VSimulators is a worldwide unique facility for exploring how people experience motion and vibrations in the build environment, such as sway in tall buildings, vibration of lively floors, or movement of footbridges. The facility consists of a pair of simulators located at the Universities of Bath and Exeter providing complementary capability in mimicking motion and environmental factors in the built environment. Using hydraulic actuators driving a climate controlled room, the Bath machine can simulate biaxial movement at ultra-low frequencies with large amplitudes primarily to study comfort and health of occupants in tall and super tall buildings which are proliferating in cities across the world. The Exeter machine uses a 6-axis electric 'hexapod' actuation system supporting a rigid 4 meter square platform. This will simulate multi-axis motion primarily to study comfort of humans using footbridges, floors and grandstands vibrating in response to occupant dynamic forces. The Bath machine will incorporate peripheral video displays of internal and external environment, systems for sophisticated environmental control and measurement of occupant physiological and psychological reactions, while the Exeter machine will use sophisticated virtual reality and full capability for force identification and motion capture of occupants. Using shared equipment (e.g. treadmills, inertial sensors, optical motion capture) and technical support the complementary capabilities will be applied to research human-structure interaction (based upon human comfort, well-being and productivity), assisted mobility and rehabilitation and populate a spectrum of vibration serviceability guidance. The facility will provide a worldwide unique capability available to researchers and practitioners from a range of industries and backgrounds. Together with this multi-disciplinary network of people, VSimulators' unique capability will transform what research we are able to do and how we carry out that research.

Cement manufacture accounts for about 5% of global carbon dioxide emissions, the single largest contribution of any man-made material. Despite this, research has shown that concrete is generally inefficiently used in the built environment. This fellowship will look to reduce the global environmental impact of concrete construction through a new method for the analysis of reinforced concrete structures that is well suited to producing the optimised designs that have the potential to significantly reduce material consumption. The new analysis method will be considered alongside practical construction processes, building on previous work by Dr Orr in this field, thus ensuring that the computationally optimised form can actually be built, and the research adopted, in industry. Most existing computational methods poorly predict the real behaviour of concrete structures, because their underlying mathematics assumes that the structure being analysed remains continuous as it deforms, yet a fundamental property of concrete is that it cracks (i.e. it does not remain continuous as it deforms). In contrast to finite element methods, this fellowship will develop a meshfree analysis process for concrete based on 'peridynamics'. The term 'peridynamic' (from 'near' and 'force') was coined by Dr Silling (see also statements of support) to describe meshfree analysis methods in solids. This new approach does not presume a continuous displacement field and instead models solid materials as a collection of particles held together by tiny forces, the value of which is a function of each particle's relative position. Displacement of a particle follows Newton's laws of motion, and is well suited to reinforced concrete since: 1) concrete really is a random arrangement of cement and aggregate particles; 2) failure is governed by tensile strain criteria, which is ideal as the only real way that concrete fails is in tension (all other failure modes in everyday design situations are a consequence of tensile failure) and the model can therefore accurately predict behaviour, and 3) since the elements fail progressively in tension, the peridynamic approach automatically models cracking behaviour, which is extremely difficult to model conventionally. A variety of force-displacement relationships can be defined to model the concrete, the reinforcement, and the reinforcement-concrete bond that together define the overall material response. The approach models the material as a massively redundant three-dimensional truss in which the randomly arranged particles are interconnected by elements of varying length. Although an optimal 'element density' has not yet been determined (see Section 2.4.1 in the case for support) proof of concept work has used tens of millions of particles and hundreds of millions of elements per cubic metre of concrete. From the simple rules and properties applied to these elements, all the complex behaviour of concrete can be predicted. Individual element definitions will be determined by laboratory tests and computational analysis, with both historic and new test data utilised. Crucially, the model has been shown in proof-of-concept work to be able to predict the cracking behaviour of concrete, overcoming a key computational challenge. Optimisation routines, in which material is placed only where it is needed, will then be integrated with the new analysis model to design low-carbon concrete structures. Consideration of the practical construction methods will also be given, building on previous work in this area by Dr Orr. The designs that result from such optimisation processes will have unconventional but completely buildable geometries (as evidenced in Dr Orr's previous work) - making them ideal for analysis using the proposed random elements approach.

