Steel hollow sections for structural applications offer better structural properties than open sections (angles, channels), thus resulting in better weight savings during Structural Design. But unlike open sections, steel hollow sections are difficult to connect because of lack of easy access for bolting and demand welding as a predominant joining method. This complicates the whole joining process for hollow sections. The joining method is one of the major hindrances for hollow steel sections to become the most popular structural element in India.
The current methods of joining are welding intensive and since hollow sections have very thin walls, welding is very challenging. Due to this the structural consultants are not comfortable using hollow sections as the skill & quality of welding required is very high and often not available.
The tube thickness varies from 2mm to 10mm. The sizes of the hollow sections vary as below:
Square Hollow Sections (SHS) [25x25] mm to [250x250] mm
Rectangular Hollow Sections (RHS)[ 50x25] mm to [300x200] mm
Circular Hollow Sections (CHS) 21.3 mm to 323.9 mm Outer Diameter
We desire to have an improved mechanism of joining, which involves very less or no welding. This new mechanism must be easy to fabricate and erect at construction sites. In addition, the new method should not exceed the cost of current methods (welding) to encourage consumption.
In most cases the steel structure is exposed and visible and hence the method should not damage the aesthetic appeal of the building.
Critical Success Factors/ Measures:
1) Ease of joining
2) Cost on par with welding
3) Should have proof of structural stability via physical tests.
4) Should not adversely impact the aesthetic appeal of the structure