Improving performance and the reliability of off-site pre-cast concrete production operations using simulation optimisation

The increased use of precast components in building and heavy civil engineering projects has led to the introduction of innovative management and scheduling systems to meet the demand for increased reliability, efficiency and cost reduction. The aim of this study is to develop an innovative crew allocation system that can efficiently allocate crews of workers to labour-intensive repetitive processes. The objective is to improve off-site pre-cast production operations using Multi-Layered Genetic Algorithms. The Multi-Layered concept emerged in response to the modelling requirements of different sets of labour inputs. As part of the techniques used in developing the Crew Allocation “SIM_Crew” System, a process mapping methodology is used to model the processes of precast concrete operations and to provide the framework and input required for simulation. Process simulation is then used to model and imitate all production processes, and Genetic Algorithms are embedded within the simulation model to provide a rapid and intelligent search. A Multi-Layered chromosome is used to store different sets of inputs such as crews working on different shifts and process priorities. A ‘Class Interval’ selection strategy is developed to improve the chance of selecting the most promising chromosomes for further investigation. Multi-Layered Dynamic crossover and mutation operators are developed to increase the randomness of the searching mechanism for solutions in the solution space. The results illustrate that adopting different combinations of crews of workers has a substantial impact on the labour allocation cost and this should lead to increased efficiency and lower production cost. In addition, the results of the simulation show that minimum throughput time, minimum process-waiting time and optimal resource utilisation profiles can be achieved when compared to a real-life case study

Digital Twin and Cloud BIM-XR Platform Development: From Scan-to-BIM-to-DT Process to a 4D Multi-User Live App to Improve Building Comfort, Efficiency and Costs

Digital twins (DTs) and building information modelling (BIM) are proving to be valuable tools for managing the entire life cycle of a building (LCB), from the early design stages to management and maintenance over time. On the other hand, BIM platforms cannot manage the geometric complexities of existing buildings and the large amount of information that sensors can collect. For this reason, this research proposes a scan-to-BIM process capable of managing high levels of detail (LODs) and information (LOIs) during the design, construction site management, and construction phases. Specific grades of generation (GOGs) were applied to create as-found, as-designed, and as-built models that interact with and support the rehabilitation project of a multi-level residential building. Furthermore, thanks to the sharing of specific APIs (Revit and Autodesk Forge APIs), it was possible to switch from static representations to novel levels of interoperability and interactivity for the user and more advanced forms of building management such as a DT, a BIM cloud, and an extended reality (XR) web platform. Finally, the development of a live app shows how different types of users (professionals and non-expert) can interact with the DT, in order to know the characteristics with which the environments have been designed, as well as the environmental parameters, increasing their degree of control, from the point of view of improving comfort, use, costs, behaviour, and good practices. Finally, the overall approach was verified through a real case study where the BIM-XR platform was built for energy improvements to existing buildings and facade renovations

Simulation-based optimisation using simulated annealing for crew allocation in the precast industry

Numerous different combinations of crew alternatives can be deployed within a labour-intensive manufacturing industry. This can therefore often generate a large number of possible crew allocation plans. However, inappropriate selection of these allocation plans tends to lead to inefficient manufacturing processes and ultimately higher labour allocation costs. Thus, in order to reduce such costs, more allocation systems are required. The main aim of this study is to develop a simulation-based multi-layered simulated annealing system to solve crew allocation problems encountered in labour-intensive parallel repetitive manufacturing processes. The ‘multi-layered’ concept is introduced in response to the problem-solving requirements. As part of the methodology used, a process simulation model is developed to mimic a parallel repetitive processes layout. A simulated annealing module is proposed and embedded into the developed simulation model for a better search for solutions. Also, a multi-layered dynamic mutation operator is developed to add more randomness to the searching mechanism. A real industrial case study of a precast concrete manufacturing system is used to demonstrate the applicability and practicability of the developed system. The proposed system has the potential to produce more cost-effective allocation plans, through reducing process-waiting times as compared with real industrial-based plans

Information lifecycle management in Structural Engineering BIM, openBIM and Blockchain technology to digitise and re-engineer structural safety information management processes

