need design example for basement wall

[Engrman]

I need an example design of a basement wall with lateral earth pressure and eccentric vertical loads. Can anybody point me to one?

 

[jike]

I can't point you to an example but wouldn't you just add the bending produced by the eccentric vertical load to the bending produced by the lateral load for the wall design?

The affects of the eccentric vertical load would also have to be included in the footing design, soil pressure, overturning moment and safety factors.

I hope this helps!

 

[SlideRuleEra]

Here is an article, "Designing Concrete Basement Walls", that may be of some value to you

http://www.jlconline.com/cgi-local/view.pdf/8a42973df1ab3de667e78d501243cb88/

http://www.jlconline.com/cgi-bin/jlconline.storefront/44240335002ca4b827177f000001053e

http://www.SlideRuleEra.net

 

[Engrman]

Thanks jike and sliderule. This is a continuing situation with an existing building that has horizontal cracks in every basement wall. Core samples show rebar on wrong side of wall. The contractor's hired gun says my calcs are wrong, the rebar may be on the wrong side but the wall has sufficient strength. Says the vertical compressive load counteracts flexural tension in the rebar. I thought an interaction diagram would show the wall on the wrong side of the curve. Just wanted a foolproof design example to put in front of them.

 

[jike]

Is his hired gun a structural engineer? It should fairly easy to prove him wrong. If this is a one story building with a basement, I would have a hard time believing that the vertical stress would even come close to the flexural stress in the wall.

You may need to first look at this wall to see if can act as an unreinforced concrete wall.

 

[dik]

An eccentrically loaded wall can provide some resistance against lateral soil pressure... how much, depends on the load and if the soil doesn't provide sufficient resistance, you have the same problem but on the other side of the wall.

You have to be careful in trying to determine the flexural resistance of plain concrete... some codes deal with this, but you may be surprised how much resistance a plain 8" conc wall can provide.

The fact that the wall has cracked horizontally is indicative of flexural loading that has failed the concrete. The crack should be just below mid height of the wall. Cracking can also be a result of heavy equipment travelling too close to the wall; this will cause an increase in the lateral pressure.

Remediation is often a matter of providing HSS vertical sections that act as beams and allow the 'plain' concrete wall to span horizontally...

Dik