Solution Summary: Pre-fabricated Wall and Column Formwork System
Using pre-fabricated wall and column formwork systems is a prevention through design (PtD) process that addresses worker health and safety risks from collapse, fall from height, heavy manual material handling, and object struck-by exposures associated with constructing traditional formwork. These formwork systems generally contain vertical panels that use push-pull props for stabilization. In addition, there are also tying components to secure the formwork such as in-between lateral joists for walls and nut and bolt systems for columns. Guardrail components may also be affixed to the systems. After a concrete pour and the concrete is cured, these panels are stripped and ready to be relocated and reconnected without dismantling and rebuilding formwork.
Pre-fabricated wall and column formwork sytems can be composed from lightweight material, such as aluminum, for easy handling and handset. For systems that require rigging, some panels may have lift rings or require auxiliary lifting hooks specific to the panels.
Although these vertical formworks can be customized and pre-fabricated based on pre-defined dimensions of a project layout, many of these systems allow for on-site customization of their height and width dimensions. Adjustable clamps can be used to accomodate fillers and connect adjacent panels to assemble into formwork gangs.
Before concrete is poured into the formwork, the panels are temporarily supported by outrigger-like elements called push-pull props. These adjustable props help distribute the lateral loads to the ground or the slab below.
Once the concrete wall or column is cured and has gained enough strength determined by a qualified engineer, the panels are stripped and ready be relocated and reused. Because of its light weight, some panels may be maneuvered by as little as one person. Pre-fabricated wall and column formwork systems can come in various designs and specifications by different manufacturers which may require additional assembly components. The figures below are illustration examples on what a wall (figure 1) and column (figure 2) formwork system may look like.
Figure 1. Assembled wall formwork system (DOMINO Panel) by Peri Group
Figure 2. Assembled column formwork systems (Lightweight Column Formwork LGR) by Ulma Construction
During the construction of traditional formwork or concrete pouring operations, workers can face the risk of falls. Falls from height typically result in severe injuries or death.
Workers in the nearby area of traditional formwork construction can also be at risk of falling objects such as tools or materials from a level (or levels) above. Being struck-by objects typically result in severe injuries or death. Cuts and punctures can also arise from manual material and tools handling (i.e. using nail guns, saws, etc.).
Lifting heavy materials during the installation of traditional timber formwork can cause injury to muscles, nerves, discs and ligaments of the low back. Repetitive lifting of multiple individual components from a traditional formwork system can lead to low back strain, ligament sprain, a bulging or herniated disc, or other back problems.
How Risks are Reduced:
In pre-fabricated wall and column formwork systems, guardrails can be attached to perimeter at the top of the panels before it is placed. Because guardrails are attached and remain fixed from the beginning to end of the work, the proactive design already establishes active fall safeguards before workers are exposed to the risk.
The reduction or elimination of labor required to construct formwork at heights (because of pre-fabrication and pre-assembly) can eliminate or reduce the need to work with tools and materials at heights thereby reducing the risk of struck-by injuries from falling objects. Associated with that, the risk of cuts and punctures from handling tools and material also decreases. Moreover, the reduction or elimination of carrying tools, coupled with the formwork systems being made from lightweight material, can generally reduce heavy lifting associated with building traditional formwork.
Provided that all manufacturer guidelines and recommendations are followed, the structural integrity of pre-fabricated wall and column formwork systems are inherently safer than traditional formwork systems (generally constructed from timber) reducing the potential of collapse. Pre-fabricated formwork systems are pre-engineered and tested by manufacturers to account for all formwork requirements and provide a systematic process of installment reducing potential human error on constructing traditional formwork that may be inadequate or insufficient.
Effects on Productivity:
Using pre-fabricated wall and column formwork systems can increase productivity. For example, the manufacturer HI-LITE claims choosing their "aluminum beam concrete wall form system over steel and wood... reduces cost and increases productivity" due to their frames' ability to be reassembled or repositined quickly. Further, since their system is made from aluminum, they claim "even the heaviest component can be lifted by a single worker for ease in dismantling and reassembling by hand or repositioning by crane." This information may be extrapolated to other pre-fabricated formwork systems that may have similar features and characteristics of this system. Further, using pre-fabricated systems reduce the need for measurement, cutting and assembling wood material on site thereby reducing operation time and the potential for errors and delays (Memarian and Mitropoulos, 2016).
- Although pre-fabrication can reduce several risks, it is also worth to note that other new risks may be introduced. For example, installing pre-fabricated materials may require using cranes which can increase risk of swing struck-by injuries.
- It is important to follow the manufacturer's equipment and operation guidelines when using their products.
- Ensure that guardrails meet any additional structural or load bearing requirements before they are used. For more information, please visit guardrails in Construction Solutions.
- OSHA 1926.703(a) provides safety and health regulations for formwork in construction.
Le, Jean Christophe, MPH - CPWR - The Center for Construction for Research and Training
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NIOSH Workplace Solutions Sheet
The National Institute of Safety and Health (NIOSH) has published a series of “Workplace Solutions”, which are easy-to-understand recommendations from NIOSH research results. Related to this Construction Solution, please find more information on: Preventing Falls from Heights through the Design of Embedded Safety Features and Supporting Prevention through Design (PtD) Using Business Value Concepts