TIA SWT Support Structure Design Supplement Draft 03292011 R0

ANSI/TIA-222-G-DS1-2011
DRAFT 3-29-2011 Rev 0
in accordance with AWS. Backer bars shall not exceed 0.375 inches [10 mm] when a
fillet weld is used to attach the backer bar to the flange plate.
11.5.5 Socketed Flange Plate Welds for Pole Structures
The inner fillet weld shall be an equal leg fillet weld with the weld size not less than the
pole wall thickness minus 1/16 inch [2 mm]. The outer fillet weld shall be an unequal
leg fillet weld with the long leg of the fillet weld along the pole wall with an approximately
30 degree angle between the fillet weld and the pole wall.
12.0 OTHER STRUCTURAL MATERIALS
This Design Supplement has been developed primarily for steel SWT supporting
structures but may also be applied to other materials using appropriate resistance
factors to result in an equivalent level of reliability.
12.1 Extreme Loading Conditions
The nominal strengths for extreme loading conditions for material other than steel shall
be based on the minimum strengths guaranteed by the manufacturer of the material or
alternately, based on tests to determine strengths of 95% survival probability with a 95%
confidence limit. Resistance factors applied to nominal strengths shall be in accordance
with Table 12-1.
12.2 Fatigue Loading Condition
The design stress range values indicted in Section 11.4 include appropriate resistance
factors applied to the nominal stress ranges for steel components manufactured in
accordance with TIA. Appropriate resistance factors for other materials shall be applied
to the nominal fatigue stress ranges in accordance with the Table 12-2.
For materials that do not display a fatigue threshold limit, the number of cycles used to
determine the nominal stress range for use with this Design Supplement shall be based
on 5 million cycles.
13.0 FOUNDATIONS
Mat foundations for self-supporting structures shall be sized so that the reactions form
the serviceability loading combination result in compressive soil bearing stress over the
full plan dimension of the mat.
Drilled shaft or pile foundations subjected to lateral load shall be designed considering
repetitive loading soil conditions.
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