Numerical Simulation and Calculation Method Study on Seamless Construction of Super-Length Raft Structures Based on Novel Magnesium Oxide Expansive Strengthening Band Method

The drive for continuous innovation in large-scale infrastructure necessitates advancements in techniques, addressing the challenges of constructing super-length concrete structures. This study investigated the emerging shift from traditional united expanding agent (UEA) to magnesia expansive agent (MEA) in conjunction with expansive strengthening bands (ESBs), marking a pivotal transition in ensuring monolithic integrity. Despite a decade of exploration, MEA–ESB implementation in real-world projects remains underdocumented, with scholarly focus primarily confined to material characterization. This research integrated empirical on-site tests of MEA–ESB with high-fidelity numerical simulations in ABAQUS. The finite element model (FEM) validation against actual test data underscored the precision of our modeling, capturing the complex thermomechanical behavior of the system. We introduced a sophisticated parametric analysis framework, elucidating the influence of critical parameters like the ESB-to-raft-width ratio and MEA concrete expansion rates. This granular understanding facilitated the fine-tuning of design parameters, advancing the practical application of MEA methodologies. A groundbreaking contribution entailed the formulation of predictive models for early-stage cracking, anchored in the guidelines of the ACI Committee 207 and refined through extensive parametric exploration. These formulae empower engineers to anticipate and mitigate cracking risks during the design phase, thereby enhancing project safety and efficiency. Notably, this study identified limitations in current prediction models, highlighting the need for future research to incorporate comprehensive lifecycle considerations, including hydration heat effects and time-dependent mechanical property evolution.