Article Preview
TopBackground
The reciprocal frame is a three-dimensional beam grillage system and is arranged to form a closed loop. The name of ‘reciprocal frame’ was coined by Graham Brown in the UK in 1989 under the title of ‘Three Dimensional Structures’ to explain the grillage structure in which the beams mutually support each other. When a load is applied to any of the beams, it is shared by all the beams equally for being reciprocal. The etymology of ‘reciprocal’ is from the Latin word ‘reciprocus’ while recus means backward, procous means forwards. Reciprocity is, therefore, meaning that back and forth, offering the return of behaviors (being support and be supported) which provides a mutual benefit (Parigi and Pugnale, 2014).
Baverel used the term ‘nexorade’ to explain RFs. The etymology of nexorade comes from the Latin word ‘nexor’, meaning link. Nexorade means a family of mutually supported repeating member assemblies. The term creates complications with the notion of RF offered by Graham Brown, but they mean the same thing (Baverel, 2000).
Each member of the nexorade is described as ‘nexor’. The simplest form of a nexorade is called ‘fan’. In other words, it is the most basic arrangement of a nexorade. The nexors are joined to each other not only at the ends but also at the intermediate points. When nexors are joined, they develop a three-dimensional frame. At the connection of a two nexor cross-section, the minimum perpendicular distance between the centroids of these cross-sections is referred to as ‘eccentricity’ (e) and the position of every nexor depends on the eccentricity. The length of each nexor is denoted by L. The distance between one end of a nexor and an intersection point on the nexor is ‘engagement length’ (λ) (Figure 1).