A Unified Civil–Structural Analysis of Megalithic Construction: Foundation Engineering, Load Path Behavior, and Seismic Stability in Monumental Stone Architecture

This work presents a modern civil–structural engineering analysis of large-scale megalithic construction, with emphasis on foundational preparation, load distribution pathways, internal stress-relief mechanisms, and long-term structural stability. Building on Parts I and II of the Unified Megalithic Engineering Series, this study synthesizes geotechnical, architectural, and mechanical principles to describe how ancient builders achieved centimeter-level leveling over large footprints, stable load transfer across millions of stone blocks, and long-duration structural integrity in high-mass pyramidal systems. The analysis outlines foundational leveling techniques—including hydrostatic leveling channels, perimeter trenching, cut-bedrock steps, and distributed survey points—and evaluates how these methods produce a stable geotechnical baseline. A detailed structural model is used to describe vertical compression pathways, lateral stress distribution, shear force migration, chamber-roof load redirection, and long-axis stability over time. Internal engineering features such as relieving chambers, corbelled ceilings, and stress-diffusion corridors are examined as intentional mechanisms for mitigating concentrated loads. Thermal expansion behavior, seasonal joint movement, micro-settling, and compression-locking effects are modeled to illustrate how large stone assemblies tighten structurally with age rather than weaken. Seismic considerations, including multi-directional stability, inertial damping through mass distribution, and interlocking core behavior, are also evaluated. Finally, the paper reconstructs the optimal sequence of construction—foundation establishment, corner locking, stepped core rise, casing installation, and upper structure completion—to provide a complete engineering interpretation of ancient large-scale stone construction. Collectively, this research offers a technically rigorous and unified civil-structural framework explaining how such monumental architectures were built to remain stable for millennia.