3.1 SCOPE: Earthquake related failures of structures that are directly traceable to poor quality control during construction are innumerable. The literature containing earthquake damage is replete with reports indicating that the collapse of structures could have been prevented had proper quality assurance been exercised. The remarkable performance during earthquakes by California schools constructed since 1933 is due in great part to the rigorous supervision of the design and construction by the Office of the State Architect, as required by state law. The Provisions are written to rely heavily on the concept of quality controls to ensure good construction.
For structures located in areas of seismic risk, and subject to potential earthquake ground motion, good quality control and verification are especially important because of the serious consequences of failure and the unique, more complex, nature of the design and construction of buildings and structures when required to resist earthquake forces. The weakest components in the seismic- force-resisting systems are those affected by lateral forces. Generally, the failures of structures can be traced directly to a lack of quality control during design or construction, or both, when these components or details are slighted.
The registered design professional in responsible charge of the structure specifies the quality assurance requirements, the prime contractor exercises the control necessary to achieve the desired quality, and the owner monitors the construction process through special inspections and testing to protect the health, safety and welfare of the general public in built environment. Thus, the special inspector is the owner's inspector. It is essential that each party recognize their responsibilities, understand the procedures, and be capable of carrying them out. Because the contractor and the specialty subcontractors are performing the work and exercising control on quality, it is essential that the special inspections be performed by someone not in their direct employ and also be approved by the authority having jurisdiction. When the owner is also the contractor, the owner should engage independent agencies to conduct these special inspections rather than try to qualify his or her own employees.
These Provisions are concerned with those components that affect the performance of structures during an earthquake or structures that may be adversely affected by earthquake motions as specified in other sections of the Provisions. The requirements included in Chapter 3 are the minimum, and it could be the decision of the registered design professionals to include all phases of construction, throughout the project, under a quality assurance plan. For many structures, the additional cost to do so would be minimal. The primary method of achieving quality assurance is through the use of specially qualified inspectors approved by the authority having jurisdiction and working on behalf of the owner. The number of such inspectors actually employed will vary widely depending on the size, complexity, and function of the structure under construction. These Provisions allow the registered design professional or his or her employees to perform these special inspections, as long as the individuals are approved by the authority having jurisdiction, and they can demonstrate reasonable competence in the particular category of work they inspect.
3.2 QUALITY ASSURANCE PLAN: Introduced in this section is the concept that the quality assurance plan ) must be prepared by the registered design professional responsible for the design of each designated seismic system that is subject to quality assurance, whether it be architectural, electrical, mechanical, or structural in nature. The quality assurance plan may be a very simple listing of those elements of each system that have been designated as being important enough to receive special inspections and/or testing. The extent and duration of the inspections shall be set forth in the quality assurance plan, as well as the specific tests and the frequency of testing that is required.
Although some registered design professionals have expressed reluctance to accept the
responsibility for the quality assurance plan, because of an assumed increase in potential liability, it has been demonstrated by the performance of schools in California that have been subjected to earthquakes, that the improved quality also acts to protect the registered design professional.
Furthermore, the registered design professional is the most qualified person to prepare the quality assurance plan since the registered design professional is the most familiar with the design of the structure.
The authority having jurisdiction, however, must approve the quality assurance plan and must obtain from each contractor a written statement that the contractor understands the requirements of the quality assurance plan and will exercise the necessary control to obtain conformance. The exact methods of control are the responsibility of the individual contractors, subject to approval by the authority having jurisdiction. However, special inspections of the work are required in specific situations to provide the authority having jurisdiction reasonable assurance that there is compliance with the approved construction documents.
The exception to the preparation of a quality assurance plan is intended for those structures constructed of light wood framing and light gauge cold–formed steel framing with a height not greater than 35 feet above grade that are located in areas of low seismic risk (SDS does not exceed 0.50g) and that satisfy all of the criteria indicated, or those structures constructed of reinforced masonry not more than 25 feet above grade that are located in areas of low seismic risk (SDS does not exceed 0.50g), and that satisfy all of the criteria indicated. All special inspection(s) and testing that are otherwise required by the Provisions are not exempt and must be performed in accordance with the applicable sections of the Provisions.
The exception will typically include structures for low–rise multifamily dwellings, commercial, mercantile, and office buildings that are included in Seismic Use Group I. The exception is also limited to those structures that do not have any of the following irregularities: torsional
irregularity, extreme torsional irregularity, nonparallel systems, stiffness irregularity (soft story), stiffness irregularity (extreme soft story), or discontinuity in capacity (weak story). Any structure that does not satisfy all of the criteria included in the exception or is otherwise exempted by the Provisions is required to have a quality assurance plan prepared by a registered design
professional. It is important to emphasize that this exception is for the preparation of a quality assurance plan, and is not an exception for the design of the structure in accordance with the requirements of the Provisions.
