Open web steel joist (4.4) 8*10*2ϕ4.5 Tirche Sanati Ettehad

Open web steel joist is a prefabricated piece, consisting of concrete and steel rebar, which, after complete application of the block joist roof, creates side beams. The joists are loaded in three stages. Firstly, it will bear the burden of transportation. In the second stage, the roof is load-bearing concrete, which tolerates the dead weight of the roof (joist weight, block and in situ concrete) and loads during the execution between the main supports to the joinery, and in the third stage, the load-bearing result from Dead and alive loads after coating the concrete and obtaining enough strength. The joists are manufactured in two types: one is a concrete heel which is made of iron by a combination of rebar and piece concrete. In this type, the gap between the joists is 5 cm in the ceiling and 50 cm wide expanded polystyrene blocks are used.  The second type of joists is called all-metal joists, or so-called chromite joists, which are 66 cm in these roofs, which are commonly used in steel frame buildings.