The construction sector is strategically important to the UK economy, employing 3.1 million people (>9% of the workforce), producing £370 billion in turnover, and exporting more than £8 billion in products and services. However, its current philosophy is resource and cost inefficient and environmentally unsustainable, through its low productivity, slow technology adoption and tendency to demolish and rebuild. Metal 3D printing offers opportunities to solve these challenges and lead to a more productive, innovative and sustainable construction sector. Metal 3D printing technology has transformed other engineering disciplines, including the biomedical and aeronautical sectors, while its application within the construction sector is still in its infancy. The technology has been fundamentally proven through the MX3D Bridge, the first metal 3D printed structure that was opened in July 2021, however there are still a number of barriers preventing more widespread adoption. Current equipment and processes produce elements that have significant material and geometric variability, within the same build and between repeated builds, which is not optimal for real-world use. Furthermore, the limited availability of suitable printing equipment has prevented research into the development of this novel manufacturing technique and its applications to the construction sector. ICWAAM will be a globally unique metal 3D printing facility, dedicated to large-scale, cost-effective applications for the construction sector. It will offer new research capabilities into the printing process, automated manufacture and the repair and upgrade of our critical infrastructure, along with the printing of complex, materially efficient geometries, which are uneconomical or impossible with standard techniques. ICWAAM will fundamentally challenge the current philosophy of the construction industry and lead to its transformation into a more productive, innovative and sustainable sector, with increased worker safety. Without direct access to large-scale metal 3D printing equipment, such as ICWAAM, researchers are unable to undertake this critical research and development, to solve the longstanding challenges in the construction sector.

When a new metro station or a deep basement are to be constructed in a city, a large hole in the ground is needed. The hole needs to be safe to work in and to allow access and very often the chosen solution is to support the sides of the large hole with a braced embedded retaining wall. These are substantial pieces of temporary works of considerable cost. Recent examples are the 230 long by 24 m wide by 23m deep excavation for the new Crossrail station at Paddington in London. An important feature of this form of construction is large props that span between the walls, to hold them up. For those tasked with designing the prop size, location, number and the walls the key issues are prediction of ground movements adjacent to the excavation (which could negatively affect buildings) and propping forces (so that the right props can be used and while guidance exists for designers in some recent publications produced by the UK construction information organisation, CIRIA, coverage of the behaviour at excavation corners as regards both design issues is poor. There is substantial published research on the computational modelling of braced excavations but only in two-dimensions (i.e. s slice through a long wall), some of it validated against field data, however accounting for 3D effects as required for the analysis of corners is rare and insubstantial. Improving our understanding of the behaviour of these corners and how it is affected by soil behaviour, system stiffness, and prop loading will lead to (a) greater economy in propping schemes and (b) more certainty in the prediction of ground movements adjacent to corners, potentially reducing the accommodation works required to prevent damage to adjacent structures. The programme of research proposed here comprises complex computational simulations of the construction of a braced excavation, taking into account differences in geometry, materials and sequences. The problem can only be properly tackled using a 3D model (unlike many other problems in geotechnical engineering) however even today, the computational tools we use struggle to deliver results quickly when we try to model in 3D. So, in this proposal we will be using a clever method where "reduced order models", (ROMs) will be made, using results from a relatively small set of the complex 3D models. A ROM is much easier to use and is generated by manipulation of a limited number of the high fidelity 3D simulations. From these ROMs we will derive results and prepare guidance for engineers designing braced excavations which will enable cheaper and simpler schemes to be used. The researchers on the project come from Durham and Dundee Universities and are supported by a Project Oversight Group comprising key figures from the UK industry.

Our long-term vision is to dramatically improve whole life construction sector sustainability and productivity by creating a culture that takes a fresh, holistic approach to the manufacture, assembly, reuse, and deconstruction of concrete buildings, leading to a healthier, safer, built environment. Currently, up to half of the concrete used in buildings is unnecessary, and is only there because it is shaped using planar formwork, used since Roman times. This leads to inefficient prismatic shapes for the beams, columns and floor-slabs, which is wasteful, architecturally constraining and a major driver of embodied emissions in construction. This need not be the case. Concrete is initially a liquid and can form structures of any shape, given the right mould. By moving the construction of concrete buildings off-site, to a highly automated, quality controlled environment, and using robotics to create optimised non-prismatic formwork, our buildings can become more sustainable and the construction industry more productive. ACORN's approach builds on the well-established computational design expertise of the team, who have developed innovative digital tools and techniques to optimise the shape, layout, structure and façade of buildings during the design phase. It will extend this approach downstream in the building process, to encompass fabrication. The novelty here lies in the creation of integrated end-to-end digital processes to automate the design and manufacture of non-prismatic building elements. It capitalises on the recent proliferation of affordable robotics, and brings them into an industry ripe for a step-change in sustainability and productivity. Something as simple as allowing beams, columns and floor-slabs to have the shape they need to do their job, rather than the shape they need to be easily formed, allows a complete rethink of the way material is used in our buildings. We can begin to ask questions like what shape should they be, what material should we make them from, how can we reinforce the elements efficiently, how can we take into account whole-life value and how should we organise our design processes to take advantage? ACORN will answer all of these questions.