Steel Flitch Plates when combined with wood are used to construct Steel Flitch Beams for residential and light commercial construction. They are used similarly to the way that built-up wood girders and headers (wooden beams that span the entirety of the area they are supporting) are used. Mostly, steel flitch beams are used in the construction of various structures that utilize wood such as houses, decks, and roofs. They are especially helpful in renovation projects which aim to build upon aging wood, however, they can be used in a wide variety of construction projects.
The name Steel Flitch Beam can be a little confusing for consumers because it implies that the beam is steel, however, the beam is primarily made of wood. Steel Flitch Beams are composed of two wooden beams (although there may be more than that added in order to strengthen the beam) and a horizontal steel flitch plate in between, all of which are held together and secured by bolts. Proper bolting is critical in making sure that the weight applied to the beam is correctly distributed between the wood and the steel plates. Usually, the weight or “load” is placed on the steel flitch beam at the top of the beam (the wooden part). Correct bolting helps ensure that the weight will move towards the steel plate and be distributed evenly. The steel component of the flitch plate Beam assembly is typically comprised of A36 Grade, ½”, ¾” and 1” Thick Hot Rolled Steel in lengths up to 20’ Long. (J. M. Ahle stocks common widths to match 2 X 8, 2 X 10 and 2 X 12 lumber; the wood component of the beam.) The construction of the beam is also straightforward. To make a flitch beam, firstly two wooden beams are cut to length. A prefabricated (Cut to length & drilled to accommodate Bolt Diameter) flitch plate is then put between the two beams and all parts are bolted together. This can also be called a composite beam. The word composite refers to the formation of a single unit from different materials (steel and wood).
Although steel is expensive, wood is not as sturdy, so steel flitch beams offer a cheaper, more cost-effective, and simple alternative to wooden beams alone or a beam made entirely of steel. Steel Flitch Plates are very important in the construction of these inexpensive beams. They make the primarily wooden beams far stronger than the wood alone without increasing costs too significantly. The wood, in turn, provides support at the sides of the slim piece of steel to prevent the plate from “lateral buckling” (bending at the sides). The load or weight that is shared between the steel flitch plate and the surrounding wood is determined by each of their respective Load Bearing Qualities. This shared load is proportional to the stiffness of each material. Some are even further reinforced with additional layers of wood or steel. The method of using steel flitch plates is especially helpful in the construction of larger buildings because the flitch plate enables the beams to be placed further apart from one another which enables the building to be larger. This creates a beam that can be used for a wide range of projects and sizes of projects.
The word “flitch” did not originate from its use in steel flitch plates and steel flitch beams today. In fact, its origin has little to do with steel or wood. It was used to describe bacon when it was cut into strips vertically from an originally large slab. Wooden beams were flitched like this--they were cut lengthwise and rotated so the potential defects of each individual half could be separated from one another. Pine beams were used before steel for their elastic properties over longer lengths. In the 20th century, steel flitch plates began to have widespread use in many different construction projects. At the time, steel became much more affordable for consumers and was considered a safer alternative to all wooden beams. The use of steel flitch beams also offered the advantage that they took up less space than wood alone did. In The American Architect and Building News, an article came out in 1883 discussing the advantages of steel flitch plates in which they were shown to be cost effective and even fire retardant.
There are several different uses for Steel Flitch Plates and Steel Flitch Beams. Steel Flitch Plates and Steel Flitch Beams are very versatile, but are best used in home projects. Firstly, Steel Flitch Beams are advantageous because of their great strength. A flitch beam is better at transferring load over long distances so they are used in those situations such as the construction of a roof. Flitch beams can sustain heavier loads and are much lighter than an all steel beam which makes it the perfect candidate for home projects such as the construction of a roof. The use of steel flitch beams ensures safety. Secondly, an all steel beam would make home projects difficult that already use many wooden beams. With steel flitch plates and beams, it is easy to add onto wooden beams by using bolts and screws. This would not be possible if all steel beams were being used. Another good use of Steel Flitch Beams is in renovation projects because they can help reinforce aging wood and they work with wood very easily. Lastly, they can also be used for aesthetic purposes in renovation projects in which the look of a wooden beam but the strength of a steel beam is required. For example, if a project called for the appearance of wooden beams with the strength of a steel beam, steel flitch beams are perfect at striking this balance.
J.M. Ahle offers high quality steel flitch plates in a variety of sizes and shapes for various uses in the Central New Jersey area. If you would like to buy them or have some questions, please contact us at (732) 238-1700.