One of the more innocuous changes in the 11th edition of the Handbook of Steel Construction is the updating of detailing dimensions in Part 6. As shown on the figure below, k and k1 depend not only on the flange and web thicknesses, respectively, but also on the radius of the round flange-to-web fillet, r. Since this radius is not a standardized dimension, it varies among steel producers. Also, the radius provided by a given producer may change over time.
The fillet radius of many W-shape and HP sections has increased since the 10th edition of the Handbook. Accordingly, the dimensions k and k1 shown in Part 6 of the Handbook have also significantly increased in the new edition.
The change has also affected other parts of the Handbook, notably Tables 3-37 and 3-38 for double-angle beam connections. The depth of the supported beam is limited by the dimension T, which is given by:
T = d – 2 k
where d is the section depth. As a result, the tabulated minimum (nominal) depth of supported beam has increased in order to provide sufficient clearance for the web-framing angle legs, taking into account the “fillet encroachment” based on Table 3-35.