Mention High Density Mobile Storage Shelving Systems and the first thing that pops into our client’s minds is “That is a lot of weight, what about my floors? Can it work for me?” The answer is an overwhelming “Yes, we can!” and at a recent installation we encountered this supremely challenging situation:
- The building was a wood-framed two-story structure with critical areas of the structure using structural steel, but not all areas.
- The building was brand new and was built to current building code standards.
- The first floor held a retail showroom and the second floor housed administrative staff and storage. Our system was headed for the second floor. The client needed High Density Mobile Storage to support both the administrative and sales function of the business.
- Space was critical on the second floor and every bit of square footage on the ground floor was needed to produce revenue. On the second floor load, the area in question was engineered for 250 psf but the floor structure was L/240. In layman’s terms, the floor could hold the weight, but under that load the floor would deflect to a point where it would no longer remain flat enough to prevent the carriages from “drifting”. Typically HDMS requires a minimum floor structure of L/360, and floors with this rating require your thinking caps to get right the first time. For full-throttle approval by your favorite structural engineer, Spacesaver High Density Mobile Storage powered systems are listed with L/480 as a minimum deflection criteria; Mechanical Assist Systems the deflection rating is L/700.
- The floor joists were perpendicular to the desired direction to co-exist with maximum capacity. The floor deck was just plywood nailed to floor joists.
Obviously, our situation of L/240 was difficult, but we crafted a very clever and strong solution. In fact, we created an L/700 floor right on top of the L/240.
Here’s a few photos that are worth a thousand words:
Here is the finished system.
Underneath each of the four rails are twin steel tubes, each individual tube is HSS 6” ht X 3” w X 1/4” thick walls.
The steel tubes are lag bolted to the wooden joists directly attached to the building’s W14X43 steel support beams. During an earthquake this bad boy is going nowhere.
The height of the steel tubes require that a subfloor be constructed between the rails. The decking is 31/32” fire retardant plywood which is mandated by Los Angeles County fire codes. The small 2” X 3” metal plates on top of the wood infrastructure are designed to accept the levelers used to make the decking perfectly flat and flush with the top of the rail…makes for the best finished floor possible.
How much did all this cost? Raw steel and lumber costs were less than three thousand, and when both material and additional labor added combined the price went up about 15% when compared to a standard installation.