When it comes to designing warehouse and logistic centers, it's all about size! Spaces are designed around volume (footprint x height) and the demand for these facilities has become insatiable over the years. Structural engineering plays a key role in making sure the bones of these mammoth facilities are strong enough to sustain a wide variety of elements.
Over the years Bala's Structures team has designed numerous spec and build-to-suit warehouses throughout the northeast for clients including retail giant URBN (brands include Urban Outfitters and Anthropologie). Our most recent project was a logistics campus in Cranbury, NJ (a hotspot for logistic centers) with Clarion Partners. The scope of the project included three 40 foot clear height (usable height for storage) buildings totaling 2.8 million sf. Amazon and Wayfair are the tenants and use the space as distribution hubs where workers pick, pack, and ship millions of customer orders.
To place some perspective on how big 2.8 million sf is, here are some eye-opening facts:
- Exceeds the square footage of One World Trade Center (yep - that's the tallest building in the United States!)
- Large enough (in terms of volume) to fit Philadelphia's Comcast Technology Center (spire included), Comcast Center AND FMC Tower (all Bala projects btw) inside with room leftover for other activities
- If you compare it at a consumer level, you would be able to squeeze in 1.6 Billion of the Roomba robo sweepers!
So how are these vast volumes created? It's a collaborative effort between the client, architect, and structural engineer. For this project, cast-on-site tilt up walls (about 660 of them) are optimized to quarter inch of thickness, including the slab on the ground. Each 1/4" of concrete added to these elements adds about $1M of project costs. In essence, it's imperative to keep pencils sharp and calculators on hand because every 1/4" is important!
The roof that caps a warehouse or logistic center is also meticulously calculated to support the dead weights of the roofing, the sprinkler systems and roof snow loads, all down to within the hundredths of a pound. Erecting these roofs over millions of square feet warrants panelizing the roof bays. This translates to piecing together the joists and stability bridging, welding down the roof deck on the ground and picking up each roof bay to place on top of the columns.
The largest threat to enormous roofs in the northeast is the snow loads from the winter months. The size and weight of the roof framing is controlled by the 1.5 feet of heavy, wet, compacted snow that is anticipated for a 50 year return snow storm in NJ. Additionally, water ponding around the drains due to drain backups has been known to develop significant loads requiring additional roof strength around the drains. When managing rain runoff from a 1+ million SF building, the drains downspout diameters can reach up to a foot in diameter.
Instead of sticking to the typical plain looking box style warehouses are known for, architectural precast panels were added at each corner. The dark concrete pigments were grinded and polished for a high-end vibe. Kudos to Clarion Partners for putting extra effort into making these facilities attractive and inviting for workers.
Next time you're driving down the stretch of I-95 between Philadelphia and New York, keep an eye out for these monster warehouses. They're easy to spot!
After a decade of work developing these buildings, the team was awarded the North NJ-ULI Award for Excellence: Industrial Division.
Owner: Clarion Partners
Contractor: RC Anderson
Architect: RGA Architects
Structural: Bala Consulting Engineers
Civil: Langan Engineering
To take a deeper dive into the structural components of warehouses and logistic centers, we currently have an AIA Accredited Course Presentation . Contact Tonya at firstname.lastname@example.org if you are interested in scheduling a presentation.