In this opportunity I’m sharing what I understand about designing padeye. Padeye usually is being used as lifting attachment. However, it can be used as pulling/tightening attachment depends on its function. Padeye or padear is easily recognized by radius on one side and hole size which is related with shackle pin diameter. Although it’s simple and tiny structure, but has critical function, comprehensive analysis shall be done. Just imagine big heavy structure during lifting is just relying on weld connection of padeye, padeye itself and rigging gears. It gives you some idea how critical this item.
Pin Hole Stress Check
I’ll share designing padeye based on AISC ASD 9th edition code. Let’s concentrate on hole first since this area has least area but all forces applied here.
- Bearing stress on the projected area shall not exceed sec. J8, Fp = 0.90 Fy.
- Allowable stress on the net area of pin hole for pin connected member is Ft = 0.45 Fy.
- Although not clear stated on section D3, allowable shear stress is Fv = 0.40 Fy.
- Bearing area is measured by pin diameter times main plate (+ cheek plate if any). Reduction factor 75% – 90% can be applied because pin surface may not 100% contact with padeye bearing area.
- Tensile area is calculated by main plate (+cheek plates if any) times least tensile area.
- Shear area is calculated by main plate (+cheek plates if any) times least shear area.
Main Body Stress Check
All loads are to be transferred from pin hole to main structure trough main body. Padeye body is usually welded to main structure. In some occasion I found main body welded to plate and bolted to main structure for easier removal. Stress check shall be done on body and welding connection.
- Bending stress check shall not more than chapter F, Beams and Flexural Members.
Of course, width-thickness ratio shall be checked whether compact, non-compact section. Most engineers tend to use Fb = 0.6 Fy as conservative value.
- Shear stress check would be same Fv = 0.40 Fy.
- Welding connection shall adequate to sustain bending, shear and both combination(?).