Masonry Gravity Wall (ASD)

How it calculates

Masonry and reinforcement properties

Material inputs establish the design basis: CMU block size (6" to 12"), masonry type (clay or concrete), specified compressive strength f'm, unit weight, and mortar type. Grout condition - partial or full - determines the effective cross-section used for all capacity calculations. Partial grouting uses the net area and net moment of inertia at the reinforced cell spacing; full grouting uses the gross section. Reinforcement is modeled as a single centered layer, with grade and bar spacing as inputs.

Load combinations (ASCE 7)

ASD load combinations per ASCE 7 are assembled and the governing case for axial and for out-of-plane bending is identified. Wind and seismic lateral pressures are applied as distributed loads per 1 ft of wall width. The calculator evaluates all applicable combinations and flags the governing demand for each check.

Out-of-plane shear (TMS 402-22, Section 8.3.5)

Applied shear demand from out-of-plane lateral loads is compared to the allowable masonry shear stress:

fv ≤ Fv

where Fv is a function of f'm and grout condition per Section 8.3.5. In-plane shear is not checked - this calculator is for gravity walls only, not shear walls.

Out-of-plane bending and axial interaction (TMS 402-22, Section 8.3.4, MDG 2022 Ch.11.4.4)

Combined axial and bending demands are checked against the allowable interaction envelope. For each applied axial load P, the allowable moment Ma is computed from the ASD provisions and the interaction ratio evaluated:

P / Pa + M / Ma ≤ 1.0

The interaction graph plots the full capacity envelope and demand points from all governing load combinations. Adjusting bar size, spacing, or grout condition immediately updates the graph to confirm the revised configuration.

Deflection checks are not included - Section 8 of TMS 402-22 does not contain deflection limits for ASD masonry walls. The fully grouted wall model does not apply the slenderness limit per MDG 2022 examples.