I need to know a good estimate on the weight (psf) of Steel Bar Grate Stair Treads & Stair Stringers. I have a stair imposing loading on a slab. I need to check the slab for the laods, but I don't know what the dead loads are for stairs of this type. I just need a safe ballpark assumption.
UcfSE,
Thanks for confirming that. Going through the iterations to get convergence is a pain if you are new to this. It's easy to get lost in the process.
At least it does appear I am on the right track.
Deep Beam Design - One span w/ Cantilever one side only:
When designing a deep beam by strut and tie I'm getting bogged down in determining the appropriate dimensions to apply to the faces of the struts.
In the ACI 318-02 Code Reference example ACI calculates these faces based on the lowest...
M
Did you ever find a software for this? I don't use ACI Appendix D often so everytime I use it I'm just bogged down. I'd rather use DBA's or Rebar and extend them to their development lengths where I can than bother with Appendix D.
Thanks for the help. I just learned of a short cut to just use a conservative rectangular section neglecting the reinforcing to get my torsional constant, which ends up being an easy calc. Since my beam does not rotate harldy at all (totally negligible) under that assumption I should be fine...
Thanks for trying to help. Wow that is ALL theory! I know some people can digest that stuff, but I'd need a decade to absorb all that. I never even saw the word "torsion constant" in the text. And why is it that all I can find is on thin walled sections? What do most people do for concrete...
Anyone know the hand calculation for the torsion constant (J or sometimes shown as Jt) of an inverted tee section of concrete? My college mechanics of material book only gives examples for thin wall tubes and pipes. I'd rather know how to do it by hand instead of letting a computer tell me the...
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The opposite end of the 2 beams is supported by columns with a doweled connection, which allows for some beam end rotation.
The end at the supporting beam could likely be designed that way. I do not like welding the bottom of the beams and it is recommended practice not to do so. However, I...
I am designing a beam that will pick up (2) other beams. The supporting beam is pocketed for the (2) beams, so there is torsion induced in the beam. I have designed the section for the shear and torsion, and it is adequate. My question is how to I make sure that the beam will not rotate such...
Thank you for the advice. I've found that hollowcore is not used frequently in parking decks these days. The double tees seem to be the product of choice for parking decks.
Thanks for reply JAE. This forum is always such a quiet one I was not sure that I would even get a response.
A recommendation I recieved was to use the same as for a cast-in-place system. Example- For a 24ft spacing requirement in CIP use every sixth plank joint. (Note: the topping is 3"...
When using hollowcore in a parking deck are tooled joints required in the topping at every plank joint? The PCI recommendations for parking structures indicates that they are recommended, but is it necessary at every joint? Would every 12ft or another spacing corresponding with 4ft plank work...
I know what you mean! I worked as a co-op with the DOT and I could not believe what I saw. I worked 3 quarters: 2 in the field and one in the main engineering office. At all 3 locations laziness was rampant. Granted the field work was paving so there is not much to that compared to other...
I have seen this type of structure before, so it is not uncommon. Sometimes braced frames are in the 4th side, or the precast wall system is designed 3 sided. You'll need to account for the eccentricity created from the center of rigidity being far from the center of the lateral load. You...
It sounds like you are using hollowcore slabs. You may want to visit http://www.coreslab.com/atlanta/DetailsATL.pdf
They have a detail similar to the one geoffdale mentioned.
If your product is extruded you'll want to use details similar to the ones they use. However, if your product is a wet...
GREAT responses.
Nothing to add except,
Hang in there, and most of us have been in your shoes...some longer than others. It was 3 years into my career before I began to feel more at ease about being an engineer. It's a big responsiblity, so your concerns are valid. It takes time to build...
