The University of Sheffield
Department of Civil and Structural Engineering

3d Printed Sleeve Formworks For Optimised Concrete Structures

Supervisor: Dr Andrew Liew

Consumer desktop 3D printers are able to produce inexpensive and relatively strong plastic additively manufactured geometries on ever-increasing print bed sizes. The additive manufacturing process can be exploited to produce almost any type of geometry multiple times using the same digital file. Although the output product size of consumer 3D printers is currently quite small, and uses a material that is not strong enough to be structurally feasible on its own in construction, it could be ideally suited to create lightweight and one-time/reusable concrete formwork components, potentially using a series of small inexpensive 3D printers in a systematic and modular manner. Utilising many printers could overcome the relatively slow print time, which is a consequence of the current technology and its high print resolution.

This project will investigate their potential use in creating linear structural elements in a sleeve formwork arrangement, to create 1D components such as columns, beams and the strut-ties of trusses, to create 2D-3D structures with high precision. By integrating structural reinforcement into the formwork designs, the resulting structures can be utilised on the construction scale, ideally with adherence to modern design codes for reinforced concrete design. The scaling-up for the construction industry requires many additional considerations such as concrete mix design, node connections and falsework design. The 3D printed material may be used either as a lost formwork, where it is not recovered from the structure with little financial consequence due to its low cost, or investigated to act as a quality surface formwork to produce an aesthetic concrete finish or acting also as a reusable component for subsequent casts. The low energy and portable nature of the formworks mean that designs can be created at one location and digital files sent close to the construction site for printing.

Additive manufacturing is particularly well suited in constructing structurally optimised geometries, as material is deposited in layers in areas where it is required most. This creates a link with with using the AM formwork production process to cast structural elements with atypical geometries, as a means to reduce material usage and also reduce construction complexity. This is preferred to many other typical subtractive methods for creating concrete formworks that involve the cutting, milling and subsequent waste of large quantities of material. Complex geometries that would not be possible with even traditional and CNC subtractive manufacturing are possible with AM, as well as potential reduced labour aspects. The research will involve using optimisation methods, digital geometric modelling, additive manufacturing resources, with the goal of realising full-scale physical demonstrators and tests after the successful completion of smaller proof-of-concept models.

This position is for a PhD student working full-time, after the successful award of a departmental EPSRC Doctoral Training Partnerships (DTP), or through a self-funded / scholarship placement. To apply please send a two-page CV and covering letter to a.liew@sheffield.ac.uk.

This project is NOT FUNDED, although Departmental/University scholarships are available for applicants who can demonstrate strong evidence of research potential.

Pre-requisite qualification

The successful applicant is likely to have a first degree in engineering or architecture. He/she will also have sound computer programming skills, to enable them to take full advantage of state-of-the-art mathematical optimisation and form-finding methods. Hands-on experience of digital fabrication processes, particularly additive manufacturing/3D printing, and also parametric design modelling tools, such as Rhinoceros and Grasshopper, are an advantage, though can alternatively be developed during the research.