International Building Code 1709.1
General. Where required by the provisions of Section
1709.2 or 1709.3 the owner shall employ a registered design
professional to perform structural observations as defined in
Section 1702.
At the conclusion of the work included in the permit, the
structural observer shall submit to the building official a written
statement that the site visits have been made and identify
any reported deficiencies that, to the best of the structural
observer’s knowledge, have not been resolved.
International Building Code 1709.2
Structural observations for seismic resistance.
Structural observations shall be provided for those structures
included in Seismic Design Category D, E or F, as determined
in Section 1613, where one or more of the following conditions
exist:
1. The structure is classified as Occupancy Category III or
IV in accordance with Section 1604.5.
2. The height of the structure is greater than 75 feet (22 860
mm) above the base.
3. The structure is assigned to Seismic Design Category E,
is classified as Occupancy Category I or II in accordance
with Section 1604.5 and is greater than two stories in
height.
4. When so designated by the registered design professional
in responsible charge of the design.
5. When such observation is specifically required by the
building official.
International Building Code 1709.3
Structural observations for wind requirements.
Structural observations shall be provided for those structures
sited where the basic wind speed exceeds 110 mph (49 m/s),
determined from Figure 1609, where one or more of the following
conditions exist:
1. The structure is classified as Occupancy Category III or
IV in accordance with Table 1604.5.
2. The building height is greater than 75 feet (22 860 mm).
3. When so designated by the registered design professional
in responsible charge of the design.
4. When such observation is specifically required by the
building official.