AntT
Structural
- Nov 28, 2017
- 5
Hello everyone,
I am working on a calc sheet to check headed anchors for Circular Foundations and in my research I have come across a way in which I may be able to calculate the concrete breakout strength in tension. However, the method I have come across is listed for octagonal foundations. If any of you are familiar with ASCE 2010 Structural Congress - Concrete Breakout Strength in Tension for Vertical Vessel Anchorage in Octagon Pedestals could you indicate to me if Method 2 (the Sawcut method with h'ef and neutral axis at the center) is applicable for circular foundations with 4 anchors? In Civil Bay's Concrete Anchorage page they utilize the Sawcut method for circular foundations but I would like further confirmation if possible.
I have also come across a document, Anchor Embedment Requirements for Signal/Sign Structures (Report No. BD545 RPWO #54), which describes a process to calculate the concrete breakout strength in shear. Utilizing a conservative method, the outer edges of the circular foundation are disregarded, being so, would this method be required for concrete breakout strength in tension?
If my explanation is difficult to follow, here is an exact quote from the text (I have also attached the document to this thread):
"In order to apply the ACI provisions to the circular foundation a section of the concrete was ignored (Figure 3-6). If the full cover, c, was used in the calculation, the failure region would have included area outside of the circle. Rather than extending beyond the edge of the concrete, the =35 degree failure cone (Figure 2-6) was extended to the edge of the shaft as shown in Figure 3-6. Equation 3-2 was developed to determine the adjusted cover, ca1."
Thanks,
AntT
I am working on a calc sheet to check headed anchors for Circular Foundations and in my research I have come across a way in which I may be able to calculate the concrete breakout strength in tension. However, the method I have come across is listed for octagonal foundations. If any of you are familiar with ASCE 2010 Structural Congress - Concrete Breakout Strength in Tension for Vertical Vessel Anchorage in Octagon Pedestals could you indicate to me if Method 2 (the Sawcut method with h'ef and neutral axis at the center) is applicable for circular foundations with 4 anchors? In Civil Bay's Concrete Anchorage page they utilize the Sawcut method for circular foundations but I would like further confirmation if possible.
I have also come across a document, Anchor Embedment Requirements for Signal/Sign Structures (Report No. BD545 RPWO #54), which describes a process to calculate the concrete breakout strength in shear. Utilizing a conservative method, the outer edges of the circular foundation are disregarded, being so, would this method be required for concrete breakout strength in tension?
If my explanation is difficult to follow, here is an exact quote from the text (I have also attached the document to this thread):
"In order to apply the ACI provisions to the circular foundation a section of the concrete was ignored (Figure 3-6). If the full cover, c, was used in the calculation, the failure region would have included area outside of the circle. Rather than extending beyond the edge of the concrete, the =35 degree failure cone (Figure 2-6) was extended to the edge of the shaft as shown in Figure 3-6. Equation 3-2 was developed to determine the adjusted cover, ca1."
Thanks,
AntT
