The Striatus bridge

Abstract

The paper describes the physical realisation of a 3D-concrete-printed, mortar-free, unreinforced masonry arched footbridge, designed for disassembly and reuse. The paper also details the novel integrated design, engineering and fabrication framework and the manufacturing and assembly processes used for the project. The research, motivated by the rapid growth in large-scale 3D concrete printing (3DCP), addresses the current lack of both design tools and integrated design-to-production solutions. It is guided by the insight regarding the applicability of design and analysis methods used in unreinforced masonry to large-scale, layered 3D printing with compression dominant materials such as concrete. Thus, the underlying computational framework and integrated design environment further extends and adapts advances in the computational design and analysis of unreinforced masonry structures to 3DCP masonry blocks. Adopting an unreinforced masonry paradigm for the design of 3DCP structures can make it possible to (i) reduce the amount of concrete used by allowing precise placement of concrete only where needed along the compressive flow of forces, (ii) reduce the amount of steel needed by reducing tensile and flexural strength requirements through a compression-appropriate design of both the global, shape and the block discretisation, and (iii) reuse components, repair the structures and recycle materials more easily. This paper builds on the relevance of the computational masonry paradigm to both delivering the ecological promises of 3DCP and to the development of a 3DCP-specific, design-to-production toolkit.