W18x40 is a rolled structural beam with wide flanges that is used in construction and other applications.
Table of Contents
W18x40 Beam Size and Dimensions
The dimensions and specifications of this structural steel beam are below:
|Web Thickness||0.32 in|
|Flange Thickness||0.53 in|
|Area Moment of Inertia||603 in4|
|Elastic Section Modulus||67 in3|
The depth of W18x40 beams may vary by 1/8” above and below the nominal value.
The flange width may vary by 1/4” above nominal and 3/16” below nominal. Flanges may be out of square by as much as 5/16”.
The distance from the center of the web to the center of the profile may be no greater than 3/16”.
The radii of fillets and toes for W-beams are not specified. Instead, these dimensions are left up to individual manufacturers.
Wide flange beams are designated by their depth x weight. The W18x40 designation indicates that the beam weighs 40 pounds per foot. A 10-foot section of W18x40 would weigh 400 pounds and a 50-foot section of W18x40 would weigh 2,000 pounds.
W18x40 Conversion to Metric
The metric equivalent to W18x40 is W460x60. This metric beam has the following specifications:
|Web Thickness||8 mm|
|Flange Thickness||13.3 mm|
W18x40 Section Properties
W18x40 Area Moment of Inertia
The area moment of inertia (or second moment area) for a W18x40 beam about the x-axis (perpendicular to the flange) can be calculated from the equation below:
The area moment of inertia of the W18x40 profile about the x-axis is approximately 603 in4.
W18x40 Section Modulus
The elastic section modulus for a W18x40 beam about the X-axis is calculated from the following equation:
The elastic section modulus for the W18x40 profile about the X-axis is approximately 67 in3.
The properties of W18x40 beams are specified by ASTM A6 “Standard Specifications for Rolled Structural Steel Bars, Plates, Shapes and Sheet Piling”