Shear Modulus of Structural Steel

G_{\mathrm{steel}} = 7.72 \times 10^{10}\ \text{Pa}

Value	7.72e10 Pa
Status	Measured: ± 1,000,000,000 Pa (0.013 relative)
Source	AISC Steel Construction Manual, 15th ed.
Categories	Material Properties Engineering & Trade mechanics

G_st in every pressure unit

pascal	77,200,000,000 Pa
kilopascal	77,200,000 kPa
megapascal	77,200 MPa
bar	772,000 bar
atmosphere	761,904.76 atm
millimeter of mercury	579,047,540 mmHg
pound per square inch	11,196,913 psi
foot of water column	25,827,458 ft H₂O
gigapascal	77.2 GPa
kip per square inch	11,196.913 ksi
inch of mercury	22,797,147 inHg
inch of water column	309,929,500 in w.g.

Learning zone

Shear modulus is not an independent measurement for an isotropic material: G = E / [2(1 + ν)]. With E = 200 GPa and ν = 0.30 that gives 76.9 GPa, and AISC rounds the design value to 11 200 ksi (77.2 GPa). It is the stiffness that governs angle of twist in a shaft, torsional buckling of an open section, and the shear component of deep-beam deflection.

Two traps. First, the same grade-independence as E applies — a Grade 8 shaft twists exactly as much as a mild-steel one of the same geometry under the same torque, it just survives more of it. Second, torsional stiffness is dominated by the section, not the material: a closed tube is orders of magnitude stiffer in torsion than an open channel or wide-flange of the same weight, because the torsional constant J for an open section is a thin-strip approximation that collapses with wall thickness cubed. If a member has to resist torsion, change the shape before you change the steel.

Used by these solvers

Shear Modulus (G = τ/γ)

G = \frac{\tau}{\gamma}

Angle of Twist (φ = TL/JG)

\varphi = \frac{T L}{J G}

Relation Between E, G and ν

E = 2G(1 + \nu)

Torsional Shear Stress (τ = Tr/J)

\tau = \frac{T r}{J}