Lean Supply Chain for Modular Construction in Practice: A Roadmap for Implementation

The construction industry, a critical economic sector in many countries, including Australia, has experienced a concerning decline in productivity growth over the last decade. This decline stands in contrast to other manufacturing industries. This decline is attributed, in part, to the poor supply chain integration within the sector. The overarching research objective of this study aimed to understand and demonstrate how lean manufacturing principles can be adapted to strengthen supply chain integration, boost productivity, and foster innovation in the construction sector. This will be shown to enhance productivity and overall performance in the construction industry, particularly through off-site construction and supply chain alternatives.

The study extends systems theory to the construction industry by implementing Mouly's system engineering principles and adapting the Practical, Robust Implementation and Sustainability Model (PRISM), incorporating operational FORRIDGE principles, rules, and associated tactics as the primary framework. These tactics, categorised as techniques and tools, including off-site construction, have been updated in this research. The implementation in real projects demonstrates significant potential in enhancing mid-rise construction productivity and playing a crucial role in the reconfiguration of construction offsite ecosystems. This adaptation has led to the creation of a novel Cold Formed Steel construction solution and the Design for Manufacturing and Assembly and Building (DfMA&B) methodology and guidelines for practitioners.

The research involved three novel in-depth case studies. The first study investigated nine real mid-rise Australian construction projects to establish the current industry landscape, while the second study developed a comparison between a Cold Formed Steel solution and traditional construction methods for midrise buildings for the first time in Australia, resulting in an exemplar solution. The third study implemented these solutions in a unique longitudinal case study of three real projects in Spain, developing the Design for Manufacturing and Assembly and Building methodology and guidelines for construction offsite supply chains reconfigurations.

This approach combines quantitative and qualitative methods, digital simulations, comparisons, simulations, and triangulation of data from experts, practitioners, and academics to provide a comprehensive understanding of the subject matter. Interviews and interactions with over 20 companies across Australia, Spain, and the UK enriched the data collection process.

This thesis demonstrates the iterative implementation of this framework through a longitudinal study encompassing three real projects across diverse construction segments in Spain. It provided a proof of concept for the construction system in the first project, streamlined the system in the second, and optimised the solution in the third, while fully developing the methodology and guidelines for comprehensive implementation. The construction system and methodology received industry recognition in 2020 and 2022 for construction system innovation in Malaga and novel methodology in Madrid, underscoring their significance. The implemented DfMA&B methodology achieved an average lead time compression of 40% compared to traditional methods, while maintaining cost parity between traditional and construction offsite approaches in Spain. It highlights the practical translation of research impact when the systems concept is meaningfully applied in practice. A broader implementation of the developed methodology holds the potential to transform the mid-rise apartment construction market globally. This research lays the foundation for upcoming studies on platform supply chain strategies and collaborative approaches within the construction industry, aligning with the trajectory of earlier investigations in this research line. Such initiatives are instrumental in nurturing the sustainable growth and development of the construction sector.