BRIDGE DECK FINISHER SET-UP GUIDE - 069596
Page 4
Placing Screed Rail & Paving Forms
•
The set-up is what determines the longitudinal profile
of your roadway paving or bridge deck surface.
• There are two screed rail setups for bridges. The
engineer or DOT specifications will determine if the
BDF will ride on the pipe located on the edge forms or
on the pipe located on the bridge girders.
FIRST TYPE OF BRIDGE DECK SET-UP:
- Look at the type and spacing of the overhang
brackets if the machine is riding on forms and
refer to the manufacturer’s specifications for size
of overhang brackets and spacing.
Consult with
the factory about your machine weight and
wheel loads.
- Once the BDF loads have been determined, THIS
will dictate placement of the Screed Rail.
- The Rail position must be accurate and conform
to the grade required. Allen Engineering
recommends 2-inch schedule 80 pipe with a
sleeve at one end to connect two sections of pipe
together.
- 24 inches on center is the recommended spacing
for the screed chairs. (Special situations may
have a maximum 30 inches).
- The rails and chairs should be double checked
after placing the machine on the deck.
- After the BDF has been set on the deck, it will
need to run up and down to take out any timber
crunch or settling of the form work.
- Double check the form-work again.
SECOND TYPE OF BRIDGE DECK SET-UP:
- When the machine is riding on bridge girders you
will need to fabricate
a screed chair stand
that will be epoxied or
welded to the beam
or a girder plate (SEE
PICTURE 7)
- We recommend you tie
the vertical tube to the rebar mats for stability.
- The top of the vertical tube will be below the
finished surface grade.
- The screed rail needs to be adjusted to
conform to the longitudinal profile which can be
accomplished in various ways.
- A folding ruler or tape measure with the use of a
level can be used to determine the quarter points
on the deck to the top of the screed rail.
- Pulling a string-line between the 2 points or
measuring from the grade-line on the form to
the top of the screed pipe to set the grade of the
pipe.
- Remember this is just an initial setup at this
time and the rails and chairs should be double
checked after placing the machine on the deck.
- Double check the form-work again.
PAVING FORM SET UP:
• A strong solid sub-base is required for all concrete
paving forms to sit on to prevent the paving forms from
sinking into the sub-grade causing an improper grade
profile.
• Allen recommends our Steel Forms or forms designed
and engineered to carry the weight and load of the
paver. The BDF will be outfitted with flat flange poly-
bogie wheels with a 3-inch width to ride on the top of
the paving form.
PICTURE 7
The screed, pipe rail, and
concrete paving forms provide the
longitudinal profile of the paving
surface and the proper set-up is as
equally important as the machine
operation.
Screed Chair
Screed Chair
Stand