Enhanced repetitive scheduling formulation for meeting deadlines and resource constraints in linear and scattered projects

Abstract

The majority of civil infrastructure projects involve activities that are repeated across a number of linear units (e.g., highway sections) or scattered units (e.g., multi-bridge rehabilitations). For these projects, Critical Path Method (CPM)/line-of-balance (LOB) repetitive scheduling combines the benefits of CPM and LOB analyses to maintain work continuity across units, yet assumes simple sequential unit order and results in schedule delays for practical projects with non-identical units, constrained resources, and (or) strict deadlines. To improve CPM/LOB scheduling, this paper introduces powerful and easy-to-use enhancements, including (1) designed interruptions to reduce time gaps; (2) efficient resource-constrained first-come first-serve crew assignment; (3) crew adjustment loop to meet deadlines; and (4) representation of flexible unit sequence. These simplified enhancements computationally produce schedules that respect deadlines, individual resource limits, and desired sequence among units. Example projects are then presented to prove that the proposed enhancements offer flexible scheduling features that can meet the strict constraints of infrastructure projects.