Hyundai Engineering wins certification for H-beam modular joint system co-developed with Hyundai Steel

Meets revised seismic design standards, paving way for commercialization

Two-way guide system and horizontal bolt fastening cut assembly time by over 20%

'Proves our capability to lead high-rise modular construction,' company says

A full-scale two-story frame test specimen built to verify the structural performance of the H-beam steel modular joint system developed by Hyundai Engineering [Hyundai Engineering]

Hyundai Engineering announced Monday that its "H-beam steel modular joint system," co-developed with Hyundai Steel, has received technical certification from the Korean Society of Steel Construction.

The certified technology governs the joint structure used when stacking and assembling box-shaped modular units — manufactured at a factory — on site. The system simultaneously addresses the two biggest challenges in high-rise modular construction: securing structural safety and improving on-site workability.

Any new steel joint technology developed in line with the revised steel structure seismic design standards — updated in May 2024 — must pass verification by the Korean Society of Steel Construction, which the Ministry of Land, Infrastructure and Transport has designated for that purpose, before it can be applied to actual projects. Hyundai Engineering cleared the requirement by completing cyclic loading tests using two or more identical specimens and passing a technical review.

Mid-rise and taller modular buildings have traditionally relied on built-up rectangular hollow section members — fabricated by cutting and welding steel plates — to bear structural loads. That approach carries drawbacks: the manufacturing process is complex and costly, quality and dimensional precision can vary by manufacturer, and material procurement is often difficult.

Hyundai Engineering addressed these issues by adopting standardized, off-the-shelf H-beam sections as the primary structural members. Using standardized materials reduces costs and improves supply stability, while the open cross-section of H-beams ensures uniform section quality. The design also makes it easier to apply fireproofing coatings, allowing the system to meet a wide range of fire-resistance requirements.

Workers install modular units at the H-Modular Lab testbed to verify the practical application of the H-beam steel modular joint system [Hyundai Engineering]

To improve workability, Hyundai Engineering incorporated a two-way positioning guide system that directs modules into precise alignment as they are lifted and set by crane, enabling fast and accurate stacking without gaps or wobble. A horizontal bolt fastening method was also adopted, enhancing worker safety and cutting on-site assembly time by more than 20 percent.

Structural safety verification was conducted with researchers from the Korean Society of Steel Construction. In cyclic loading tests — simulating severe shaking from earthquakes or strong winds using a full-scale two-story frame — the system maintained stable performance with no structural damage or strength degradation at an inter-story drift of 4 percent, well above the 2 percent maximum required under the current Korean Design Standard.

The technology was also applied at the H-Modular Lab testbed, where stacked construction verification was successfully completed.

Hyundai Engineering plans to expand the application of off-site construction technology to the data center and industrial building sectors on the back of the certification.

"The H-beam steel modular joint system has achieved all three goals — absorbing construction tolerances, ensuring worker safety, and meeting seismic performance requirements," a Hyundai Engineering official said. "We expect it to set a new standard for the high-rise modular construction market going forward."

Meanwhile, Hyundai Engineering is also building a foundation for entry into the global water electrolysis market through the development of hybrid electrolysis plant technology linked to renewable energy.

lucky@heraldcorp.com