Ambiguous RFI Answer Treated as Approval for Post-Installed Anchors
A 6-story office project is in structural framing. RFI 47 asks whether the curtain-wall anchor embeds shown on Sheet S-301 can be replaced with post-installed anchors because the embeds were misplaced by 2 inches at 18 locations on floors 2 and 3. The structural engineer of record responds: 'Coordinate with curtain wall manufacturer; maintain design intent.' The curtain wall subcontractor treats that as approval, installs 18 post-installed anchors over two days, and covers them with fireproofing. The curtain wall manufacturer's engineer later states the anchors do not meet the 5/8-inch embedment and 3,000 psi concrete requirements. The general contractor says the RFI answer authorized the work. The owner's representative learns of it in the weekly OAC meeting and asks for a path forward. The project is 7 weeks from curtain wall delivery.
1. What communication failure occurred, and why does it matter?
Read the worked answer
The failure is ambiguous communication treated as approval. The RFI answer said 'coordinate with curtain wall manufacturer; maintain design intent,' which is not a directive to use post-installed anchors and does not delegate design authority to the contractor. The contractor should have obtained a written response from the structural engineer of record and the manufacturer before installing. The architect/engineer also failed to close the RFI with a clear disposition. 'Coordinate' is a process instruction, not a design change. The fireproofing cover-up made verification harder. The general contractor's claim that the answer authorized the work is not supported by the text.
2. What immediate actions should the design and contracting team take?
Read the worked answer
Suspend further anchor work, expose the 18 locations, and issue a nonconformance report. Notify the structural engineer, curtain wall manufacturer, owner, and contractor in writing. Require the engineer of record to evaluate the post-installed anchors against the 5/8-inch embedment and 3,000 psi concrete requirements and to design a repair if they are inadequate. Require pull tests or other verification as directed. Do not accept the anchors based on the contractor's interpretation. Track cost and schedule separately; the curtain wall delivery is 7 weeks away, so remediation must be fast. The owner's representative should get a written recovery plan at the next OAC meeting.
3. How should the team document the resolution and prevent recurrence?
Read the worked answer
Revise the RFI response to state explicitly: 'This response does not authorize a design change; submit post-installed anchor design to the engineer of record for approval before installation.' Close RFI 47 with that clarification and attach it to the record. Require shop drawings for any post-installed anchor and a manufacturer's letter. In the OAC meeting, remind all parties that only written directives from the architect/engineer authorize work. Add a field observation and photo log. After resolution, issue an ASI or change order if the repair changes cost or time. The lesson is to make RFI answers definitive and to separate 'coordinate' from 'approved.'