Excavation Slope and Bench-Step Plan

OSHA Appendix B slope ratios A 0.75:1 / B 1:1 / C 1.5:1 turned into spoil volume (yd^3), surface footprint, and bench-step layout. Competent person on-site governs the final plan.

horizontal_offset = depth * ratio (A 0.75 / B 1.0 / C 1.5). top_width = bottom_width + 2 * offset. cross_section = (top + bottom) / 2 * depth. volume_yd3 = cross_section * length / 27. Bench layout (A/B): 4 ft per bench; horizontal_step = bench_height * ratio.

OSHA 29 CFR 1926 Subpart P Appendix B and §1926.652.

ecfr.gov.

Math aid for personal verification. Stop work and consult the qualified person on site if any number does not match the field condition.

Field names used by the API: depth_ft, soil_class, surcharge, length_ft, bottom_width_ft, top_width_ft, spoil_volume_yd3, footprint_ft2

• Soil classes A 0.75:1, B 1:1, C 1.5:1OSHA Subpart P Appendix B
• Bench height 4 ft typicalOSHA Subpart P engineering practice
• Surcharge bump +0.25 H:V additive when surcharge load presentengineering practice
• Bottom width default 2 ft (utility-trench common case)engineering practice
• Depth ceiling above 20 ft requires PE design per 1926.652(b)(4); tile stops thereOSHA 1926.652(b)(4)