Steel Joist and Stone or Precast Concrete Slab Floors

Stones are available in several parts of the country and therefore, this flooring is used for economy and ease in construction. This type of floor is quite general in locations whereas flag-stones or stone-slabs are readily available in spans of 1 to 3 metres and widths 30 to 60 cm. While stone slabs are not available, precast concrete slabs could be used. The slabs are placed at the lower flange of rolled steel joists (RSJ), specially whereas plain ceiling is need, though in this case the bearing to the slabs is small (Figure 5(b)) Or else, the slabs could be supported on the upper flange of RSJ through inserting huge stone bedding plate, called suboti among the flange and the slab (Figure 5(c)). While the slabs are placed on the lower flange, of joists, the space among the top of the slab and top of RSJ is filled along with lime concrete or light weight cement concrete, after encasing the steel joists totally in cement concrete so in which they do not get rusted. On the top of it, regular flooring is laid.

                                  Figure: Stone Slab Floor Supported on Steel Joists

The spacing of the rolled steel joist is depends upon the length of available stone slabs. The joists have the clear span equivalent to the width of the room (Figure 5(a)). The bearing of joists on the wall should at least be equivalent to depth of the joist, but in no case less than half the width of the wall. It is better if bearing is remain, just equal to the width of the wall so in which eccentric load of the wall is eliminated. A bed plate is given below each end of the joist, to suitably distribute the load to the wall. Stone slabs are available in lengths of 1 to 3 m, if the width of the room is slightly less than this value, stone slabs could be directly supported on the walls, without using steel joists. Like a construction is quite cheap.