When constructing high-rise buildings or multi-storey structures, efficiency and safety are top priorities. One of the most effective methods for vertical concrete construction is the jumpform system, also commonly known as a "jump."
First introduced over 50 years ago, jumpforms transformed the process of building lift and stair cores, offering a controlled, efficient and safe approach to working at heights.
Today, they remain a key solution in modern construction - it’s not uncommon to pass construction projects nowadays and notice one or more jumpforms constructing the vertical aspects of the structure.
A jumpform is a modular and adaptable climbing formwork system used in vertical concrete construction. It was designed to advance upwards as construction progressed, providing an enclosed working platform for builders. These systems continue to be used in both external open-air environments and within existing structures.
Examples of jumpform applications are in the images below.
Jumps are generally made up of modular components which are versatile and adaptable to suit most requirements.
Once engineered and fabricated, jumpform systems are pre-assembled into manageable components for delivery and installation on-site. There are two primary types of jumpform systems:
Self-climbing jumpforms: These use hydraulic jacks to lift the system to the next level, reducing reliance on tower cranes and optimizing resource allocation.
Manual jumpforms: These require external lifting mechanisms but offer similar efficiency benefits.
Workforce access is facilitated through external stairs or internal hoists, depending on the size and complexity of the jumpform system. On larger jumps, internal hoist access is often achieved by using a hoist within a lift shaft.
The fully enclosed design enhanced safety when it was first introduced and still provides fall and weather protection today. The standardised construction sequence promotes efficiency and repeatability.
| BENEFITS | DRAWBACKS |
| Efficiency & Repetitive work: Consistent cycle times and repeatable processes improve productivity. |
Higher Initial System Cost: The upfront investment may be significant, but long-term savings usually offset the cost. |
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Accelerated Construction: Allows construction of vertical elements ahead of floor slabs, reducing delays. |
Lead Time Considerations: Engineering, procurement and assembly require careful planning to avoid delays. |
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Enhanced Safety: Enclosed platforms provide fall protection and shield workers from adverse weather when working and loading platforms. |
Planning Sensitivity: If not well-coordinated, jumpform use can disrupt project timelines. |
| Quality & Reduced Waste: Precision in formwork results in better-quality finishes and minimal material wastage. | - |
| Versatility & Adaptability: Modular design suits various project requirements. | - |
A jumpform construction cycle differs from a conventional pour cycle, where vertical elements were built floor by floor before proceeding with slab formwork. The jumpform method enabled concurrent construction of vertical cores and slabs, leading to long-term program efficiencies.
Initially, jumpform construction appeared slower due to assembly and setup. However, once established, the ability to progress simultaneously with slab construction resulted in faster overall project completion.
From a programme point of view, jumpforms prove to be a better solution for multi-storey and high-rise structures. A typical jump cycle can vary in duration based on several key factors such as size and reinforcement density in walls. An example of the day-to-day tasks within a cycle has been stepped out below.
From a construction planning perspective, jumpform systems have proven to be a strategic choice for high-rise developments. Their efficiency, safety benefits, and long-term program advantages continue to make them an optimal solution for building cores and vertical structures.
Below we provide an example of a conventional pour structure cycle vs a jumpform structure cycle. The conventional cycle considers the verticals elements being constructed before the next level of slab formwork (on a level-by-level basis). Whereas the jump cycle considers the initial assembly of the jump and the ability to construct the jump verticals concurrently with the slabs.
From the graph above, a jumpform approach is generally a slower in the short-term programming because of the assembly and initial construction sequence to clear the first suspended slabs. However, the ability to construct the slabs and jumpform concurrently (once established) promotes longer term programme efficiency.
The Zancon team have diverse experience in all aspects of building construction, which is a key value add for all our clients. Reach out to see how we can complement your team with our experience and service offerings.
- Matt Weatherhead