Circular Foundation w/ Rectangular Headed Anchor Bolt Group

[AntT]

Hello everyone,

I am a Co-op working within an Electric Utilities' Civil/Structural Engineering group, and I am working on a headed anchor bolt calc sheet. I have completed an anchor bolt calc sheet for rectangular/square foundations, however, I have hit a roadblock in developing a similar calc sheet for circular foundations. Upon my research, I have not been able to find anything of use to me. Most anchor bolt design documents that I have encountered discuss circular anchor groups, however, my superiors would like me to develop the calc sheet so that it can apply to rectangular anchor groups (2 different spacings between anchors). With a rectangular anchor group, I am also unsure how I would calculate the concrete breakout in tension (more specifically, ANc (the projected concrete failure area of a single anchor or group of anchors, for calculation of strength in tension)Could anyone provide me a reference to a technical document that discusses this matter or some general guidance?

Thank you,
AntT

 

[racookpe1978]

How many bolts in the circle? Large enough for tanks and towers?

 

[AntT]

@ racookpe1978

There are to be 4 headed anchor bolts with 2 different spacing variations between the anchors (much like a rectangles 2 different side lengths). As for the size of the foundation, I am unsure as I am simply developing a calc sheet to be used in the future by the group. My best educated guess would say that these circular foundations would typically be used for Steel Dead End Structures.

Also note that in my research I have come across a document titled "Concrete Breakout Strength in Tension for Vertical Vessel Anchorage in Octagon Pedestals" from the 2010 ASCE Structures Congress document. This document details the "Saw Cut" Method to calculating the concrete breakout strength for octagonal pedestals. I have reached out to the authors of the document and am waiting for official confirmation if the methods used within the document are applicable for circular foundations. It looks promising as I have seen other sources use the method for circular foundations.