PRECISION STEELWORK QA

Anchor Bolt Pattern QA

Separate global setting-out shift, pattern rotation and individual bolt distortion before steelwork installation or costly rework.

✓ Best-fit 2D analysis✓ Shift & rotation diagnosis✓ Spacing & level checks✓ Plan view & PDF report

PROJECT & CRITERIA

Anchor bolt acceptance basis

Project Client Contractor Prepared by Drawing / model reference Report reference Survey date Coordinate system Pattern placement tolerancemm centre shift Pattern rotation tolerancedegrees Individual residual tolerancemm after best-fit Level tolerancemm Spacing tolerancemm pair-to-pair Warning threshold Display exaggeration Report revision

Acceptance note: obtain written tolerances for the actual base plate, holes, bolt diameter, grout, erection method and steelwork package. Best-fit analysis diagnoses the pattern; it does not remove a global setting-out error.

DESIGN VS MEASURED

Anchor bolt coordinate schedule

Pattern / base	Bolt ID	Design E	Design N	Design RL	Measured E	Measured N	Measured RL	Bolt Ø mm	Hole Ø mm	Evidence / note	Action

PATTERN DIAGNOSIS

Setting-out and fabrication status

Patterns0

Bolts0

PASS0

WARNING0

FAIL0

Incomplete0

SearchPatternStatus

Pattern / bolt	Raw ΔE	Raw ΔN	Raw horizontal	ΔRL	Best-fit residual E	Best-fit residual N	Residual vector	Worst spacing Δ	Clearance remaining	Status	Action

PLAN VIEW

Design and measured bolt positions

Displayed pattern

Design Measured Best-fit design

Measured error vectors are exaggerated by the selected display factor. Coordinate axes remain north-up; numerical results are not exaggerated.

QA DELIVERABLE

Actions and verification report

Engineering conclusion Survey method and limitations

I have checked the coordinate reference, bolt identities, design revision and acceptance criteria used in this report.

GUIDANCE

How to verify anchor bolt patterns

Confirm the controlled design. Verify the grid, base plate orientation, bolt labels, coordinates, levels and drawing/model revision.
Measure a consistent point. Observe the same geometric point on every bolt and consider bolt lean, thread damage and access.
Review raw offsets. Raw ΔE/ΔN indicates the actual setting-out error relative to design.
Review best-fit diagnostics. Centre shift identifies translation; rotation identifies orientation; residuals identify local pattern distortion after rigid alignment.
Check spacing and clearance. Base-plate fit depends on pairwise spacing, bolt/hole diameters, washers, sleeves and erection tolerances—not coordinates alone.
Resolve failures before steel arrives. Confirm the survey independently, communicate restrictions and obtain an engineered repair or concession where required.

What is best-fit rotation?

A least-squares rigid 2D rotation aligns the design pattern to measured bolts after removing their centroids. It helps distinguish a rotated but internally consistent cage from individually displaced bolts.

Why show raw and residual offsets?

Raw offsets matter for global installation position. Residual offsets show the internal shape error after translation and rotation are removed. Both affect engineering decisions.

Does positive clearance guarantee base-plate fit?

No. The simplified clearance is hole diameter minus bolt diameter minus twice the raw horizontal offset. Real fit also depends on simultaneous bolt positions, plate rotation, sleeves, bolt lean and fabrication tolerances.

Is coordinate data uploaded?

No. Calculations, drawing and report preparation run locally in the browser.