Rebar Compliance: The Case for Independent BBS Verification
The Challenge
Reinforcement steel is one of the single largest cost line items in any concrete structure. For that reason, Bar Bending Schedules submitted by contractors alongside Running Account (RA) Bills deserve rigorous, independent scrutiny. Yet on most projects they receive little more than a cursory check.
On this engagement, CQRA was commissioned to conduct a detailed bar bending schedule verification of the contractor’s BBS submission against approved structural drawings and a RA Bill. The client’s concern was straightforward: were the reinforcement quantities being billed actually consistent with what the drawings specified? CQRA’s BBS Verification unearthed the real situation on site.
The CQRA Approach
CQRA’s structural reinforcement QA team performed a detailed rebar schedule compliance review, cross-referencing every element like bar diameters, spacings, lengths, development lengths, hook details, member counts, and pour designations against the approved structural drawings.
Several categories of discrepancy emerged through the BBS audit.
Unauthorised additions. The contractor had claimed reinforcement bars in 1,600 mm and 1,800 mm thick raft foundations that were not shown on any approved drawing.
Systematic rounding abuse. A round-up formula applied to bar counts in the raft, staircases, and NS walls consistently inflated quantities beyond what geometry and spacing actually required.
Development length manipulation. In the Thickening Slab, the contractor calculated bar lengths using Ld + 10d at supports, whereas the approved drawings specified only Ld — quietly extending every bar claim in that zone.
Non-compliant spacing. In Pour 03 – Slab 07 (PTS2), the contractor adopted 75 mm spacing instead of the approved 100 mm spacing, directly increasing the number of bars claimed per bay.
Duplicate claims. Reinforcement already billed within one structural wall had been claimed a second time in an adjacent wall.
Cascading errors. The same spacing, hook, diameter, and member-count discrepancies observed at lower levels were carried forward, largely unchanged, from Level 12 through Level 16, indicating systemic errors embedded in the BBS preparation methodology, not isolated oversights.
This construction quality audit approach — element by element, level by level is the only reliable method for catching errors that compound quietly across dozens of poured cycles.
The reinforcement bar audit identified a net discrepancy of –88.547 MT in the contractor’s favour — reinforcement that was billed but not substantiated by approved drawings. Preventing payment on that quantum represents a direct, measurable financial recovery for the client, achieved before funds left the project account.
“The level of detail in CQRA’s BBS review went far beyond what our internal team could achieve at pace. The findings paid for the audit many times over.”
Book a call with CQRA’s structural QA team at cqra.com to quantify the rebar compliance risk on your current project.
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