Structural Connection

in engineering, a connection serving to join the individual members of a structure, to ensure the reliability of the structure, and to provide for the proper functioning of the structure as a whole in accord with the requirements of use and assembly. Connections are also used to join separate structures in order to provide rigidity, spatial distribution of structures, and construction of reinforced building units. A distinction is made between shop connections, which are made while fabricating the structure at the plant, and field connections, which are made at the construction site. The choice of a connection is dictated by the magnitude and nature of the loads involved, the material of the members being connected, and the operating conditions of the structure or building.

In prefabricated, reinforced-concrete construction, the two types of connections used for joining beams, columns, slabs, and panels are the reinforced-concrete type and the metal type. In the reinforced-concrete type, provision is made for the transfer of forces by welding or by an overlap of the reinforcing rods with subsequent sealing of the joint with concrete. In the metallic type of connection, the forces are transferred by welding together steel insertion elements anchored inside the units being joined.

In metal construction, welded connections, which are the most common, riveted connections, and bolted connections are the principal types. The use of welded connections in structures subject to alternating or dynamic loads, for example, bridges and the booms of heavy-duty cranes, is limited in view of the adverse effect of such loads on the durability of welded joints. In riveted connections, forces are transferred either directly through the members being joined, as in a lap joint, or by means of of additional plates, as in a butt joint. Bolted connections are used mainly in assembly; their design and functioning is similar to that of riveted connections. Bolted connections using high-strength bolts made from heat-treated steel are very effective.

In modern wood construction, glued connections are preferred. They permit an increase in both the cross section and length of the joined members and guarantee that the joints have the same strength as the construction material itself.

Connections of other types, such as those using laminated dowels made of oak or impregnated birch and connections made with bolts, nails, and dowels of round steel, are becoming increasingly rare. Mortise-and-tenon connections are now obsolete.