Smart questions
Smart answers
Smart people
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Member Login




Remember Me
Forgot Password?
Join Us!

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips now!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

Join Eng-Tips
*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Donate Today!

Do you enjoy these
technical forums?
Donate Today! Click Here

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.
Jobs from Indeed

Link To This Forum!

Partner Button
Add Stickiness To Your Site By Linking To This Professionally Managed Technical Forum.
Just copy and paste the
code below into your site.

RNP (Structural)
2 Nov 99 18:42
Is there a good reference on Grade Beam Design? Is it designed like a spread footing?
Helpful Member!  legner (Structural)
4 Nov 99 12:54
Please clarify - do you mean grade beam as in concrete beam spanning between caissons or grade beam as in combined footing supporting multiple columns?
Helpful Member!  RNP (Structural)
6 Nov 99 13:05
Grade Beam supporting a masonry wall and supported at it's endes by buttress walls! I think analizing as a combined footing sounds the most accurate. What do you think?
legner (Structural)
13 Mar 00 13:29
We typically design grade beams without considering any soil support. However, what you are talking about sounds more like a continuous footing with unusual end supports. I would recommend designing it as a beam on elastic foundation, either by the classical formulas while ignoring the end supports, or with an analysis program. Either way, you will need the subgrade modulus.
RUSSRASCAL (Structural)
14 Mar 00 11:12
THE POST-TENSIONING INSTITUTE HAS A LINE LOAD ANALYSIS FOR GRADE BEAMS IN THE SLAB ON GROUND PROGRAM. PERSONALLY, FOR THE LAST FORTY YEARS I'VE BEEN DESIGNING THEM LIKE A WALL FOOTING. THE PROOF IS IN THE PUDDING. SO FAR SO GOOD.
RNP (Structural)
21 Mar 00 11:09
To:Legner, your solution was interesting.In my situation, I considered the grade beam to span between buttress walls that are supporting masonry walls above them. The grade beams were designed to limit deflection to 1/8 in. This was to prevent cracking in the masonry walls. I ignored the soil all together because, I was not sure if the the soil was totally activated in bearing.
zhol (Structural)
17 Apr 00 7:29
you must also consider wheather the soil is expansive or not because if it is then it is better to isolate the beam's sofit than to support it directly on soil
DENIRO (Structural)
17 May 00 3:23
we always design it as a beam on elastic foundation...
using any FEA sofware...
Helpful Member!  zbolf (Structural)
17 Oct 00 8:59
I would say that if the grade beam is supported at the ends then it should be designed as the framed beam without the help of the soil below. The settlement in the soil is something very difficult to estimate. The beam might in couple of years end up with the gap betwwen the bottom of the beam and the grade. Thus using the soil to reduce the beam size and/or reinforcement may result in under-designed beam.
The other option is to design the continuous footing under the load. In this case you can use Winkler model to assess the forces and the deformation.

Inquisitive (Automotive)
19 Jun 01 7:17
I would like to know the sanctity of having a grade beam resting on the ground without any excavation and supporting RC wall and roof.  I would analyse the beam with the Winkler model.  Would that be correct?  I would like to specify that this type of structure is to be set up in an earthquake prone area.
IJR (Structural)
21 Jun 01 5:49
Inquisitive

You are probably talking about a very light structure. To my knowledge statics is only one part of foundation engineering and though I am not an expert here, I know that the other side of the story is protection of your foundation. So placing a footing on level 0.00 (vegetation)grade is not healthy. Please check out stuff like snow depth, vegetation soils, expansive soils etc.

Since your proposition is completely out of question for a large building, where earthquakes hit better and foundations play a significant role, then I will not attempt to comment on placement of foundation at level 0.00

good luck.
IJr

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close