Section Properties  
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Diagram shows an “I” bar consisting of three sections, 1, 2 and 3. The section 1 on top is horizontal with a length of 3.0 inches. The section 2 has a thickness of 0.5 inches and is between the sections 1 and 3. The section 3 is horizontal and has a length of 6.0 inches. The centroid is at the origin of the x y axes on the vertical section 2 at a height of 2.645 inches from the bottom edge of the horizontal section 3 and at a distance 5.355 below the top edge of the section 1.

Before continuing, the centroid location and the area moment of inertia of the flanged shape about the centroidal axis must be computed.


In the vertical direction, the centroid is located 2.645 in. above the bottom surface of the flanged shape and 5.355 in. below the top surface. The neutral surface for the cross section is located at the centroid for the shape. At this location, bending strains and stresses are zero.

The area moment of inertia about the z axis is Iz = 87.044 in.4.