1. Slip form construction is a method where concrete is poured into a continuously moving form to construct structures like buildings, towers, bridges in a joint-less manner. 2. There are two main types - vertical slip forming for tall structures and horizontal slip forming for structures like roads. 3. Slip form construction allows for high production rates, better quality concrete with superior finishes, reduced costs for taller structures, and minimal maintenance needs.

1. SLIP-FORM CONSTRUCTION
REPORT-2
BUILDING CONSTRUCTION
NAME-APRAJEETA
B.ARCH-7TH SEM
R.T.I.A.D

2. Slip form construction, or continuously formed construction, is a construction method in
which concrete is poured into a continuously moving form.
INTRODUCTION
Basically, this method involves the continuous placing of concrete in a shallow mold
having the same plan as the building to be constructed. This rigid mold, or "slip-form" as
it is called, forms the working deck which is jacked slowly upwards at a controlled rate
until the required
elevation is reached.

3. Slip-form Technique is one of the most productive techniques for construction of High-rise
structures like communication towers, chimneys, bridge piers, silos etc. Vertical Slip forming
allows concrete to be erected as a monolithic or a joint-less structure, while reducing overall
project duration. Slipform paving has enabled concrete road pavements, airport aprons,
taxiways, runways, canal lining etc. Slip-form Technique has also been successfully applied to
various structures including offshore drilling platforms and nuclear facilities etc.
.

4. ADVANTAGES OF SLIP FORM
WORK CONSTRUCTION
 Speed Of Between 7ft And 30 Ft Per 24 Hours Are Possible.
 Slip Forming Is A Continuous Extrusion Process.
 Slipforming Provides A Superior Concrete Finish With No Horizontal Joints.
 The Exposed Concrete Can Be Finshed At The Bottom Of The Rising Formwork.
 Crane Use Is Minimised.

5. Types of Slip-form Construction
1- Vertical Slip-form
In vertical slip forming, the concrete
form may be surrounded by a
platform on which workers stand,
placing steel reinforcing rods into
the concrete and ensuring a
smooth pour. Together, the concrete
formand working platform are
raised by means and working
platform are raised by means of
hydraulic jacks. Generally, the slip-
form rises at a rate which permits
the concrete to harden by the time
it emerges from the bottom of the
form.

6. 2- Horizontal Slip-form
In horizontal slip forming for pavement and traffic separation walls, concrete is cast, vibrated,
worked, and settled in place while the form itself slowly moves ahead. This method was initially
devised and utilized in Interstate Highway construction initiated during the 1950s.

7. Factor - Description
1. Time - High production rates can be
achieved by careful planning of
construction process.
2. Durability - Better concrete; a joint less and
watertight structure.
3. Cost - Slip forms showed cost advantages
for more than 20 stories and larger
than 600 m2 formed area per floor.
4. Maintenance - Availability of the different
working platforms in the formwork system
allows the exposed concrete at the bottom of the
rising formwork to be finished, making it an
integral part of the construction process
. 5. Flexibility - Certain formwork systems permit
construction of tapered cores and towers.
6. Labor - Slip form systems require a few but
highly skilled workers.
7. Machinery - Slip form construction minimizes
crane use.

8. • Applications of Slip-form Construction
Slip-form construction is used for tall structures, such as towers, buildings, and dams, as
well as horizontal structures, such as roadway barriers. It enables continuous, non-
interrupted, cast-in-place joint-less concrete structures which have superior performance
characteristics over construction methods using discrete form elements. Slip forming
relies on the quick setting properties of concrete, and requires a balance between quick-
setting capacity and workability.

9. 1. The formwork and the access platform are
assembled on the ground.
2. The assembly is raised using hydraulic
jacks which are mounted on strategically
located steel frames to lift the formwork as
the concrete is poured into the forms.
3. As the formwork rises continuously,
continuous concrete and rebar supply are
needed until the operation is finished.
4. As the formwork is raised, reinforcement is
held in the correct position using guides,
horizontal reinforcement is tied to the
vertical reinforcement.
5. Concrete is poured into the forms in layers
of approximately 200 mm. The setting
rates of concrete are constantly monitored
to ensure that it is matched with the speed
at which the forms are raised. The jacks lift
the form approximately 25mm per stroke
generally producing a slip-forming rate of
300 mm per hour.
Construction Sequence

10. 6. Slip forming can be performed on either
a continuous basis (i.e. 24 hours per
day), or a discontinuous basis (i.e.
pouring to a predetermined height
usually within one working day) .
7. Block outs for doors and windows can
be formed with either timber or steel.
These are in-stalled as the slip form
proceeds and can be stripped from the
trailing decks .
8. Recesses are made to host the
connections between the beams, slabs
and the slip form walls
9. When the formed concrete is exposed
from the bottom of the steel form
panels it can be sponged or treated if
required .
10. At the end of the operation the
formwork is removed using a crane, the
entire process is thoroughly inspected
and highly controlled.
Construction Sequence

11. Slip forming relies on the quick-setting properties of concrete, and requires a balance
between quick-setting capacity and workability. Concrete needs to be workable enough to
be placed into the form and consolidated via vibration. This strength is needed because the
freshly set concrete must not only permit the form to "slip" passed the concrete without
disturbing it, but also support the pressure of the new concrete as well as resist collapse
caused by the vibration of the compaction machinery.
Construction Sequence

12. • Slip form construction is a construction method
in which concrete is poured into a continuously
moving form.
• There are two types of slip-forms; vertical and
horizontal.
• Slip-form construction consumes very less time
but requires careful planning of construction
process to achieve high production rates.
• Due to continuous concrete pouring in slip-form
construction it produces better concrete joint
less and watertight structures.
• Slip form systems require a few but highly skilled
workforce.
• Slip-forming is also used in the construction of
tapered structures involving changing
thicknesses in walls, diameters and/or shapes.
• Another but similar method that is in use for this
type of construction is the “jump form method”.
In this method the form work jumps up to the
next layer after the bottom layer is cast. The
concrete pouring is not continuous as in the slip form
method.
Summary