Civil Engineering Reference
In-Depth Information
End plate
A
P
P
d
M
e
e
l
A
Section A-A
b
Side elevation of beam
FIGURE 9.7
Simple welded beam framing connection.
A flexible end connection will deform and resist very little bending moment. Sim-
ple beam framing connections (Figure 9.7) that exhibit the characteristics of a flexible
connection may be designed for shear force,
P
, only (
M
e
=
0). AREMA (2008) rec-
ognizes that most connections actually exhibit some degree of semirigid behavior and
allows flexible connection design (with angle thickness that allows for deformation
∗
)
provided the design shear force is increased by 25%. Therefore, flexible welded beam
framing connections may be designed considering shear on the outstanding legs of the
connection and, due to the eccentricity of the shear force, the combined shear and tor-
sion on the leg of the connection angles fastened to the web of the beam. Otherwise, a
semirigidconnectiondesignconsideringbothbeamendmomentandshearisrequired.
Rigid connection
End moment
Range of typical
connection behavior
Semirigid
connection
Flexible connection
End rotation
FIGURE 9.8
Typical moment-rotation curves for welded beam end connections.
∗
In particular, the outstanding legs must be sufficiently flexible to disregard any beam end bending effects.
