| 摘要 |
A B-shaped structural member including a linearly extending back-wall section running substantially the entire length of the member, a first sidewall section and a second sidewall section, each sidewall section being integrally formed with and extending from a respective side of the back-wall section, a first front-wall section and a second front-wall section, each front-wall section integrally formed with the extending from respective sidewall sections, first and second inwardly turned flange sections integrally formed with and extending from respective front-wall sections, and a linearly extending slot defined intermediate the inwardly turned flanges. The ends of the inwardly turned flange sections provide engagement surfaces to grippingly receive a fastener which is inserted into the slot. The engagement surfaces of the inwardly turned flanges are configured to permit easy insertion of the fastener but to retard the disengagement of the fastener from the structural member. The B-shaped cross section of the structural member provides approximately equal bending strength about both neutral axes and also provides a high ratio of bending strength to weight per lineal foot.
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