Raised Runway - Need a Carpenter's Opinion

[ClintonMagus]

We are building a raised runway that will normally be used indoors, but can be moved outdoors for street vaults, etc. Rather than build it with a 2x10 framework, we have been given a very good price on some 2.5x11.75 "engineered" wood I-beams. Of course, from a weight standpoint, this would be wonderful. We will seal all of the wood for outdoor use.

My question is, can this engineered lumber be used as a direct substitute for regular 2x10s? In other words, in this portable application, will they be as sturdy as screwed/glued 2x10s?

Thank you.

[PVJunkie]

YES, they are structurally stronger than a 2X10. Its a shame you got the 11.75 version, I think there is a shorter version that could have reduced your weight even more.

If you use a 2X8 (7.25" tall) with 2x4's (1.5" tall) to span the 2X8 rails then put your plywood (.5" tall) on top you end up with about 9" tall. More than enough to accomodate an 8" deep box. The less mass you add the lighter you end up.

For my last runway build I made my own "joists" out of 2x4's and even with the rubber glued to each section they are manageable with 2 people.

[ClintonMagus]

They do come in 9.5 inch also, but they would have actually cost more than the taller ones. The distributor has an overabundance of the 11.75 in stock, and is willing to cut us a deal to get rid of some of them. He can also ship those directly from his location with the rest of the Home Depot shipment, while the shorter ones would have to be freighted separately.

We even thought about building the beams ourselves, but for the price and the labor involved, it's worth it to buy them.

[ClintonMagus]

Runway update:

As it turned out, a friend of mine works for the distributor and was able to make us a very good deal through the school system. he ordered the 9.5-inch beams, but 11.75-inch beams were delivered so, to cut out as much weight as possible, I cut them down to 9.5 inches.

Here is an early photo, before cross-bracing and section connectors were added:

[Kstumpenhorst]

How often did you put cross bracing on your runway? Also how wide is this runway and was it necessary to have a I joist running down the middle as well? I am starting to build one myself, and for the money I don't want to do it again. Thanks for any advice or pictures

Kyle

[ClintonMagus]

It is 42" wide. We didn't put cross-bracing in anywhere except at the box end. There is a LOT of bracing there. We have had folks from 90 pounds to 170 pounds on the runway for more than six months, two nights a week plus extras, and there has never been any sign of instability.