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ANSI/TIA 222-G-2005 EXISTING STRUCTURES |
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15.5.1
Feasibility Structural Analysis A
feasibility structural analysis is used as a preliminary review to
identify the impact of proposed changed conditions. This type of analysis
determines the overall stability and the adequacy of the main structural
members to support a proposed changed condition. Acceptance of changed
conditions shall be based upon a rigorous structural analysis in
accordance with 15.5.2. A feasibility structural analysis does not include
the evaluation of connections and may consider that the structure has been
properly installed and maintained. The
reactions from a feasibility structural analysis may be compared to the
original design reactions to identify the impact on foundations due to
proposed changed conditions. When the original design reactions are based
upon an Allowable Stress Design procedure, the original reactions shall be
multiplied by a 1.35 factor for comparison to the reactions determined in
accordance with this Standard. 15.5.2
Rigorous Structural Analysis A rigorous structural analysis is used to determine the final
acceptance of proposed changed conditions and/or required modifications.
This type of analysis determines the overall stability and the
adequacy of structural members, foundations and connection details.
A rigorous structural analysis may consider that the structure has
been properly installed and maintained.
For
a rigorous analysis of a foundation, site-specific geotechnical and
foundation data are required. Note:
Certain foundation details and connection details (such as inside weld
sizes of flanged leg connections) cannot be determined without dismantling
the structure or extensive field nondestructive testing. The assumptions
regarding these types of details shall be documented along with the
results of the rigorous structural analysis. 15.5.4
Structural Analysis Report The structural analysis report shall specify the type of analysis
(feasibility or rigorous). A feasibility report shall state that final
acceptance of changed conditions shall be based upon a rigorous structural
analysis. 15.7
Modification of Existing Structures 15.7.1
Design Modifications
to existing structures shall be based on a rigorous structural analysis.
A design document shall be prepared indicating the proposed reinforcement
of existing members and/or connections and all proposed additional
members. Prior to implementation of the changed conditions
and/or modifications, the data designated on the design document requiring
verification shall be validated. 16.0
INSTALLATION Rigging
and temporary supports such as temporary guys, braces, false work,
cribbing or other elements required for the erection/modification shall be
determined, documented, furnished and installed by the erector accounting
for the loads imposed on the structure due to the proposed construction
method. To
purchase a copy of 222-G please contact Global Engineering Documents
(800-854-7179) or contact TIA. |