An Eco-Effective Structure

Abstract

Globally the construction is a major contributor to the severity of the anthropogenic environmental impact. The sector emits 39% of the global CO2 and is responsible of 40-50% of material flows. The focus of reducing the environmental impact in buildings is, in the past, mostly attributed to the operational energy. However, due to increasing renewables and efficiency, that share is declining. Making the embodied impact in a building relatively more significant. The structure encompass the largest part of the embodied impact in buildings. The materials, components, and systems embedded in a structure are often still of high value when the building reaches its end of life, i.e. the technical service life is not yet achieved. To reduce the environmental impact of structures and therefore buildings as a whole, one should integrate design measures for new constructions to grasp the most value out of the incurred embodied impact. Three eco-effective structural design criteria are established that encapsulate the structure's whole life cycle - material environmental costs (product and construction stage), service life (use stage), and residual value (end of life and benefits beyond system boundary stage). These structural design criteria are merged from the following structural design perspectives - material selection and material use (material environmental costs); durability, maintenance, adaptability, and flexibility (service life); and waste effectiveness, disassembly, reusability, and recyclability (residual value). In the eco-effective paradigm, one focuses on the future value of a product. This may entail that more material environmental costs could be made, but in the end you will be rewared with either a longer service life or more residual value. Therefore, the emphasis is put on the latter two structural design criteria. A crucial bottleneck of not attaining the technical service life of a structure on a building level, is the functional service life. The functional service life should be equalized with the technical service life to grasp the full potential of a building structure. Three strategies have been constructed based on the structural design perspectives and the structural design criteria. Design for Durability; thus, equalizing the functional service life with maximization of the technical service life. For this strategy, it is imperative that solely one function will inhabit the building. Examples are churches, temples, museums, i.e. buildings with a sentimental and/or historical value. The second strategy is Design for Multifunctionality. This is for buildings that have proven not to stand the test of time. Therefore, conditions should be created in the structure that it could be possible for the function to be converted (n functional service life = technical service life). These two strategies are on a building level. The following strategy is on equalizing the functional and technical service life on a component level. This is done by Designing for Disassembly. In this strategy, it is known that the service life of the building relatively small. These eco-effective structural design strategies can be used by structural engineers during the conceptual design to reduce the environmental impact on the long-term.