Economical design with BRBF

Comparative studies (e.g. Star Seismic Europe cost analysis; Dasse report) as well as completed construction projects confirm the advantages of BRBF system. BRBF can be superior to other common dissipative structures with global respect to cost efficiency due to the following reasons:

  • superior ductile and energy dissipative behavior,
  • low seismic loads (due to high behavior factor and usually increased fundamental period),
  • easy-to-control structural behavior,
  • smaller member sizes (columns, beams),
  • smaller and simpler connections,
  • larger efficient plan area of the building, which also increases the real estate value,
  • lower demand on foundations - specially, the arising tension loads are drastically decreased,
  • easy and fast erection providing significant time savings,
  • easy-to-adopt in seismic retrofitting,
  • easy post-earthquake investigation and replacement if needed.

"Cost advantages of Buckling Restrained Braced Frame buildings in accordance with Eurocode" study of Star Seismic Europe compares Buckling Restrained Braced Frames to Concentrically Braced Frames as primary lateral load resisting systems from an economical perspective. It investigates the expected total costs of a 3-story and a 7-story steel frame structure for three different bracing options.

earthquake cost savings

Cost of elements, Star Seismic™ BRBF compared to CBF q=1.5 and q=4

earthquake cost savings

Cost of lateral force resisting system of CBF and Star Seismic™ BRBF buildings

The cost study indicates that significant, 30 EUR/m2 saving can be achieved in comparison to a moderate dissipative, q = 4 CBF system. Compared to low dissipative, q = 1.5 CBF systems, even higher, 86 EUR/m2 and 95 EUR/m2 can be saved in case of the 3-story and 7-story buildings respectively, meaning so significant cost advantages in building construction that may extremely improve design firms' competitive advantage.

As an illustrative example, comparative study of Special Concentrically Braced Frame, (SCBF, R = 6) and BRB (R = 8) is completed in the Dasse report summarizing the primary cost savings of the structure. In their study, application of BRB reduced the primary cost of the lateral load resisting system by 34%.

As per PROHITECH: BRBF systems are extremely cost effective

The final report of the "PROHITECH WP5, Innovative materials and techniques", the 4 year long European Union-funded research project, which involved 12 countries declares:

"In addition to exhibiting high seismic performance and preventing damage to the primary structural members through absorbing seismic input energy, BRBF systems are extremely cost effective" - "the weight of steel framing members used in the entire building can easily be reduced by 5-10%, which is a significant cost advantage in building construction.".

Retrofit savings

Ideal for retrofit construction, Star Seismic Europe's pinned and welded Buckling Restrained Braces (BRB) can be used with existing beams, columns and connections, enabling occupancy during the construction cycle.

retrofit savings

Using existing connections, structural engineers replaced the existing braces with Star Seismic Europe BRBs. Anti-seismic resistance of the structure was increased with no frame modifications.

Frame-building savings

Because Star Seismic Europe's bracing system incorporates high behavior factors (seismic response, response modification factors), a building can be designed for lower force levels. Reduction in structural member size and in gusset plate size means more material savings and reduced man-hours.

frame-building-savings

The Star Seismic Europe BRB system was selected in the California Lottery design; the result was fewer braces, less material, smaller beams and columns.

frame-building-savings

With Star Seismic BRBs, smaller connections were incorporated in the frame design of Plum Point project and also significant foundation savings were resulted with a reduced number of piles.

Connection savings

By incorporating Star Seismic's patented collar system, no stiffeners are required in the gusset. And, because ductility is designed into each brace, Star Seismic BRB connection sizes are minimal.

postquake-savings

With Star Seismic BRBs, the Ritz Carlton saved $1.2 million by reducing the number of braces and therefore connections by over 50% and by reducing the size of the connection material and welds.

postquake-savings

Star Seismic's highest tested capacity buckling restrained brace, the 9800kN Redundant Core System was used for added stability in the steel plate shear wall system. By using a Star Seismic-engineered BRB outrigger system, efficient load distribution was achieved and drift was reduced.

Post-quake savings

Testing shows that Star Seismic BRBs are engineered to withstand multiple seismic events without significant damages. However, if a brace is selected for replacement, Star Seismic braces are significantly easier and less expensive to replace than moment frames, columns and beams or link elements of eccentrically braced frames.

postquake-savings

To maximize survivability during and after a seismic event, over 300 Star Seismic BRBs have been used in the UCSF Medical Center project in San Francisco, USA.

postquake-savings postquake-savings

BRBs are an ideal system for long-duration seismic events, since the ductility is maintained over repeated loading cycles. Due to the protected airplanes' significant value and because BRBs can be used in a single diagonal configuration which reduces overall structural costs, Star Seismic BRBs were used in the F-22 Hangar of the United States Air Force.

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