Tension Member

[MOOK]

This question regarding design of Tension members

In case of double angle back to back tension member with 3 or more bolts. We need to determine the effective area Ae

Ae= u * An

The factor u = 1 - xbar/L OR

u for double angle can be treated as single angle and we can determine it from Table D3.1 AISC.

Some references use the first method and the others use the second method.

Does anyone know what is the correct method for double angle case?

Thanks

 

[JKuhn]

Table D3.1 does not mention what to do with double angles. If you have the CD that came with the AISC 13th ed. there is a design example for double angles that only uses case 2 (U=1-xbar/L). It looks like if you use case 8 (U=0.8 or 0.6) you would be more conservative so I don't think there's harm in that. A double angle is just two single angles right? Of course you aren't going to get any points on a test for being conservative.

On a test I would say use case 2, there's nothing I can find in AISC that says case 8 is ok for double angles.

 

[MOOK]

Table D3.1 does not mention what to do with double angles. If you have the CD that came with the AISC 13th ed. there is a design example for double angles that only uses case 2 (U=1-xbar/L). It looks like if you use case 8 (U=0.8 or 0.6) you would be more conservative so I don't think there's harm in that. A double angle is just two single angles right? Of course you aren't going to get any points on a test for being conservative.
On a test I would say use case 2, there's nothing I can find in AISC that says case 8 is ok for double angles.

Thanks JKuhn for your reply

What makes me confused is the NCEES solution, they ignored the equation U=1-xbar/L and used the single angle case in the table Case (8) and got u =0.60 which is completely different from the u if you use the equation.

 

[Mike_NC]

I hope this topic is a Structural PM.

Does anyone have general types of design questions asked in the AM for civil?

The Structural section of the CERM is overwhelming.

Mike

 

[MOOK]

I hope this topic is a Structural PM.
Does anyone have general types of design questions asked in the AM for civil?

The Structural section of the CERM is overwhelming.

Mike

I am not sure if this opic in afternoon only.

However, structural part in CERM is less than half of what you have to learn for strucural afternoon.