In Plain English
Quick Answer
Steel bars placed inside concrete to give it tensile strength and prevent cracking.
Definition
Definition
Rebar (reinforcing bar) is deformed steel bar placed inside concrete to provide tensile strength, since concrete is strong in compression but weak in tension. Rebar is specified by bar size (No. 3 through No. 18 in the US), yield strength (typically 60,000 psi), and grade. Proper rebar placement, cover, and splicing is critical to structural performance.
Context
Why It Matters in Bidding
Rebar is a major concrete-package cost driven by tonnage, fabrication, and placement labor, all of which trace back to bar size, spacing, lap splices, and accessories in the structural drawings. An estimator who undercounts splices, chairs, or ties — or misreads the specified grade — will misprice both material and the labor-heavy placement scope, exposing the bid to loss once the steel is detailed and installed.
Example
Example
Detailing a foundation bid, the estimator converts the rebar schedule to tons and adds lap-splice lengths and tie wire so the fabricated steel and the ironworkers' placement labor are both fully captured.
See Also
Related Terms
FAQ
Questions Contractors Ask
How is rebar quantity calculated for a bid?
Estimators take off bars by size from the structural schedules, total the linear footage including lap splices and development lengths, then convert to weight using unit weights per bar size to get tons. Accessories like chairs, bolsters, and tie wire are added separately, since fabrication and placement are priced against tonnage and piece counts.
Why do lap splices matter in rebar estimating?
Splices add length that does not appear as a single bar on the plan but consumes real material and creates extra placement work. Code-required lap lengths grow with bar size and conditions, so ignoring them understates tonnage. Estimators add splice allowances per the drawings and specs to keep the quantity honest.
Should rebar be bid as material only or installed?
It depends on the trade split. A rebar fabricator may furnish detailed, cut, and bent steel delivered to site, while a separate placing sub or the concrete contractor installs it. Estimators must confirm where the scope line falls so fabrication, delivery, and placement labor are each captured once and not duplicated.
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