A simplified method based on eco-efficiency indicators to estimate and optimize the embodied carbon of gridshell structures

The study presents a simplified methodology for estimating environmental impact values in gridshell structures. These lightweight and geometrically complex systems represent an emerging field in structural design where material efficiency and environmental performance are closely interrelated. The proposed methodology is based on optimised eco-efficiency indicators that link structural performance with environmental impacts. Although current regulations increasingly require life cycle analysis as a methodology for assessing the environmental impact of products and processes, there is still a lack of practical tools to facilitate decision-making in the early stages of design, especially in unconventional structures such as gridshells. The proposed methodology combines structural performance in terms of stiffness and strength with environmental data as embodied carbon (formerly indicated as GWP-GHG according to IPCC 2013 GWP 100a). This allows for a comparative analysis between different materials and geometries without the necessity of calculating complete structural models. The methodology introduces eco-efficiency factors for both the material and the project, revealing the optimisation potential of each structural solution. In particular, the solutions applied to the Mannheim Multihalle reference project show that timber models offer a better balance between structural and environmental performance, while solutions based on steel or aluminium have significantly higher embodied carbon values. The Mannheim Multihalle, designed in 1974–75 by Frei Otto in collaboration with Carlfried Mutschler, stands as a landmark in gridshell design for its vast free-spanning timber lattice shell and its pioneering integration of form-finding, structural optimisation, and lightweight construction. Achieving spans of 60–85 m without intermediate supports, it remains the largest self-supporting timber gridshell in the world. This approach allows environmental impact to be integrated as a fundamental parameter favouring more eco-efficient structural solutions in architecture and engineering. • Influence of Materials and Geometry on Efficient Gridshell Design. • New Methodology for Integrating Eco-Indicators into Gridshell Pre-Dimensioning. • Eco-Indicators as Guiding Parameters for Optimized Gridshell Design. • Factor Material and Factor Project quantify structural-environmental performance.