2.1.7.4
Sheaves
**************************************************************************
NOTE: Select "24" if custom design load block with
trunnion has been specified; otherwise, select "16".
**************************************************************************
Provide steel sheaves. Machine or grind the grooves to contour and rim
toughen or flame or induction harden to not less than 320 BHN. Provide
minimum pitch diameters of running sheaves of not less than [24][16] times
the rope diameter. Provide sheave groove depth of not less than 1.15 times
the hoisting rope diameter.
2.1.7.5
Drum
Provide drum with turned helical grooves cut right and left hand to
receive, in a single layer, the full winding length of the rope plus not
less than two dead wraps on each end.
The drum shall be of steel construction. Design drum so that not less than
two dead wraps of hoisting rope will remain on each anchorage when the hook
is in its extreme low position. Drum grooving shall be right and left
hand. Minimum drum groove depth, shall be 0.375 times the rope diameter.
Minimum drum groove pitch shall be either 1.14 times the rope diameter, or
the rope diameter plus 3 mm 1/8 inch, whichever is smaller. Minimum drum
pitch diameter shall be [16] [18] times the rope diameter. The surface of
the drum which comes in contact with wire rope shall not be painted,
coated, or galvanized.
2.1.7.6
Hoist Brake
Provide electro-mechanical holding brake and mechanical load brake.
2.2
STRUCTURAL
2.2.1
Welding
AWS D14.1 for welding design and procedures, including pre-weld and
postweld heat treatments. However, the minimum classification of electrodes
shall be the E70 series.
2.2.2
Structural Bolted Connections
Make structural connection of girder to end truck with ASTM A 325M ASTM A
325 plain (non-coated) bolts; appropriate ASTM A 194/A 194M or ASTM A 563M
ASTM A 563 plain nuts; and ASTM F 436M ASTM F 436 plain, through hardened,
flat, circular washers. Match bolt and nut threads (oversize tapping is
not permitted); bolt and nut threads shall conform to ASME B18.2.2 and ASME
B1.1. Galvanized or coated bolts and ASTM A490 bolts shall not be used.
Make structural bolted connections not referenced above with ASTM A 325M
ASTM A 325 or ASTM A 307 bolts. Install ASTM A 325M bolts in accordance
with AISC S329.
SECTION 14637N
Page 14
Previous Page
