A shape-morphing structure made from interconnected multistable tubes rapidly transforms from a compact configuration into a full-scale reinforced concrete mold during casting. This self-deploying formwork system could simplify reinforced concrete construction, making it faster, simpler, and maybe even more sustainable. These findings were published in Communications Engineering.
Study: Self-deploying reinforced concrete structures. Image Credit: eugene_p/Shutterstock.com
Addressing the Challenges of Conventional Formwork
Reinforced concrete remains one of the world's most widely used construction materials, and most cast-in-place construction depends on temporary formwork to shape fresh concrete.
Manufacturing, transporting, assembling, and removing these molds require substantial materials, labor, and time, making formwork one of the most resource-intensive stages of construction. Temporary timber formwork also generates large amounts of waste and contributes to greenhouse gas emissions throughout its life cycle.
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Researchers have proposed several alternatives, including reusable metal formwork, fabric molds, mesh systems, pneumatic formwork, and concrete 3D printing. Although these approaches improve certain aspects of conventional formwork, they often require specialized equipment, external actuation, or complex construction methods.
Many methods may also lack integration between the formwork and the structural reinforcement, increasing installation time and limiting design flexibility.
Deployable structures inspired by origami and multistable metamaterials have emerged as another promising alternative. These systems transform from compact configurations into larger structures by releasing stored elastic energy or using fluid-driven actuation.
However, most existing designs have focused on lightweight deployable structures rather than reinforced concrete applications.
To address these challenges, the researchers developed a self-deploying reinforced concrete formwork system based on interconnected multistable tubes. They evaluated its deployment speed, structural performance, and potential to reduce construction time, material consumption, and environmental impact compared with conventional formwork systems.
Engineering a Self-Deploying Reinforced Concrete Formwork System
The researchers developed a deployable formwork system using multistable polymer tubes that rapidly expand from a compact configuration
into a full-scale concrete mold without external mechanical assistance.
The multistable tubes can transition from compact to expanded configurations. At the meter scale, gravity drove this transition as the cementitious mixture was pumped into the structure. By connecting multiple tubes into a lattice framework, the researchers created a self-supporting structure capable of defining the geometry of reinforced concrete elements.
The experimental structures used polypropylene multistable tubes together with integrated steel cables and several three-dimensionally printed components. The thin polymer walls of the multistable tubes acted as permanent formwork, containing the cementitious material during casting and remaining around the cured concrete.
Unlike conventional temporary formwork, the membrane remained part of the finished structure and contributed to its structural performance.
To validate the concept, the team constructed a 2.36 meter structure with integrated steel reinforcement. The compact assembly deployed into its final configuration in approximately 14 seconds as the cementitious mixture was pumped into the system. The authors note that the proposed method is also compatible with self-compacting concrete.
The researchers also developed a theoretical computational model to simulate deployment, structural deformation, and load transfer, enabling direct comparisons between numerical predictions and experimental results.
The integrated polymer shell could also reduce reliance on disposable timber formwork. First-order estimates indicated lower material-production emissions and material costs for the proposed system, while the experimental deployment was substantially faster than the conventional formwork-installation value used for comparison.
However, the analysis did not include transportation, installation, labor, maintenance, reuse, or end-of-life processing.
Structural Performance and Construction Efficiency
The self-deploying system demonstrated rapid and reliable deployment without external actuation. The interconnected multistable tubes maintained the required geometry throughout concrete casting, while the polymer membrane effectively retained the fresh concrete until curing. The framework remained stable throughout the construction process, suggesting its suitability for practical applications.
Structural testing showed that the permanent polymer shell significantly improved the performance of the reinforced concrete element. By remaining as part of the finished structure, the shell provided additional confinement to the concrete core, enabling the system to achieve approximately three times the load-bearing capacity of comparable specimens without the integrated shell.
These findings demonstrate the benefits of combining formwork and reinforcement within a single structural system.
The integrated polymer shell also improved the sustainability of the construction process by replacing disposable timber formwork. First-order assessments showed reductions in construction time, material consumption, labor requirements, and carbon emissions compared with conventional cast-in-place construction.
The system’s compact pre-deployment configuration also reduced transportation volume, making the system potentially well-suited for prefabricated construction, remote projects, and rapidly deployable infrastructure.
The simulated deployment showed good agreement with the meter-scale experiment, supporting the model's ability to predict deployment behavior, final configuration, and stability under the conditions investigated.
Although the study demonstrated the concept using a single prototype, the researchers suggest that the same design principles could be extended to columns, walls, shells, and other reinforced concrete components.
Advancing Sustainable Reinforced Concrete Construction
This study demonstrates how deployable structural systems could improve reinforced concrete construction by integrating formwork, reinforcement, and structural functionality into a single system.
The researchers’ approach simplifies construction, reduces reliance on temporary formwork, and improves material efficiency, as the permanent polymer shell serves both as the casting mold and as part of the finished structure.
By potentially reducing material consumption, construction waste, carbon emissions, and transportation requirements, this system could prove to have significant implications for future construction. These advantages could benefit prefabricated buildings, remote construction, and rapidly deployable infrastructure.
The researchers note that the current work is a proof of concept and recommend future studies on larger structures, more complex geometries, long-term durability, and large-scale manufacturing. Overall, the study provides a promising framework for faster, more resource-efficient, and lower-carbon concrete construction.
Journal Reference
Ben-Abu, E., Zigelman, A., et al. (2026). Self-deploying reinforced concrete structures. Communications Engineering, 5(1), 133. DOI: 10.1038/s44172-026-00725-1. https://www.nature.com/articles/s44172-026-00725-1.
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