Quick Design Section Properties

The Quick Design Section Properties library has been developed to standardize the creation of custom steel cross-sections in quick design calculations. These functions take the dimensions of a custom section and return a section object with commonly used section properties. The section object mimics the format of a section pulled from the SkyCiv database using the await Database.getSection() function. The sample return format is outlined below.

NOTE: All section properties are taken with respect to the global Z and Y axis. This axis is equivalent to the principal axis for all shapes other than angle sections. These functions do not produce results relative to the principal axes for angle sections.

var sect = {
    "shape": "ibeam",
    "dimensions": {
        "BFt": 
        "BFw": 
        "TFt": 
        "TFw": 
        "Wt": 
        "h": 
        "r": 
        },
    "results": {
        "A":  //Gross section area
        "Cy": //Centroid taken from the bottom of section
        "Cz": //Centroid taken from the left side of section
        "Iyp": //Moment of Inertia about Y axis
        "Izp": //Moment of Inertia about Z axis
        "ry":  //Radius of Gyration about Y axis
        "rz":  //Radius of Gyration about Z axis
        "shear_area_y": //Shear area in Y direction (Not available for hat, angle or solid sections)
        "shear_area_z": //Shear area in Z direction (Not available for hat, angle or solid sections)
        "r0":  //Polar Radius of Gyration (Not available for hat or angle sections)
        "shear_center": [Z, Y] //Distance from shear centre to centroid in Z axis (first value) and Y axis (second value) (Not available for hat or angle sections)
        "Qy": //First/static Moment of area about Y axis (Not available for hat sections)
        "Qz": //First/static Moment of area about Z axis (Not available for hat sections)
        "Zyp_top": //Elastic section modulus about Y axis (centroid is taken from right side of section)
        "Zyp_btm": //Elastic section modulus about Y axis (centroid is taken from left side of section)
        "Zzp_top": //Elastic section modulus when about Z axis (centroid is taken from top of section)
        "Zzp_btm": //Elastic section modulus when about Z axis (centroid is taken from btm of section)
        "PNAy": //Plastic neutral axis location taken from btm side of section
        "PNAz": //Plastic neutral axis location taken from left side of section
        "Syp": //Plastic section modulus about Y axis
        "Szp": //Plastic section modulus about Z axis
        "J": //Torsion constant (Not available for hat sections)
        "Iw": //Warping constant (Not available for hat sections)
    }
}

Installation#

You can install the section props library as follows:

const sectionProps = SectionProps;

Supported Sections#

I Sections
T Sections
Channel Sections
Angle Sections
Rectangular Hollow Sections
Circular Hollow Sections
Hat Sections
Solid Rectangular Sections
Solid Circular Sections

Region Option#

Some shapes properties are calculated differently in different design codes. The region option is used to control which code is adopted. Supported regions are outlined below. AS is the default region for all shapes.

Code	Standard
`AS`	AS 4100
`EN`	EN 1993-1-1
`US`	AISC 360
`CA`	CSA S16

Functions#

`ISectionProperties(d, b, t_f, t_w, r, region)`#

Calculates the section properties for a custom I section.

Parameter	Type	Description
`d`	number	Total section depth
`b`	number	Total flange width
`t_f`	number	Section flange thickness
`t_w`	number	Section web thickness
`r`	number	Fillet radius (Default r = 0)
`region`	string	Design code region (Default is AS = AS 4100)

Returns: object - Object containing section properties.

Example Code#

In the calculate.js (or util) file.

const sectionProps = SectionProps;
let sect = sectionProps.ISectionProperties(d_input, b_input, t_f_input, t_w_input, r_input, "AS");

`TSectionProperties(d, b, t_f, t_w, r, region)`#

Calculates the section properties for a custom T section.

Parameter	Type	Description
`d`	number	Total section depth
`b`	number	Total flange width
`t_f`	number	Section flange thickness
`t_w`	number	Section web thickness
`r`	number	Fillet radius (Default r = 0)
`region`	string	Design code region (Default is AS = AS 4100)

Returns: object - Object containing section properties.

Example Code#

In the calculate.js (or util) file.

const sectionProps = SectionProps;
let sect = sectionProps.TSectionProperties(d_input, b_input, t_f_input, t_w_input, r_input, "AS");

`PFCSectionProperties(d, b, t_f, t_w, r, region)`#

Calculates the section properties for a custom Channel section.

Parameter	Type	Description
`d`	number	Total section depth
`b`	number	Total flange width
`t_f`	number	Section flange thickness
`t_w`	number	Section web thickness
`r`	number	Fillet radius (Default r = 0)
`region`	string	Design code region (Default is AS = AS 4100)

Returns: object - Object containing section properties.