Over the past decade, the building information modelling (BIM) approach has increasingly been used in both professional practice and research relating to the fields of civil and structural engineering. Indeed, it has been adopted across the globe, with some governments demanding its use in public projects involving bridges, tunnels and railways, as well as for strategic facilities like hospitals and schools. In Europe, most countries comply with Directive 2014/24/EU of the European Parliament and of the Council on public procurements, which allows such clients to demand the use of BIM methodologies. Some countries, meanwhile, have decided to enforce digital delivery; for example, the United Kingdom has required the use of BIM in all government projects since 2016, while the Italian government published a timeline in 2018 mandating the use of BIM methodologies in all construction work by 2025. As a consequence, companies involved in the AEC sector are embracing the BIM approach by employing new tools and workflows, even though they face obstacles in relation to issues like training costs and time or low initial productivity. BIM-based workflows, innovative tools and collaboration platforms can be employed throughout the lifecycle of an asset, and have been the catalyst for innovation in the entire architecture, engineering and construction (AEC) industry. However, the BIM approach does not have its own agenda for research purposes only, but this has one in applied research with the purpose of aiding professional practice. Thus, this thesis will address the use of BIM in structural engineering not for the sake of the research itself, but with the practical intent of summarizing and presenting the current experience of the use of BIM in structural engineering and then contributing to expanding knowledge about the possible uses of BIM in this regard. This thesis proposes innovative processes for the lifecycle information management of information that refers to the discipline of structural engineering. The proposed processes are based on the BIM approach, an information management framework that allows to standardise information flows using processes that implement tools such as BIM-authoring software, BIM tools and collaboration platforms. In detail, the BIM-based processes here proposed are in the number of three and refer, respectively, to the authorization phase, the testing and closeout phase, and the operation and maintenance phase of the lifecycle of a facility. A further novelty of this work is investigating the use of the open format industry foundation classes (IFC) in the processes that refer to the authorization phase and the operation and maintenance phase, and the use of blockchain technology in the testing and closeout phase. The first aim of this thesis, therefore, is to start bridging that gap by 1) providing the first state-of-the-art on the use of BIM in structural engineering. Additionally, this thesis is original in that it addresses the production, management, and storage of information that pertains to structural engineering. Accordingly, this work aims at: 2) Proposing an open BIM-based process for the application for seismic authorization, in Italian 'autorizzazione sismica' (authorization phase). 3) Proposing a proof-of-concept for the integration of blockchain technology and smart contract into information flows among common data environments (CDEs) in the construction process of structural systems (testing and closeout phase). 4) Proposing an open BIM-based process for the operation and maintenance phase of structures

A review on the mechanical and physical properties of natural fiber composites

Research on the use of natural fibers as replacement to man-made fibre in fiber reinforced composites have received more interest and opened up further industrial possibilities. Natural fibre presents many advantages compared to synthetic fibers which make them attractive as reinforcements in composite material. They come from abundant and renewable resources, which ensures a continuous fibre supply and a significant material cost saving to the plastics, automotive and packaging industries. The paper reviews the previous and current research works published in the field of natural fiber reinforced composite material with special reference in mechanical properties of the natural fiber reinforced composite

A comparison of processing techniques for producing prototype injection moulding inserts.

This project involves the investigation of processing techniques for producing low-cost moulding inserts used in the particulate injection moulding (PIM) process. Prototype moulds were made from both additive and subtractive processes as well as a combination of the two. The general motivation for this was to reduce the entry cost of users when considering PIM. PIM cavity inserts were first made by conventional machining from a polymer block using the pocket NC desktop mill. PIM cavity inserts were also made by fused filament deposition modelling using the Tiertime UP plus 3D printer. The injection moulding trials manifested in surface finish and part removal defects. The feedstock was a titanium metal blend which is brittle in comparison to commodity polymers. That in combination with the mesoscale features, small cross-sections and complex geometries were considered the main problems. For both processing methods, fixes were identified and made to test the theory. These consisted of a blended approach that saw a combination of both the additive and subtractive processes being used. The parts produced from the three processing methods are investigated and their respective merits and issues are discussed

Reducing risk in pre-production investigations through undergraduate engineering projects.

This poster is the culmination of final year Bachelor of Engineering Technology (B.Eng.Tech) student projects in 2017 and 2018. The B.Eng.Tech is a level seven qualification that aligns with the Sydney accord for a three-year engineering degree and hence is internationally benchmarked. The enabling mechanism of these projects is the industry connectivity that creates real-world projects and highlights the benefits of the investigation of process at the technologist level. The methodologies we use are basic and transparent, with enough depth of technical knowledge to ensure the industry partners gain from the collaboration process. The process we use minimizes the disconnect between the student and the industry supervisor while maintaining the academic freedom of the student and the commercial sensitivities of the supervisor. The general motivation for this approach is the reduction of the entry cost of the industry to enable consideration of new technologies and thereby reducing risk to core business and shareholder profits. The poster presents several images and interpretive dialogue to explain the positive and negative aspects of the student process