Concrete formwork reuse in a supply chain with dynamic changes using ABMS and discrete events

Concrete formwork is a system supporting and shaping concrete components and its potential reuse has been increasingly considered in recent years. On-site concrete formwork reuse contributes to cost savings and material waste reduction. However, concrete formwork reuse among different construction sites is still limited. In addition, on-site formwork planning is inherently complicated, and dynamic processes of formwork reuse increase the complexity since on-site emergencies result in various changes. This study aims to provide an appropriate approach to analyze the dynamic processes of formwork reuse among construction sites, for minimizing both the total cost of each site and the overall formwork consumptions. A mathematical model is first developed to analyze formwork utilization on a single site, and an agent-based model is then proposed along with discrete events to implement and simulate formwork reuse with dynamic changes among construction sites configuring a supply chain. The mathematical model minimizing the total cost of concrete formwork enables the understanding of decisions and behaviors of a single construction site and provides a basis for simulation modeling. In the agent-based model, four major decision agents consisting of construction sites, commercial formwork suppliers, waste disposal centers, and transportation trucks are developed. Considering asymmetric information, a negotiation protocol is integrated into agents’ behaviors to facilitate interactions. With the agent-based modeling and simulation, the optimal strategies for construction sites to reuse formwork can be generated. The results of a case study indicate that formwork reuse in the supply chain can outperform that on a single site and results in a cost saving of 25.38%, a quantity reduction of 33.56%, and a surplus reuse value reduction of 73.18%.