Shelf Angle Anchorage

[countervail]

Hi

I have shelf angles supporting a set of RC stairs. I speced welded starter bars as I couldn't achieve enogth anchorage on the main bars.

The contractor left out the welded bars and now wants to cut some slots, weld in the bars and grout up. This doesn't sound to me like it would works as I don't think a grouted slot acts like proper concrete. Any thoughts?

 

[countervail]

 

[Agent666]

Are the bars you specified to stop it falling off the angle (is it a detail parallel or perpendicular to the flight? Or is the landing retained by a similar detail on the other side? What I'm trying to get at is if its somehow retained between two walls and spanning between these walls supported on the angle, then are you happy with it just sitting there bearing on the angle if there is no way it can fall off, do you really need to develop the bars in this situation. It's no different in a way to seating some precast flooring 75mm onto another surface. If you are simply looking to retain it, could you alternatively add a tag welded to the horizontal leg of the angle and bolt up into the underside of the landing at appropriate centers?

I fail to see how they will be able slot and weld the bars at 100 ctrs unless they remove all of the concrete. Seems like a lot of reinforcement at 100 ctrs, compared with the bolts at 300 ctrs, do you need all of it for some reason (that is not wholly apparent to me based on the info given?)

 

[KootK]

Nice detail.

Slot, grout, and weld seems difficult but, if it can be done, I feel that it would work for your purpose. That said, I'm surprised that your contractor is willing to do this and that it's necessary.

1) What's your shear demand here?

2) What are the size and spacing of the flexural bars coming in?

3) How much do you think that the flexural reinforcing laps the angle?


HELP! I'd like your help with a thread that I was forced to move to the business issues section where it will surely be seen by next to nobody that matters to me:

http://www.eng-tips.com/viewthread.cfm?qid=456235

 

[TLHS]

I also am confused about why you need that development so early. However, if you do, can you replace the load path with a plate bolted to the underside of the concrete. How I'd detail it depends on what you're trying to accomplish. Perhaps weld it to the shelf angle and then anchor it a ways back (or periodically if you need composite action).

This could have fire rating implications.

 

[countervail]

Thanks,

The bars are running parallel to the span. Based on standard detailing requirements I need 50% of the main steel area to run 12dia past the line of support, I take the line if support as mid point of the angle and then take off 25mm of cover so I get 25mm past the line of support to get my anchorage in which with a hook I get as about 11dia so I have just provided bars welded to the angle to do the job (which haven't been installed).

I can probably sharpen my pencil to work out the actual main steel required to resist shear and then check the actual bond stress generated on the 11dia anchorage, I was just being lazy.