Design optimization of hybrid steel/timber structures for minimal environmental impact and financial cost: A case study

In the overall aim to build more sustainably, the energy performance of buildings has received a lot of attention in the past decade. In consequence, the embodied impact of buildings has become relatively more important. As the load-bearing structure is responsible for a large share of this embodied impact, it is important to design it in such a way that its environmental impact is as low as possible. Unfortunately, the best construction materials in terms of environmental impact are not necessarily the cheapest. Reducing the environmental impact of the design may therefore lead to a higher financial cost, which may exceed the available budget. In such cases, hybrid structures, consisting of two (or more) different materials, might offer a solution, as they allow the designer to finetune the trade-off between environmental impact and financial cost. In this paper, we present a method to determine the best design of hybrid steel/timber structures in terms of environmental impact within the limits of the available budget. The method is based on the solution of a multi-objective structural design optimization problem involving environmental life cycle assessment and life cycle costing. It is applied to two test cases: a statically determinate and a statically indeterminate truss structure. The structures are optimized for three different design scenarios and typical load cases. This results in a Pareto front in the environmental and financial life cycle cost spectrum, allowing the designer to select the most appropriate solution, given the available budget. The results show that, depending on the design conditions, hybrid steel/timber structures are in some cases Pareto-optimal.

Publication year:2022

Accessibility:Open