Purlin & Girt Design

1. Project

ProjectDesignerMember mark

2. Material (shared)

Yield strength (Fy)MPaTensile strength (Fu)MPaElastic modulus (E)MPaShear modulus (G)MPa

3. Purlin (sloped roof member)

Geometry & bracing

Span (L)mSpacing (s)mRoof slope (θ)Sag-rod lines (n)Comp. flange braced, gravity (+)?

Comp. flange braced, uplift (−)?Unbraced length (Lu−)mMoment gradient (ω₂)

Ly = L/(n+1)

3.75 m

Section (CISC Handbook)

Section typeDepth (d)mmFlange width (bf)mmFlange thick. (tf)mmWeb thick. (w)mmArea (A)mm²Ix 10⁶ mm⁴Iy 10⁶ mm⁴Sx 10³ mm³Sy 10³ mm³Zx 10³ mm³Zy 10³ mm³J 10³ mm⁴Cw 10⁹ mm⁶

Loads & limits

Dead (D)kPaSnow (S)kPaRoof live (Lr)kPaWind down (Wp)kPaWind uplift (Wu)kPaVariable L/ Total L/ Weak-axis Ly/ Axial (optional) (Cf)kN

4. Girt (horizontal wall member)

Geometry & bracing

Span (L)mSpacing (s)mSag-rod lines (n)Comp. flange braced, pressure (+)?Unbraced length (Lu+)mComp. flange braced, suction (−)?

Moment gradient (ω₂)

Ly = L/(n+1)

3.00 m

Section (CISC Handbook)

Loads & limits

Cladding dead (Dc)kPaWind pressure (Wp)kPaWind suction (Wu)kPaWind L/ Gravity Ly/ Axial (optional) (Cf)kN

Cold-formed light-gauge Z/C purlins are outside CSA S16 — design those to CSA S136. Steel self-weight (A × 77 kN/m³) is added to dead load automatically.