Applying triangular load on plates/shells in ETABS or SAP200

[groszni awesome]

Assalamualaikum SE Pakistan, im about to design a retaining wall and would like to know is there any option/ is it possible to apply a triangular load on shells/paltes/membrane? or im just gonna model it as a 2D thing?

regards

[EngrJunaid]

W.Salam,
 

There is no option for the Triangular loading in ETABS.

But in SAP2000 you can use the JOINT PATTERN option for the application of Triangular Loading...

[WR1]

2 hours ago, groszni awesome said:

Assalamualaikum SE Pakistan, im about to design a retaining wall and would like to know is there any option/ is it possible to apply a triangular load on shells/paltes/membrane? or im just gonna model it as a 2D thing?

regards

You can do like this;

What you have to do is to note down the z coordinate of each shell element along the height (in Excel e.g.) and calculate the force at top and bottom node of each element, then apply the average pressure in local axis 3 (plus or minus).

Tip: Always model retaining walls/swimming pool etc so that all the walls have local 3 axis either inside the pool/container or outside. So you can select all the walls once and apply the pressure in one go. And for that turn on 3d view in XZ or YZ in ETABS and select top most mesh, apply pressure and so on. Its not that difficult.

To calculate average pressure you can either make your own excel sheet or use the following I once made.

Water Pressure on Walls in ETABS.xlsx

 

[Saad Pervez]

Sir @Rana, can we use dummy lines? A dummy line can be drawn replicated every unit length and tributary triangular load applied to that line.

[WR1]

On 2/19/2017 at 7:49 AM, Saad Pervez said:

Sir @Rana, can we use dummy lines? A dummy line can be drawn replicated every unit length and tributary triangular load applied to that line.

Yes or by any other mean like manually applying the joint loads.

[groszni awesome]

@Saad Pervez @Rana @EngrJunaid thanks alot for the response, is it better to make the reinforcement to 2 layers of bar or just 1 but more tight space?

[Waqas Haider]

I always follow the same method but while reporting of forces by etabs, it reports excessively high shell stresses near corners and joints? How to overcome this issue to get realistic value? What i did in last project i neglected the value of stress of bottom most plates near joints upto a distance equal to half thickness of the bottom slab. But i still doubt the value because it use to b higher than the manual calculations.

[WR1]

17 hours ago, Waqas Haider said:

I always follow the same method but while reporting of forces by etabs, it reports excessively high shell stresses near corners and joints? How to overcome this issue to get realistic value? What i did in last project i neglected the value of stress of bottom most plates near joints upto a distance equal to half thickness of the bottom slab. But i still doubt the value because it use to b higher than the manual calculations.

That is a common FEA problem. You get infinite stress at supports due to infinite stiffness.This is a problem of stress concentration. For commercial design purposes what you did is okay.

[Sardar Ali]

 I have tried by assigning non uniform load on the wall in etab and I faced problem of finding value of (A,B,C,D )but later I have prepare a sheet excel to find (A,B,C,D ) from some input value shown in high lighted blue I will try to attach the excel sheet here and it is use full only for lateral water forces for tank or swimming polls and I will try to prepare additional sheet for other type 

WATER FORCE ON WALL.xlsx

[Beenay Beenay]

triangular load can be provided by assigning non-uniform shell load via equation as described in etabs documentation. My issue is how do I find the reinforcement for the out of plane forces in retaining wall or basement wall. I think what etabs gives is the reinforcement for the in-plane forces assuming it a shear wall by default. But retaining wall or basement walls are different animals. they are simply a cantilever slab or a two way or a one-way slab just placed vertically. how do I design a vertical slab? or get etabs to treat wall as a slab rather than shear wall?

Edited April 4, 2019 by Beenay Beenay