|Comparing .060 Evergreen angle to REAL WORLD|
The .060″ Evergreen angle is closest in size to 3″ angle. The Engineering Toolbox – steel angles page lists six sizes of 3″ angle – from a 3/16″ to 1/2″ which I show in the drawing.
The most obvious difference is that the Evergreen shape is squared off while the ‘real world’ example is rounded off. This could be easily done with a few swipes of a file – that additional thickness of the Evergreen shape is only .004″ would be completely obscured by the rounded flange. In fact – since the ends of the angle are hidden, it would be difficult to tell what thickness the angle was.
|Spacing of Web Stiffeners|
The proper spacing of web stiffeners is a question to which (…) so many theories advanced.
(…) little reliance is placed in most of these theories (…) as the spacing of the web stiffeners in most cases depends on practical considerations, e.g. pitch of rivets, position of cross-girders, (…) bracing, etc.
There should always be a stiffener over the edge of a bearing plate, and at every cross-girder, or at points where any concentrated loads occur.
In girders over about 4 ft. deep, the distance between centres [sic] of stiffeners should not exceed the depth of the girder, with a maximum of 4 to 6 ft.1
Near the ends, the spacing of stiffeners shall be one-third to one-half the depth. They shall be composed of two angles, one on each side of the web and shall fit tight between the legs of the flange angles.2
The ends of plate girders are stiffened by stiffeners on each end of the bed-plates.
The arrangements usually employed are represented in Figs. 13, 14, and 15, in which c are the stiffeners; d, the sole plates; and e, the bedplates. The arrangement represented in Fig. 13 is most used, although that shown in Fig. 14 is somewhat better on account of the fact that in it the bearing of the stiffeners is not so close to the edge of the bed-plate; the pressure is therefore more evenly distributed over the area of the bedplate. In the arrangement represented in Fig. 15, the additional stiffeners d are added. The plates g are called reinforcing plates, and are added to distribute the stress more evenly over the web.3
Shearing stresses are usually provided for by web reinforcement plates or by vertical web-stiffener angles, which are often spaced very much closer together at the points of support than elsewhere.4
- The Practical Design of Plate Girder Bridges, Harold Hughes Bird, 1920 – Pg.87 [↩]
- Bridge specifications: Design of plate girders, International Correspondence Schools, 1908 – Pg.15 [↩]
- Bridge specifications: Design of plate girders, International Correspondence Schools, 1908 – Pg.31 [↩]
- Types and Details of Bridge Construction: Plate girders, Frank Woodward Skinner, 1906 – Pg.124 [↩]