Tolerances in field of civil engineering

1. 1
Amardeep Singh
Inspection of Pre
and Post
Concreting works

2. 2
OBJECTIVES
 To enable systematic process within reasonable
cost and time.
 To have standard Quality System .
 Measuring constructed works against Workmanship
standards, Drawings and Specifications.
 Acceptable Quality /Tolerances for Concrete
Works.
 Independent Structure report.
 Address Corrective action.

3. 3
WHAT TO
CHECK ?

4. 4
FORMWORK
Visual
 Free from Defects.
 No gaps at joints.
 Interiors free from debris.
 Adequate support, bracing and tie-back
Dimensions
 Cross-sectional dimensions as per drawing.
 Penetration / opening for services.
 Length of precast members (major dimension of unit).
Alignment
 Departure of any point from its position.
 Verticality.
 Mean level of staircase thread to temporary benchmark.
 Level for cast in-situ elements.

5. 5
EMBEDDED ITEMS
Visual
 Surface Defects -cracks/ damaged threads
 Twist/ bend/warpage.
 Application of sleeves
Dimensions
 Numbers as per drawings.
 Sizes as per drawings.
 Inclination of Pockets for smooth extraction after pouring.
Alignment/Fixing
 C/C distances between Bolts/Pockets.
 Verticality .
 Stability of Fixing arrangement (welding in case of Bolts/IPs).
 Removability of Pockets

6. 6
Dimension for elements / opening for services
FINISHED CONCRETE
 Cross-sectional dimension of cast in-situ and precast elements.
 Required opening for services.
 Precast members:
– Length
– Straightness or bow (deviation from intended line)
– Dimension
– Twist
– Flatness

7. 7
FINISHED CONCRETE
Alignment, plumb and level
 Departure of any point from its position.
 Verticality
 Deviation from mean level.
 Camber at mid span
Exposed surface
 No visual exposure of coarse aggregates.
 Cold joint & formwork joint must be smooth.
 No bulging of structural elements.
 Free from formwork, nails, zinc strips, etc.

8. 8
FOR PRECAST CONCRETE
Lifting points / inserts
 Free from Damages.
 Position / Placement
Sleeve System / Connections
 Free from concrete droppings or corrosion.
 Sleeves, grout holes, grout tubes not congested with debris.
 Position / Placement.
 Bar protrusion length according to requirements. Bars should be
free from bending, cracks or damages.

9. 9
FOR PRECAST CONCRETE
Interface / Joint Requirements
 Alignment of horizontal and vertical joint.
 Joint taper alignment.
 Jog in alignment of matching edges
 Sitting of element as per specifications.
 Installation of sealant and waterproofing as per specifications.
Cast-in steel items / welded & bolted connections
 Position of embedded steel items / Pockets as per drawing.
 Position of openings for bolt connections.
 Other requirements as per drawing.

10. 10
TOLERENCES
FOR
CHECKING

11. 11
1
Tolerance for cross-sectional dimensions of cast in-situ & precast
elements: +12mm / -6mm
Tolerance for penetration / opening for services: +10mm for size
and ±25mm for location
Tolerance for length of precast members (major dimension of
unit):
· Up to 3m: ±6mm
· 3m to 4.5m: ±9mm
· Additional deviation for every subsequent 6m: ±12mm
1) Tolerance for departure of any point from its position: 10mm
2) Tolerance for plumb: 3mm / m, maximum 20mm
Maximum deviation of mean level of staircase thread to
temporary bench mark: ±5mm
For cast in-situ elements, the deviation of level of any point from
the intended level: ±10mm
1) Formwork must be free from defects
2) Before concreting, the interior must be free from debris
3) All formwork joints must not have gaps to prevent leakage
There must be adequate support, bracing and tie-back for the
formwork to prevent bulging or displacement of structural
elements
Alignment, plumb
and level
1b
Formwork (Cast in situ & Precast)
1c
Condition of
formwork,
1)
2)
3)
3)
4)
4)
Formwork
dimensions and
openings for
services
1a

12. 12

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14. 14

15. 15
2
1) According to structuraldrawings(numbers/sizes)
2) Spacing of Rebars- +15mm.
2b Anchorages& lap
lengths
1) Required lap length not lessthan that specified
2c Coverprovision 1) +10mm/-0mmfromspecified.
1) According to structuraldrawings(numbers/sizes)
2) Spacing of linksnot morethan specified
1) Rebarsmust besecurelyand properlytied in place
2) Rebarsmust befreed fromconcretedropping,corrosion etc
2e
Rebar
RebarCondition
2a
Main & Secondary
rebars
Links,stirrupsand
trimming bars
2d

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23. 23
3
1) Visual Defects - No cracks/ damaged threads/ rusting
2) Tolerance Bending of Bolts - 1mmper 500 mmlength
3) Protection measures for Bolt threads
4) Warpage of Insert Plates - 2mmper 500 mmin any direction
5) Welding of lug with insert plates - Full weld or as drg, without visual defects
1) Numbers- Strictly as per Drawing
2) Diameter of Bolts - +1mm-2mm
3) Length /breadth of Insert Plates - + 20 mm-5mm
4) Thickness of IP - + 1mm
5) Inclination of Pockets - Min 10% (10mmper 100 mmdepth)
1) Fixing of Insert plates/Bolts - Welded properly with reinforcement.
2)
Fixing of Pockets -Restricted for horizontal & downward movement but easily
removable restriction in up ward direction.
3) C/c Distance between Bolts:- + 2mm.
4) Verticality of Bolt: +3mm/meter
5) C/c Distance between Pockets/Insert Plates:- + 10mm.
6) Position of Bolts/Pocket/IP WRTFormwork : - + 5mm
7) Diagonal Distance between Bolts:- + 5mm.
Embedded Items
Visual3a
3c
Fixing / Alignment
Tolerances
Dimensional
tolerances
3b

