Restrained (Basement) Retaining Wall (IBC 2021)
US structural engineers designing restrained retaining walls, commonly basement walls, to IBC 2021, ASCE 7-16, and ACI 318-19. Covers Rankine lateral earth pressure theory with at-rest or active soil assumptions, flexural reinforcement design, and one-way shear checks.
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What it calculates
Design restrained retaining walls, commonly basement walls, to IBC 2021, ASCE 7-16, and ACI 318-19. Rankine theory estimates lateral earth pressure with retained soil at-rest or active, optionally. Excludes wind and seismic.
Code standards
- IBC 2021
- ASCE 7-16
- ACI 318-19
Who uses this calculator
US structural engineers designing restrained retaining walls, commonly basement walls, to IBC 2021, ASCE 7-16, and ACI 318-19. Covers Rankine lateral earth pressure theory with at-rest or active soil assumptions, flexural reinforcement design, and one-way shear checks.
Design retaining walls restrained at the top, covering basement configurations the cantilever calculator cannot handle.
How it calculates
The Restrained (Basement) Retaining Wall calculator designs propped retaining walls - typically basement walls braced at the top by a floor diaphragm - per IBC 2021, ASCE 7-16, and ACI 318-19. It uses Rankine theory for lateral earth pressure and performs limit state design checks on the wall stem and footing.
Lateral earth pressure (Rankine theory)
Lateral soil pressure is estimated using Rankine theory for granular backfill. The calculator supports either at-rest pressure (K_0 = 1 - sin phi, appropriate for restrained basement walls that cannot rotate) or active pressure (K_a). A triangular pressure distribution is used. The design lateral load H_total represents the total horizontal force from soil, water table (if present), and surcharge - both dead load (q_D) and live load (q_L) surcharge are included.
Stability checks
Since overturning is fully prevented by the top restraint, no overturning check is performed. Sliding resistance is verified:
FS_sliding = F_resist / F_slide ≥ 1.5
Where F_resist combines base friction (c_base × L_heel) and passive soil resistance in front of the toe. Maximum bearing pressure q_max is checked against the allowable bearing capacity q_a.
Stem flexural and shear design (ACI 318-19, Cl. 22.2 and 22.5)
The wall stem is designed as a one-way vertical slab spanning between the top restraint and the footing. The governing moment demand M_u,stem and shear demand V_u,stem are computed from the tabulated lateral soil load distribution. Capacity checks:
utilization = M_u,stem / (phi × M_n,stem) ≤ 1.0 utilization = V_u,stem / (phi × V_n,stem) ≤ 1.0
Combined flexural and axial capacity is also checked for the stem per ACI 318-19 Cl. 22.4, accounting for the weight of soil and wall above.
Footing flexural and shear design (ACI 318-19, Cl. 22.2 and 22.5)
The footing is checked for moment demand M_u,ftg and shear demand V_u,ftg at the critical sections in the toe. Upward soil pressure on the heel is conservatively neglected for strength design.
utilization = M_u,ftg / (phi × M_n,ftg) ≤ 1.0 utilization = V_u,ftg / (phi × V_n,ftg) ≤ 1.0
Assumptions and scope
No shear key is modelled. The backfill is flat with no slope. Only dead load surcharge, live load surcharge, wall self-weight, and soil loads are considered. Axial wall loads are not included. Rebar is continuous over the full wall height. Concrete detailing must be checked separately. Expansive soils are not considered.
What engineers say
I like that Calcs.com shows the code reference section for each calculation and function. That means every time I use it, there's a potential for me to learn something.
Lawrence Bowen
Founding Principal, CPBD, VQ Design
Calcs.com simplified my beam analysis. It made structural checks easy and impressively fast.
Aaron D. Obermiller, P.E.
Engineer, REO Engineering
Frequently asked questions
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