chapter 3 rigid pavement - DOT On-Line Publications - Department ...

SAMPLE DESIGN CALCULATIONS: The design of compression seals is a
simple procedure. The following examples show how a design
process could be used.
EXAMPLE A:
A State wants to use preformed compression seals on all new PCC
pavement projects. Their standard design calls for a 60-foot
joint spacing on a granular base. The expected temperature range
is from 14'F to 90'F.
Step 1 - Determine the anticipated joint movement.
AL = CL (aAT + E:)
= ( 0.8 )( 60 * 12 )[ ( 5.5*10* ) ( 76 ) + ( l.O*lO* ) ]
= 576 ( 4.18*10d + l.O*lO‘* )
= 0.3 inch
Step 2 - Select width of uncompressed seal.
(This particular sealant manufacturer recommends an
operating range of 55 percent to 20 percent)
W 2AL + (C, - C,)
2 0.3 + ( 0.55 - 0.20 )
1: 0.3 + 0.35
2 0.86 inch
use W = 1 inch
Step 3 - Select width of sawcut.
rusta11 PC = c* + .
temr;, - *ln tem
Maximum temp - Min temp 1;1
Sc=(l -Pc)*W
Case 1: Installation temperature = 80'F
* (Cma - Glh)
PC = 0.2 + [ ( 66 i 76 ) * ( 0.55 - 0.2 ) ]
- 0.2 + ( 0.87 ) * ( 0.35 )
- 0.50
SC =(l- 0.5 ) * 1
= 0.5 inch
Case 2: Installation temperature = 40'F
PC = 0.2 + [ ( 26 + 76 ) * ( 0.55 - 0.2 ) J
= 0.2 + ( 0.34 ) * ( 0.35 )
= 0.32
SC =(l- 0.32 ) * 1
= 0.68 inch
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