24. 24
1
1) Tolerance for cross-sectional dimension of cast in-situ and
precast elements: +10mm / -5mm
2) Tolerance for opening: +10 for size and ±25mm for location
3) Tolerance for length of precast members (major dimension of
unit):
· Up to 3m: ±6mm
· 3m to 4.5m: ±9mm
· Additional deviation for every subsequent 6m: ±12mm
4) Straightness or bow (deviation from intended line) of precast
member:
· Up to 3m: 6mm
· 3m to 6m: 9mm
· Additional for every subsequent 6m: 6mm
5) Squareness of precast member - Difference between the greatest
and shortest dimensions should not exceed the following:
Length of shorter sides
· Up to and including 1.2m: 6mm
· Over 1.2m but less than 1.8m: 9mm
· 1.8m and over: 12mm
6) Twist of precast member - Any corner should not be more than
the deviation stated from the plane containing the other 3 corners:
· Up to 600mm wide and 6m in length: 6mm
· Over 600mm wide and for any length: 12mm
7) Flatness: 6mm per 1.5m
1) Tolerance for departure of any point from its position: ±10mm
2) Tolerance for plumb: 3mm / 1m, maximum 20mm for floor to
floor height and 40mm for the entire building height
3) Maximum deviation of mean level: ±10mm
4) For cast in-situ elements, the maximum deviation of levels within
the element: 10mm
5) Camber at mid-span: according to specifications
1) Should not have visual exposure of groups of coarse aggregates
resulting from grout leakage
2) Cold joint & formwork joint must be smooth
3) No bulging of structural elements
4) All formwork, nails, zinc strips, etc must be removed
Exposed surface1c
Exposed Surface
Dimension for
elements / opening
for services
1a
1b
Alignment, plumb
and level

25. 25
2
1) Bolts - Removal of all concrete laitances, greasing of threads
2) Insert - Removal of cement Slurry and complete exposure of plate.
3) Pocket - Removal of all pieces of Forms, no concrete debris
1) Bolts Wrapping of bolts with gunny bags / suitable means to protect its threads
2) Demarcation of bolts - Signal tap or isolation of fdn from movement areas.
3) Painting of Insert plates - Anticorrosive paint/ Red oxide application
2b
Protection of
embedded itesm
Cleanliness2a
Embedded Items
3
Center of Form Work in both direction
a) For padestals of Equipment Fdns, pipe racks &column 1st lifts etc - + 5mm
b) For footings - + 25 mm or 5% of length / width which ever is less.
2) RL of marking of Top of concrete - + 10mm WRT Drawings requirements.
1) Co-ordinates/Distance of center of bolts - + 2 mm.
2) Co-ordinates/Distance of center of Pockets/Insert plates - + 5 mm.
3) Top level of Bolts - + 10 mm, - 5 mm.
4) Top level for top Insert plates - + 2 mm, - 5 mm.
5) Level of top/center line for side Insert plates - + 5 mm.
Location of
Embedded Items
w.r.t. co-ordinate
lines / Bench Mark
levels
3b
Location (applicable only for Equipment Fdn, Pipe rack Fdn/pedastals/column 1st lifts.
1)
Location of Form
Work w.r.t. Co-
ordiante line / Bench
marks levels
3a

26. 26
1) Tolerance for position: ±20mm from centre line location in
drawing
2) Lifting devices and inserts free from damages
1) Tolerance for position: ±6mm from centre line location in
drawings
2) Bar protrusion length according to requirements. No bending,
cranking or damages to bars
3) Bars free from concrete droppings or corrosion
4) Sleeves, grout holes, grout tubes not congested with debris
1) Joint taper:
· Over 3m length: 6mm
· Maximum for entire length: 9mm
2) Alignment of horizontal and vertical joint: ±6mm
3) Jog in alignment of matching edges: 6mm
4) Sitting of element: according to specifications
5) Installation of sealant and waterproofing: according to specifications
Precast Specific Requirements
4a
Lifting
points/inserts
4b
Sleeve system/
connections
Interface/joint
requirements
4c

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31. 31
TOLERANCE LIMITS OF LOCATION
4
Center of FormWork in both direction
a) For padestals of Equipment Fdns, pipe racks &column 1st lifts etc - + 5mm
b) For footings - + 25 mmor 5%of length / width which ever is less.
2) RL of marking of Top of concrete - + 10mmWRTDrawings requirements.
1) Co-ordinates/Distance of center of bolts - + 2 mm.
2) Co-ordinates/Distance of center of Pockets/Insert plates - + 5 mm.
3) Top level of Bolts - + 10 mm, - 2 mm.
4) Top level for top Insert plates - + 2 mm, - 5 mm.
5) Level of top/center line for side Insert plates - + 5 mm.
Location of
Embedded Items
w.r.t. co-ordinate
lines / Bench Mark
levels
4b
Location (applicable only for Equipment Fdn, Pipe rack Fdn/pedastals/column 1st lifts.
1)
Location of Form
Work w.r.t. Co-
ordiante line / Bench
marks levels
4a

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