The extent of the qualifications of the contractor and subcontractors can vary considerably, hence the extent of the quality control can vary considerably. The quality assurance plan, therefore, is an
opportunity to identify those areas of special concern that must be addressed during the construction process. Those areas include but are not limited to types of testing, frequency of testing, types of inspections, frequency of inspections, and the extent of the structural
observations to be performed.
3.3 SPECIAL INSPECTIONS: The requirements listed in this section, from foundation systems through cold formed steel framing, have been included in the national model codes for many years, and it is a premise of these Provisions that there will be available an adequate supply of knowledgeable and experienced inspectors to provide the necessary special inspections for the various structural categories of work. Special training programs may have to be developed and implemented for the nonstructural categories.
A special inspector is a person approved by the authority having jurisdiction as being qualified to perform special inspections for the category of work involved. As a guide to the authority having jurisdiction, it is contemplated that the special inspector is to be one of the following:
1. A person employed and supervised by the registered design professional in responsible charge for the design of the designated seismic system or the seismic-force-resisting system for which the special inspector is engaged.
2. A person employed by an approved inspection and/or testing agency who is under the direct supervision of a registered design professional also employed by the same agency, using inspectors or technicians qualified by recognized industry organizations as approved by the authority having jurisdiction.
3. A manufacturer or fabricator of components, equipment, or machinery that has been approved for manufacturing components that satisfy seismic safety standards and that maintains a quality assurance plan approved by the authority having jurisdiction. The manufacturer or fabricator is required to provide evidence of such approval by clearly marked on each designated seismic system or seismic-force-resisting system component shipped to the construction site.
The extent and duration of special inspections, types of testing, and the frequency of the testing must be clearly delineated in the quality assurance plan.
3.3.9 Architectural Components: It is anticipated that the minimum requirements for architectural components will be complied with when the special inspector is satisfied that the method of anchoring or fastening and the number, spacing, and types of fasteners actually used conforms with the approved construction documents for the component installed. It is noted that such special inspection requirements are only for those components in Seismic Design Categories D or E.
3.3.10 Mechanical and Electrical Components: It is anticipated that the minimum
requirements for mechanical and electrical components will be complied with when the special inspector is satisfied that the method of anchoring or fastening and the number, spacing, and types of fasteners actually used conforms with the approved construction documents for the component installed. It is noted that such special inspection requirements are for selected electrical, lighting, piping, and ductwork components in all Seismic Design Categories except A, and for all other electrical equipment in Seismic Design Categories E and F.
3.4 TESTING: The specified testing of the structural materials follows procedures and tests long established by industry standards. The acceptance criteria for each material to be tested should be included in the construction documents prepared for the project.
3.4.5 Mechanical and Electrical Equipment: The registered design professional should consider requirements to demonstrate the seismic performance of mechanical and electrical components critical to the post–earthquake life safety of the occupants. Any requirements should be clearly indicated on the construction documents. Any currently accepted technology should be acceptable to demonstrate compliance with the requirements.
3.5 STRUCTURAL OBSERVATIONS: The requirements included in this section are for the structural observation of those structures included in Seismic Design Categories D, E, or F when one or more of the following conditions exists: the structures is included in Seismic Use Group I or Seismic Use Group II or the structure is more than 75 feet above grade. The intent of
requiring structural observations by a registered design professional for the aforementioned structures is to assure that the seismic-force-resisting systems and the designated seismic systems are constructed in general conformance with the construction documents.
3.6 REPORTING AND COMPLIANCE PROCEDURES: The success of a quality assurance plan depends upon the experience, training, and knowledge of the special inspector and the
accuracy and thoroughness of the reports prepared by the special inspector. It should be emphasized that both the special inspector and the contractor are required to submit to the authority having jurisdiction a final certification that the completed work is in conformance with the approved construction documents. The contractor, having day-to-day knowledge of the construction of the project, is in the best position to state whether or not all the construction has been completed in accordance with the approved construction documents. To be fully aware, however, the contractor must institute a system of reporting within his or her organization that enables the contractor to effectively practice quality control. The special inspector can only attest to the work that he or she has personally inspected and, therefore, the special inspector acts more as an auditor or monitor of the quality control program exercised by the contractor and the testing conducted by the testing agency.
Continuous inspection does not imply that the special inspector has observed all of the work as it is being installed, rather it implies that the special inspector has observed all of the critical
conditions of the work to be sufficiently confident that the work was completed in conformance with the construction documents.