Section Property Calculator

This app is created for assisting engineers to calculate section properties of the most commonly used sections in bridge structures. It may also used by students studying structural engineering. This app may calculate the section properties of the following cross sections:

Solid Rectangular Section
I-Shape Section
L-Shape Section
T-Shape Section
Channel Section
Solid Circular Section
Circular Pipe Section
Hollow Rectangular Section
Cross-Shape Section
One Cell Box Section
Two Cell Box Section
Three Cell Box Section
I-shape Composite Section

The unit of all the input parameters must be consistent, while ρ is the mass density of the material (for composite section, ρc and ρs are the mass density of concrete and steel respectively), and Ec and Es are the corresponding Young's modulus. The output of this app includes the coordinates of gravity centroid Yc and Zc relative to the coordinate system shown in each section plot, area A, area moment of inertia Iy about Y-direction through the centroid, area moment of inertia Iz about Z-direction through centroid, torsional constant J, and mass moment of inertia Im which is calculated relative to the centroid of the section. All these calculations have been verified by specific examples.

The mass moment of inertia Im is only used for dynamic analysis. If this property is not needed, the mass density of the material ρ may be set to be any value (e.g 1.0.)

The torsional constant of an open section is usually calculated using formular b*t3/3, which is valid only for thin-wall sections with b/t ≥ 10. To be more accurate, the formular used in this app is modified based on different b/t ratios.

For I-shape composite section, concrete slab is assumed to have no cracks. The effective width of concrete slab should be determined by the user based on design code. The section properties are given in equivalent steel section.