This type of form is usually small in area and can be handled as a secondary
operation in relation to construction of the balance of the building- In
apartment, hotel, and similar residential-type multistory buildings, the
slip-form method of construction is highly effective, if constraints on
architectural and structural design features are properly followed.The ultimate
approach in incorporating a slip-form into building construction is to sup-form
all vertical concrete. This makes the slip-form the primary operation
controlling the other phases of construction. All vertical concrete structural
elements are extruded by the slip-form.

First, before discussing details of a slip form operation, we should evaluate
the advantages and disadvantages of the basic system in order to determine
whether a job should be slip formed. It is generally recognized that slip
forming is a faster method of construction than conventional forming; so it
follows that if the construction cycle is geared to the slip form as the
controlling item, an earlier completion date can be obtained. From the owner’s
standpoint, an earlier completion date means an earlier return on invested
capital. From the contractor’s standpoint, an earlier completion date means
lower overhead costs and more jobs that can be completed within the organization
in a given period of lime.

Under ideal conditions a slip form will provide substantially lower construction
costs, which directly result in lower completed-building costs. This may make
possible the building of projects that otherwise could never have been built
because of limited financing. Slip forming is one system of automation which can
be more broadly included in building-design systems. The efficiency of its use
depends on the building design and its adaptability lo construction details that
are necessary to slip-forming and which are discussed later in this chapter. In
order lo achieve this automation, work of all the various trades must be
organized and coordinated so that they mesh with each other with a minimum of
conflict. The materials deliveries, such as concrete and reinforcing steel,
should be made on schedule in order to develop a maximum rate of slip.
Specialized help is required for the duration of the slip form work, much more
so than in conventional construction. It is imperative that some person
thoroughly familiar with the overall operation be on the form at all times If
care is taken in the planning stage and carried through the complete operation,
many of the normal pitfalls can be avoided and an efficient operation can be

Not all jobs are suitable for slip forming, and each should be evaluated to
determine whether a slip-form is feasible. This should be done in consultation
with (architect and structural engineer, for sometimes limitations of structural
or architectural design preclude the possibility of making the changes necessary
to set up a slip-form operation, If the design is in an early stage, it is
sometimes possible to design around a slip-form or. in other words, make the
basic design for one that can he slip formed. Many owners have resorted to this
method of architect-engineer-contractor coordination and cooperation in order to
obtain the most for their money.