Crack Depth & Width Measurement(IS 13311 Part 1 — UPV Technique)
Non-destructive measurement of crack depth by the ultrasonic transit-time technique per IS 13311 (Part 1) and crack width by calibrated optical gauges — quantifying cracks against the IS 456 acceptance limits.
What is Crack Depth & Width Measurement?
Not every crack is a problem — but every problem crack needs numbers. IS 456:2000 accepts surface crack widths up to 0.3mm in normal environments (tighter for aggressive exposure); beyond width, depth decides severity — a shallow shrinkage craze is cosmetic while a deep structural crack intersecting reinforcement is a corrosion highway. The ultrasonic transit-time method (IS 13311 Part 1 technique) measures depth non-destructively: pulse path around the crack versus across sound concrete yields the depth by the standard computation.
Global Lab maps cracks with calibrated optical crack-width gauges and microscopes, measures depths ultrasonically, classifies each crack (structural / non-structural, active / dormant with tell-tale monitoring where needed), and reports against code limits with repair recommendations.
How the Crack Depth & Width Measurement is Conducted
- 1
Crack Mapping
Cracks are traced, photographed and mapped on elevation/plan sketches with orientation and pattern noted. - 2
Width Measurement
Widths are measured at defined stations with calibrated crack gauges / optical microscope to 0.05mm resolution. - 3
Ultrasonic Depth Measurement
Transducers are placed across the crack per the transit-time technique; depth is computed from the path-time relationship. - 4
Activity Assessment
Where movement is suspected, tell-tales or repeat readings over time establish active vs dormant status. - 5
Classification & Reporting
Cracks are classified with code-limit verdicts and repair recommendations, issued via Autovity QLMS.
Applicable Test Standards
| Standard | Title | Scope | Type |
|---|---|---|---|
| IS 13311 (Pt 1):1992 | Non-Destructive Testing of Concrete — Ultrasonic Pulse Velocity (Reaffirmed) | Depth Technique | Indian Standard |
| IS 456:2000 | Plain and Reinforced Concrete — Code of Practice | Crack Width Limits | Indian Standard |