Flitch beam

[1] Similarly, a wooden beam was flitched by cutting it lengthwise; one half was then rotated 180 degrees both longitudinally and laterally to ensure that any defects were separated.

An 1883 article from The American Architect and Building News compares three alternatives in a hypothetical railway station "in which the second story is devoted to offices, and where we must use girders to support the second floor of 25-foot span, and not less than 12 feet on centres if we can avoid it.

An adaptive use project in the UK, changing stables into offices, required cutting the beam supporting a floor down its entire length, and then inserting a similarly sized steel plate.

The resulting flitched beam was then secured with resin and bolts, preserving appearance while providing strength.

The steel plate is treated as an equally stiff piece of wood, with its width modified by the ratio of their moduli of elasticity.