Splice of unequal flanges sections

[ahmedhegazi]

Hello All

I have got a splice in an I steel section where flanges are unequal(the top one is 380mm wide and bottom one is 550mm)

Difference in dimension as it is a composite beam,i am bout to design the splice,common practie for designing splice is always diving the moment by depth of the section and get two equal forces in both flanges which would result in same number of bolts, my concern is it does not sound reasonable to have same bolts in different sizes flanges!

anyone would recommend other way for disturbing the force?

 

[Lion06]

I assume you're not specifying a full pen weld for the flanges. I would design each flange for it's own force - Fy* Af. The assymetrical section shouldn't be treated differently. Even though the force in each flange is not equal the contibutiom to the resisting moment is. The distance from both the ENA and the PNA to the smaller flange is bigger so even though the flange force is smaller it's contributing as much to the resisitng moment as the bigger flange with the smaller moment arm.

 

[paddingtongreen]

Concisely, the stress in the bigger flange is lower than in the smaller flange. If you ignore the web, the flange forces must be the equal and opposite.

Michael.
Timing has a lot to do with the outcome of a rain dance.

 

[wiktor]

The forces at both sides of the splice are the same, so the number of the bolts shall be the same, as long as the capacity of the bolts is controlled by the shear of the bolts, not the thickness of the flanges.
Ask some experienced engineer to check your design anyway to be on the safe side...