Tuesday, August 5, 2008

RE: more aci 318

Daryl,

 

As I understand, if the concrete fails first….brittle failure which is what I was having until I arrived at the adequate conc. thickness and bolt embedment.

 

The code does allow a ductile connection to the bolt to fail prior to concrete failure so you could get around it that way. In my case I am dealing with a pre-manufactured cabinet that I am reluctant to monkey with.

 

Mark

 

From: Daryl Richardson [mailto:h.d.richardson@shaw.ca]
Sent: Tuesday, August 05, 2008 9:49 AM
To: seaint@seaint.org
Subject: Re: more aci 318

 

Mark,

 

        Why does the bolt itself have to fail in ductile failure?  Why can't a plate or similar detail that is connected to the bolt be used to provide the ductile failure?

 

Regards,

 

H. Daryl Richardson

----- Original Message -----

Sent: Tuesday, August 05, 2008 10:09 AM

Subject: more aci 318

 

This bolt thing is becoming more frustrating.

 

I have been doing anchor bolt shear/tension calc for a 1000# piece of electrical equipment mounted on a pad with ½” dia. anchor bolts (manufacturers frame provides holes for ½” dia bolts). The pad is 8’ by 8’.

 

I have found that a 14” deep concrete pad with cast in place bolts embedded 8” is required for ductile failure, my closest edge distance is 18”. I cannot have brittle failure due to seismic category D.

 

What used to be a 30 minute calc for loading and bolt design has turned into hours of *&^$%#@ and a pad design that is embarrassing to provide the client and contractor.

 

Aaaargh !!

 

Mark D. Baker

Baker Engineering

 

 

 

 

 

 

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