The SectProp spreadsheet computes cross-sectional properties of structural members. Sections can be described either by node coordinates or by layer definitions (for uniaxial properties). Section properties are determined by evaluating line integrals along the closed polygonal path defined by the section’s vertices (nodes). The formulas were published on the back of the original RPN HP calculator manual. For more information see this document Formulas and Theory.
Sectprop also computes torsional characteristics of thin-walled open sections of any configuration. This advanced analysis employs a recursive algorithm to determine the shear center location and the warping moment of inertia.
