Concrete Slab Dimension Tolerances ACI-347 Help 2

[gtidan]

I'm preparing a field measurement summary for a client regarding a loading dock ramp that was designed at an unacceptable slope (10%), and would like any input someone may have regarding tolerances of slab measurements.

The project specs refer to ACI-347 for the formwork, as well as ACI-301, however I have not been able to come across any mention of a length/width tolerance. The ramp portion of the slab is approximately 40' by 26'.

Thank you!

 

[SlideRuleEra]

Tolerances for formwork apply to accuracy of construction, they don't apply to the design itself. Tolerances for overall length and width could vary depending on how the design was dimensioned. Even in the worse case, allowable construction tolerances for a structure 40' by 26' would likely be less than plus or minus an inch, each way.

http://www.SlideRuleEra.net

 

[cvg]

here are some typical tolerances for formwork for concrete structures

TOLERANCES FOR FORMED SURFACES

1. Variations from the plumb:
In any 10 feet of length 1/4 inch

a. In the lines and surfaces of columns, piers, walls and in arises
Maximum for entire length 1 inch

b. For exposed corner columns, control-joint
In any 20 feet of length 1/4 inch

grooves, and other conspicuous lines Maximum for entire length 1/2 inch


2. Variation from the level or from the grades indicated on the drawings:
In an 10 feet of length 1/4 inch
In any bay or in any 20 feet of length 3/8 inch

a. In slab soffits, ceilings, beam soffits, and in arises, measured before removal of supporting shores
Maximum for entire length 3/4 inch

b. In exposed lintels, sills, parapets, horizontal grooves, and other conspicuous lines

In any bay or in any 20 feet of length 1/4 inch
Maximum for entirelength 1/2 inch


3. Variation of the linear building lines from established position in plan
In any 20 feet 1/2 inch
Maximum 1 inch


4. Variation of distance between walls, columns, partitions per 10 feet of distance 1/4 inch
but not more than 1/2 inch in any one bay
and not more than 1 inch total variation


5. Variation in the sizes and locations of sleeves, floor openings, and wall opening
Minus 1/4 inch
Plus 1/2 inch


6. Variation in cross-sectional dimensions of columns and beams and in the thickness of slabs and walls
Minus 1/4 inch
Plus 1/2 inch


7. Footings:
a. Variation of dimensions in plan when formed,
Minus 1/2 inch Plus 2 inches
or when placed against unformed excavation plus 3 inches


b. Misplacement of eccentricity
2 percent of the footing width in the direction of misplacement but not more than 2 inches


c. Reduction in thickness
Minus 5 percentof specified thickness