The Tunnel Formwork System
What is a Tunnel Formwork System?
A tunnel formwork system is a system formwork construction method that combines wall formwork and slab formwork into an integrated structure. During construction, the walls and slabs can be cast in a single construction cycle, forming a concrete unit similar to a "tunnel," which is where the system gets its name.
Compared with traditional phased construction methods, tunnel formwork can significantly improve the construction pace, reduce uncertainty in the process, and ensure the consistency of concrete structure quality. Globally, tunnel formwork is considered a typical application of system formwork.
GETO has successfully launched its tunnel formwork, which balances construction convenience, overall cost, and product turnover rate, achieving a balance between construction cost, construction efficiency, and construction technology. It is also the fastest and most economical way to build high-quality earthquake-resistant apartments, villas, student dormitories, and hotels.
As a key component of Green Construction solutions, the modern tunnel formwork system is designed not only for speed and economy but also for environmental sustainability. Its high-reuse rate and precision-engineered components significantly reduce material waste. Furthermore, the system offers remarkable flexibility, capable of efficiently handling complex structural geometries and varying floor plans through adjustable and modular components, making it a versatile choice for contemporary building challenges.
Working Principle of the Tunnel Formwork System
The core logic of the tunnel formwork system lies in "structural integration" and "construction standardisation." In each construction cycle:
· The formwork system is installed as a whole.
· Wall and slab reinforcement are tied simultaneously.
· Concrete is cast in a single pour.
· The formwork is demolded as a whole after the specified time and moved to the next construction unit.
This process makes the construction pace highly predictable, making it very suitable for fast-paced, large-scale engineering projects.
Tunnel Formwork Components
The tunnel formwork system mainly consists of a formwork system, a support system, and a connection system, supplemented by lifting platforms (bay platforms, stairwell platforms, elevator shaft platforms) and external wall working platforms as auxiliary systems.
These tunnel formwork components together constitute a reusable, systematic formwork structure. Its modularity directly affects construction efficiency and the difficulty of on-site management.
Main Types of Tunnel Formwork Systems
Based on different materials and structural forms, tunnel formwork systems are mainly divided into the following two categories:
Aluminium Tunnel Formwork
Aluminium tunnel formwork is characterised by its lightweight design, combined with high strength and good reusability. The main body is an integrated aluminium formwork.
Its advantages include:
· Fast overall installation speed.
· High standardisation, and high material reuse rate, with a wide range of application areas.
· Flexible assembly and disassembly, simple process, reduced labour input, relatively low cost, and high safety performance.
· High scrap value of aluminium material.
· Lower deadweight and smaller crane specification requirements.
· Seamless integration with the quick deck concept, high turnover rates.
Steel Tunnel Formwork
Steel tunnel formwork is known for its structural strength and stability, and is usually used in building structures with high load-bearing requirements or large spans. The main body is a monolithic steel formwork.
Its advantages include:
· Simple formwork erection process, low labour force.
· Tightly spliced, not easy to deform
· Good integrity of formwork, strong seismic resistance,
· Good insulation performance, conducive to winter concrete insulation.
· Large formwork dismantling with a high level of mechanisation.
Core Advantages of the Tunnel Formwork System
From an engineering practice perspective, the main advantages of the tunnel formwork system are reflected in the following aspects:
· Superior Concrete Finish: The system ensures high flatness and verticality of concrete surfaces, providing a smooth, fair-faced finish that significantly reduces or eliminates the need for subsequent plastering and leveling work.
· High Turnover & Long Lifespan: Manufactured with robust materials and strict quality control, the system is engineered for hundreds of reuses. This high durability drastically lowers long-term project costs and minimizes construction waste.
· Accelerated Project Schedule: The modular, standardized design enables rapid installation and striking, dramatically shortening the overall construction cycle and reducing reliance on intensive manual labor.
· Enhanced Structural Integrity: Walls and slabs are cast monolithically in a single pour, improving overall structural consistency and seismic performance.
· Improved Site Safety: Reduced on-site procedures and the systematic handling of large formwork sections contribute to a safer working environment.
Specific advantages may vary depending on the project type, structural design, and construction organisation methods, and usually require evaluation based on specific engineering conditions.
