Pier and Spandral

[drasticxxxx]

Hey, what is the difference between pier and spandral in RC structures
also what is the different if i simulate them using frame or shell element in etbas

thanks

 

[Illbay]

Are you speaking in general terms, or are you referring to the terms as they are used specifically in ETABS?

If the former:

1. A PIER can be: (a) a short column ( e.g. "pedestal"), (b) a deep foundation (e.g. "drilled pier"), (c) an interior support for a bridge superstructure that is in turn typically supported by a foundation ("bridge pier"), or (d) supports for a dock or wharf typically over water.

2. A SPANDREL is usually a girder at the edge of a slab system into which floor beams are framed, and which is considered to resist torsion as well as flexure resulting from the framing members.

I'm not sure how you can reliably compare the two as aside from the fact that they are structural elements, they aren't really similar. What is your application?

 

[Akeee]

Hi,
See:

http://www.eng-tips.com/viewthread.cfm?qid=379703

 

[drasticxxxx]

THANK you all.

Now I understand that simply pier is a column and spandrel is a beam, but I still have two questions,

I think etabs allow you to draw the pier and spandrel both using shell and frame element, so is there any difference between them(frame and shell) in this case of analysis?

Also, when I use the ACI modifiers of o.35 or 0.7, I usually apply this to moment modifiers, but I ve seen posts how apply this to axial as well, so why this is the case? Please explain it to me? And this raise the question of apply to shear maybe???

 

[Akeee]

Ok so you dont draw pier or spandrel first, you draw the shell or frame element and the you assign labels like pier or spandrel.
This labels dont interact or affect the FEM stress analisys at all, their role is to integrate, sum, the stresses to give you the axial force, shear and bending moment for that section that you label. So in the analisys no, it doesnt matter, it matters if you let ETABS do the design for you,from what i read on this forum, i never used design option so far, for example to calculate necesary reinforcement areas.
I also never tried to invert them, pier and label, to see what happens but i said that integrated forces are the same because ther is only one why to integrate stress, so..