Example Code#

In the calculate.js (or util) file.

const sectionProps = SectionProps;
let sect = sectionProps.PFCSectionProperties(d_input, b_input, t_f_input, t_w_input, r_input, "AS");

`AngleSectionProperties(d, b, t_f, t_w, r, region)`#

Calculates the section properties for a custom Angle section.

NOTE: All section properties are taken with respect to the global Z and Y axis. The principal axes for an angle section are generally not equivalent to the global Z and Y axis, meaning the function results for angle sections are not about the principal axes.

Parameter	Type	Description
`d`	number	Vertical leg length
`b`	number	Horizontal leg length
`t_f`	number	Horizontal leg thickness
`t_w`	number	Vertical leg thickness
`r`	number	Fillet radius (Default r = 0)
`region`	string	Design code region (Default is AS = AS 4100)

Returns: object - Object containing section properties.

Example Code#

In the calculate.js (or util) file.

const sectionProps = SectionProps;
let sect = sectionProps.AngleSectionProperties(d_input, b_input, t_f_input, t_w_input, r_input, "AS");

`RHSSectionProperties(d, b, t_f, t_w, r, region)`#

Calculates the section properties for a custom Rectangular Hollow Section.

Parameter	Type	Description
`d`	number	Total section height
`b`	number	Total section width
`t_f`	number	Horizontal (top) wall thickness
`t_w`	number	Vertical (side) wall thickness
`r`	number	Fillet radius (Default r = 0)
`region`	string	Design code region (Default is AS = AS 4100)

Returns: object - Object containing section properties.

Example Code#

In the calculate.js (or util) file.

const sectionProps = SectionProps;
let sect = sectionProps.RHSSectionProperties(d_input, b_input, t_f_input, t_w_input, r_input, "AS");

`CHSSectionProperties(d, t_f, region)`#

Calculates the section properties for a custom Circular Hollow Section.

Parameter	Type	Description
`d`	number	Outer diameter
`t_f`	number	Wall thickness
`region`	string	Design code region (Default is AS = AS 4100)

Returns: object - Object containing section properties.

Example Code#

In the calculate.js (or util) file.

const sectionProps = SectionProps;
let sect = sectionProps.CHSSectionProperties(d_input, t_f_input, "AS");

`HatSectionProperties = (d, b_1, b_2, t_f)`#

Calculates the section properties for a custom Hat section.

Parameter	Type	Description
`d`	number	Total depth of section
`b_1`	number	Top flange width
`b_2`	number	Btm leg width
`t_f`	number	Thickness of section

Returns: object - Object containing section properties. Note, this function does not currently calculate J or Iw values for a hat section.

Example Code#

In the calculate.js (or util) file.

const sectionProps = SectionProps;
let sect = sectionProps.HatSectionProperties(d_input, b_1_input, b_2_input, t_f_input);

`SolidRectangleProperties = (d, b)`#

Calculates the section properties for a custom Solid Rectangle section.

Parameter	Type	Description
`d`	number	Total depth of section
`b`	number	Top width of section

Returns: object - Object containing section properties.

Example Code#

In the calculate.js (or util) file.

const sectionProps = SectionProps;
let sect = sectionProps.SolidRectangleProperties(d_input, b_input);

`SolidCircleProperties = (b)`#

Calculates the section properties for a custom Solid Circle section.

Parameter	Type	Description
`b`	number	Outer diameter of section

Returns: object - Object containing section properties.

Example Code#

In the calculate.js (or util) file.

const sectionProps = SectionProps;
let sect = sectionProps.SolidCircleProperties (b_input);

Installation#

Supported Sections#

Region Option#

Functions#

ISectionProperties(d, b, t_f, t_w, r, region)#

Example Code#

TSectionProperties(d, b, t_f, t_w, r, region)#

Example Code#

PFCSectionProperties(d, b, t_f, t_w, r, region)#

Example Code#

AngleSectionProperties(d, b, t_f, t_w, r, region)#

Example Code#

RHSSectionProperties(d, b, t_f, t_w, r, region)#

Example Code#

CHSSectionProperties(d, t_f, region)#

Example Code#

HatSectionProperties = (d, b_1, b_2, t_f)#

Example Code#

SolidRectangleProperties = (d, b)#

Example Code#

SolidCircleProperties = (b)#

Example Code#

`ISectionProperties(d, b, t_f, t_w, r, region)`#

`TSectionProperties(d, b, t_f, t_w, r, region)`#

`PFCSectionProperties(d, b, t_f, t_w, r, region)`#

`AngleSectionProperties(d, b, t_f, t_w, r, region)`#

`RHSSectionProperties(d, b, t_f, t_w, r, region)`#

`CHSSectionProperties(d, t_f, region)`#

`HatSectionProperties = (d, b_1, b_2, t_f)`#

`SolidRectangleProperties = (d, b)`#

`SolidCircleProperties = (b)`#