Tetris-inspired approach for generating tightly-packed repetitive schedules

• Published in: Automation in construction 2021-04, Vol.124, p.103601, Article 103601
• Main Authors: Hegazy, Tarek, Mostafa, Kareem, Ojulari, Saidat
• Format: Article
• Language: English
• Subjects: Computation; Computer application; Crew arrangement; Delivery rate; Geometric method; High rise buildings; Interruption; Optimization; Parallel crew; Repetitive projects; Schedules; Scheduling; Task scheduling; Tetris; Time synchronization
• ISSN: 0926-5805; 1872-7891
• DOI: 10.1016/j.autcon.2021.103601

Scheduling repetitive projects such as highways and High-rise buildings to meet strict deadlines is challenging, particularly when the repetitive units (sections/floors) are non-identical and resources are limited. In this case, conventional CPM/LOB schedules exhibit large time gaps, causing project delays. This paper proposes computational and geometrical enhancements to generate tightly-packed repetitive schedules, envisaged by the game of Tetris. The paper introduces novel procedures to overcome existing scheduling challenges: (1) revised computation to better determine tasks' delivery rates that meet deadlines; (2) formulation of mid-activity interruption time and mid-activity rate changes that synchronize task delivery rates; (3) multi-crew arrangement method, As-Soon-As-Possible, that better suits non-identical units; and (4) a simplified heuristic combining all procedures above to generate tightly-packed schedules with shorter durations. As presented in the paper through examples, the proposed techniques reduce the duration of complex repetitive projects using enhanced schedule computation and geometry rather than using expensive acceleration/optimization methods. •Repetitive scheduling is treated as a Tetris game where activities can change shape to reduce gaps and save project duration•New geometric procedures developed to reduce project gaps for cases of identical and non-identical units in repetitive tasks•Mathematical computation is developed to calculate interruptions that improve task geometry for tasks with identical units•New crew arrangement method, ASAP, developed to minimize schedule time gaps, for complex tasks with non-identical units•A simplified heuristic process, and computer program, developed to generate tightly-packed schedules.