Additive Building Manufacturing (ABM) is transforming the construction industry through the 3D printing of buildings and building components. A number of countries are now demonstrating ABM can substantially reduce construction time, material and transport costs, improve worker safety standards and alleviate construction's impact on urban traffic congestion and the environment. ABM also provides geometrical variety at no additional cost. In contrast to most manufacturing sectors, variety is a necessity within construction to satisfy different client requirements and adapt to unique terrain, boundary and laws governing each physical site. However, current ABM systems are difficult to deploy on construction sites due to their large size and fixed 3D Print build volumes that are not sufficiently flexible to deal with the complexities of most building scenarios, or provide adequate measures for human safety. These ABM technologies are unable to undertake maintenance and repair work, or construct buildings in many urban or elevated sites. They are also not able to be utilised for post-disaster reconstruction activities where their manufacturing speed would be of great assistance. To address this limitation, this research proposal aims to develop the world's first Aerial Additive Building Manufacturing (Aerial ABM) System consisting of a swarm of aerial robots (Unmanned Aerial Systems (UAS)) that can autonomously assess and manufacture building structures. Aerial ABM offers major improvements to human safety, speed, flexibility, and manufacturing efficiency compared to existing ABM and standard building construction technologies. We have already developed and demonstrated pilot results using UAS that can extrude 3D Print material during flight and we have developed simulation environments that allow for autonomous planning and execution of manufacturing with swarms of UAS working in collaboratively. Using the resources of the EPSRC grant, we will co-develop and demonstrate a working Aerial ABM system that will manufacture structural elements such as walls and a freeform building pavilion. This will require innovation and major technical contributions in Hardware, Autonomy as well as in Materials and Structures. Building on the consortium's world-leading expertise in these areas and support from industrial partners (Skanska, Ultimaker, BuroHappold, Dyson and BRE), we aim at delivering the following main research contributions through this grant: Aerial ABM Hardware - A novel Aerial ABM robot design with autonomous vision based stabilisation, navigation and mapping of a dynamically changing environment that is optimised for flight and 3D Printing tasks. Aerial ABM Autonomy - A framework for autonomous manufacturing that utilises swarm intelligence for collaborative robot-to-robot operations, dynamic task sharing/allocation, adaptive response to context and dynamic environment content involving functions such as new methods of collision avoidance. - Develop new modes of communication and control that enable the safe co-existence and cooperation of human workers, other robots and Aerial ABM robots on construction sites. Novel research in human-robot interaction, feedback and haptic interface functionalities will enable manufacturing flexibility suitable for construction sites that are always unique in size, shape and contextual complexity. - An integrated design and real-time structural analysis software that delivers optimal structural integrity from minimal material weight within building design strategies that leverage this free-form manufacturing process to create innovative building design possibilities. Aerial ABM Materials and Structures - Development of new high-performance 3D-printable composite material and deposition procedures for the additive manufacture (3D Printing) of free-form light-weight building structures utilising autonomous UAS.

The UK and the European Union have legally binding targets for reducing carbon dioxide emissions and for the increasing renewable energy generation. As about 25% to 33% of the UK's annual energy usage is expended on space heating, the provision of renewable heat energy is an area of critical importance if emissions and energy targets are to be achieved. Increased use of ground energy systems within foundations and other underground structures would be beneficial in both these respects, and will be eligible for financial support through the forthcoming government Renewable Heat Incentive. However, despite a recent increase in the use of ground energy systems, there remain key areas of uncertainty about their performance. This is especially important in the long term, where multiple installations will interact with each other and where unbalanced heating or cooling loads will lead to changes in the thermodynamic regime in the ground. This project aims to address some of the uncertainties surrounding ground energy systems installed in foundations by comprehensively instrumenting and monitoring two sites in contrasting ground conditions. This will allow the real response of the ground to known heating and cooling loads to be measured, and comparisons made with predictions based on analytical and numerical models. The use of contrasting geological regimes will allow investigation of the impact of groundwater on the performance of systems, something rarely considered and not well understood. The field monitoring will be accompanied by a programme of in situ and laboratory testing to assess differences in thermal behaviour at different scales and temperatures relevant to ground energy systems. The testing programme will address questions relating to degrees of uncertainty in determining key thermal properties and how this may compare with other uncertainties in the system design, such as heating/cooling loads. Numerical modelling, including back analysis of the in situ thermal response testing and operation of the ground energy systems, will allow assessment of the sensitivity of the systems to different input parameters. The modelling will also allow evaluation of the numerical and analytical techniques currently used for the design of ground energy systems and assessment of the importance of key factors (geological variation, groundwater, surface boundary conditions, geothermal gradient) not currently accounted for in existing methods. Taken together, the various strands to the project are expected to provide an important dataset which will add substantially to the understanding of the performance of ground energy systems. By addressing uncertainties surrounding design input parameters, geological conditions and design approaches, the project will also provide relevant lessons for direct application to the design and construction of ground energy systems installed in foundations, which it is expected will ultimately form part of improved guidance for industry.

