GeoStructPy
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Disclaimer: This tool is intended for use by the APEC Consultancy team for preliminary geotechnical calculations only. The developers assume no liability for design decisions made based on the output of this application. All results must be verified by a qualified geotechnical or structural engineer before use in any project.

Mononobe-Okabe Seismic Earth Pressure

Pseudo-static active/passive earth pressure on retaining walls (Okabe 1926; Mononobe & Matsuo 1929), with the exact Zarrabi-Kashani critical wedge, Seed–Whitman resultant location, and an independent wedge-equilibrium QA check.

Geometry
Backfill Soil
Seismic Coefficients

Enter effective coefficients: the PGA reduction factor already applied (kh = α·amax/g, typically α = 0.5). Ref: AASHTO §11.6.5.2.

References & Methodology

  1. Das, B.M. & Sivakugan, N. (2019). Principles of Foundation Engineering, 9th Edition, SI. Cengage Learning. Ch. 16: §16.7 Coulomb active (Eq. 16.26, p. 658); §16.9 Active earth pressure for earthquake conditions — granular backfill (M-O method, Eq. 16.38, p. 668); §16.10 c′-φ′ backfill (p. 672); §16.17 Passive force with earthquake. Ch. 17: §17.10 Gravity wall design for earthquakes.
  2. Okabe, S. (1926). General theory of earth pressures. J. Japan Society of Civil Engineers, 12(1).
  3. Mononobe, N. & Matsuo, H. (1929). On the determination of earth pressures during earthquakes. Proc. World Engineering Conference, Tokyo, 9, 177–185.
  4. Seed, H.B. & Whitman, R.V. (1970). Design of earth retaining structures for dynamic loads. ASCE Specialty Conf. on Lateral Stresses in the Ground and Design of Earth Retaining Structures, 103–147. (ΔKae ≈ ¾kh; increment at 0.6H.)
  5. Zarrabi-Kashani, K. (1979). Sliding of gravity retaining wall during earthquakes. M.S. thesis, MIT. (Exact critical failure-plane angle αAE.)
  6. Kramer, S.L. (1996). Geotechnical Earthquake Engineering, Ch. 11, Eqs. 11.6–11.10. Prentice Hall.
  7. AASHTO (2020). LRFD Bridge Design Specifications, §11.6.5 — Seismic earth pressure on retaining walls.
  8. Eurocode 8 Part 5 (EN 1998-5:2004), Annex E (M-O method).