Thanks for all your posts.
All of you have essentially used the Blodgett method. But AISC Design guide 1 says:
The plate and the concrete may not be in contact everywhere. So, there is no reason that we can assume plane sections remain plane. Also, the strain diagram may not be linear in the...
Hi All,
I am trying to design a base plate with axial load and bending moment. I have different cases of eccentricity: L/6 < e < L/2, L/2 < e < L and e > L.
I found that different references have different methods of designing it:
1) Blodgett uses the assumption of plane section remains...
Thanks for your responses.
JedClampett, can you explain a bit more by "any angular deflection in the pile cap and piles is going to control".
msquared48, I forgot to mention that the W36 columns are tied at 6 places along the height. The tie beams connect the columns 37'4" apart.
Also, I...
Hi All,
I am designing the upper support of a semi-gantry crane, with the following details:
1. Total wheel loads along with impact factor = 650 kips
2. The crane length = 135 feet (centerline of upper rail to centerline of lower rail)
3. Height of upper rail = 84 feet from top of pile...
thank you for all your responses.
hokie66, let me know your opinion about my reasoning here:
since the openings in the slab are huge, the structure is effectively beams running from column to column, and added mass around them from the slab portion.
If this resoning is OK, then I think that...
hokie66 and rapt,
thanks for your valuable inputs. The open gallery of 4 ft is right in the zone from column to column. from what hokie66 said, I believe this portion of the beam will not take any torsion. But will this portion take substantial beam shear. If yes, then how...
hokie66, thanks for your interest in the problem. I am sorry, the no. of columns is still 10, it was a typo. I am glad you pointed it out.
Each concrete beam has 10 legs of stirrups(5 nos. of 2 legged closed tie stirrups). I placed the 2 legged closed ties symmetric about the vertical center...
I am designing a slab 180 ft x 51 ft in plan and 8 ft thick. The slab is supported by columns 8 ft x 8 ft (total 8 columns). The columns are 100 ft long and standing on 8 ft mat foundation. On the top slab, there are 4 nos. of 26 ft diameter cutouts. So, I think essentially, the slab is divided...
thanks for all your responses.
cooperDBM, post-tensioning is not an available option.
miecz, actually, due to flexure requirement, I need 4 layers (top and bottom) of rebars at any section. even with this, do you think that I can offset the rebars radially? if so, can you please explain in...
I tried to place rebars in lengthwise, crosswise and at 45 degrees, and at a clear cover of 2 inches from the circular concrete edge. This leaves an unreinforced area near the opening with one dimension as 1.2 ft. How can we take care of this area?
the opening is actually a 16 sided polygon. so, running rebars parallel to each side of the polygon will create so many layers of rebars that they will fill most of the slab thickness (as i have 4 layers of rebars top and bottom, for both the straight rebars as well as for rebars at 45 degrees)...
hey guys,
sorry to catch your posts a little late.
the columns are 43 ft apart center to center. so the drum openings are OK. the 8 ft thickness is also OK. the slab dimensions are 170 ft x 50 ft. sorry for giving the dimensions in m instead of ft in my earlier post.
Hi Guys,
I am trying to design an 8 ft thick table top slab (52 ft x 15 ft rectangular) standing on concrete columns 8 ft x 8 ft. The columns stand on an 8 ft thick mat.
--- The table top slab has 4 circular openings of 26 ft dia each.
--- Very heavy circular drums will sit on anchor bolts...
asixth, could you please elaborate on "account for this eccentricity", "full moment fixity" and "rigid offset".
Specifically, I want to know: where to put full moment fixity, and how to model rigid offset.
StructuralEIT and JAE, I think its a very good practical suggestion. I will try both with 300 mm and with 0.0000001 and see the difference. If 0.0000001 works, then its good. Else will try a longer distance.
Thanks for the good suggestion.
Thanks to all of you guys for your time and suggestions.
StructuralEIT, yes, the steel bottom end is the also the top of the concrete pedestal in the model.
Clansman, you are right and thats what i have done. the problem is that of the bracing connection, as JAE pointed out.
JAE, I think you...
Hi Guys,
I am trying to analyse and design a steel 3D frame structure 9m wide x 30 m high x 52m long. The transverse frames are at 13m spacing. There are beams at 3 elevations. The end frames along the longitudinal direction are braced at all elevations. The transverse direction wind is...
dougantholz, i would definitely love to read it sometime.
MiketheEngineer, surely i also would not lay my hands on it, but it is a topic I always think about.
csd72, thanks for the link. seems to be a very helpful book.