Wooden I-Beam

The Wooden I-Beam

Steel - the most common material used in building or for reinforcing man-made structures is itself a fabricated material; by adding carbon to naturally soft(er) and pliable element that is iron. Once infused with carbon iron is now steel. But the one attribute that cannot be avoided is its weight, specially on "long span" applications. So, to counter the sagging effect of weight to strength ratio over long spans, the I-Beam was invented. The I-Beam allowed for countless structures to be created with less weight and material - from railroad tracks to steel frames for skyscrapers to long-span bridges, even to car chassis, etc.

Timber and wood are also one of the most widely used construction materials and technology also caught up with their development along the path taken for iron. Modern engineered wood begun with the creation of plywood and laminated wood. Today, wide plywood boards laminated with narrow boards along opposite edges make for a very rigid material that resist bending with a lower weight to high strength ratio.

In a much smaller scale, this is my version of the I-Beam made from the most common wooden material - stock lumber from the home center and plywood construction sheets and glue. I think the photos are self-explanatory enough except for a few notes on certain tips.

First, 2 X 4 stock lumber ripped to witdh and cut to length.

Stacked dado blade cut the 1/2 inch channel along the length of the work pieces cut to width.

Narrow strips of 1/2 inch plywood ripped to desired width.

Tip: Sometimes lumber, stripped to narrower widths, might warp or curve. Next two photos show two thicker, more rigid flat lumber used as backer boards from which clamps are anchored during glue up.  When the glue dried the finished I-Beam will have been relatively free of any significant curving or warping.

Had a similarly-dimensioned lumber been used the span will at first be straight and appear stiff, but once weight is added it will over time sag towards the middle.  This I-Beam construction, using only two spans and lighter than solid pieces of the same or even thicker dimensions, will remain straight and rigid. This has potential for other construction applications, such as work benches and heavy duty shelves.