AASHTO LRFD Retaining Wall Design Spreadsheet (v2023)

The spreadsheet implements the Load and Resistance Factor Design (LRFD) methodology mandated by AASHTO for highway infrastructure, emphasizing reliability-based design through calibrated partial safety factors for loads (γ) and resistances (φ). It supports two primary wall types: reinforced concrete cantilever walls (with stem, heel, and toe slabs) and counterfort walls (featuring vertical stiffeners), each subjected to earth pressure (active, passive, at-rest), surcharge, hydrostatic, and seismic loads per AASHTO Articles 3.11, 10.6, and 11.6. Key analysis modules include global stability (factor of safety against overturning and sliding per Article 11.5.4), bearing pressure distribution under the base (checking for tension and maximum pressure per Article 11.5.3), and section-level strength design per ACI 318–19 as adopted by AASHTO, including moment and shear capacity with φ-factors (e.g., φ = 0.90 for flexure, φ = 0.75 for one-way shear). The v2023 edition incorporates updated seismic provisions from AASHTO’s 2023 Interim Revisions—including dynamic active earth pressure via Mononobe-Okabe method—and refined resistance factors for reinforced concrete elements. Input validation, unit consistency checks (US Customary or SI toggle), color-coded pass/fail flags, and printable calculation reports enhance usability for peer review and regulatory submittal.