Shear - Tensile - Compression Stresses Slip Ted 126 Spring 2007

Shear Shear strength in mechanical engineering and structural engineering is a term used to describe the strength against the type of structural failure where a component fails by shearing when it splits into two parts that slide past each other. The shear strength of a component is most important for beams but also relevant for e.g. plates. In a reinforced concrete beam, the main purpose of stirrups is to increase the shear strength.

Shear Riveted and bolted joints may also be mainly subjected to shear stress. Cantilevers, beams, consoles and column heads are subject to composite loading, consisting of shear, tensile and compressive stress.

Tensile stress Tensile stress (or tension) is the stress state leading to expansion; that is, the length of a material or compression member tends to increase in the tensile direction. Tensile stress is the opposite of compressive stress. Structural members in direct tension are ropes, soil anchors and nails, bolts, etc. Beams subjected to bending moments may include tensile stress as well as compressive stress and/or shear stress.

Tensile Strength The tensile strength of a material is the maximum amount of tensile stress that it can be subjected to before failure. The definition of failure can vary according to material type and design methodology.

Compressive stress … applies to materials resulting in their compaction (decrease of volume). When a material is subjected to compressive stress then this material is under compression. Usually compressive stress applied to bars, columns, etc. leads to shortening.

Slip A slip joint is a mechanical construction allowing extension and compression in a linear structure. A slip-critical joint, from structural engineering, is a joint which relies on friction (rather than shear or tensile strength) to hold two things in place.

Slip The most common slip-critical joint is where a girder meets a larger beam. Typically an angle plate joins the two. One beam is welded to the angle plate, the other has holes which are generally oversized or slotted. The bolt through this plate doesn't actually take the load as a shear joint or a bearing joint, –it simply creates normal force and therefore friction between the two steel faces.