An introduction to slipform construction method

Slip form is a technique in which concrete is poured continuously in moving form and is also known as continuous poured, continuously formed or slipform construction. This technique is most commonly used for building tall structures such as bridges, towers, high-rise residential buildings, dams. However, this method is not limited to only tall structures. It can also be used for horizontal structures like roadways.

This method of construction relies on the quick setting properties of concrete and requires a balance between the quick-setting capacity and workability. The concrete used in this method needs to be workable enough to be placed to the formwork and strong enough for developing early strength. This can help ensure that the form can slip upwards without any disturbance to the freshly placed concrete.

One of the notable used of slipform construction method is the Skylon Tower in Niagara Falls, Ontario, which was completed in 1965.After this successful endeavour, this technique was soon used to build Inco Superstack in Sudbury, Ontario and the CN Tower in Toronto. Most of the buildings with a high-rise structure use this construction method in Australia. This technique allows continuous, non-interrupted, cast-in-place “flawless” concrete structure. These structures have superior performance features to piecewise construction using discrete form elements (The Constructor, SLIPFORM CONSTRUCTION METHOD, n.d.).

In the second type, i.e. slipforming of horizontal structures such as pavement and traffic separation walls initially concrete is laid down. Then, it is vibrated, worked, and settled in place while the form itself moves ahead. The Interstate Highway Construction was built using this kind of construction technique by the Eisenhower Administration in 1950’s.

The other types of this construction method are conical, traditional and gantry slipforming.

The following are a few ways in which any project can benefit by using this construction method for taller concrete structures like storage tanks, high-rise residential buildings, etc.

1. Early Assembly- This kind of construction setup is compact and can be pre-assembled. Once the foundation is ready, the slipform can be quickly placed & construction can start at the same time.

2. Continuous process- Slipform technique does not need to set and strip forms every few feet. Also, one does not even require a crane for as compared to the conventional handling of formwork.

3. Safety- Since this method does not require any kind of dismantling and re-assembly of formwork by a crane during the construction phase and the complete set-up is assembled on the ground; it makes it a safe construction method.

The above-mentioned points explain the overview, types, uses and benefits of slipform construction method.