a new use for construction debris.
Shape | Anatomy of a System | course overview.
This term’s studio course emphasized refining prototypes through a bottom-up approach, integrating sustainability by considering material recyclability and availability. We developed precise prototypes using new technologies, bridging robotic fabrication with traditional craft techniques to explore sustainable architectural solutions.
State of the art.
Our research of steel began with an examination of robotic construction innovations in bending, assembling, and joining steel elements from industrial applications to more architectural form.
Bending
Robotic assistance enables precise multi-planar angles A CNC Wire Bender, created by BLM Group (2023) shows a feeder, gripper and two independant bending components, enabling multiplaner bending of linear steel members in four moving parts.
Assembly
The Temple, Roth Architecture (below left, 2023) demonstrates manual pending and assembly of rebar into a habitable frame. Rodiator and the Means (Maria Smigielska, Bendilicious, Zurich, right) demonstrate cleaner more accurate forms, a hybrid of manual and robotic assembly yields optimal results.
Joining
Robotic Tying (Advanced Construction Robotics, Pittsburgh, 2023, below left) shows automated joining from aerospace and automotive industries moving into the heavy construction industry. Prefab Joints by Bendilicious (2018, center) offers a custom clasp to join metal members. Peri Group, Weissenhorn (right) shows architectural scale rebar welding using a robotic arm.
Previous IaaC research
Projects like Aye Big Bender and Learning to Be a Space Frame integrate robotic bending and AI-generated modular designs, merging digital design with fabrication.
Traditional techniques.
Rebar emerged from early metalworking, evolved through François Hennebique’s innovations, fortified wartime infrastructure, and shaped modern architecture. French Industrialist, François Coignet, introduced tensile structures to concrete construction, fostering advancements in architectural scale, speed and strength. French Architect, Jeane Prouve’, took steel bending automation from industrial to architectural scale, creating furniture with a steel bending machinery.
Gabion baskets span 70 centuries– from Egyptians securing riverbanks, Romans building defensive walls, to da Vinci’s foundations in Milan– inspiring sustainable solutions today. Gabion baskets offer modular, transportable solutions, repurposing discarded steel while reducing carbon emissions.
Mechanical joining remains more feasible than robotic welding in our lab, utilizing bolting, clamping, tying, and coiling.
Experts in Catalonia.
Local craftsmen were all very busy due to extreme demand– Mold Arc, Taller Collage, Oxido Taller, Blanch, Villedecans, ReCamLaser, Luciano Carrizz, and Rodrigo Aguirre — were invited to provide technical advice on our project. The demand for their expertise further underscores the opportunity for robotic integration in the architectural metalworking.
Sourcing of materials.
Reinforcement steel is lightweight, strong in tension, and flexible, after only 50 years of use, rebar is often discarded, creating excessive waste. Because rebar small enough to bennd on the ABB IRB 160 was challenging, scrap aluminum and 3mm steel wire coil was used for our initial lprototypes. Fortunately, Barcelona’s scrap metal industry facilitates sourcing of pre-used rebar.
A scalable application would involve utilizing a larger robot with greater torque for salvaged construction materials.
Hand tests.
Bending
Reinforcement steel is lightweight, strong in tension, and flexible, after only 50 years of use, rebar is often discarded, creating excessive waste. To get precise angles and curve of bends by hand in the same way a robotic arm may approach it, a set of manual grippers (or pliers) were necessary. Manual bending lacked precision without custom jigs, reinforcing the benefits of robotic accuracy.
Assembly
To continue Prouve’s work, our team employed computational design and robotic bending processes for more human scale applications. Because the recycled steel may lack its intended initial strength due to corrosion, our team sought an exoskelatal system assembly, where the steel frame is only integral to the construction phase and becomes a redundant form once the fill is properly loaded within.
Joinery
Hand made mock-ups were employed to understand what constraints may be imposed by robotic operations.
Mechanical joints tested with 6mm rebar intended for future full-scale mockups.
Robotic tests.
Reducing bending to its most fundamental mechanics to best program the robotic arm, a system of two grippers– one mounted on the table and one mounted on the robotic arm along with the bender– acheived multiple bends from a linear steel rod. For our first scale model, the planar module originally generated by hand was re-created to compare the outcomes of these processes. From this preliminary mockup, we learned the advantages and limitations of the robotic process.
With each unique geometry, new limitations related to range of motion and tolerance of joinery may become evident. The motion of the robotic arm– grip, bend, pull, release, repeat– in front and side elevation can be seen by the diagram here.
Conclusion.
The robotically-made model (right below) had to be scaled up from the handmade model (left). Once the robotic process was optimized, the process became increasingly more efficient. In the coming term, with our optimized Grasshopper code for bending, a diverse catalogue of geometries may be used to create a variety of steel bent forms for bespoke structures. For the coming semester, we look forward in taking inspiration from the tensile grid shells structures of Dr. Mariana Popescu, reverse engineering forms to linear steel members, for robotic bending members into complex geometric modules. Further, mounting a mechanical joining tool with sensing technologies may give rise to new accuracy connecting steel members.
This research demonstrates the constructability of robotic fabrication in steel rebar construction. Automated bending, assembly, and joining of recycled steel create modular, transportable frameworks that reduce waste while increasing efficiency. Future work will refine computational design, robotic manufacturing, and automated mechanical joining techniques, advancing sustainable and innovative architectural solutions. This study bridges emerging technologies with traditional construction, to ultimately address the demand of the affordable housing sector.
References.
tudelft.nl/en/staff/m.a.popescu
jpbotelho.com.br
bendilicious.com
