Lightweight. Optimised. Built for the Future: WAAM Delivers a New Structural Connection for Steel Portal Frames
Aston University set out to rethink how steel portal framesare designed. Their research showed that switching traditional open section columnsto tubular sections could deliver up to 40% weight savings, but only ifa new type of rafter-to-column connection could be created. The geometryrequired was too complex for conventional fabrication. This challenge made thisproject a perfect match for Wire Arc Additive Manufacturing (WAAM).
WAAM3D partnered with the Aston Universityresearch team and Dr Marina Bock to turn their generatively designedconcept into a real, testable steel component to demonstrate how additivemanufacturing unlocks entirely new possibilities for structural engineering.
The Challenge: A ConnectionThat Can’t Be Made Traditionally
Tubular sections offer excellent torsional stiffness andbuckling resistance but connecting them to open section rafters is notoriouslydifficult. The transition region must handle significant bending, shear andaxial forces which is resulting in complex, three-dimensional load paths.
Generative design produced the ideal geometry: a hollow,branching, truss-like form optimised for strength and minimum mass. Butproducing this shape through machining or fabrication was either impossible oruneconomic.
WAAM’s ability to print large, hollow,topology-optimised steel geometries made it the only viable option. Nevertheless,there are still access and overhang issues with the tubular sections due to thecomplexity of the part.
The WAAM Solution
WAAM3D manufactured the half-scale demonstration part usinga 6+2-axis robotic WAAM system and proprietary Wire Plasma Arc deposition.
Key Highlights
✓ Printed in a single 15-hour build
✓ Full prototype deliverd in 8 days
✓ Built on a 20 mm S355 plate
✓ Rotational build strategy ensured vertical deposition of truss features
✓ Final machining ensured flatness and drilling accuracy
Why WAAM Made the Difference
✓ Manufacturability of highly complex geometry
The optimised hollow form is only achievable using WAAM, enabling full designfreedom.
✓ Faster development cycles
What would require weeks with casting or fabrication was produced in days.
✓ Superior structural performance
FE analysis confirmed the printed 8 mm-wall design delivers rigid,full-strength moment transfer.
✓ Material-efficient and sustainable
Only the necessary material is deposited which is reducing waste and supportinglower-carbon manufacturing.
✓ Scalable for large structural components
High deposition rates and large build volumes make WAAM uniquely suitable forcivil-engineering applications.
Looking Ahead
This WAAM-manufactured connection is now undergoingextensive testing at Aston University, including 3D scanning, assembly trials,and structural testing The early results show strong promise for futurelightweight steel portal frame designs and highlight how WAAM is becoming apowerful enabler for advanced construction engineering.
References
1. Aston University White Paper
Bock, M.,Theofanous, M., Pinter, Z. & Kumaran, A. Generative Design for Additive Manufacturing of Rafter-to-Column Connections in Steel Portal Frames. The International Colloquium on Stability and Ductility of Steel Structures. In: ce/papers: 10.1002/cepa.70057.
About WAAM3D
Established in 2018 as a spin-out from Cranfield University,WAAM3D has evolved into an innovative technology company specialising in Wire Arc Additive Manufacturing (WAAM), a revolutionary metal 3Dprinting process that is transforming the manufacturing industry. WAAM3D is the only provider of a total, turnkey solution delivered via a coherent ecosystem that integrates in-house developed hardware and software products. Coupled with extensive knowledge and experience, WAAM3D is helping companies across multiple industries such as Aerospace, Defence, Energy, Machinery, Marine, to unlock new manufacturing possibilities, from first-right-part development to industrialization with the right equipment and capabilities.