Slip form Concrete

Slip form concrete is a method of construction in which concrete is poured into the top of a continuously moving shallow form. As the concrete is poured, the formwork is raised vertically at a speed which allows the concrete to harden before it is free from the formwork at the bottom. To move the formwork vertically, a hydraulic jacking system is used. The rate of lifting is determined primarily by the concrete pour rate, the time required to add reinforcing steel/opening blockouts, and the setting time of the concrete.

The slip form construction rig includes working levels, or decks. The lower deck provides access to the newly exposed concrete so that surface finishing processes can be completed. The work deck is used to install the reinforcing steel and to facilitate placement of the concrete. Slip form is a very safe method of construction since there is no need for continuous dismantling and re-assembly of formwork by crane during the construction phase. The complete set-up is assembled only once at ground level before “take off,” which saves a great deal of time throughout the construction process.