Niazit Ceiling Industrial Group

Niazit-Joist components

Niazit open web steel Joist:                                                                                    

Niazit joist is an open web steel joist steel with 2D vertical truss design having the capacity of the bearing dead and live load of the roof or floor (free-standing joist) before and after strengthening concrete.

Structural joists using the strap as bottom chord (tensile chord), and T (tees) steel as top chord (composed compressive chord) and single rebar in the web joist used as shown in fig a1 and a2

 

Open web joist in steel structure

(fig 1)

 

Open web joist in concrete structure

(fig 2)

 

The advantages of Niazit-joist due to previously joist are:

A- New type of web joist

B- Especially the ends support of joist

C- Composed section (top chord)

D- Using T (tees) steel type (top chord). Finally with lighter material we can have more resistance.

 

Consideration:

The steel joist built up of bars or other section and those fabricated by expanding rolled section shall be designed as trusses.

 

A- Top chord:

Top chord is a compressive element usually using as T steel section with equal radius of gyration in X and Y direction to compere double angle it is more suitable in assembling and also economical. Top chord with a concrete formed as composite section.  

 

Composite section:

Specification detail of composite Niazit-ceiling is the top chord embedded with concrete formed of cross-section trapezoidal (composite section) as shown in figure 1 due to National Building Regulations of Iran, Section 10. so the joist no need shear studs, indeed doing solidarity of ceiling which helped in bearing capacity of joist .

 

 

B- Web members:

The web composed of single round or ribbed bar as individual (vertical and diagonal) with no bending and any crave so it is obvious the straight element  compare to round continuous bent bar have more resistible in web joist. Vertical bars act as compression and diagonal bars as a tension, After forming composed section decrease less deflection due to loading see fig 1and 2. Indeed in designing you can omit the concrete section from the zone of tension. So you can have a lighter joist finally it can decrease the cost of charges.

 

C- Bottom Chord:

Using steel strip (ST37)