt ( Fy )                  
  Fv = ( Fy x Cv ) / 2.89 <=0.4 Fy = Label [ksi] Eq F4-2
Allowable shear stress Fv =       = Label [ksi]  
Actual shear stress fv = Vy / ( d x tw ) = Label [ksi]  
  ratio = fv /Fv     = Label Label  
                   
Check Web Sidesway Buckling           AISC Design Guide 7
Use LRFD 13 instead of ASD 9 to increase web sidesway buckling resistance when flexural stress in the
web is less than 0.66Fy
Example 18.1.2 notes
on Page 61
(h / tw) / (Lb / bf) = Label Label       AISC 360-10
Max actual bending stress fb = Label [ksi]          
When fb < (Fy / 1.5) = 0.66 Fy Cr = Label [ksi]          
When fb >= (Fy / 1.5) = 0.66 Fy Cr = Label [ksi]          
  Rn = = Label [kips] Eq J10-7
  Ra = Rn / Ω = Rn / 1.76 = Label [kips]  
  Pv-impt = Pmax x a (impact factor) = Label [kips]  
  ratio = Pv-impt / Ra = Label Label  
                   
Check Runway Beam Deflection           Code Reference
Crane serviceability criteria based on  
CISC Guide for the Design of Crane-Supporting Steel Structures 2nd Edition Table 4.1 item 14,15
AISC Design Guide 7: Industrial Buildings-Roofs to Anchor Rods 2nd Edition Section 18 on Page 56
CMAA 70-04 Specifications for Top Running Bridge and Gantry Type Multiple Girder Electric Overhead
Traveling Cranes
Clause 1.4.3
CMAA crane service class Label Label  
Ver deflection limit (no impact , max wheel load) Bv = Label  
Hor deflection limit (no impact , 10% max wheel load) Bh = Label  
Runway beam span L = Label [in]          
Vertical Deflection                  
Unfactored max ver. wheel load Pmax = Label [kips / per wheel] impact factor NOT included
  Ix = Label [in4]          
Max deflection at center Dmax = Label = Label [in]  
Allowable deflection Da = L / Bv     = Label [in]  
  ratio = Dmax / Da = Label Label  
                   
Horizontal Deflection                  
Unfactored max hor. wheel load Ph = Label [kips / per wheel]  
For top running crane, only top flange moment of inertia is considered for deflection check  
Top flange It = Label [in4]          
For underhung crane, only bottom flange moment of inertia is considered for deflection check  
Bottom flange Ib = Label [in4]          
Max deflection at center Dmax = Label = Label [in]  
Allowable deflection Da = L / Bh     = Label [in]  
  ratio = Dmax / Da = Label Label