Energy and Cost Assessment of Adaptive Structures: Case Studies

Abstract

This paper demonstrates how adaptive design (details published elsewhere) can be employed to save, on average, 70% of whole-life energy on a range of spatial structures, the whole-life energy deriving from an embodied part in the material and an operational part for structural adaptation. Assuming some statistical distribution for the probability of occurrence of the loads, whole-life energy is minimized by combining optimal material distribution and strategic integration of the actuation system, which is only used when loading events exceed a certain threshold. Instead of using more material to cope with the effect of the loads, the active elements change the shape of the structure in order to homogenize the stresses and keep deflections within limits. Five case studies are investigated here: a tall building core, a trussed portal frame, a long-span arch bridge, a 3-pin roof arch, a double-curved shell, and an office tower supported by an exoskeleton structural system. The purpose of the case studies described in this paper is to study (1) adaptive structure performance in terms of mass and energy savings as well as monetary costs for both strength-and stiffness-governed design problems; and (2) design scalability to complex spatial configurations. The case studies confirmed that even for large complex structures, significant energy savings can be achieved, the more so as the structure becomes more stiffness-governed. In this case, the adaptive solution becomes competitive also in terms of monetary costs.