Why DuraFuse TRU

Economy, Constructability & Resilience.

DuraFuse Frames TRU revolutionized the design and construction of field-bolted steel moment connections. As the first replaceable fuse, fully-restrained connection prequalified in AISC 358, DFF TRU offers both steel tonnage and construction schedule efficiencies. Its fuse mechanics and connection geometry deliver the highest stiffness-to-weight ratio, resulting in lighter frames than any other steel moment connection. By confining earthquake damage to the fuse, DFF TRU eliminates the need for seismic lateral bracing and minimizes the protected zone. Collaboration with steel fabricators ensured simple and safe fabrication and erection. In addition to construction cost savings, the connection’s post-earthquake repairability offers significant long-term benefits. Independent studies show repair costs and downtime are reduced by at least 60% after a design-level earthquake. DuraFuse Frames TRU reduces overall frame construction costs while improving facility function recovery.

Elimination of Seismic Lateral Bracing.

For Special and Intermediate Moment Frames, seismic lateral bracing is required in Section D1.1 of AISC 341 to ensure the beam can develop the requisite ductility without excessive strength loss (e.g. flange buckling). DuraFuse Frames is the only fully restrained prequalified moment connection that eliminates the requirement for seismic lateral bracing. For DuraFuse moment frame beams, the only lateral bracing is that which is required by AISC 360. Because the beam remains elastic, the supplemental lateral bracing is not required. This elimination is allowed by the code (AISC 358), as all the DuraFuse Frames qualification tests were successful without any lateral beam bracing.

The table below shows a comparison of brace point requirements between highly ductile special moment frame beams that require bracing in accordance with AISC 341 requirements [0.086E/(RyFy)] and the number of braces required for DuraFuse Frames. The number of braces required for DuraFuse is reduced by at least 80% for these projects.

The benefits of eliminating the lateral bracing include material, fabrication, which is typically in the range of $600 – $800 per brace. Additionally, the lack of bracing in the ceiling space simplifies coordination of the mechanical, plumbing, HVAC, fire protection, and other building systems. Elimination of seismic lateral braces is a significant cost and time benefit to frame construction.