Masonry Anchor Bolt in Shear (TMS 402 ASD)
The allowable SHEAR of an anchor bolt in grouted masonry.
Example
You enter
- Masonry strength f'm (psi) 1500
- Effective embedment lb (in) 5
- Edge distance lbe (in) 4
- Bolt effective tensile area Ab (in², net: 1/2 in 0.142, 3/4 in 0.334) 0.334
- Bolt yield fy (psi, A307 = 36000) 36000
You get
- Bv (lb) 1216.6
- Masonry crushing Bvc 1,656 lb
Checked against published worked examples from: NCMA / CMHA.
Details, formula, and sources
ScopeTMS 402-13 ASD (as NCMA TEK 12-03C prints it) allowable shear = LEAST of four modes: masonry breakout Bvb = 1.25 x Apv x sqrt(f'm) with Apv = pi lbe^2 / 2 (edge distance lbe), masonry crushing Bvc = 350 x (f'm Ab)^(1/4), anchor pryout Bvpry = 2.0 x Bab, and bolt steel Bvs = 0.36 x Ab x fy. A 3/4in A307 bolt in 1,500 psi masonry, 5 in embedment 4 in from an edge -> 1,217 lb (masonry breakout governs near the edge); the same bolt away from edges gives 1,656 lb (crushing governs; Ab 0.334 in^2 net). Breakout controls near an edge, crushing usually controls in the field, pryout only at very shallow embedment. Combined tension+shear use the unity check separately. A design aid; the engineer of record's stamped design governs.
Formula or tableBv = least of: masonry breakout Bvb = 1.25 x Apv x sqrt(f'm), Apv = pi x lbe^2 / 2; masonry crushing Bvc = 350 x (f'm x Ab)^(1/4); anchor pryout Bvpry = 2.0 x Bab, Bab = 1.25 x (pi lb^2) x sqrt(f'm); bolt steel Bvs = 0.36 x Ab x fy.
Source and editionTMS 402-13 (Building Code Requirements for Masonry Structures) allowable-stress anchor-bolt shear provisions, as NCMA / CMHA TEK 12-03C (2013) prints them, by name; TMS 402-16 changed the crushing capacity and the interaction.
Free accessCMHA TEK 12-03 anchor-bolt design notes are free public CMHA technical notes; the crushing coefficient 350 x (f'm Ab)^(1/4) is the 402-13 value in NCMA TEK 12-03A and 12-03C, and the breakout / pryout / steel arithmetic is public.
What governsEstimate. AHJ and licensed professional govern.
API field namesfm_psi, lb_in, lbe_in, ab_in2, fy_psi, bv_lb, bvc_lb
- Four modes, least governs Bvb (breakout), Bvc (crushing), Bvpry (pryout), Bvs (steel); Bv = minTMS 402-13 via NCMA TEK 12-03C
- Crushing coefficient Bvc = 350 x (f'm x Ab)^(1/4), the 402-13 value (TMS 402-16 raised crushing)NCMA TEK 12-03A / 12-03C
- Full half-cone Apv = pi x lbe^2 / 2 assumes a full breakout half-cone; edge and overlap reductions are separateTMS 402