Joist Strut

Open roofpro can work as strut.

The joist strut introduced here refers to those roofpro with enhanced bottom chord as square section or round section pipe. This kind of bottom chord obtains good horizontal actuating ability except for acting as roof bearing structure. In view of workshop and warehouse which have big column space and workshop with heavy crane and big column, the joist strut can solve the horizontal actuating on the roof effectively. With the features of bigger rigidity in plane and restraining performance with other members out plane, the joist strut can save greatly steel consumption under same actuating condition than traditional non lattice form strut. To be more superior, Open joist strut combines roof purlin and strut together with benefit of not only saving material but also enhancing two way bearing capability.

Open Joist Strut

Open joist strut use patented M or U shape cold formed thin steel as top chord, round pipe as web, H section, square section or round section steel as bottom chord. Two ends of web are squeezed to be welded with top and bottom chord. Bottom chord will be bolted with main steel beam at two ends by high strength bolt. (see image one)

image one: connection between bottom chord and main beam

Pressed struts are usually set between joints of the braces at the roof span with horizontal braces. To obtain a more reasonable structural system of the building, interval of wind column at gable wall should be adjusted and space between roof purlins must be arranged at average. If the whole structure system fails to have a reasonable arrangement due to preset of the wind columns, the interval of it can be adjusted without binding of pre-arrangement.

image two: sketch of brace at one roof span

Specification of joist strut is indicated as following:

example: in a ship building yard?? height:15m?? column space:12m?? frame span:30m?? interval of wind columns:10m?? wind load: 0.6KN/m?? What kind of joist strut will be available on the roof?
What about its bearing capacity?

Answer:
wind press on upper end of wind column
F=10m*15/2*0.6*1.14=51.3KN
Joist strut of 600XG2.3/□70*3.0 can be used. It is learned by Opentool's calculation that the bearing force of it can reach 101KN under the assumption of roof dead load of 0.4KN/m, live load of 0.5KM/m, and one set of braces between joist at interval of 3m out plane joist strut.

If non lattice strut is used, steel round pipe ofф180*5.0 can be taken with weight of 21.47kg per meter.