The influence of life cycle inventory approaches on the choice of structural systems to reduce the embodied greenhouse gas emissions of tall buildings

Abstract

The construction of tall buildings generates a high spatial and temporal concentration of greenhouse gas (GHG) emissions. Research has shown that as building height increases, more resources per floor area are required to withstand the increasing effects of wind and earthquake loads. This has major implications for the environmental performance of tall buildings since the embodied GHG emissions (EGHGE) of structural systems tend to represent the greatest portion of the life cycle GHG emissions of tall buildings. In mitigating the effects of climate change, life cycle assessment (LCA) has been proposed as an early stage design tool to facilitate the choice of structural systems for tall buildings. However, international standards on LCA do not specify which of the three main life cycle inventory (LCI) approaches to use - process analysis, environmentally-extended input-output analysis or hybrid analysis. The aim of this paper is to evaluate the influence of LCI approaches on the choice of structural systems for tall buildings to minimise their embodied GHG emissions.

The effects of LCI approaches on the choice of structural systems for tall buildings are evaluated using 10 tall buildings, ranging in height from 10 to 50 storeys, parametrically designed using finite element modelling. Two alternative structural systems are proposed and various LCI approaches are used to compare their EGHGE. The paper demonstrates that varying the LCI approach can significantly influence the values of EGHGE of structural systems for tall buildings by up to 116%. Notably, the paper demonstrates that, in minimising EGHGE, the adopted LCI approach can influence the choice of structural systems for tall buildings. The findings of this study confirm the need for clarity, transparency and comprehensiveness in the use of LCI approaches for comparative LCA studies, particularly in the structural design of tall buildings.