Section Moment Resistance 6

[dik]

I'm writing an SMath program for a bolted splice and am determining the moment capacity of the section. Is the resistance determined by deleting the area of steel from the holes at the first line of bolts? or do you consider the 'clamping' action from the first line of bolts as increasing the Mr? I've spec'd lots of these connections but never looked at them in detail. I've never run them up to more than about 60% of the capacity, but for the sake of the program I'm splitting hairs...

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[Yao1989]

Not sure if it helps, but in Canadian code you would take the lesser of "net section" which subtract the steel area for hole, you use tensile strength instead of yield strength (albeit tensile stress has lower resistance factor), or take gross section but use yield strength.

 

[Tomfh]

Same in Australian code.

Take minimum of:

A. Fu over net area

B. Fy over gross area

 

[dik]

Thanks... that's what I thought. I didn't know if the 'clamping' action from the bolts should be included in some fashion, or if it actually contributes.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[Logan82]

Hi dik,

There are some provisions from CSA S16-09 in articles 14.1 and 14.3.3 regarding bolt holes in beams.

 

[Logan82]

By the way, which version of SMath are you using? I tried the one from the Windows Store, but I found it lacked some menus that are found in some SMath videos.

My version:

The version I see checking tutorial videos:

 

[dik]

This one...

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[BridgeSmith]

AASHTO bridge design code has you check fracture at the ultimate tensile strength on the 'effective' section (a calculated area that's between net and gross section) and yielding on the gross section at the Strength (design, ultimate) loading combination. At ultimate load, it's assumed that the slip resistance has been exceeded and is no longer contributing to the resistance.

Rod Smith, P.E., The artist formerly known as HotRod10

 

[dik]

thanks Bridge... didn't know that, but makes sense. What is the 'effective' section?

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[BridgeSmith]

Well, I was apparently remembering this incorrectly. The effective area (Ae) is used to determine the design yield capacity of the flange, which the capacities of the splice plates and bolts must meet or exceed. The splice plates are checked for yielding on the gross section (Fy*Ag) and fracture on the net section (Fu*An).

Anyway, the effective area:

Rod Smith, P.E., The artist formerly known as HotRod10

 

[dik]

thanks very much for the added info...

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik