erection tolerances pci 6th edition

PCI Design Handbook/Sixth Edition 8�9

Figure 8.2.3 Local smoothness variation

�architectural panel� tolerances. If more restrictivetolerances are required, they must be clearly indi-cated in the contract documents, and subsequentlyincreased costs anticipated.

8.3 Erection Tolerances

8.3.1 General

Erection tolerance values are those to whichthe primary control surfaces of the member shouldbe set. The final location of other features andsurfaces will be the result of the combination of theerection tolerances and the product tolerances givenin Section 8.2.

Because erection is equipment and site depen-dent, there may be good reason to vary some of therecommended tolerances to account for uniqueproject conditions. In general, the more restrictivethe erection tolerances, the higher the cost oferection will be. Combining liberal producttolerances with restrictive erection tolerances mayplace an unrealistic burden on the erector. Thus,the designer should review proposed tolerances withmanufacturers and erectors prior to deciding on thefinal project tolerances.

To minimize erection problems, the dimensionsof the in-place structure should be checked prior tostarting precast erection. After erection, and beforeother trades interface with the precast concretemembers, it should be verified that the precast ele-ments are erected within tolerances. [7]

8.3.2 Recommended Erection Tolerances

Figures 8.3.2 to 8.3.9 show erection tolerancesfor the following four mixed building systems:

Precast element to precast element.Precast element to cast-in-place concrete.Precast element to masonry.Precast element to structural steel construction.

See Ref. 4 for recommended erection toler-ances for additional precast members.

These tolerances should be considered guide-lines for the development of project specific toler-ances for erection.

8.3.3 Mixed Building Systems

Mixed building systems combine precast andprestressed concrete with other materials, usuallycast-in-place concrete, masonry or steel. Eachindustry has its own recommended erection toler-ances which apply when its products are used exclu-sively. The compatibility of those tolerances with theprecast tolerances should be checked and adjustedwhen necessary.

Example 8.4.2 shows one problem that canoccur when erection tolerances are chosen for eachsystem without considering the project as a whole.

8.3.4 Connections and Bearing

The details of connections must be consideredwhen specifying erection tolerances. Space must beprovided to make the connection under the mostadverse combination of tolerances.

Bearing length is measured in the direction ofthe span, and bearing width is measuredperpendicular to the span. Bearing length is oftennot the same as the length of the end of a memberover the support, as shown in Figure 8.3.1. Whenthey differ, it should be noted on erection drawings.

The Engineer may wish to specify a minimumbearing for various precast products. For furtherinformation, see Ref. 7.

Figure 8.3.1 Relationship between bearinglength and length over support

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PCI Design Handbook/Sixth Edition8�10

Table 8.3.1 Beam erection tolerances



Table 8.3.1 Beam erection tolerances (Cont.)

The primary control surfaces are usually as shown, although this needs to be confirmed on ajob-by-job basis.

a ã Plan location from building grid datum........................................................................o1 in.

a1 ã Plan location from centerline of steel*.........................................................................o1 in.

b ã Bearing elevation� from nominal elevation at support:Maximum low ............................................................................................................... Q/S in.Maximum high.............................................................................................................. Q/F in.

c ã Maximum plumb variation over height of element:Per 12 in. height ...........................................................................................................Q/K in.Maximum at rectangular or L-beam .............................................................................Q/S in.Maximum at inverted tee beam.................................................................................... E/F in.

d ã Maximum jog in alignment of matching edges:Architectural exposed edges........................................................................................ Q/F in.Visually non-critical edges............................................................................................Q/S in.

e ã Joint width:Architectural exposed joints .......................................................................................oQ/F in.Hidden joints...............................................................................................................oE/F in.Exposed structural joint not visually critical................................................................oQ/S in.

f ã Bearing length� (span direction).................................................................................oE/F in.

g ã Bearing width� ............................................................................................................oQ/S in.

Note: When bearing pads are used at unarmored edges, they should be set back a minimumof Q/S in. from the face of the support or at least the chamfered dimension at chamfered edges.

* For precast elements on a steel frame, this tolerance takes precedence over tolerance on dimension �a�.

�Or member top elevation where member is part of a frame without bearing ledges.

� This is a setting tolerance and should not be confused with structural performance requirements set by thearchitect/engineer. The nominal bearing dimensions and the allowable variations in the bearing length andwidth should be specified by the engineer and shown on the erection drawings.



Table 8.3.2 Floor and roof member erection tolerances



Table 8.3.2 Floor and roof member erection tolerances (Cont.)

