I'm really struggling with this topic. I'm utilizing the Simpson Strong Tie Anchor Designer Software and I'm having a real hard time getting any anchors to work. Maybe what I'm trying to do is as impossible as the program is making it seem. I'd appreciate some help with this.
What I have:
I have a steel-reinforced concrete pit wall that is 10' in the ground and braced at the top. The wall is 10" thick and reinforced appropriately for the soil and hydraulic loads that it will be subjected to. In the plane of the wall I have a W12x22 column that needs to be anchored at finish floor height. I have a shear load (non-factored) of 6.6k and 22 ft-kips of moment. My anchor spacing that I'm trying to get to work in my base plate is 16" apart.
What I've tried:
I've tried a four-anchor solution (two at each end) and that doesn't work in the program because my edge distances are too small. I've tried a two-anchor solution so that I could center a large anchor in the center of the wall and have 5" edge distances. This doesn't work according to the program............and I think OSHA might have a problem with me not having a 4-bolt anchor situation for erection purposes. I've tried plugging this into the program using the previously mentioned moment AND shear forces and it doesn't work. I then tried breaking that moment into an uplift force-only (figuring I can try and handle my shear forces separately) and that gets me a lot closer but still nowhere near working. I'm not sure what else to do.
Questions that I have:
1. I am factoring the loads to put into the program which I believe is correct.....right?
2. Regardless of embedment depth, the program doesn't allow anything to work. I recognize that short embedment depths could cause problems but I have a hard time believing that 48" of embedment is going to cause problems when I'm loading a column in the plane of the wall. What am I missing?
3. Should I even be using this program? Can I look at this wall as though it's a couple 10" x 10" columns side by side, use stirrups where my anchors are going and embed anchors with enough depth that I get the appropriate development length that I'm not popping concrete out?
4. How would you engineers on this site approach this problem? I'd really rather not have to thicken my wall at this point if I don't have to. Do I just need to face the music and thicken it? Can I make an embed bracket with a shear lug on it so that my shear forces are transferred into the concrete by the lug and then my steel studs that are tied to the plate handle my uplift forces and shear forces on this column? My gut tells me that I should be able to place reinforcement in the wall such that I shouldn't have to worry about edge distance if I keep my anchors within my "cage" reinforcement.
5. If I was able to get a two-anchor solution to work, is there any way that I can erect this safely (it's only an 18' tall column) in terms of what OSHA would require? Shoot.......my base plate will be thick enough already that by the time I anchor this thing to the concrete, it's NOT going to go over sideways any easier than any other 4-bolt anchored column.
Thanks for your thoughts!
What I have:
I have a steel-reinforced concrete pit wall that is 10' in the ground and braced at the top. The wall is 10" thick and reinforced appropriately for the soil and hydraulic loads that it will be subjected to. In the plane of the wall I have a W12x22 column that needs to be anchored at finish floor height. I have a shear load (non-factored) of 6.6k and 22 ft-kips of moment. My anchor spacing that I'm trying to get to work in my base plate is 16" apart.
What I've tried:
I've tried a four-anchor solution (two at each end) and that doesn't work in the program because my edge distances are too small. I've tried a two-anchor solution so that I could center a large anchor in the center of the wall and have 5" edge distances. This doesn't work according to the program............and I think OSHA might have a problem with me not having a 4-bolt anchor situation for erection purposes. I've tried plugging this into the program using the previously mentioned moment AND shear forces and it doesn't work. I then tried breaking that moment into an uplift force-only (figuring I can try and handle my shear forces separately) and that gets me a lot closer but still nowhere near working. I'm not sure what else to do.
Questions that I have:
1. I am factoring the loads to put into the program which I believe is correct.....right?
2. Regardless of embedment depth, the program doesn't allow anything to work. I recognize that short embedment depths could cause problems but I have a hard time believing that 48" of embedment is going to cause problems when I'm loading a column in the plane of the wall. What am I missing?
3. Should I even be using this program? Can I look at this wall as though it's a couple 10" x 10" columns side by side, use stirrups where my anchors are going and embed anchors with enough depth that I get the appropriate development length that I'm not popping concrete out?
4. How would you engineers on this site approach this problem? I'd really rather not have to thicken my wall at this point if I don't have to. Do I just need to face the music and thicken it? Can I make an embed bracket with a shear lug on it so that my shear forces are transferred into the concrete by the lug and then my steel studs that are tied to the plate handle my uplift forces and shear forces on this column? My gut tells me that I should be able to place reinforcement in the wall such that I shouldn't have to worry about edge distance if I keep my anchors within my "cage" reinforcement.
5. If I was able to get a two-anchor solution to work, is there any way that I can erect this safely (it's only an 18' tall column) in terms of what OSHA would require? Shoot.......my base plate will be thick enough already that by the time I anchor this thing to the concrete, it's NOT going to go over sideways any easier than any other 4-bolt anchored column.
Thanks for your thoughts!
