| 摘要 |
Two relatively thin sheets of metal are placed in stacked relation and bent so as to form two nested members, each having a pair of spaced parallel flanges, a central web portion at right angles to the flanges, and two inclined web portions connecting the central web portion with the flanges. The inner formed plate is then removed from the outer plate, reversed, and its flanges inserted within the flanges of the outer plate. The beam sections are then secured together.
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