The primary control surfaces are usually as shown. A majority of the time, there is nodesignated vertical primary control surface, and in some scenarios there are no primary controlsurfaces at all. This needs to be determined on a job-by-job basis.

a ã Plan location from building grid datum........................................................................o1 in.

a1 ã Plan location from centerline of steel support*............................................................o1 in.

b ã Top elevation from building elevation datum at member ends:Covered with topping .................................................................................................oE/F in.Pretopped tee/carpet di rect hollow-core slab.............................................................oQ/F in.Untopped roof.............................................................................................................oE/F in.

c ã Maximum jog in alignment of matching edges(both topped and untopped construction) .....................................................................1 in.

d ã Joint width:0 to 40 ft member .......................................................................................................oQ/S in.41 to 60 ft member .....................................................................................................oE/F in.61 ft plus member........................................................................................................o1 in.

e ã Differential top elevation as erected (for units of same design and length):Field topped.................................................................................................................. E/F in.Pretopped tees at dr iving lanes/carpet direct hollow-core slabs.................................. Q/F in.Untopped roof� ............................................................................................................. E/F in.

f ã Bearing length� (span direction) .................................................................................oE/F in.

g ã Bearing width� (n/a for hollow-core slabs)..................................................................oQ/S in.

h ã Differential bottom elevation ofexposed hollow-core slabs§ ......................................................................................... Q/F in.

Note: When bearing pads are used at unarmored edges they should be set back a minimum ofQ/S in. from the face of the support or at least the chamfered dimension at chamfered edges.

* For precast concrete erected on a steel frame building, this tolerance takes precedence over tolerance ondimension �a�.

� It may be necessary to feather the edges to oQ/F in. to properly apply some roof membranes.

�This is a setting tolerance and should not be confused with structural performance requirements set by thearchitect/engineer. The nominal bearing dimensions and the allowable variations in the bearing length andwidth should be specified by the engineer and shown on the erection drawings.

§ Untopped installations will require a larger tolerance.



Table 8.3.3 Column erection tolerances



Table 8.3.3 Column erection tolerances (Cont.)


a ã Plan location from building grid datum:Structural applications ...............................................................................................oQ/S in.Architectural applications ..........................................................................................oE/K in.

b ã Top elevation from nominal top elevation:Maximum low .............................................................................................................�Q/S in.Maximum high............................................................................................................õQ/F in.

c ã Bearing haunch elevation from nominal elevation:Maximum low .............................................................................................................�Q/S in.Maximum high............................................................................................................õQ/F in.

d ã Maximum plumb variation over height of element (elementin structure of maximum height of 100 ft)....................................................................o1 in.

e ã Plumb in any 10 ft of element height..........................................................................oQ/F in.

f ã Maximum jog in alignment of matching edges:Architectural exposed edges......................................................................................oQ/F in.Visually non-critical edges..........................................................................................oQ/S in.



Table 8.3.4 Structural wall panel erection tolerances



Table 8.3.4 Structural wall panel erection tolerances (Cont.)


a ã Plan location from building grid datum* .....................................................................oQ/S in.

a1 ã Plan location from centerline of steel support ............................................................oQ/S in.

b ã Top elevation from nominal top elevation:Exposed individual panel ...........................................................................................oQ/S in.Non-exposed individual panel ....................................................................................oE/F in.Exposed relative to adjacent panel ............................................................................oQ/S in.Non-exposed relative to adjacent panel.....................................................................oE/F in.

c ã Support elevation from nominal elevation:Maximum low ............................................................................................................... Q/S in.Maximum high.............................................................................................................. Q/F in.

d ã Maximum plumb variation over height ofstructure or over 100 ft which ever is less* .................................................................o1 in.


f ã Maximum jog in alignment of matching edges...........................................................oQ/S in.

g ã Joint width (governs over joint taper) .........................................................................oE/K in.

h ã Joint taper over height of panel..................................................................................oQ/S in.

h10 ã Joint taper over 10 ft height........................................................................................oE/K in.

i ã Maximum jog in alignment of matching faces:Exposed to view .........................................................................................................oE/K in.Not exposed to view...................................................................................................oE/F in.

j ã Differential bowing or camber as erectedbetween adjacent members of the same design � ......................................................oQ/S in.

* For precast buildings in excess of 100 ft tall, To lerances �a� and �d� can increase at the rate of Q/K in. per storyto a maximum of 2 in.

�Refer to Section 8.2.8 for description of bowing tolerance.



