Page 316 - Handbook of Structural Steel Connection Design and Details

Partially Restrained Connections

Partially Restrained Connections 301

11. Check block shear on the plate. Assume shear failure along the bolts and
tensile failure across bolt gage and U 1.0:
bs

A 2 (25 4 1/2)(1.25) 51.25 in 2
gv
A (5)(1.25) 6.25 in 2
gt
A 51.25 2(6.5 1.125)(1.25) 32.97 in 2
nv
A 6.25 (1 1.125)(1.25) 4.85 in 2
nt
R n 5 0.6 F u A nv 1 U bs F u A nt # 0.6 F y A gv 1 U bs F u A nt
R n 5 0.6s65ds32.75d 1 s1.0ds65ds4.85d # 0.6s50ds51.25d
1 s1.0ds65ds4.85d
R n 5 1592 kips # 1853 kips
R n 5 s0.75ds1592 kipsd 5 1194 kips ok

12. Detail the shear connection to the web: The design of the shear connection
for this case will not be carried out in detail here (see Chap. 2 for design of
shear connections). From the AISC Manual, a 5/16-in pair of angles with
five 1-in A325N bolts provide 145 kips of shear resistance. This is equal to
the 145 kips required for design.
13. Check connection stiffness: For a quick check assume the plate has just
begun to yield at the column face and a linear distribution of the force along
the plate. Compute the elongation of the plate and add 1/32 in for the slip of
the bolts:

s plate,yield sL>2d s1.1 3 50 ksidds25 in/2d 1
conn 5 1 slip 5 1
E 29000 ksi 32
5 0.023 1 0.031 5 0.055 in

From this computation, elastic strains in the plate contribute approxi-
mately 40% and slip approximately 60% to the total deformation. Assume
that the connection rotates about the center of the beam. The connection
rotation is

0.055 in
conn
conn 5 5 5 0.00396 rad
sd/2d s27.7 in/2d
The connection stiffness is

s1.1 3 50ds13 3 1.25ds27.7d
M yield, plate
K conn 5 5
conn 0.003968 rad
6
5 6.25 3 10 kip-in/rad

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