What happens when a slab is poured but the support system underneath can’t take the weight? It falls.
It’s a scenario that no contractor wants to face, whether it’s during the structural expansion of a luxury hotel or the complex demolition of a recreational site.
Fortunately, it’s entirely preventable with proper propping, which ensures that load-bearing structures remain stable during construction or modification.
In this blog post, we’ll break down what propping is, walk you through the main types and describe how each is positioned. So let’s start.
What is Propping in Construction?
Propping in construction is the installation of a system, often using steel props, frames or jacks, to support load-bearing structures during phases of a build or demolition. These supports are critical in reinforcing beam support and maintaining structural integrity when permanent elements are not yet in place.
For example, during the construction of a multi-story hotel, when a concrete slab is freshly poured and yet to gain strength, a propping framework ensures the weight of the wet concrete is safely distributed. Without this support, the structure above may become vulnerable and so do the workers operating on it.
It protects both people and property by preventing potential collapses, deflections or delays caused by premature load-bearing.
Propping is an essential part of the construction industry. According to research by MarketWatch, the formwork industry is expected to grow at a CAGR of 4.9%.
Types of Propping
There are different types of propping, depending on the project’s complexity, duration and load requirements. They can be broadly classified into temporary and permanent propping solutions.
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Temporary propping and its types
Temporary propping provides short-term stability throughout active construction or demolition stages. They do the heavy lifting until the permanent structure is ready. Some of the common subtypes include:
- Acrow pops: These telescopic props are used for beam support or holding formwork systems in place while concrete sets. Ideal for varying floor heights or load needs, their supervised use results in various benefits. A study by Darlington found that the use of Acrow-prop technology decreased the construction time by 30% and costs by 10-20%.
- Titan props: Titan props are designed for heavier loads and larger spans. Common in commercial builds, like hotel basements or bridge decks, they offer high load capacity with fewer support points. Our titan props, for example, have a maximum working load of 128kN.
- Multi props: Multi props are an adjustable, modular propping system with alignment mechanisms. Usually thinner than titan props, they are ideal for tight spaces and tall heights, like atriums and lift shafts. The maximum load our multi props can hold is 102kN.
- Shoring props: Shoring props provide support to vertical loads. Shoring props might look the same as multi props, but they’re not. Engineers generally use shoring props as individual supports, while they design multi props to function as a modular system.
- Tilt props: They are angled support systems engineered to stabilize tilt-up concrete panels during erection. Usually made of high-tensile steel, they handle both vertical and lateral loads.
Permanent propping and its types
Builders integrate permanent propping into the final structure. They often use it to support heavy loads and compensate for architectural constraints. This includes:
- Embedded steel beams: They are used in long-span designs like ballroom ceilings or underground car parks. These props become a part of the building’s load transfer system.
- Hybrid propping solution: In this solution, contractors design props that initially serve as temporary supports but later remain embedded, saving both time and material.
How Can Props Be Positioned?
Proper positioning of props is more than just structural. It’s about the precision of the structure and the safety of the workers.
Whether you’re stabilizing a multi-ton concrete slab or holding a heritage facade in place, choosing the right propping framework can mean the difference between smooth sailing and structural chaos. Let’s look at the types.
- Vertical propping
Vertical props, being the simplest form of support, are used to carry loads from above. These props transfer vertical loads directly to the ground and are essential in high-rise floor casting or hotel atrium construction. The video below shows an example.
- Horizontal propping
As the name suggests, engineers design horizontal propping to resist horizontal forces such as those acting on retaining walls or excavation faces that need stabilization. You’ll often see them in basement digs or where pressure builds up between two structural elements.
- Ranking propping
Need to brace an unstable wall during demolition? Ranking props come in at an angle, usually 60-75 degrees, and form a triangle of stability.
They resist horizontal loads and redirect them to the base, much like a tripod supporting a camera.
Now, let’s discuss some of the challenges that occur during propping.
Challenges of Propping In Construction
Major challenges of propping in construction include load miscalculation, incompatibility with site logistics and adherence to safety standards.
- Load miscalculation
Each prop has a maximum safe working load (SWL), which decreases as its extension increases. For example, an acrow prop rated for 40 kN at a closed height might only handle 25 kN at near extension.
If a contractor relies on its upper load limit without adjusting for extension length or factoring in the strength of bolted joints, failure can occur.
This is explained by John Breen, RMD Kwikform commercial director, as well. He says,
“The loading that a proprietary prop can manage will depend on the strength of the bolted joints between sections and hydraulic capacity of the system.”
- Incompatibility with site conditions
Ground conditions, adjacent activities and structural obstructions can severely limit the effective placement of props. Soft or uneven soil, for example, can lead to uneven load distribution, even when using steel sole plates.
Props installed without considering soil compaction or the use of material in the supported structure may fail under extensive loads.
- Adherence to safety standards
In Australia, propping systems must comply with AS 3610 (Formwork for Concrete) and AS/NZS 1576 (Standard for Scaffolding). Failure to meet these standards, such as inadequate bracing, can result in legal liabilities and stop-work orders.
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Partner With Legend Hire For Your Propping Needs
Our expert propping team provides complete propping solutions, from engineering to onsite installation and rigging, under the expertise of Australia’s #1 propping expert, Mac Griffin.
We are a family-run business and take pride in it because what you want in a propping partner, we have it. And what’s that?
Passion for construction, expertise of 20+ years, a commendable portfolio of successful projects and a reputation for no hold calls but quick action.
