Structural Observation is defined as the visual observation of the structural system by a registered design professional for the general conformance to the approved construction documents at significant construction stages and at completion of the structural system. Structural observation does not include or waive the responsibility for the inspections required by CBC section 108, 1701 or other sections of the code.
When structural observation is required it is ultimately the responsibility of the owner to ensure that it is provided. It is important to understand that this is an added protection for the client to ensure that construction is preceding in general conformance with the approved plan set. If the client does not wish to have structural observation performed on the project, they will be assuming responsibility for any discrepancies between the approved drawing set and as-built construction. They also assume the risk for any resulting defects in the structure that are related to such discrepancies.
The requirements for structural observation is defined by Section 1702 of the California Building Code and generally requires observation for important structures located in zone 3 or 4, any structure in zone 4 located near a fault, or when such observation is required by the architect, engineer or building official. Additionally, CBC Section 106.3.5 provides that when structural observation is required, an Inspection and Observation Program shall be submitted by the architect or engineer of record for approval prior to issuance of the building permit.
As a rule of thumb, structural observation is always recommended for projects that fall outside of the specific requirements set forth in section 1702 of the CBC if the project is of a complex nature (i.e. projects with complex lateral and/or gravity systems). As the project complexity tapers off, so to does the need to utilize structural observation. Some specific project components warranting the need for structural observation may include, post-tensioned concrete structures, buildings four stories or higher, prefabricated units and their connections, etc.