Civil Engineering Association

This thesis is dedicated to developing a new structural concept which is rapidly
deployable and structurally effective. During the recent hundred years, various types of
spatial structural systems have been developed for different civil engineering and space
applications such as stadium cover, exhibition roof, communication boom, etc. Some
of these systems are structurally effective and thus have been used widely such as
double-layer space trusses. Some other types of spatial structures have been proposed
to be effective in construction time such as deployable structures. The structural
products developed in this research inherit both advantages of double-layer space
trusses and deployable structures in one system, which is named as Deployable
Tension-Strut Structure (DTSS).
Structural morphology of DTSSs is related to their mechanical features. The
morphology study shows geometric rules which is linked to deployability of the
structures and the locking mechanism. These geometric rules (shape grammar) serve as
a basis to develop an exhaustive design creation algorithm which is able to
automatically find numerous viable forms of DTSS. Although the algorithm is a
generative design tool, it is controllable in comparison with stochastic methods such as
genetic algorithm. The reason is shape grammar of DTSS is implemented from the
beginning of the design creation process.
Structural behaviour of the proposed DTSSs is investigated by advanced non-linear
structural analysis. The understanding of structural performance is a basis to deduce
the optimum design parameters of DTSS such as the span to depth ratio, and the
number of module in a span length. The newly proposed DTSS is also compared with
conventional double-layer space trusses by using a proposed Structural Efficiency
Index, which consider both self-weight and stiffness of the structure in the evaluation.
The result shows that DTSS is comparative to double layer space truss in terms of
structural efficiency.
Rapid deployment concept of DTSS is proved by prototyping and computer modeling.
The computer models show the possibility of deployment and the prototypes show that
the details of proposed joint system are suitable to accommodate deployability.
Experimental investigations show that the designed steel joints are stronger than the
structural steel members. The stiffness of joints allows folding of the structure
(removal) after full service load is applied. The tests show that service load level
causes insignificant deformation in the joints.