Conflicting Drawings, an Unresolved f'm, and No Special Inspection Program
A new elementary school gymnasium has 26-ft-tall CMU perimeter walls carrying open-web steel joists on a bond beam. The architectural drawings show 12-in. CMU with no. 5 vertical bars at 24 in. on center. The structural drawings show 8-in. CMU with no. 6 verticals at 24 in. on center. The specification requires ASTM C270 Type S mortar and f'm = 1,500 psi; the structural general notes state f'm = 2,000 psi. The building is assigned to SDC D. Anchor bolts appear on the architectural plans only as a spacing, while the structural plans call for 3/4-in. bolts with a specific embedment. The contractor wants to begin laying on Monday. Unit certificates, mortar and grout mix designs, and reinforcement certificates have not been submitted, no statement of special inspection has been issued, and grouting is scheduled in three weeks.
1. What should the inspector do about the conflicts before any masonry is placed? Be specific about authority and communication.
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The inspector's authority is to verify that the work conforms to approved construction documents. It is not to choose between two drawings, infer which note governs, or redesign the wall in the field. Here the conflicts are not clerical: an 8-in. wall with no. 6 bars and a 12-in. wall with no. 5 bars have different effective depths, cell geometry, grout volume, cover, and capacity, and the f'm conflict changes the unit strength or prism basis and therefore what the inspector must verify all project long.
I would document each conflict precisely, with sheet numbers, and require the contractor to issue a written request for information to the architect and engineer of record. Masonry in the affected scope should not proceed, and no cells should be grouted, until written direction is issued. If the resolution is a design change, it should come back as revised drawings or a sealed supplemental detail, possibly with a permit revision, not as a verbal instruction.
If the contractor begins laying before resolution, I would record it in the daily report and notify the building official, who holds the stop-work and enforcement authority. I would also require the outstanding submittals to be reviewed and approved before the corresponding work, since unit certificates and mix designs are the basis for everything inspected later.
2. Outline the hold points and inspection items you would establish for these walls, including items that are specific to SDC D.
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The plan needs to be written before work begins, tied to the documents as finally resolved, and reviewed at a pre-construction meeting. Hold points I would set:
- Pre-construction: verified submittals (ASTM C90 unit certificates, mortar and grout mix designs, reinforcement certificates), the statement of special inspection, and the sampling and testing plan including prism frequency.
- Foundation and first course: embedded items, dowel location, flashing and weep coordination, layout, and story poles for plumb control.
- Reinforcement before grouting: bar size, spacing, laps, dowels, cover, and anchor bolt size, embedment, and position. This is a mandatory hold point because after grouting, corrections become demolition.
- Pre-grout: cleanouts, clean and unobstructed cells, and written sign-off by the inspector.
- Grouting: continuous observation of placement, consolidation, and lift heights.
- Sampling: mortar and grout specimens, prisms at the specified frequency, and slump checks.
- Final: plumb and tolerance verification, anchor bolt projection, and bond beam condition.
In SDC D, masonry special inspection is triggered under the building code, and the required items must match the approved statement of special inspection, including continuous versus periodic designation. Work should not start until that program is in place; an inspector cannot substitute personal observation for a required special inspection program.
3. How does the anchor bolt information gap affect what must be verified before grouting, and what would you require?
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Anchor bolts in grouted bond beams are a one-shot item. Once grout is placed, the bolts cannot be moved, added to, or given greater embedment without a designed repair, so their verification belongs at the pre-grout hold point, not at steel erection. The architectural plans give spacing only; the structural plans give size and embedment. Those two pieces of information must be combined and confirmed in writing before any bolt is set.
Before grouting I would require a written location and setting detail that resolves the two sheets, showing bolt size, embedment, edge distance, projection, and how the bolts and bond beam reinforcement coexist in the same cells without hard contact and without losing required grout cover. I would then verify actual position against the tolerance stated in the documents, verify embedment by measurement of the bolt and depth of the cell, and verify that plate washers and nuts will fit the available bearing area.
If a bolt is later found out of position, the inspector cannot authorize bending it straight or welding to it. The disposition belongs to the engineer of record, and the inspector documents the as-found condition and the written resolution.