Shaped beams: unlocking new geometry for efficient structures

Abstract

Society is building at an unprecedented rate: to house over 200,000 people moving to cities each day building stock will need to double by 2060. Importantly, the embodied carbon of construction due to material extraction, manufacturing, transportation, and demolition accounts for 11% of global carbon emissions, and this number is only expected to rise. With no end to construction in sight, it is essential that we develop better building practices. The research presented in this paper begins with the critical issue of embodied energy in horizontal structural systems. In high-rise buildings, between 60 and 80% of the mass and embodied energy of the structure can be found in the floors, suggesting a compelling starting point for materially efficient design. A reduction in a floor system's mass can lead to a similar reduction in the mass of vertical (columns, walls) and lateral systems. This paper focuses on the design of horizontal spanning elements, such as floor beams and slabs, and has two parts. The first part evaluates and compares historic methods of shaped beam design and classical methods of structural optimization. The second part presents a new flexible method of beam shape optimization. These design methods for structural efficiency allow us to build far more with far less, reducing the environmental and economic costs of construction while meeting the demands of a growing population.

Evaluation of the dynamic response for scaled models of shaped concrete floor slabs

“…20,21 One potential solution to reduce the carbon footprint of concrete floors is through reducing material by geometric optimization, since typical floors are designed for ease of construction and thus often overuse material. [22][23][24] Optimized structures can ensure structural integrity while reducing material consumption and corresponding carbon emissions, with possible material savings up to 70%. [21][22][23] Yet lighter, geometrically optimized floors may have adverse effects on the dynamic performance of the structure when they are not properly considered, 25 potentially inadvertently affecting the natural frequency and the sound attenuation.…”