Optimal assembly scheduling based on BIM for precast-enabled construction using tower cranes Lihui Huang a,1 , Roshan Pradhan b,1 , Souravik Dutta b,c , Yiyu Cai a,b,c,* a SJ-NTU Corporate Lab, Nanyang Technological University, 61 Nanyang Avenue, 637335, Singapore b School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore c Energy Research Institute @NTU, Interdisciplinary Graduate Programme, Nanyang Technological University, 50 Nanyang Drive, Research Techno Plaza, 637553, Singapore Abstract This research addresses the task of assembly scheduling in crane-assisted precast construction while considering issues of building layout interference and optimal crane lifting paths. Traditionally, assembly scheduling and lifting path planning are treated as separate investigations due to their distinct natures. The current work introduces an approach that combines these two aspects of scheduled construction to achieve a comprehensive and cost-effective solu- tion. A BIM-based Intelligent Assembly Scheduler (BIAS) is designed to be used in conjunction with the Computer-Aided Lift Planning system developed at Nanyang Technological University, Singapore. The scheduler takes inbuilt macro-scheduling data from BIM as input and provides the micro-schedule as output in terms of the assembly sequence of precast building elements. This micro-scheduling task is formulated as a multi-objective optimization problem based on the relative importance of precast components’ physical properties and the conflicts among the elements’ relative positions and planned lifting paths. A Multi-level Elitist Genetic Algorithm (MEGA) is proposed to generate the optimal assembly sequence. A case study is performed with a floor plan of a * Corresponding author Email addresses: lhhuang@ntu.edu.sg (Lihui Huang), roshannpradhan@gmail.com (Roshan Pradhan), souravik001@ntu.edu.sg (Souravik Dutta), myycai@ntu.edu.sg (Yiyu Cai) 1 Co-first authors Preprint submitted to Journal of Automation in Construction September 7, 2021