Automated Generation of Precast Concrete Slab Stacks for Transportation in Offsite Construction Projects

Abstract

In an off-site construction (OSC) project, how to transport the components has a significant impact on the project performance. During the transportation, slab stacks are usually generated in the process of loading precast concrete (PC) slabs on a trailer. Because there are various factors for consideration and numerous ways of composing the stacks, it is difficult for production managers to generate the stack quickly and effectively without the help of a computer. This study sought to formalize the process of generating PC slab stacks, which consists of the following six phases: (1) input data and parameters, (2) make a preliminary stack by tolerance, (3) refine the stack with stackability and installation sequence, (4) divide stacks by maximum layer, (5) check loadability of stacks, and (6) calculate and report metrics. As a result, a prototype developed based on the formalized process offered more stable and errorless stacking results that limit the reshuffling effort of site installers than experts (prototype: 93.0% stability, zero errors, and zero reshuffling work; experts: 88.6% stability, 1.5 errors, and 1.1 reshuffling work). This study contributes to the transportation theory of OSC by identifying considerations for PC slab stacking and formalizing the specialized stacking process reflecting them, which enables the development of an automated PC slab generation tool in OSC projects.