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Concrete & Masonryaka: concrete vibratoraka: pokeraka: stingeraka: immersion vibrator

Vibrator

In Plain English

A tool that shakes freshly poured concrete to remove air bubbles and ensure it fills every corner and space around rebar.

Definition

An internal or external mechanical device that transmits high-frequency vibrations to freshly placed concrete to eliminate air voids and ensure complete consolidation around reinforcement and into form corners. Internal (immersion) vibrators are the most common type, with heads ranging from 1 to 6 inches in diameter. Vibrator insertion spacing should not exceed 1.5 times the vibrator head radius of action.

Why It Matters in Bidding

Concrete vibration is a labor and equipment line that many estimators underprice, yet inadequate consolidation causes honeycombing, rejected pours, and patching that destroys margin. Pricing the right number of vibrators, backups, and crew accounts for placement rate, wall thickness, and rebar congestion. On large or congested pours, vibration capacity directly affects how fast concrete can be placed without cold joints.

Example

Bidding a heavily reinforced foundation wall, the estimator includes two immersion vibrators plus a spare in the equipment line so a breakdown mid-pour will not cause a cold joint or a failed inspection.

Related Terms

ConsolidationFormworkRebarCompressive Strength

Frequently Asked Questions

Match vibrator count to placement rate and congestion: a basic rule is one working unit per pour crew plus a backup, since a single failure mid-pour can ruin the work. Heavily reinforced walls, columns, or deep sections may need multiple heads. Price spares as cheap insurance against rejected, honeycombed concrete.
It is usually folded into the placing and finishing labor and equipment rates rather than broken out, but estimators should verify the crew and equipment assumptions cover it. On congested or architectural pours requiring extra consolidation, calling it out explicitly helps justify the labor rate and protects against under-bidding the placement scope.
Poor consolidation produces honeycombing, voids around rebar, and surface defects that fail inspection. Repairs mean grinding, patching, epoxy injection, or in severe cases demolition and re-pour, all uncompensated unless an owner change applies. Adequate vibration equipment and crew in the original bid is far cheaper than the rework risk.

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