Composite joist floor system
Embodiments of the present invention provide systems for connecting a flooring system to a vertical wall. In one embodiment the building structure includes a floor comprising a cementitious slab and a wall supporting at least a portion of the cementitious slab. A plurality of stand-off screws extend from the top of the wall into the cementitious slab and are configured to transfer forces between the cementitious slab and the wall. The stand-off screws comprise a lower screw portion and an upper stand-off portion. The lower screw portion is drilled into the top of the wall, and the upper stand-off portion extends above the top of the wall and is encapsulated within the cementitious slab. In some embodiments, at least a portion of the lower screw portion is heat treated to a higher degree of hardness relative to the remainder of the stand-off screw.
1. A building structure comprising:
a floor comprising a cementitious slab;
decking for supporting at least portions of the cementitious slab;
a plurality of floor joists for supporting at least portions of the decking and the cementitious slab;
a wall supporting one or more of the plurality of floor joists and at least a portion of the cementitious slab; and
a plurality of stand-off screws extending from the plurality of floor joists and from the top of the wall into the cementitious slab and configured to transfer forces from the cementitious slab to the plurality of floor joists then to the wall supporting the one or more of the plurality of floor joists, wherein each of the stand-off screws comprises a lower screw portion and an upper stand-off portion, wherein the lower screw portion is screwed through the floor joist and/or into the wall, and wherein the upper stand-off portion extends from the plurality of floor joists and/or the wall and is encapsulated within the cementitious slab located above both the plurality of floor joists and the wall.
2. The building structure of claim 1 , wherein the plurality of stand-off screws extend from the top of the wall and/or from the floor joists and are configured to transfer horizontal diaphragm forces between the cementitious slab and the wall.
3. The building structure of claim 1 , wherein the lower screw portion of the stand-off screws is screwed into the floor joist and/or the top of the wall, wherein the lower screw portion has a generally greater hardness than that of the upper stand-off portion of the stand-off screws.
4. The building structure of claim 1 , wherein the upper screw portion of the stand-off screws extends above the top of the wall and/or the floor joist, such that the upper screw portion is encapsulated with in the cementitious slab, wherein the upper screw portion is generally more ductile than the lower screw portion.
5. The building structure of claim 1 , wherein the lower screw portion of the stand-off screw comprises a self-tapping tip for drilling into the metallic structure.
6. The building structure of claim 1 , further comprising:
one or more closures positioned at the top of the wall to form the cementitious material in the region over the wall, wherein at least some of the stand-off screws are further used to fasten the one or more closures to the top of the wall.
7. The building structure of claim 1 , wherein the plurality of floor joists each comprises a joist shoe at one end, wherein the wall supports the one end of the floor joist at the joist shoe, and wherein one of the plurality of stand-off screws fastens the joist shoe to the top of the wall.
8. The building structure of claim 1 , further comprising a welded wire fabric encapsulated within the cementitious slab.
9. The building structure of claim 1 , wherein the floor further comprises:
the decking for supporting at least portions of the cementitious slab between the wall and one or more other walls or support structures;
the plurality of floor joists for supporting at least portions of the decking and the cementitious slab; and
a plurality of stand-off screws for fastening the decking to the joists, wherein the lower screw portions of each of the stand-off screws are drilled through the decking and into the joists, and wherein the upper stand-off portions of each of the stand-off screws extend above the decking and are encapsulated in the cementitious slab.