A data center equipment yard in Santa Clara, California, needed a sturdy cable bus support structure and a multi-story maintenance access platform. These were essential for servicing and sustaining critical equipment to keep the facility running with zero downtime.
Image Credit: Strongwell Corporation
The team originally planned to use steel for this large, complex structure. However, the design would have required nearly half a million pounds of structural steel—posing significant challenges in transportation, fabrication, and erection. With a tight construction schedule, a limited supply of skilled labor, and difficult site access due to the weight of key steel components, this approach proved impractical.
Image Credit: Strongwell Corporation
Facing strict constraints on time, labor, and space, the data center’s owners turned to Frost Engineering & Consulting to design a durable, fast-erecting alternative to steel—one capable of withstanding high seismic activity in a densely populated area.
The result was a 120,000-pound FRP structure, significantly lighter than the original 400,000-pound steel design. Spanning 7000 square feet, this dual-purpose exterior structure includes a 3400-square-foot cable bus support on a single level and a 3600-square-foot, two-story generator access platform.
Source: Strongwell Corporation
| Technical Data |
| Product: |
Cable Bus Support Structure and Multi-Story Maintenance Access Platform |
| Process: |
Pultrusion, Fabrication |
| Materials & Sizes: |
EXTREN® Structural Shapes:
- Wide Flange Beams: 6" x 3/8", 8" x 1/2", 10" x 1/2"
- I-Beams: 8" x 4" x 3/8", 10" x 5" x 1/2", 12" x 6" x 1/2"
- Angle: 4" x 1/2", 6" x 1/2"
- Channel: 12" x 1/2"
|
| For: |
Frost Engineering & Consulting |
| User: |
Data Center in Santa Clara, California |
Below are four of the more distinct design issues that the design team faced:
- Project Schedule:
Challenges in obtaining raw materials, supply chain delays, and the requirement for post-fabrication weatherproofing (galvanization) made steel an impractical choice for this project. Instead, the value-engineered FRP solution was designed, manufactured, and fully assembled before the first steel shipment was even expected to arrive. One of the most significant benefits highlighted by the installer was the substantial weight reduction of the primary structural components—averaging 60 % to 70 % less than steel. This lighter design improved maneuverability, eliminated the need for heavy machinery, and significantly sped up installation.
- High Seismicity:
This FRP structure is the third heaviest free-standing FRP structure ever built and the largest all-FRP structure constructed in a high-seismic region. The owner also required it to be classified as an essential facility (Risk Category IV), meaning the design had to withstand a 1-in-2500-year seismic event while incorporating all seismic overstrength and elevated importance factors. To meet these stringent requirements, the design team utilized advanced ACMA seismic design standards alongside finite element analysis (FEA) modeling, ensuring approval from both the owner and regulatory authorities.
- Prying Action:
Due to the significant lateral demands and the absence of a diaphragm system, most FRP beams experienced varying levels of axial loading. The prevalence of these beam-axial forces required the design team to carefully evaluate the effects of prying action on FRP connection elements. Drawing from equations in the AISC Steel Construction Manual and insights from relevant research papers, Frost Engineering & Consulting developed a closed-form, FRP-specific prying capacity equation to accurately assess the performance of typical beam-end connections.
- Elevated Temperatures:
Specific coordination and design considerations were used to resolve concerns arising from the generators' broad range of exhaust temperature output, sometimes nearing 800 degrees Fahrenheit.
All parties involved were happy with the project from beginning to end in such a way that the owner has selected FRP as its preferred material solution for the project’s future phases. It is also worth mentioning that this project was awarded the 2021 Award for Composites Excellence for Most Creative Application of Composites.
FRP Structural Connections and Technical Design
By leveraging extensive Building Information Modeling (BIM) during the structural layout, Frost Engineering & Consulting was able to model connections with a high level of precision, ensuring installation clearances as tight as 1/8". The three most commonly used connection types for this project were:
- WT Shape gusset (Figure A), mainly used in medium-duty vertical braced frames.
- Traditional gusset plates (Figure B), mainly used in heavy-duty vertical braced frames.
- Double clip angles (Figure C) utilized for typical beam end connections.
Image Credit: Strongwell Corporation
The cable bus structure (Figure D) features vertical bracing exclusively in the E-W direction, while a system of horizontal bracing redirects lateral forces in the N-S direction to the generator platform’s lateral force-resisting elements.
The generator platform (Figure E) incorporates vertical bracing in both primary directions, utilizing a combination of portal frames and knee-braced frames to ensure stability while maintaining necessary walkway clearances.
Image Credit: Strongwell Corporation
This information has been sourced, reviewed and adapted from materials provided by Strongwell Corporation.
For more information on this source, please visit Strongwell Corporation.