Multi-perspective approaches for enhancing offsite logistics of modular construction in high-rise high-density cities

Abstract

Modular construction emerges as a game-changing technology to address the multiple challenges confronted by the building industry, especially in high-rise high-density cities such as Hong Kong, Singapore and London. However, its adoption is still limited. One primary barrier to adopting modular construction is the concerns over offsite logistics, which encompasses complicated processes of module manufacturing, transport and storage, seeking to deliver modules to sites timely and cost-efficiently. Offsite logistics must be well addressed to achieve successful modular high-rises in high-density cities. Nevertheless, research focusing on offsite logistics management is scarce, and approaches and strategies to enhance offsite logistics have not been sufficiently understood and explored. This thesis aims to provide multi-perspective approaches that enhance the efficiency and certainty of offsite logistics of modular construction in high-rise high-density cities. This research incorporates a holistic literature review, an exploratory questionnaire survey, and follow-up approach exploration and development with the use of a mixed-method research design. The survey with professionals and stakeholders involved 285 respondents, and the results show the perceived significance and challenges of offsite logistics in practice. The multi-perspective explorations were guided by an analytical framework from four interrelated perspectives, namely, industry, supply chain, project, and technology perspectives. Exploration from the industry perspective examines the opportunities for and constraints to offsite logistics considering macro business environments. A fourteen-dimensional system framework of the opportunities and constraints is developed that demonstrates the multifaceted, region-specific, transferable, and interactive nature of the dimensions. Exploration from the supply chain perspective identifies and categorises the sources of uncertainties (SoUs) that affect offsite logistics. An uncertainty circle model of the SoUs is developed that evaluates the likelihoods and impacts of thirty key SoUs from the supply chain. Exploration from the project perspective presents an integrated scheduling approach based on an extended stochastic Petri net (ESPN) method. This approach supports multi-criteria decision-making by visualising the completion time, total cost, storage capacity utilisation, and production process stability under what-if scenarios. Exploration from the technology perspective focuses on the potential of using automated guided vehicles (AGVs) in module manufacturing and transport. Two scenarios, namely, “smart manufacturing” and “last-mile delivery” of modules, are demonstrated, together with analyses with respect to strengths, weaknesses, opportunities, and threats, and recommendations on research directions. The four interrelated perspectives together help comprehend and address offsite logistics within the technological, economic, social, policy, regulatory and geographical contexts. These findings are triangulated to form an integrative multi-perspective model for the continuous enhancement of offsite logistics. This research has made original contributions to the knowledge of offsite logistics. Methodologically, the research presents a variety of analytical approaches for enhancing offsite logistics, in terms of opportunity and constraint examination, supply chain-focused uncertainty management, project integrated scheduling and technological innovation. Practically, it provides industry practitioners with useful tools and strategies for offsite logistics management. Theoretically, the derived integrative multi-perspective model for offsite logistics builds up a system-integrated foundation for the research and industry community, which promotes a broad and in-depth understanding of offsite logistics. The findings should underpin sustained enhancement of offsite logistics to support wide and rapid adoption of modular construction.