I was curious what ideas you guys may have for rock anchors in a Karst environment. Borings indicated a variable limestone but once through the upper few feet was fairly consistent. I have some anchors that are consistently not getting grout return after +3X theoretical grout volume with...
For a conservative design I agree...but that is not always the case. Where trying to limit deflections, often the most economical method designing a fixed head connection even when it requires more embedment. From there you just have to deal with the moments with casing size/reinforcement...
I agree. Another DOT ( I think Oregon) did one with micropiles and the deflections even at 6" embedment mimicked the expected fixed head deflections. Often times when dealing with piles in either a grade beam setting or diaphragm, it is not feasible to get that kind of embedment but it is...
Spangler has some guidance on stone columns. Oddly enough we have found that a close approximation to Spangler is to find the area percentage your fill occupies the theoretical failure wedge...then use that as a reduction for the applied passive pressure. Other than that some geometric methods...
FHWA gives guidance of a micropile attaining full head fixity at 24" of embedment. With a top plate attached and threaded bar/nut/ embedded into the pile, could the connection not be designed for fixity with a lesser pile cap embedment? Basically check that breakout on the bottom side of the...
I have had some conversations about a concrete anchorage breakout with another engineer. The issue is (for example) you have anchorage into large footing or other large concrete mass and you have a solid concrete wall that sits on the projected failure area, how does it affect your breakout...
I am familiar with the mentioned project. It is a DOT type project. So I am assuming you get your load factors from whichever Strength Limit State you use. Then you use the Service Limits State to get factors to check deflections. Where would the Extreme Limit State be used? I appreciate...
