PixelFrame: A reconfigurable, precast, post-tensioned concrete structural system for a circular building economy

The demand to build for a growing urban population conflicts with the need to reduce the AEC (Architecture, Engineering and Construction) sector’s contributions to global CO₂ emissions. Structural systems are a key factor in this challenge, as they contribute substantially to a building’s mass and are typically overdesigned. In this paper, we present PixelFrame, a new precast concrete structural system that is algorithmically designed to use less carbon upfront and be reused across multiple lifecycles. We achieve a high reuse potential for structural elements through building load demand analysis, a segmental externally post-tensioned design, and an integrated optimal assignment strategy. In addition to improving reuse potential, a segmental optimization strategy also yields higher efficiency in comparison to traditional prismatic concrete structural elements. The detailing of concrete mixes is informed by a statistical analysis of anticipated building load demands and a custom clustering asymmetric distance function and clustering algorithm. Compared to previous work in this area, our contribution is original in its bidirectional algorithmic approach; both the target building structure and the circular material inventory are computationally generated to achieve versatility while minimizing emissions.