JOURNAL OF THE INTERNATIONAL ASSOCIATION FOR SHELL AND SPATIAL STRUCTURES: IASS 179 LIGHT-WEIGHT SELF-STRESSED SYSTEMS OR TENSEGRITY Messaoud Saidani 1) , Emmanuel Remise 2) 1) B.Eng. Ph.D. M.ASCE. Senior Lecturer, Coventry University, School of Science and the Environment, Civil Engineering Division, Priory Street, Coventry CV1 5FB, England, UK 2) 8 Rue Bellevue, 48120 Saint Alban, France (Previously Research Student, Coventry University) SUMMARY The word tensegrity is a contraction of tensional integrity. In simple structural terms, tensegrity systems are self- stressed pin-jointed networks. Each node receives at least one strut (compression member) and three cables (tension members). Tension members are thus prestressed against adjoining compression members. This is a pure form of tensegrity where only compression and tension members co-exist to form free-standing structures requiring minimum anchorage system compared with conventional types of structures. Double layer tensegrity systems are interesting because the compression members are relatively short, making the network quite rigid and compact. In the non-prestressed state, the system could be easily deployed. The present paper reviews limited research so far conducted at Coventry University on double layer tensegrity networks. It also reviews future directions in research into this fascinating field that has yet to be fully explored and exploited to find proper applications for it in the civil engineering discipline Keywords: Tensegrity, Self-Stressed Systems, Tension Structures. 1. INTRODUCTION Tensegrity, a contraction for tensional integrity, is a fascinating concept developed by sculptor Kenneth Snelson [1], [2] (Fig 1) and later patented and explored by Buckminster Fuller [3]. Since then, these structures did not stop posing intriguing and interesting questions to mathematicians, architects, and engineers alike. The concept of tensegrity relies on using a suspension of discontinuous compression, which effectively acts as a stiffening system, in a continuous tension system. To date some work has been done with the aim of understanding these structures from geometry point of view but also from an engineering viewpoint (structure and its mechanics). However, the main problem is to find applications of the system in practical terms as to its suitability in construction. Over the years, researchers have attempted to find a suitable definition to the system, but the characteristic that is unique to tensegrity is the fact that they are lightweight self-stressed and self- supported systems. It must be stated that, while the cables are obviously rectilinear, the struts, however, don't have to, they could be rectilinear but they could also be curved for example (although this would introduce bending in the struts because of the eccentric loading). Work undertaken to understand their structural performance has been conducted by Emmerich [4], Motro [5] and [6], and Hanaor [7] and [8] among others. However, there is still a lot to be achieved before tensegrity could compete with traditional structures. Some of the problems hindering the use of this fascinating system are: 1. Large deflections as compared with conven- tional forms of construction even for relatively small loading; 2. Difficulty in pre-determining with precision the initial geometry of the structure (dependent on the level of pre-stress present); 3. Complexity of the fabrication process, this is exasperated by the difficulty in connecting all the different elements together without intro- ducing bending forces in the struts (main- taining pin-jointed connections); 4. Congestion of elements especially for large structures (such as for space enclosing purposes);