Ultra-lightweight construction

Abstract

Preface 'Lightweight construction-a demand of our time' was the title of an article written by Fritz Leonhardt 1 in 1940. Against the background of Germany's economic situation at that time-strongly affected by a lack of resources resulting from the recently erupted war-Fritz Leonhardt considered topics such as the availability of raw materials and the importance of mass flows. From these considerations, he derived instructions for the building industry. The instructions could be summed up as an overarching demand for 'lightweight'. In the decades after the war, Frei Otto then laid the foundations for a fulminant development of lightweight construction, which led to spectacular buildings such as the Munich Olympic roofs. Today, the developments initiated by Fritz Leonhardt and Frei Otto are more relevant than ever: The ever more noticeable consequences of global demographic growth as well as large migration movements and the imminent exhaustion of various resources are distinctive challenges that lie in front of us all. Again, it comes to the careful use of limited resources, but now on a much larger scale. Today, more than ever, we need a 'lightweight for all', with a scope that is much larger (both thematically and geographically speaking) than before. Lightweight construction of the future will not only strive to minimize the volume and weight of materials used. It will also have to pay close attention to a minimization of embodied energy and to the development of recycling-friendly construction methods. Another important feature will be that lightweight construction will have to provide solutions for many different countries and cultures because the problems confronting us are global and can only be tackled with a global approach.

Force and Shape Control Strategies for Minimum Energy Adaptive Structures

“…Several systems have been studied to control the structural response including building frames equipped with active bracings/columns (Reinhorn et al, 1993;Wagner et al, 2018;Weidner et al, 2018) and variable stiffness joints as well as bridges equipped with active cable-tendons (Rodellar et al, 2002;Xu et al, 2003). Through integrated structure-control optimization (Smith et al, 1991;Begg and Liu, 2000;Soong and Cimellaro, 2009;Frohlich et al, 2019) civil structures can be designed to adapt (e.g., react positively) to rare loading events of high intensity in order to operate closer to required limits, which results in a better material utilization compared to equivalent weight-optimized passive structures (Teuffel, 2004;Sobek, 2016;Böhm et al, 2019). Material savings, however, are only possible at a cost of energy that is required to operate the adaptive system.…”

Using Influence Matrices as a Design and Analysis Tool for Adaptive Truss and Beam Structures

“…Overall, the building industry accounts for 35% of all global CO 2 emissions, thus being a significant contributor to the ongoing climate change. Furthermore, 35% of the global energy consumption can be attributed to the built environment and 50% of the global resource consumption (UNEP, 2011;Sobek, 2016), leading to an ongoing depletion of vital resources, like sand (Peduzzi, 2014). The global growth of population and the increasing wealth in several parts of the world further intensify this effect (UN, 2019).…”

“…While there are early examples of supporting structures with integrated active components (e.g., Domke, 1992), most studies concentrate on the possibilities of active control of the dynamic properties of a given structure (Soong and Manolis, 1987;Reinhorn et al, 1992;Holnicki-Szulc et al, 1998;Issa et al, 2010). The manipulation of quasi-static deflections and internal forces with the declared goal of a resource-and emission-efficient design as formulated in Sobek et al (2006) and Sobek (2016) is still relatively new. This approach separates adaptive systems into three different states: first, the passive state, in which the structure acts as a conventional system under external load; second, the active state, in which the structure is subjected to actuation; and third, the adaptive state, the superposition of passive and active states.…”

Integration of LCA in the Planning Phases of Adaptive Buildings

“…By integrating actuators and sensors into façade systems, the building skin can also be transformed from a typically static system into a dynamic one, for example, by regulating air, light, and heat permeability in real-time as required. With the integration of adaptive elements into load-bearing structures and skins, the building is able to react to changes in the environment and on differing user demands [2,3].…”