Composite Connections

The vast majority of steel buildings built today incorporate a floor system consisting of composite beams, composite joists or trusses, stub girders, or some combination thereof [29]. Traditionally
the strength and stiffness of the floor slabs have only been used for the design of simply-supported flexural members under gravity loads, i.e., for members bent insingle curvature about the strong axis of the section. In this case the members are assumed to be pin-ended, the cross-section is assumed to be prismatic, and the effective width of the slab is approximated by simple rules. These assumptions allow for a member-by-member design procedure and considerably simplify the checks needed for strength and serviceability limit states. Although most structural engineers recognize that there is some degree of continuity in the floor system because of the presence of reinforcement to control crack widths over column lines, this effect is considered difficult to quantify and thus ignored in design.

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