Through-Bolt Design

[SamETABS]

Hi Gents,
I am trying to design a 300mm Diam. through-bolt which penetrates through 200mm THK reinforced concrete wall and it is under both axial and shear force. The checks that I am trying to apply are as follows:

1-Concrete bearing capacity ----> not sure how to calculate it for a through-bolt? what is the effective bearing length, I've to assume?
2-Punching shear (axial force in bolt generates a pull out force that tends to punch through wall)
3-shear capacity of bolt

I appreciate that if you can help me.

Regards,

Sam

 

[paddingtongreen]

Did you mean 30mm Diameter?

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

 

[SamETABS]

paddingtongreen,

my apology, it was a typo. it should be 30 mm.

 

[asixth]

Item 3 is the easiest, it is designed as a pin in shear. The equation should follow:

?V=?*0.62*fyp*ns*Ap (Limit State Format)

where ? is the material reduction factor (0.9 for steel but refer to your steel code); fuf is the yield stress of the pin; ns is the number of shear planes and Ap is the cross-sectional area of the pin.

I think the design would be governed by one of the first two items.

 

[paddingtongreen]

I'm not up to date on which authorities control this stuff now, but I would be tempted to get the handbook from Hilti to, at least, get a feel for the concrete pullout cones for the combined load.

asixth, does he need a special method for combining shear and tension in the bolt, as we used to do in working stress, or was that just friction bolts?.

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

 

[SamETABS]

Asixth:
thanks for the comment. What code r u using?

paddingtongreen:
the main technical authorities would be ETAG001, Annex C, ETA-02/0042

But gents the main issue is defining the modes of failure. HILTI and other technical literatures discuss mainly about partially peneterated anchors (as attached), ACI for example specifically points out that the calcs do not cover through bolts. to my knowledge the modes of failure should be different between partially peneterated bolts and through-bolts.

what u reckon?

thanks
Sam

 

[paddingtongreen]

Sam, I suggested the Hilti book only for an insight into combining the pullout cones for tension and for shear. Since I retired, there have been transfers of responsibility between the code authorities and I don't know who governs nowadays. You can certainly improve the tension situation with a plate washer on the back side.

I seem to remember that there were diminishing returns on the shear cone with greater depths because of the bending of the rod. I thought you might find the limit in Hilti

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