Floor form with connected truss supports

Claim 1

In formwork for constructing a composite steel and concrete floor, the combination which comprises: a steel joist having top chord means, a bottom chord, and web means joining and separating the top chord means and the bottom chord; said to chord means including: a top portion generally horizontally disposed relative to said web means, a lower portion generally horizontally disposed relative to and extending along the top of said web means, and an intermediate portion connecting said top portion to said lower portion, said intermediate portion extending obliquely between the top and lower portions to connect one edge of the top portion to the opposite edge of the lower portion; said joist having means extending vertically below the other edge of said lower portion for connecting said top chord means and web means; at least an additional steel joist substantially alike the first-mentioned steel joist, the additional steel joist being laterally spaced from and extending parallel to the firstmentioned steel joist with the said intermediate portion of each top chord means of both joists extending in the same oblique direction so that the said opposite edges of the respective lower portions of each top chord means extend along the same side of the respective joists and the said vertically extending means of each joist extends horizontally along the corresponding other side of each said joists; at least two spanner bars extending laterally between and being connected to said vertically extending means of each of said first-mentioned and additional steel joists for spacing said vertically extending means a predetermined distance apart, the tops of said bars being a given height below the said lower portion of each steel joist; and a substantially rigid pouring form having a thickness of substantially said given height, said form being supported directly by the spanner bars and having a width of substantially said predetermined distance extending horizontally substantially from said vertically extending means of the first-mentioned steel joist substantially to said vertically extending means of the additional steel joist with one edge of said pouring form being underneath and held down by the said lower portion of the top chord means of one of said joists while being directly supported as aforesaid by said bars closely adjacent said one lower joist lower top chord portion, so that a concrete slab may be poured upon the form to embed the top chords down adjacent the level of the lower portions thereof to create a composite steel and concrete floor below which the web means and lower chords of the steel joists depend, with the aforesaid substantiallY rigid, horizontally extending held down and directly supported pouring form contributing to the development of diaphragm action in and hence lateral stability of said formwork both before any concrete pouring and during the setting of a poured concrete floor.