Foundation Design Spreadsheet: Mat

The soil report was a nightmare: erratic clay, high water table, and a building load of 45 stories pushing down. A conventional spread footing was impossible. It had to be a mat foundation—a continuous concrete raft under the entire building. The problem was the design process. Every change in column load meant redoing pages of algebra: punching shear, two-way shear, bending moment strips, reinforcement ratios. Her team used a mix of old textbooks, fragmented MathCAD sheets, and gut instinct.

She changed one cell. The entire sheet rippled. New thickness, new effective depth, new shear capacities. Column C-7 dropped to 0.92. Green. The now showed 18 mm—acceptable. mat foundation design spreadsheet

She typed in the new dimension. The grid recalculated instantly. All pressures dropped to 148 kPa or less. Green. The soil report was a nightmare: erratic clay,

"Problem," Maya said. "The building’s core is offset. We need to extend the mat by 1.2 meters on the north side." The problem was the design process