What Is Formwork?
Formwork is an essential framework used in construction and civil engineering for creating concrete structures like foundations, columns, and floors. It consists of molds, including panels and various fittings like supports and separators, to shape concrete according to specific designs. Plywood panels are a common choice for formwork.
Concrete’s extensive use in buildings, bridges, roads, and other structures necessitates precision in formwork. If formwork dimensions are incorrect, or if deformations or damages occur before the concrete sets, the structure may deviate from the design, leading to significant issues. Hence, accuracy and strength are crucial in formwork.
Uses of Formwork
Formwork is crucial in creating reinforced concrete structures, especially in seismic areas, where buildings, bridges, roads, and tunnels must withstand earthquakes. Combining concrete’s compressive strength with steel’s tensile strength in reinforced concrete structures enables them to endure seismic activity.
Assembling formwork on construction sites involves surrounding pre-assembled reinforcement, pouring concrete into it, and allowing it to cure. Once the concrete sets, formwork is dismantled, marking the completion of that work section. This process requires skilled formwork carpenters for assembly and dismantling.
Principles of Formwork
1. Components
- Separator: A metal rod that maintains concrete thickness within formwork and prevents outward expansion during pouring.
- Form Tie: Connects separators from outside the formwork through P-cones, tightening the formwork.
- P-Cone: Stabilizes the separator and form tie connections, buried in concrete, and removed post-curing.
- Spacer: Ensures cover thickness for structures like columns, securing space between the reinforcement and formwork panels.
2. Construction
Formwork construction involves fabricating panels based on design blueprints. While small projects might involve on-site cutting, larger projects usually use prefabricated panels from a factory. Precise alignment with the design and protection against deformation before concrete sets are critical for structural integrity.
For complex shapes like tunnels or curved structures, three-dimensional formwork and robust support materials are necessary.
How to Choose Formwork
Choosing the right formwork requires understanding the construction site’s specific needs, including soil and terrain factors. Effective communication about the site overview, blueprint specifications, and early site visits are vital for selecting appropriate formwork. This proactive approach helps anticipate challenges and fosters constructive dialogue with formwork providers.