Panel-Zone Shear Under High Column Axial (AISC 360 J10-10/J10-12)
How column axial load cuts panel-zone strength.
Example
You enter
- Column yield Fy (ksi) 50
- Column depth dc (in) 14
- Column web tw (in) 0.5
- Column gross area Ag (in²) 26.5
- Axial demand Pr at the joint (kip) 600
- Panel-zone deformation in the analysis? no
You get
- Py (kip) 1325
- Axial ratio 0.45283
- Axial reduction factor 0.9472
- Rn (kip) 198.906
- Phi rn (kip) 179.015
Details, formula, and sources
Past Pr = 0.4 Pc the basic panel-zone strength takes (1.4 - Pr/Pc) (Eq. J10-10), past 0.75 Pc the deformation-modeled strength takes (1.9 - 1.2 Pr/Pc) (Eq. J10-12), Pc = Py = Fy Ag. A W14-class column at 45% of axial yield loses 5% of its panel zone; at 83% it is losing 1.2% per additional percent of axial. Below the thresholds it matches the unreduced panel-zone strength exactly. A design aid, not a connection design.
Py = Fy Ag; ratio = Pr/Py; not modeled: ratio <= 0.40 -> Rn = 0.60 Fy dc tw (J10-9), else x (1.4 - ratio) (J10-10); modeled: ratio <= 0.75 -> Rn = 0.60 Fy dc tw [1 + 3 bcf tcf^2/(db dc tw)] (J10-11), else x (1.9 - 1.2 ratio) (J10-12); phiRn = 0.90 Rn.
The AISC 360-16 Section J10.6 panel-zone shear strength with column axial load, Eq. J10-10 and J10-12, by name.
AISC 360 is available through AISC; the J10.6 panel-zone provisions are published design equations.
Estimate. AHJ and licensed professional govern.
Field names used by the API: fy_ksi, col_depth_dc_in, col_web_tw_in, col_area_ag_in2, pr_kip, pz_in_analysis, py_kip, axial_ratio, reduction_factor, rn_kip, phi_rn_kip
- Axial thresholds the reduction starts at Pr = 0.4 Pc (not modeled) or 0.75 Pc (modeled); Pc = Py = Fy Ag for LRFDAISC 360-16 J10.6
- Capacity only the joint shear demand comes from the steel-panel-zone-shear sibling; this tile returns the reduced capacityAISC 360-16 J10.6