What criteria do you consider when deciding upon whether to use Jump form or Slip form?

Question

If you are a sub-contractor, main contractor or even a structural engineer [design does play a significant role in this], what criteria do you consider when deciding upon whether it is better to construct the core in a tall building [36 storey or more] using jump form or slip form?

Howard Gregory · Answer

Designing Buildings Wiki provide a good explanation of these types of construction at https://www.designingbuildings.co.uk/wiki/Jumpform_v_slipform.

The decisions to use are cost and programme led. At this time, it is a general norm that slip forming is more expensive than jump forming due to the 24 hour processes utilised.

To utilise the advantages of speed with the more expensive "slip forming", there has to be a way to benefit the programme for the construction in question.

If for example, it is a simple concrete chimney construction, the benefit is in how quickly the chimney can be constructed to become operational.
If a concrete residential tower core, the benefit is in how quickly the surrounding floors could be completed to "catch up" with the completed concrete core in the speed of construction. Slow "catch up" with the floors means you have simply built an expensive core by by slip forming which provides no programme advantage.

So the decision is a benefit analysis on cost and programme.

What criteria do you consider when deciding upon whether to use Jump form or Slip form?

Concrete

Programme

construction

formwork

cost

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