UFC 4-023-03
25 January 2005
3-2.7.2
Combined Axial and Flexure.
The acceptability criteria for elements undergoing combined axial loads and
flexural loads is based on the provisions given in the material-specific design code. For
elements that are controlled by flexure, follow the procedure outlined in Section 3-2.7.1.
For elements controlled by buckling, remove the failed element from the model and
redistribute the loads per Section 3-2.4.3.
3-2.7.3
Shear.
If the shear design strength is exceeded for any construction type, remove the
member and redistribute the loads from that element per Section 3-2.4.3, before the
analysis continues.
3-2.7.4
Connections.
If the design strength for any connection failure mode is exceeded, remove
the connection. If the connections at both ends of an element have failed, remove the
element and redistribute the loads from that element per Section 3-2.4.3, before the
analysis continues.
Use the guidance provided in the material-specific design codes or other
sources to develop connection details that can provide the required strength while
undergoing potentially large deformations. In a number of the material-specific design
codes, provisions for seismic design are presented, including connection details;
incorporate this information, as appropriate, in designing connections.
3-2.7.5
Deformation Limits.
Deformation limits are defined in terms of the deflections and rotations in the
structural elements, connections and frame. Excessive deflections or rotations imply
that the element or portion of the frame has deformed to the point that it can no longer
carry load. Calculation of rotations for members, connections, and frames is illustrated
in Figures 3-10 and 3-11.
If an element or connection exceeds a deformation limit, remove it from the
model. The values for the deformation limits are specific to each type of construction
and are listed in the appropriate sections (Chapters 4 to 8).
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