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1. SLIP FORM CONSTRUCTION
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AGLAIA

2. SLIP- FORM
Slip forming, continuous poured, continuously formed, or slip form construction is a
construction method in which concrete is poured into a continuously moving form.
 Slip forming is used for tall structures (such as bridges, towers, buildings, and dams), as well as
horizontal structures, such as roadways.
 Slip forming enables continuous, non-interrupted, cast-in-place "flawless" (i.e. no joints) concrete
structures which have superior performance characteristics to piecewise construction using discrete
form elements.
SLIP FORM

3. 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), yet quick-setting enough to emerge from the form with strength.
 This strength is needed because the freshly set concrete must not only permit the form to "slip"
by 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.
SLIP FORM

4. COMPONENTS OF SLIP-FORM
The slip form system is designed with varied features.
 Generally, it consist of yoke legs. Yoke legs are employed to lift and sustain the weight of the entire structure, so that
it behaves as a single unit. Yoke legs are also used to connect with the beams, scaffoldings and working platforms to
serve the supporting purpose.
To the yoke legs, walk-away brackets are connected. These walkway brackets will enable proper placement of the
concrete.
 The whole slip form assembly is lifted by means of strand rods and lifting jacks.
 These primary components are located at equal intervals so that the uniform and good distribution of weight is
performed.
 In some construction, lifting process are supported by means of hydraulic pump components.
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5. SLIP FORM

6. PROCEDURE
Assembly can only start once the foundations are in place and the wall starter is in correct alignment.
Slip form shuttering is aligned with the help of yokes.Horizontal crossbeams connect these yokes.
Hydraulic jacks are attached to these crossbeams for simultaneous upward movement.
Height of the slip form ranges from 1.1 to 1.5 meters.
Yokes and crossbeams also used to support the working platform.
Structure should be rigid and shape maintained at all times. Make sure there is no lag or else it prevents
the structure from free upward movement.
 It is also possible to reduce wall thicknesses as the construction gains height and arrangements have to
be made in the slip form structure that will enable such reduction at regular intervals.
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7. TYPES OF SLIP-FORM CONSTRUCTION
VERTICAL SLIP-FORM
HORIZONTAL SLIP-FORM
TAPERED SLIP-FORM
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8. 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 form and working platform are raised by means of hydraulic jacks.
The slip-form rises at a rate which permits the concrete to harden by the time it emerges from
the bottom of the form.
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9. SLIP FORM

10. 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.
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11. SLIP FORM

12. TAPERED SLIP-FORMING
Slip-forming is also used in the construction of conical chimneys, cooling towers, piers and
other tall concrete structures involving constant or changing thicknesses in walls, diameters
and/or shapes.
A form is used with sections which overlap so that one gradually slides over the other.
This is commonly done in chimney construction but it is not satisfactory for architectural
concrete because the lap shows.
While the tapered slip-forming process is similar to that used on the standard slip-forming,
it requires greater attention, contractor experience and expertise ensures the success of
such projects.
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13. Slipform Construction of Collie Power Station, Western AustraliaSLIP FORM

14. Continuous slip formed gravity-based structure supports under construction in a Norwegian fjord. The visible jib
cranes would each be delivering buckets of concrete to the support cylinders during the continuous pour of
concrete creating seamless walls. SLIP FORM

15. FEATURES OF SLIPFORM CONSTRUCTION TECHNIQUE
The slip form construction technique is a rapid and a economic construction method compared to the
conventional formwork technique. This helps to achieve huge cost saving.
The technique is best suitable for large building structures and bridges. When small structures are
concerned, the projects with identical geometry can be easily completed by slip form construction.
Continuous movement of formwork in upward direction is performed in slip form technique. The
movement is facilitated by hydraulic jacks and jack rods.
 In the construction of vertical structures, the rate of rising the formwork upwards will be almost in the
rate of 300mm per hour. These rise with the help of the supports from other permanent parts of the
building.
The technique of slip form construction will vary based on the type of structure constructed. Based on
this the frameworks required to support the system will vary.
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16. ADVANTAGES
 Height
This technology becomes very competitive starting at about 60 ft of height and continues to improve with
increasing height thereafter.
 Early Assembly
The slip form setup is very compact and can be pre-assembled ahead of time. Once the foundation is
ready, the slip form can quickly be placed on the foundation and construction can start almost immediately.
 Speed of Construction
Speeds of between 7 ft and 30 ft per 24 hours are possible. Many times, this speed allows reuse of
formwork on repetitive elements without impacting the overall schedule, thus reducing your total formwork
cost.
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17.  No Form Ties
No ties are required because the limited concrete pressure is taken by the slipform yoke directly. Without
ties, there are also no form holes to fill, which reduces labor costs, improves appearance and makes for a
water-tight structure. This is particularly important for offshore structures such as gravity oil and gas
platforms.
 No Rebar Bolsters
Unlike in standard wall construction with panel forms, slip forming does not require lost rebar bolsters in
every pour to control the rebar cover. In slip form construction, sliding guides are mounted on top of the
slip form. These guides push the rebar into position and accurately control the rebar cover as the slip form
moves upwards.
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18.  Safety
The slip form setup provides a safe and protected work environment for your crew. Relatively little
climbing is required, the work area is compact and unchanging and weather protection can easily be
added to the formwork setup. Enclosed spaces can be heated during the cold weather periods.
 Flexibility
A slip form is of low overall height and very compact. That makes it is easier to handle and modify for
changing concrete cross-sections. Also, the extension past the hardened concrete line is very short,
so very little wind force has to be considered in the formwork design.
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19.  Easy To Stop
The slip form operation can be stopped and resumed at will, to suit the contractor’s schedule. Slip
form operations can be suspended for the weekend or during parts of the day as dictated by
external factors. This is done by climbing another 18 in. or so after the last concrete has been
poured. This gives the concrete time to set and helps to break the form adhesion to the fresh
concrete.
 Standard Concrete Mix
No special concrete is needed for a typical slip form project. For certain offshore structures,
advanced concrete mixes have been developed to improve the performance of the structure in the
ocean environment. However, these types of structures are rare and the vast majority of buildings
and towers can be slip formed with ordinary concrete mixes.
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20.  Continuous Process
Slip forming is a continuous extrusion process. There is no need to set and strip forms every few
feet. You do not need to tie up a crane as for handling conventional formwork.
 Quality Finish
Slip forming provides a superior concrete finish with no form fins to clean up and without horizontal
joints. A sponge finish and other surface treatments are easy to apply from the second work
platform suspended from the slip form assembly
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21. DISADVANTAGES
High –cost for initial setup.
Requires Specialized workers and expertise.
Need sophisticated Equipment.
Dimensional Accuracy can go low in certain conditions.
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22. 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. Capital Gate Tower, Abu Dhabi King Abdul-
Aziz Airport Inn Canal, Germany
SLIP FORM

23. THANK YOU!!For more…. Mail to aglaiaconnect2018@gmail.com
SLIP FORM