‘Special Moment Connection’ Certification
Withstands Magnitude 7.0 Earthquake
30% Reduction in Structural Member Usage
Pos-H, one of POSCO InnoBuilt's flagship products, has been recognized for its superior seismic performance with the world's highest beam height.
On the 11th, POSCO announced that on the 28th of last month, it received certification from the Korean Society of Steel Construction for a 'Special Moment Connection' on beam-column joints using Pos-H with the world's highest beam height of 1500 mm. This is the highest grade of seismic connection performance, meaning it can safely withstand earthquakes of magnitude 7.0. In the United States, which sets global standards in architectural structures, the highest certified beam height for special moment connections is 1400 mm. Considering that the maximum beam height currently in practical use is 920 mm, POSCO has secured the best seismic performance for the world's highest beam height.
Previously, in 2020, POSCO was the first in Korea to receive the same grade certification for beam-column joints with a beam height of 1000 mm. The performance of beam-column joints is a crucial factor in determining the seismic performance of buildings. The joints must have ductility that allows them to bend well without breaking to enable the building to withstand seismic shocks.
A seismic test scene of the world's tallest 1500mm-high Pos-H beam and column joint conducted last December at the steel structure testing building of the POSCO Steel Solutions Research Institute in Songdo. It can be seen that the beam withstands the earthquake until the end without any failure of the beam or column, even under large-scale seismic forces. [Photo by POSCO]
Pos-H is a customized welded steel section that can be manufactured in optimal sizes according to customer needs. It is made from POSCO’s seismic-grade thick plates and hot-rolled steel to enhance seismic resistance. It is mainly used as beams and columns connecting columns in large-scale architectural structures. Recently, as buildings have become larger, the demand for structures with wider spacing between columns and heavier loads has increased, while rising raw material prices have led construction companies to demand cost reductions. Applying Pos-H, which has an increased height compared to conventional beams, to large steel structures can reduce the amount of materials used, enabling economical construction.
Seismic performance refers to the comprehensive ability of the building’s framework, consisting of columns and beams, to withstand seismic shocks. When designing buildings, seismic performance is enhanced by securing both the 'strength' to support loads and the 'ductility' to flexibly respond to shaking. Among these, the performance of beam-column joints has the greatest impact on the overall seismic performance of the structure.
Beam-column joints are classified according to their seismic performance level, which determines how safely a building can deform laterally during an earthquake: low performance 'Ordinary Moment Frame', intermediate 'Intermediate Moment Frame', and the highest grade 'Special Moment Frame'. The higher the seismic performance, the better the ductility, allowing the structure to deform flexibly without collapsing.
When POSCO’s newly certified 'Special Moment Connection' is applied to buildings, it ensures safety even during magnitude 7.0 earthquakes and can reduce structural member quantities by up to 30% compared to 'Ordinary Moment Connections' without seismic certification.
A bird's-eye view of the Capital Land Goyang Data Center, where Pos-H with a beam height of 1100 mm, certified for special moment connections with the highest seismic performance rating, is applied. It is scheduled to be completed in September. [Photo by POSCO]
Meanwhile, POSCO received a patent from the Korean Intellectual Property Office last month for this certified connection. POSCO’s special moment connection method is simpler and easier to manufacture compared to existing complex methods, enabling shorter construction periods and cost reductions, and has already attracted design inquiries.
The 1100 mm high Pos-H beam with special moment connection certification has been applied to the CapitalLand Goyang Data Center, which is nearing completion. Negotiations are also underway to apply Pos-H products to large-scale building projects both domestically and internationally.
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