Optimum Assembly Planning for Modular Construction Components

Abstract

Geometric variability often creates challenges for component aggregation in the assembly of interchangeable components in modular construction. Despite complete interchangeability-based design, geometric variability resulting from production processes creates variances between the as-built states of identical components. This inevitable occurrence of discrepancies between design and fabrication creates challenges for component aggregation on site and causes rework during assembly and erection. This paper presents a framework for optimally planning the order and arrangement of components such that the impacts of geometric variability, and the rework it can cause are minimized. The proposed framework compares the critical interface points of components in order to optimize the assembly plan in two distinct approaches: (1) minimization of the overall assembly geometric deviation, and (2) avoidance of rework caused by component aggregation. The proposed framework can be carried out for serial-parallel assemblies and for volumetric assemblies utilizing the as-built state in the form of three-dimensional (3D) point cloud data. The results of the two case studies in this paper demonstrate that not only can the assembly plan of interchangeable components be optimized to reduce the impacts of geometric variability, but geometric deviations can also be quantified, which is of vital importance for proper construction planning.