406 — DRILLED HOLES IN MASONRY AND STRUCTURES 2026 STANDARD SPECIFICATIONS FOR CONSTRUCTION AND MATERIALS CATEGORY 400 STRUCTURES SECTION 406 — DRILLED HOLES IN MASONRY AND STRUCTURES
406.01 Description
Drill holes for grouting of bars, bolts, or anchorages. In portions of masonry structures that will remain in the final structure, the drilling of holes for temporary construction purposes is prohibited, unless approved in writing by the Director or Deputy Director of the Office of Structures. Do not drill holes for temporary construction purposes in new or existing masonry structures without a prior written approval from Director or Deputy Director of Office of Structures.
406.02 Materials
Grout 902.11(c)
406.03 Construction
Drill holes only in the solid portion of masonry. Do not drill where cracks exist. Drill holes at least 1/2 in. larger than the insert and at least 6 in. from all non-intersecting masonry surfaces. When dowel bars are used, use at least No. 6 dowel bars. Clean the holes and fill two thirds full of grout. Place the insert, keep it in place and allow to set at least 24 hours, until it reaches a compressive strength of at least 3 000 psi, or until it is set to achieve the strength required for the contract application, obtaining the required strength according to the manufacturers’ specifications. If grouted bar, bolts, or anchorages for temporary construction are no longer needed, remove them as specified in 420.03.02(n).
406.04 Measurement and Payment
Drilled Holes in Masonry and Structures will be measured and paid for at the Contract unit price per linear foot of drilled hole. The payment will be full compensation for all material, labor, equipment, tools, and incidentals necessary to complete the work. Inserts will not be measured but the cost will be incidental to other pertinent items. Drilled holes and removal of temporary items for which no specific pay item is included in the Contract Documents will not be measured but the cost will be incidental to the other pertinent items.
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