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11.3 Testing Requirements for Evaluating the Performance of Existing Mechanical Fasteners
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A testing program shall be instituted to determine the capacity of mechanical fasteners used to anchor nonstructural components including the bracing of pipes, ducts and conduit, and the attachment of equipment and other components listed in the 1995 CBC, Part 2, Title 24, Table 16A-0. Anchors shall be categorized as either seismic bracing of pipes ducts or conduit or equipment and other component anchors.
For anchors used in the seismic bracing of pipes, ducts or conduit, the following shall apply:
- If an anchor fails the tension test, 20 anchors, installed by the same trade, in the immediate vicinity of the failed anchor shall be tested prior to resuming to a 20 percent sampling rate for testing.
- A minimum of one anchor of a given size shall be tension tested for each piece of equipment or other component under consideration. Where the number of anchors for the piece of equipment or component exceeds four, a minimum of 20 percent of the anchors shall be tension tested. Where none of the anchors in the group have calculated tension, testing shall consist of torque testing.
- If a single anchor fails, all anchors in the attachment group shall be tested. If two or more anchors fail, the component shall be retrofitted for the forces as for new construction.
- Testing of anchors shall be accomplished by the application of externally applied direct tension force to the anchor. The testing apparatus shall not restrict the probable shear cone failure surface of the concrete or masonry.
- Torque testing is not permitted in lieu of tension testing unless specifically allowed in these provisions.
In lieu of testing in accordance with Section 11.3.1 or 11.3.2, a test load may be established by the evaluating engineer. The allowable load that the anchor can resist shall be determined by dividing the test load by the appropriate factors noted in Section 11.3.1 or 11.3.2. No one-third increase is permitted for seismic or wind loads.
Allowable shear loads on anchors shall be determined by either of the following:
- Shear values listed in Table 19B-E of 1998 California Building Code (CBC) or equivalent provision in later version of the CBC, or
- Shear values shall be obtained by analysis using Strength Design of Anchorage to Concrete, Section A.6, published by the Portland Cement Association, 1999, with the specified reduction coefficient(s) to convert the "strength" values to allowable stress design values of 1.7.