POST+and+LINTEL

POST AND LINTEL

It is a system in which two upright members (posts, columns, piers) hold up a third member ( lintel, beam, girder, rafter) laid horizontally across their top surface. This is the basis for the evolution of all openings.

The job of the lintel is to bear the loads that rest on it without deforming or breaking. Failure occurs only when the material is too weak or the lintel is too long. Lintels composed of materials that are weak in bending, such as stone, must be short, while lintels in materials that are strong in bending, such as steel, may span far greater openings.

The job of the post is to support the lintel and its loads without crushing or buckling. Failure occurs, as in lintels, from excessive weakness or length, but the difference is that the material must be especially strong in compression. Stone, who has this property, is more versatile as a post than as a lintel.

Ancient uses of the post – and – lintel were refined but not fundamentally altered until the production of cast – iron columns, which, offering greater strength and smaller circumference, greatly reduced the mass and weight of buildings. Much construction in modern materials is based on the post – and – lintel system of the post.