The construction industry consumes around 400 million tonnes of materials every year, a quarter of all raw materials used in the economy. It also produces annually three times the amount of waste generated by all UK households combined. The industry produces 90 million tonnes of inert waste every year, and approximately 10% of UK carbon dioxide emissions are associated with the manufacture and transport of construction materials and the construction processes. It is therefore important that the construction industry changes the way it designs and builds to reduce its environmental impact and to enable the UK to meet its carbon dioxide reduction commitments. The main theme of this proposal is to achieve the goal of this initiative from the geotechnical aspects of building construction using the outcome of an EPSRC project Smart Foundations with Distributed Fibre Optics Technology (EP/D040000/1) . The project delivered the following research outcomes: (i) a foundation design tool that optimises the layout and geometries of foundations (both piles and raft), thereby minimising the use of construction materials while achieving similar building performance, (ii) a foundation design tool that considers reuse of existing foundations for new buildings, and (iii) an inexpensive optical fibre strain measurement system to ensure the foundation based on the optimised design is performing as predicted in both short- and long-terms. This follow-on project aims to commercialise the research outcomes by converting the complex algorithms developed on research-based platforms to more user-friendly formats so they can be used directly by the industry. It consists of the following two major efforts: (a) development of middleware that converts raw Optical Fibre Strain (OFS) data to engineering performance data and (ii) coding of the foundation design tool into C++. The expected outcome is an engineering software package that aids the design and optimisation analyses of new and reuse foundations, determines the need and optimum locations of foundation instrumentation, and converts raw OFS data into engineering data for short- and long-term monitoring endeavours.

Construction is significantly behind other UK sectors in productivity, speed, human safety, environmental sustainability and quality. In addition to inadequate building supply and affordability in the UK, humanitarian demand and economic opportunity for construction is set to increase substantially with global population growth over the next 40 years. However, with an aging work-force and construction considered to be one of the most dangerous working environments, the industry needs to explore radically new approaches to address these imminent challenges. While increased off-site manufacturing provides a partial solution, its methods are not easy to automate. Where individual mass-produced parts can be moved efficiently through production assembly lines that separate workers from dangerous machinery, building manufacturing involves mass-customisation or one-off production at a larger scale. This requires machinery and people to move around, and potentially work inside of a fixed manufacturing job e.g. a prefabricated or on-site house, as various independent and parallel tasks are undertaken in safety-compromised, overlapping work-zones. To address these issues, this project investigates fundamentally new operational and delivery strategy for automation to offer new ways of working with robots. Automation of shared construction environments requires robotic capabilities to be flexible and adaptive to unpredictable events that can occur (indoors or outdoors). Social insects such as termites, despite their small size and individual limitations, show an ability to work collectively to design and build structures of substantial scale and complexity; by quickly and efficiently organising themselves while also providing flexible, scalable coordination of many parallel tasks. Inspired by this model of manufacture, this project will develop an innovative multi-agent control framework that enables a distributed team of robots to operate in a similar way for the manufacture and assembly of buildings undertaken by off-site manufacture, on-site construction, or hybrid solutions using on-site factories. This requires the enhancement of existing robots, and development of new capabilities for collision avoidance and collaborative working. As many building tasks require specialist equipment, heterogenous teams comprised of different robot platforms such as agile mobile ground vehicles (UGVs), aerial vehicles (UAVs), alongside larger scale industrial robot arm, track and gantry systems, will be able to collaborate, and collectively undertake tasks beyond the capabilities of each individual robot such as lifting objects heavier than any one robot's payload capacity. To address construction relevant challenges, we will integrate capabilities for additive manufacturing, manipulation and assembly for building and building-component scale manufacture, in addition to computational means for individual robots to make local decisions. The final research deliverable will be the demonstration of the world's first collective multi-robot building manufacturing system that can autonomously build parts such as a façade or roof, assemble a structure, or construct a freeform building pavilion. We will also integrate these technologies within prototype building systems themselves, to create a new type of 'active' building that can use a multi-agent system to self-regulate energy and harvest data to provide a closed operational ecology between design, manufacturing, construction and building use, revolutionizing the way we manufacture, operate and use buildings. Further, evaluation frameworks will be developed to assess multi-robot construction and obtain objective measures for collective systems to deliver greater resource efficiency, quality, speed, safety and up-time compared with established construction methods. In doing so, we will establish new metrics quantifying the impact of these technologies from both economic and environmental perspectives.

Design limits are frequently based on strain developing in the structure. Although strain measurement is well established, current practice has until recently been restricted to measurement of point-wise strains by means of vibrating wire (VWSG) or metal foil strain gauges and more recently by fibre optics utilising Fibre Bragg Grating (FBG) technology. Where structures interact with soil, (e.g. underground infrastructure such as foundations, tunnels or pipelines) or indeed in the case of a soil structure (road or dam embankments), the state of the structure is not fully understood unless the complete in situ strain regime is known. In the context of monitoring strain in piled foundations, tunnels, pipelines, slopes or embankments, capturing the continuous strain profile is often invaluable to pinpoint localised problem areas such as joint rotations, deformations and non-uniformly distributed soil-structure interaction loads. In this project, we propose to use a unique fibre optics technology called the 'Brillouin optical time-domain reflectometer (BOTDR)'. The novel aspect of this new technology lies in the fact that tens of kilometres of fibre can be sensed at once for continuous distributed strain measurement, providing relatively cheap but highly effective monitoring systems. The system utilizes standard low cost fibre optics (potentially 0.1/m) and the strain resolution can go down to 2 micro strains. We will demonstrate the importance of distributed strain measurements to monitor the performance of building foundations at field sites in the UK and US. Using the distributed strain data, a design tool that optimises the performance of foundations that require rehabilitation, repair and reuse will be developed with industrial collaborators. The project has supports from UK Industrial partners as well US collaborators (National Science Foundation and Northwestern University).