Rebar Substitution and a Verbal Approval

Immediate actions, in sequence:

1. Instruct the site, in writing, to suspend preparation and not to pour those two column lines. Verbal instructions are not enough; a signed email or site instruction within the hour, copied to the contractor's project manager and the developer, creates the record that protects everyone if the pour proceeds anyway.
2. Confirm the facts against the controlled documents: the issued-for-construction drawing revision, the bar bending schedule, and the delivery dockets for the steel actually on site. Photograph the cages with a scale, and record bar size, spacing, tie spacing and lap lengths before anything is covered.
3. Issue a formal non-conformance report describing the as-placed condition versus the drawing, and stating that no acceptance decision has been made.
4. Check whether the substitution could be acceptable at all - for example, 16 mm bars at reduced spacing giving equivalent area, if congestion, lap length and anchorage permit. That is a design change and requires your written reanalysis, not a schedule amendment.
5. If the pour proceeds, stop the works, record the time and the instruction, and consider whether the concrete must be removed from those columns and recast.

Why axial capacity is not the test. The quick check (about 4,700 kN against a 2,850 kN factored load) is reassuring only about pure compression. The column is part of the lateral-force-resisting frame: it must carry moments from wind and seismic action and provide ductility, and the 1.0% minimum reinforcement ratio is a prescriptive requirement precisely because compressive strength does not capture those demands. Below 1% steel, the section loses moment capacity, curvature ductility and confinement, and the 16 mm bars may also fail spacing and tie requirements. A substitution like this cannot be approved on an axial check; it needs the same analysis the original design received, and quite possibly cannot be approved at all.

On the approval: a verbal instruction from a project manager is not a design approval and cannot be one. Responsibility for the structural design sits with the engineer of record and is evidenced by the sealed drawings; only a written change notice, prepared or reviewed by the EOR, transfers that responsibility. The PM has no authority to waive a design requirement, and if you proceed you would be certifying work you did not design and have not checked. Say this plainly and in writing, on the same day:

• 'No substitution has been approved. The as-placed reinforcement does not comply with the issued drawings. Pouring those columns will create non-conforming work that may have to be demolished.'
• Restate the technical basis (36% less steel, below the 1% minimum, columns in the lateral system), not just the procedural point - the PM is more likely to accept a reasoned risk statement than a bureaucratic one.

On the commercial pressure: the fee renewal is a conflict of interest and must be managed, not absorbed quietly. Disclose it within your firm - to your principal or a designated reviewer - so the decision is not yours alone, and confirm that the technical position will not be influenced by the renewal. If the pressure continues, escalate to the developer's senior management and to your own firm's leadership in writing.

Framing that often works: the $18,000 of cancelled concrete is trivial compared with the cost of demolishing and recasting two column lines, and a verbal waiver gives the developer no protection either - if the building later has a problem, the absence of a written approval is precisely what will be held against them. Offer the practical alternative: hold the pour on those two lines only, keep the rest of the programme moving, and source 20 mm bar for tomorrow; the two column lines are almost certainly not on the critical path for the whole floor.

Obligations. As EOR you have a duty to protect the public, not just to advise your client. That means you cannot simply record your objection and carry on certifying the building as though the issue had been resolved.

Actions, in order of increasing severity:

1. Written notice to all parties - developer, contractor, and the independent certifier or financier if one exists - stating that the works are non-conforming, that the columns must not be poured, and that if they are poured you will not certify them without demolition and reconstruction or a fully documented design check that you are prepared to seal. Send it before the pour, not after.
2. Record everything contemporaneously: site photographs, the drawings and their revision status, your site instruction, the suspension instruction, the PM's instruction to proceed, and the time-stamped call log. If the matter is later litigated or investigated, a clear timeline is the difference between a defensible position and an indefensible one.
3. Notify the regulator where the jurisdiction requires it - most professional-engineering regimes require notification where a client persists with work that the engineer considers unsafe or non-compliant, and building-control regimes usually require the certifier to be told. Do not assume the developer will tell them. Use the statutory or professional-body channel rather than an informal one.
4. Consider withdrawing from the affected work if the developer proceeds. Withdrawal is the last resort, but a professional who remains involved while a known non-conforming structural element is built is lending their name to it. If you withdraw, do so with a written explanation limited to the technical facts, and take advice before making any public statement.
5. Do not trade silence for the fee renewal. Any suggestion that certification depends on the contract is itself a matter to report to your professional body.

Continuing involvement. If the columns are poured, insist on a documented resolution: destructive investigation (core samples, cover-meter and rebar-locator survey), a full reanalysis by a competent structural engineer, and a design remedy such as jacketing or additional columns, reviewed and sealed independently. Only then can the building be certified - and only if the resulting structure meets the original performance requirement, not merely the original axial-load number.