Masonry Compressive Strength f'm, Unit-Strength Method (TMS 602 Table 2)
The net-area masonry compressive strength f'm every CMU wall tile consumes but none derives -- from the net-area unit strength and the mortar type by the TMS 602-16 Table 2 unit-strength method, no prism test. f'm is not the unit strength: a 2,000 psi (net) concrete unit gives f'm 2,000 psi in Type M or S mortar but only 1,750 in Type N, a 12.5% cut from the mortar alone; a 3,250 psi unit in Type M/S gives 2,500 (77% of the block). Linear interpolation between Table 2 rows; 2,000 psi is the ASTM C90 net-area minimum and the table caps f'm (a higher value needs a prism test). Feeds cmu-wall-axial, cmu-wall-flexure, cmu-shear-wall, and masonry-anchor-bolt. A specification aid, not a substitute for TMS 602 and the engineer of record.
Formula and source
f'm = TMS 602-16 Table 2 (concrete masonry, unit-strength method), interpolated on the net-area unit strength for the mortar type: Type M/S 2000->2000, 2600->2250, 3250->2500, 3900->2750, 4500->3000; Type N 2000->1750, 2650->2000, 3400->2250, 4350->2500 psi.
TMS 602-16 (ACI 530.1 / ASCE 6) Specification for Masonry Structures, Article 1.4 B unit-strength method, Table 2 for concrete masonry, by name.
Audience
This tile is built for trades and the adjacent professions in the Carpentry and Construction group. The interactive calculator runs entirely in your browser. No account, no fee, no advertising, no tracking.
Related tools
Posture
Rough Logic answers the math question the working professional asks on the job. The site is a calm, fast, ad-free, account-free, ever-free reference. It does not interpret code. It does not replace the licensed professional. It does not store your inputs. The Authority Having Jurisdiction governs all installations and inspections.