FP-96 English Version - Eastern Federal Lands Highway Division

Section 555(b) Use hardened washers under both the head and the nut whenAASHTO M 253 bolts are installed in material having a specifiedyield point less than 40 kips per square inch regardless of the tighteningmethod.(c) Use a hardened washer conforming to ASTM F 436 whereAASHTO M 164 bolts of any diameter or AASHTO M 253 boltsequal to or less than 1-inch diameter are to be installed in oversize orshort-slotted holes in an outer ply.(d) Use hardened washers conforming to ASTM F 436M, except with0.31 inches minimum thickness, under both the head and the nut inlieu of standard thickness hardened washers where AASHTO M 253bolts over 1 inch in diameter are to be installed in an oversize or shortslottedhole in an outer ply. Multiple hardened washers with a combinedthickness equal to or greater than 0.31 inches do not satisfy thisrequirement.(e) Where AASHTO M 164 bolts of any diameter or AASHTO M 253bolts equal to or less than 1 inch in diameter are installed in a longslottedhole in an outer ply, provide a plate washer or continuous barof at least 0.31-inch thickness with standard holes with sufficient sizeto cover the slot after installation and is structural grade material thatneed not be hardened.When AASHTO M 253 bolts over 1 inch in diameter are used in longslottedholes in external plies, use a single hardened washer conformingto ASTM F 436 with an 0.31-inch minimum thickness in lieu ofwashers or bars of structural grade material. Multiple hardened washerswith combined thickness equal to or greater than 0.31 inches donot satisfy this requirement.Alternate design fasteners conforming to Subsection 717.01 with ageometry that provides a bearing circle on the head or nut with a diameterequal to or greater than the diameter of hardened washers conformingto ASTM F 436 satisfy the requirements for washers specifiedherein and may be used without washers.445