3.5. Other General Information

3.5.1. How are tolerances determined if they are not addressed in the applicable standards?

The fabrication and erection tolerances in the AISC Specification, the AISC Code of Standard Practice, AWS D1.1 and other applicable specifications and codes have evolved for nearly a century. Although these standards generally present a workable format for the fabricator and erector, they tend to address individual members rather than the role of individual members in the completed structure.

Tolerances for assemblies—such as those on shop-assembled bents, frames, platforms, pairs of girders, etc.—are not covered by any code or standard. AWS D1.1 Clause 5.23.12 states that “other dimensional tolerances of members not covered by [Clause] 5.23 shall be individually determined and mutually agreed upon by the contractor and the owner with proper regard for erection requirements.” This practice is recommended in all cases. The agreed-upon tolerances should account for the erection tolerances specified in the AISC Code of Standard Practice.