Tilt Panel Point load

[civeng80]

I’m designing some tilt up wall panels using design charts (recommended practice design of tilt up concrete wall panels by concrete institute of Australia). The wall panel is shown on the diagram.
The panel is not supported by a footing along its whole length because of protruding pads from the neighbouring building (the client owns the neighbouring building also).
My question is would the load distribution at panel mid height from the point load be either AC or just BC (on the diagram). I’ve been debating this and my feeling is that it is AC. But I’m up to any comments on this.

 

[BAretired]

Well I am pleased that you are up for any comments about this. My comment is what the hell is AC or BC? And why do you find it so much trouble to explain what it is you are trying to say?

My suggestion to you is..."stop using abbreviations which nobody but you understands".

BA

 

[civeng80]

BA have you looked at the diagram attached ?
The point load is distributed at an angle in accordance with the dashed lines to either AC or BC so that a force per unit width can be evaluated.
I dont see this as being all that hard to follow. If you do not have any constructive comments then I suggest you skip this post.

 

[BAretired]

civeng80,

I did look at the diagram attached, but I missed the letters because they were written in text a little smaller than my eyesight is accustomed to reading. Now that I see the text, I am wondering why you would even consider the point load spread over the length BC or, for that matter AC, because there is clearly an eccentricity involved.

I find your last comment truly offensive. My only constructive comment to you is that if you want an answer to your question, try applying simple statics.

BA

 

[rowingengineer]

put it back in the pants guys.

before we can establish distribution we need to figure out how this is working.

i see a few options.

1. connect the walls sufficently such that they form a beam that spans the footing.
2. the tilt panel is connected sufficently to the footing such that it can handle the both the tension and compression created by the eccentricty.

i would prefer bc for option 2.

http://www.nceng.com.au/

"Programming today is a race between software engineers striving to build bigger and better idiot-proof programs, and the Universe trying to produce bigger and better idiots. So far, the Universe is winning."

 

[civeng80]

BA
I do have alot of respect for most comments you make in these posts but I was surprised by your comment to this one.

I was also very offended by your first response and my reaction was spontanious.

The dotted lines shown on the panels are assumed load dispertion (or distribution)lines of the point load from one end of the panel to the base. If the panel was supported by the strip footing along its entire length then the dispertion lines would be such that the load/unit length would be calculated from length AC.

However the panel is not supported along its entire length as there is a gap because of a protruding pad footing from the building adjacent. So the dispertion line of the point load may not intersect the panel at mid height for the length AC maybe it would be BC. If it is BC then load/unit length is greater than for distance AC.

WHY WOULD YOU THINK SIMPLE STATICS WOULD GIVE AN ANSWER, WHEN THE PROBLEM IS HIGHLY STATICALLY INDETERMINATE ?

 

[rowingengineer]

question is supported in what way, compression only or both

http://www.nceng.com.au/

"Programming today is a race between software engineers striving to build bigger and better idiot-proof programs, and the Universe trying to produce bigger and better idiots. So far, the Universe is winning."

 

[civeng80]

Im not concerned about tension here, just the compression per unit length that results at midheight from the point load which is a downward force in this case. Also the moment per unit length from eccenticity due to this downward force. The dispertion lines are an approximation to reality. Im not worried about eccenticity in the plane of the panel, thats not a problem.

 

[rowingengineer]

good for u, i however believe it is important and the key to your problem.

http://www.nceng.com.au/

"Programming today is a race between software engineers striving to build bigger and better idiot-proof programs, and the Universe trying to produce bigger and better idiots. So far, the Universe is winning."

 

[civeng80]

The point load (which is not large) is very close to the edge of the strip footing. There is no tension.
Its all compression.

 

[BAretired]

civeng80

My comment yesterday was off base. I apologize.



BA

 

[ztengguy]

I would assume for the flexure of the panel its AC, the middle of the panel doesn't know that the footing inst there for AB.

 

[UcfSE]

I'm not familiar with the particulars of Australian design, but I would tend to go for AC, and limiting AC to whatever effective wall width you have available (if you have such a limit) on each side of the concentrated load. Perhaps consider a strut-and-tie approach too. That would get you out of questions about load dispersion and effects of wall openings.

 

[civeng80]

BA
Apology accepted. Please accept my counter apology.
Your comments are always welcomed.

 

[TLHS]

Honestly, my initial instinct is to fiddle with the wall arrangement so that the gap falls at midspan. Is there a significant cost impact switching to four equally sized panels instead of three, or two of the current width and two half width?

Regardless of the math working, I feel like I'd want good restraint at a panel corner/edge if at all possible.

 

[BAretired]

civeng80

Thanks. I am not familiar with this method of analyzing wall panels, so I think I will just fold my tent and gently steal away.

BA

 

[TLHS]

Or fill the gap with a tie beam between the left and right footing, if there's space. Then you have continuous support.

 

[haynewp]

It looks like a relative stiffness problem where there isn't really enough information to answer exactly. If the sketch is to scale, I would expect AC is reasonable.

 

[civeng80]

Perhaps I should elaborate a bit further on this one.
The design method I’m adopting is Titled Recommended Practice Design of Tilt up concrete Wall panels by Concrete Institute of Australia. The method involves calculating the effective width of the panel for beam point load by dispersing from the point load at 30 degrees on both sides and finding the intersection points with a horizontal line at mid height of the panel.
When the width is calculated then work out the load /unit width and Moment/unit width due to eccentricity of the beam reaction and go to charts to check thickness and reinforcement.
See typical diagram and charts in illustration.
Ztengguy I think you know what I’m talking about and I like your answer which was sort of what I had in mind since the reaction at the base would be at a 30 degree angle outwards also.
TLHS the bridging beam is a good idea but I don’t know If I have enough depth.
Does anyone use this method ? Does anyone have any other references or methods ?

 

[hokie66]

So this is for bending moment transverse to the plane of the wall? If so, AC looks like the answer. I see no reason to neglect the AB part.