Building Design and Construction Handbook - Merritt - Ventech!

TABLE 7.25 Maximum Bolt-Hole Sizes, in*
Bolt
diameter, in
1 ⁄2
5 ⁄8
3 ⁄4
7 ⁄8
Diameter
of standard
hole
STRUCTURAL STEEL CONSTRUCTION 7.93
Diameter
of oversize
hole
9
⁄16
5
⁄8
11
⁄16
13
⁄16
13
⁄16
15
⁄16
15
⁄16
1 1 ⁄16
Short-slot
hole
(width � length)
9 ⁄16 � 11 ⁄16
11 7
⁄16 � ⁄8
13
⁄16 � 1
15 ⁄16 � 1 1 ⁄8
Long-slot
hole
(width � length)
9 ⁄16 � 1 1 ⁄4
11 ⁄16 � 1 9 ⁄16
13 ⁄16 � 1 7 ⁄8
15 ⁄16 � 2 3 ⁄16
1 1 1 ⁄16 1 1 ⁄4 1 1 ⁄16 � 1 5 ⁄16 1 1 ⁄16 � 2 1 ⁄2
1 1 ⁄8 d � 1 ⁄16 d � 5 ⁄16 (d � 1 ⁄16) � (d � 3 ⁄8) (d � 1 ⁄16) � (2.5 � d)
* Approval of the designer is required for use of oversize or slotted holes. Larger holes than those listed in
the table, if required for tolerance in location of anchor bolts in concrete foundations, may be used in
column base details.
loading. Washers, hardened when used with high-strength bolts, should be placed
over oversize and short-slot holes.
Long-slot holes may be used in only one ply of the connected parts at an individual
faying surface. When the slot is in an outer ply, plate washers or a continuous
bar with standard holes should be installed to cover the entire slot. Washers
or bars for A325 or A490 bolts should be 5 ⁄16 in or more thick but need not be
hardened. If hardened washers are required, they should be placed over the outer
surface of a plate washer or bar.
7.30.2 LRFD for Bolts
The design strength of bolts or threaded parts is �R n (tabulated in Table 7.26)
applied to the nominal body area of bolts and threaded parts except upset rods (see
footnote h for Table 7.26). The applied load is the sum of the factored external
loads plus the tension, if any resulting from prying action caused by deformation
of connected parts. If high-strength bolts are required to support the applied loads
by direct tension, they should be proportioned so that the average required strength
(not including initial bolt tightening force) applied to the nominal bolt area will not
exceed the design strength.
The design strength in tension for a bolt or threaded part subject to combined
tension and shear stresses is also listed in Table 7.26. The value of ƒ v, the shear
caused by the factored loads producing tensile stress, should not exceed the values
for shear alone given in Table 7.26.
Table 7.25 lists maximum dimensions for standard, oversize, and slotted bolt
holes. The limitations on these are the same as those for ASD (Art. 7.26.1).
The design bearing strength at a bolt hole may be taken as �R n � �3.0dtF u,or
with � � 0.75, as 2.25dtF u, where d is the nominal bolt diameter, t is the thickness
of the connected part, and F u is the tensile strength of the connected part.
7.31 LOAD CAPACITY OF WELDS
For welds joining structural steel elements, the load capacity depends on type of
weld, strength of electrode material, and strength of the base metal. Fillet or groove