2. Ever wanted a tour of a construction site
for a concrete structure?
Don’t just stare at the skyline, come on
and take a closer look…
3. Often, parking garages have one or more levels below grade, so
excavation is a big part of the project, and occurs before work on
the structure ever begins.
Excavation on this project went down more than 50 feet in some locations.
4. At RedBuilt's facility in Delaware, OH, form
tables were fabricated on a leveled jig in a
climate-controlled environment.
This can improve safety and productivity during
form table fabrication, and can have a
substantial impact on the consistency and
quality of workmanship in building the forms.
Just-in time delivery of form tables can be arranged
so that material arrives on the truck bed ready to
be moved immediately onto the shoring towers.
5. Tables can be moved in stacks directly to the
shoring, either by crane or by forklift.
Preattached dunnage simplifies movement and
stacking of tables.
Tables can then be set into place one at a time and
aligned by workers using the steel beam forms to
access tables.
6. I-Joists for the deck form are often supported
by a steel W8x10.
This configuration works well where the I-Joists
cantilever out beyond the supporting member,
because full bearing can be consistently
achieved when slight changes in table length
occur (small plan changes to beam layout,
ramp areas, etc.).
When a table is set adjacent to an already installed
table, they need to be butted tight. Plyform is typically
cantilevered past the last joist, and the cantilevered
edge of the plyform is supported by leading joist of the
prior table.
It is common to butt the plyform sheets directly over
the center of the flange on the leading joist. A 2x4 is
often used to stiffen and align the cantilevered plyform.
7. Protective guardrailing may either be mounted to the beam forms—as
shown here—or may be directly attached to the deck form tables.
8. While parking garages are often notorious for their low ceiling profiles, the
system can also be used similarly where ceiling height is much higher. In cases
like this, additional shoring is required.
9. Alignment of the forming tables can
help determine the aesthetics of the
beam-to-slab intersection.
Table length, table squareness and
installation of tables are important
in order to get consistent
aesthetics here.
Construction on the Horseshoe Casino continues
with the Cincinnati skyline in the background.
10. Since RedForm I-Joists are available in depths up
to 20” and can be manufactured with camber, they
can often be used for up to 30’ bay widths to carry
slabs without any center supports.
This can make for a very clean jobsite that is fast
and efficient for both the formwork contractor and
subsequent trades.
When a perpendicular beam runs through the
building, steel beam forms can be run parallel to
the form deck tables. This may require additional
detailing to support the adjacent deck table(s) and
transition from the I-Joists to the steel beam form.
11. Once forming tables are placed, setting of post tensioning cables and rebar
can begin.
12. Alignment of adjacent tables can be important to maintain
aesthetics of the finished slab and to prevent mortar
leakage that can bind to the underside of the formwork.
The deck panel inserts are attached to a threaded rod
that is used to temporarily support the formwork tables
during the stripping process.
The inserts shown here are cast into the concrete slab.
13. Fabrication of the beam’s rebar
cage can be simplified by building
it above the deck.
Once the rebar cage is fabricated above the
deck, it can be dropped down into the beam form.
14. Now the “real fun” begins. Concrete is now ready to be placed on the formed-out
deck. Beams and slabs are cast together in the same pour.
15. During an active pour, workers move concrete out
to prevent it from piling up in one area.
Relatively uniform placement of concrete during
the pour can help prevent undue stress or
deflection on forming and shoring below.
After the concrete slab has been poured, leveled
and screened, the concrete is allowed to cure
undisturbed until the concrete has gained sufficient
strength to carry its own weight.
16. On larger projects, it is common to pour a portion of each deck level.
The subsequent pour is then connected to the prior pour through rebar
and stressing tendons.
17. Once concrete has obtained enough strength to be self-supporting,
the forming and shoring can be removed.
Here, the shoring and steel beam form are being removed first. The
deck form is now being held in place by the anchor bolt inserted into
the concrete slab.
Reshoring will be added per the reshoring plan prior to placement of
concrete at the next level.
Tables hang from the anchor bolt in the slab until they
are ready to be dropped and relocated. Here the forklift
driver uses a "stripping truss" to lower the table.
Quality of the finished concrete structure can be affected by the quality and
condition of forming materials used, fabrication and installation of tables,
form maintenance, handling and inspection.
Depending on the project, some imperfections in the concrete are
permitted to an extent, but some require repair work to meet project
requirements.
18. Once the deck is poured, fabrication of rebar cages and formwork for columns
on the next level can begin.