Anchor Bolts in Shear & Tension

[BrianMc]

Does anyone have any reference material on anchor bolts designed in shear and tension? I was at a seminar where they stated that the equations in the code are non-conservative, but they did not elaborate any further.

 

[Polecat]

Brian, I have been struggling with this one for years.

I am frequently called upon to design flange plate connections for spliced concrete poles which are invariably subjected to a combination of tension and shear (as well as torsion).

Between Chen's Structural Engineer's Handbook, ASCE Manual 72 and the AISC Spec's on this subject, I was finally able to come up with a reasonable solution, which ends up with a unity check for the connection based on LRFD.

I have also shared some information with Chris Rosencutter of MECA Consultants, who designs flange plate connections for stacks and has developed some pretty good Excel programs for this and other applications.

You may contact him at

http://www.mecaconsulting.com

(tell him that I sent you there), and you can reach me at

http://www.spiraleng.com.

Between the two of us, you may find some answers.

William Ford

The Polecat

http://www.spiraleng.com

I invite people to visit my website if you wish to discuss these issues further.

 

[whymrg]

Accoding to Steel Design Guide Series # 7 "Industrial Buildings. Roof to Column Ancorage" (AISC Pub. No D807)Shear Force may be resisted by shear friction (p. 29).
Using this concept, the design of anchor bolts for shear becomes a design for tension with the Tensile Force in anchor bolt evaluated as:
Tsf=V/(N*mu)
where Tsf - tensile force per bolt due to shear friction
V - Shear Force per connection
N - number of bolts per connection
mu - appropriate coefficient of friction (0.55 for grouted condition with the contact plane between grout and as-rolled steel exterior to concrete surface - normal condition).

Total tensile force per bolt equql to tensile force due to tension load plus tensile force due to shear friction.

 

[StructuralDzine]

There is a thread on this in the "concrete engineering" forum

 

See 4th Quarter/ 1992 of the Engineering Journal of the American Institute of Steel Construction. There is a 4 page article dealing with exactly this question.

 

[ishvaaag]

I have posted in the Mathcad Collaboratory worksheets pertaining to Anchors to Concrete and are for free download; if you have access to Mathcad 2000 professional you can download them and use. Sheets are based in ACI and PTI methods, plus other investigators such Cannon and others. Other sheets cover corbel seats etc in steel-steel joints. For the ACI designs I myself never would design in some cases for the optimized (minimum) results if the load was to be dynamic; I see the results being smaller than I judge safe.