These are great. Terribly great.
I was talking to a contractor today, they were drilling holes for anchors in some tilt up panels and hit rebar.
"After the panel is lifted, that rebar is pointless anyway, right?"
...at least he asked...
Well now that we’re on the subject, what determines the compressive strength of grout that you specify? Our spec program defaults to 7000psi or 10000psi, it also was apparently reviewed and endorsed by TCA. However, I don’t like to blindly follow a recommendation if I don’t know where it came...
Thanks everyone for your responses. The gap varies. I would say 2"-4" max. While i was out there it looked like the footings were poured low and thats why they wanted to use pea gravel instead of grout (cheaper for the larger space.) I know why we specify it, for a constant bearing connection of...
A contractor is requesting to use pea gravel 3000psi concrete underneath the tilt panels instead of the 7000psi non-shrink grout we specify (panel to foundation bearing connection). Can anyone think of any reason why this would be unacceptable? I'm assuming they would dry pack it
The only...
For the slender wall method (Chapter 14.8 in ACI 318-08) the modulus of rupture is listed as 7.5*lambda*sqrt(f'c).
For structurally plain concrete (Chapter 22 of the same code), it is given as 5 * lambda * sqrt(f'c).
Why are these values different? Why is the modulus stronger for the slender...
TDIengineer:
That is a good idea. However, the ICC no longer gives shear (or tension) values for adhesives since the adoption of Appendix D. The only products that publish those kinds of values are for uncracked concrete, and have no ICC report to back them up. (ICC only supports adhesive...
Thanks for all of your responses. I'm relatively new to the profession and still learning - all of theses responses help.
Sandman:
How would my typical rebar not fall within ASTM A615? On my general notes its states "All reinforcing shall be high strength deformed bars conforming to ASTM A615...
I was under the impression that rebar is not included in the scope of Appendix D. If it were, then the rebar development lengths from ACI would be mute and most all would fail in some other failure mode. (Rebar at 4" apart would surely breakout). I believe the failure from rebar embedment is...
I know this has been discussed fairly often in this forum, but I am looking for everyone 2 cents on epoxy anchors. I have a situation where the contractor has poured a footing wrong so I am trying to extend the footing back to contract dimensions. I am looking pour a new strip and to dowel and...
JoshPlum:
I read on the Risa reference guide that a Von Mises stress of above 36ksi would represent yielding of a 36ksi plate. Does this translate to mean as long as my Von Mises stresses are under 36ksi, my plate will not yield?
I understand this is very complex and gets into FEA theory and...
Structures33:
I am using Risa as well. By looking at the contour stresses, do you mean the values in the small legend at the top right of the screen? This legend is called "Plate moment x, kft-ft." The maximum in this chart is 11.1 (rather than the 10.4kft-ft from the table.) Why would these...
I have a problem similar to the question in thread507-232128 and am looking for some advice.
I am trying to design an embed plate for 98k load and am having trouble figure out how to size the plate for bending. The 98k load comes from a beam which is attached by an all welded double angle...
I have a question! I was looking at the design of a masonry lintel in a masonry wall. I tried two different ways and ran into an issue.
1.) I applied loads to the beam (used arching action, effective span) to determine the maximum shear and moment. I then looked at the TEK 17-1B " Allowable...
@CANEIT When using a series of welds you need to consider load deformation compatibility. Since the transversely loaded weld is not as ductile, it will tend to fracture before the longitudinally loaded weld will obtain its full strength.
AISC says: "In lieu [of considering this load...
What do you guys assume for the shear modulus of concrete?
I am looking at rigidity analysis in a shear wall. I am following guidance out of masonry textbook to determine the deflection of each wall and thus its relative rigidity and thus how much shear force it is likely to take.
In order to...
In my AISC (13th edition), the available bolt shear for a 1" dia bolt (A307) is 14.1k (LRFD). I used Table 7-1.
Table 7-1 assumes the nominal bolt area is 0.785in^2. This is bigger than the "effective area" of the 1" dia bolt used for calculation in ACI(.606in^2).
That could account for...
I was wondering this same thing. I never took a wood design class in school so now I am trying to teach myself through Breyers book. Solutions (or even answers) would be helpful!
I have used the "Elastic Foundation" to analyze the foundation of a large generator. To check the foundation for flexure, I analyzed a 1' strip of the foundations as a "beam" with the applicable point and distributed loads (from fuel and water and what not). This gave me the necessary rebar for...
