Monday, November 12, 2007

Re: Transfer force of large tie beam

Jordan,

Thanks again for your response. I really appreciate it.

I don't understand your description of the angles. I was thinking of 4
rods, 2 rows and 2 columns. I would put a vertical angle tying the two
rows together on each side of the anchor bolt group. This would be easy
to get concrete around. I hesitate on a horizontal angle because I think
there is too high a potential for a void somewhere. I may tie the two
vertical angles together with some flat bars. I would then wrap all of
this in a rebar cage for the pier.

You figured out my pattern for the email address. Actually, it's been a
while since I had to change addresses. I think they have done better at
deleting the spam off the server. I guess it now comes from harvesting
them from the archives. I occasionally change my email address to prevent
some of the spam.

Rich


> I was thinking the same thing for the rods - make a weldment of the
> anchor rods, an angle (or four) to form an L in the pier, then rebar (or
> A36 rods) welded along the axis of the angle which extend into the
> subslab trench. Now, there are still some moments to deal with, so the
> concrete in the pier isn't really out of the load path completely. But
> that's why we make the big bucks, right?
>
> Jordan
>
> PS - I noticed you're up to serial number 4 on your email. I lost about
> 2 weeks of seaint recently when my previous address became a
> spam-magnet, and I think the server just gave up and deleted almost
> anything coming into that account.
>
> seaint04@lewisengineering.com wrote:
>> Jordan,
>>
>> Thanks for the response.
>>
>> I looked at my numbers a little more closely this morning and realize my
>> maximum load combination is 88.9 kips horizontal thrust. The 60 kips
>> was
>> from the roof snow load. I also have drifted snow load on the worst
>> case
>> frame, plus the dead load.
>>
>> I wasn't thinking of using 40 grade steel reinforcing. I was
>> considering
>> using A36 rods. It would be too confusing to try to get 40 grade rebar
>> for the project. If I limit the stress to 22 ksi I need (4) 1.125 dia
>> rods. I'm still wondering about an efficient way to get the force out
>> of
>> the anchor bolts and into the rods. I 'm considering using some angles
>> to
>> 'dead head' the rods in the pier. I can see I would put a significant
>> cage of rebar around the bolts. I would detail a concrete tie beam
>> below
>> the floor slab. I'm still not comfortable with how the force load path
>> travels from the bolts to the tie rods.
>>
>> Rich
>>
>>
>
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