3345Design Checks for the Shear Transfer Regions

Region 7 is the shear transfer region between the concrete slab and the exterior stub, and the combined shear and longitudinal compressive capacity of the slab in this area must be determined. The shear transfer region between the slab and the interior stub always has a smaller shear force.

Region 7 is critical and several studies have shown that the slab in this area will fail in a combination of concrete crushing and shear [4-7]. The shear failure zone usually extends from corner to corner of the steel deck, over the top of the shear connectors, as illustrated in Figure 33.8. This also emphasizes why the placement of the longitudinal reinforcing steel bars in the central flute of the steel deck is important,

Concrete slab

Shear failure zone

Concrete slab

Shear failure zone

FIGURE 33.8 Shear failure zone in concrete slab above stub.

Steel deck Concrete crushing zone

FIGURE 33.8 Shear failure zone in concrete slab above stub.

as well as the location of the transverse bars: both groups should be placed just below the level of the top of the shear connectors (see Figure 33.2). The welded wire mesh reinforcement that is used as a matter of course, mostly to control shrinkage cracking in the slab, also assists in improving the strength and ductility of the slab in this region.

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