Table 8.3.5 Architectural walls/spandrel erection tolerances



Table 8.3.5 Architectural walls/spandrel erection tolerances (Cont.)


a ã Plan location from building grid datum* .....................................................................oQ/S in.

a1 ã Plan location from centerline of steel support�...........................................................oQ/S in.

b ã Top elevation from nominal top elevation:Exposed individual panel ...........................................................................................oQ/F in.Non-exposed individual panel ....................................................................................oQ/S in.

c ã Support elevation from nominal elevation:Maximum low ............................................................................................................... Q/S in.Maximum high.............................................................................................................. Q/F in.

d ã Maximum plumb variation over height of structureor 100 ft whichever is less* .........................................................................................o1 in.


f ã Maximum jog in alignment of matching edges:Exposed relative to adjacent panel ............................................................................oQ/F in.Non-exposed relative to adjacent panel.....................................................................oQ/S in.

g ã Joint width (governs over joint taper) .........................................................................oQ/F in.

h ã Joint taper maximum..................................................................................................oE/K in.

h10 ã Joint taper over 10 ft length........................................................................................oQ/F in.

i ã Maximum jog in alignment of matching faces ............................................................oQ/F in.

j ã Differential bowing or camber as erected betweenadjacent members of the same design ......................................................................oQ/F in.

k ã Opening height between spandrels............................................................................oQ/F in.

* For precast buildings in excess of 100 ft tall, Tolerances �a� and �d� can increase at the rate of Q/K in. per storyto a maximum of 2 in.

�For precast elements erected on a steel frame, th is tolerance takes precedence over tolerance onDimension �a�.



Table 8.3.6 Single, double, and triple stadium riser erection tolerances



Table 8.3.6 Single, double and triple riser erection tolerances (Cont.)

The primary control surfaces are usually as shown, although this is something that needs to beconfirmed with the contractor on a job-by-job basis. Local building codes may require morerestrictive riser height tolerances which could also affect product tolerance.

a ã Plan location from building grid line datum .................................................................o1 in.

b ã Plan location from theoretical centerline ofsupport structure .........................................................................................................o1 in.

c ã Top elevation from building elevation datum atmember�s end. (This datum may be adjusted to accommodate existing field conditions.) ....................................................................oQ/S in.

d ã Maximum jog in alignment of matching edgesat the horizontal primary control surface...................................................................... Q/F in.

e ã Maximum jog in alignment of matching edgesat the vertical primary control surface .......................................................................... Q/S in.

f ã Bearing in span direction.............................................................................................�1 in.

g ã Joint width (horizontal) at end of piece. (Jointwidth needs to be Q/F in. minimum.) ............................................................................oQ/S in.

h ã Joint width (Joint width needs to be Q/F in. minimum in either case.)90-deg angle ..............................................................................................................oQ/S in.Joint width at skewed ends .......................................................................................oT/K in.

j ã Differential camber (at midspan as erected)between adjacent members of the same design ......... oE/AH in. per 10 ft of member length.

k ã Differential sweep (at midspan as erected)between adjacent members of the same design ......... oE/AH in. per 10 ft of member length.



Table 8.3.7 Room module erection tolerances



Table 8.3.7 Room module erection tolerances (Cont.)

The tolerances listed below are used at the primary control surfaces only, and only thosetolerances that are applicable to that surface. Normally, the primary control surfaces are thefront face of the cell unit as the vertical primary control surface, and either the head of the door(as shown at left), top of cell, or the bottom of balcony as the horizontal primary control surface.Note: on jobs where pre-topped balconies are cast as part of the cell unit, the horizontalprimary control surface may be the top surface of the balcony.

a ã Plan location from building grid line datum ................................................................oQ/S in.

b ã Vertical control (at primary control surface)from a horizontal datum .............................................................................................oE/K in.

c ã Actual grout joint........................................................................................... Q/S in. minimum

d ã Plumb at element height .............................................................................................. Q/F in.

e ã Maximum jog in alignment of matching edges.............................................................Q/F in.

f ã Vertical joint width ......................................................................................................oE/K in.

g ã Joint taper......................................................................................................Not applicable



Table 8.3.8 Stair unit erection tolerance



Table 8.3.8 Stair unit erection tolerance (Cont.)

The primary control surface for stair units is the top of landing at floor levels. Tolerances listedbelow are the same whether landings are monolithic or separate pieces. Local building codesmay require more restrictive riser height tolerance which could also affect the producttolerance.

a ã Plan location from building grid line datum ................................................................oQ/S in.

b ã Differential elevation as erected* ...............................................................................oE/K in.

c ã Joint width ..................................................................................................................oE/F in.

d ã Maximum jog in alignment of matching edges.............................................................1 in.

e ã Maximum jog in alignment of stair tread nosings(This tolerance overrides �d� if needed.) ...................................................................... Q/S in.

f ã Maximum jog in alignment of matching edgesat the primary control surface* .....................................................................................E/K in.

g ã Bearing (in span direction) .........................................................................................oE/F in.

* At stair units that have pre-topped precast landings, the maximum jog between stair units as well as from stairunit to finish floor cannot exceed Q/F in. However, units which have landings that are topped have more leeway.This needs to be discussed and agreed upon with the general contractor .


erection tolerances pci 6th edition

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