funicule structure and function
Answers
Answer:
Explanation:
Conceptually, a funicular structure could be said to be a structure which can achieve equilibrium state by adopting a mechanism of a 'right' form (shape/geometry) corresponding to the applied loads. This ‘right’ form is referred to as the ‘funicular’ geometry.
Medieval vault builders created complex forms carefully balanced in compression
For eg: A catenary cable is a ‘funicular’ geometry for uniformly distributed loads. Under any other loading pattern, this shape is non-funicular, as the cable mechanism needs to move considerably to find an equilibrium state.
In order to achieve a stable structure, the geometry of the structure needs to be funicular (i.e, reciprocal) to the loading condition . The process of tailoring the geometry (form) of the structure to be funicular to the loading condition is called ‘form finding’.
Funicular structures’ geometry could be said to be derived from the funicular polygon, a term from graphic statics.
A french mathematician Pierre Varignon (1654-1722) introduced the funicular polygon and the polygon of forces. He described a way to construct the form of a hanging rope with attached weights graphicaly. Based on this principle, a technique called graphic statics was developed in the 19th century.
The basic principle of graphic statics is the reciprocal relation between force polygon and funicular polygon and utilization of graphic methods of analysis using geometric constructions.
The primal grid and dual grid are related by a reciprocal relationship. The equilibrium of a node in one of them is guaranteed by a closed polygon in the other and vice versa.
Check out this excellent link on geometric constructions of force polygons and Funicular polygons: An Introduction to Graphic Statics.
The same principles can be extended to three dimensional structures.
Three-dimensional extension of graphic statics, based on polyhedral form and force diagrams, for compression-only and tension-only spatial structures with externally applied loads.
Catenary curves are generally considered synonymous to funicular curves. Gaudí was among the first to use this element in architecture. Catenary arches allowed Gaudí to add an element of great strength to his structures, by distributing the weight regularly and evenly.
An upside down force model of the Colònia Güell, Sagrada Família Museum
Gaudi used inverted scale models of his proposed structures using weights supported by strings which produced the correct catenary curves and surfaces required to minimize stresses in the design and allowed him to eliminate supporting beams or buttresses which had been necessary until then.
Architecturally, funicular designs result in highly efficient integral structural design and opens up a whole new design vocabulary. Funicular design forms seem natural and impart a certain lightness to the structure.
Some modern methods of form finding include Thrust Network Analysis (TNA), an interactive design tool for exploring and designing funicular structures.