Discussion Groups

## Robot Structural Analysis

New Member
Posts: 2
Registered: ‎06-22-2011

# minimum reinforcement﻿ of foundation

1188 Views, 5 Replies
06-22-2011 04:34 AM

Hi everyone,

I would like to Know how what is the expression of Eurocode, that the Robot use to calculate the minimum reinforcement﻿ of the foundation.

Thank you, best regards:

Ricardo Moreira (Portugal)

Edited by

Mentor
Posts: 162
Registered: ‎01-24-2009

# Re: minimum reinforcement﻿ of foundation

06-23-2011 11:36 PM in reply to: ricardo_moreira

Hi,

I don't know what  kind of criterion Robot uses but Eurocode 8 prescribes minimum reinforcement only for beams and not for the footings for which local ductility is not required. See attached Page.

Product Support
Posts: 317
Registered: ‎12-13-2010

# Re: minimum reinforcement﻿ of foundation

06-27-2011 03:55 AM in reply to: GabrieleNovembri1027

If the results from the minimum value that the answer is as follows:
We accept that the elements are reinforced ones.

Due to the limitation of damage to fragile bent elements the condition (9.2.1.1-beams, 9.3.1.1 - boards) is always used:

AsMin = 0.26 * (fctm / fyk) * b * d

When grown fck then fctm grows too.

Also the minimum reinforcement﻿ grows with it.

Jakub Brożonowicz
New Member
Posts: 2
Registered: ‎06-22-2011

# Re: minimum reinforcement﻿ of foundation

06-28-2011 06:41 AM in reply to: Jakub.Brozonowicz

Thank you,

When we define a load in "RC_Foundation design" with nature of design the programm don't use this expression "AsMin = 0.26 * (fctm / fyk) * b * d﻿" to calculate the minimum reinforcement. It´s possible to change it ?

Best Regards:

Ricardo Moreira

Product Support
Posts: 317
Registered: ‎12-13-2010

# Re: minimum reinforcement﻿ of foundation

06-30-2011 04:49 AM in reply to: ricardo_moreira

This condition is SLS oriented one.

In case of Design load only ULS state check is done and other formulas taken as reference.

Jakub Brożonowicz
Distinguished Contributor
Posts: 198
Registered: ‎01-12-2013

# Re: minimum reinforcement﻿ of foundation

02-25-2014 06:37 AM in reply to: Jakub.Brozonowicz

"

This condition is SLS oriented one.

In case of Design load only ULS state check is done and other formulas taken as reference.

"

I don't understand this answer, and I have similar problem.

For my spread footing, Robot calculates minimum reinforcement as 4,17cm2/m' for bottom zone, and 3,14cm'/m' for top.

According to EN 1992-1-1, this values should be calculated as:

As,min = 0.0013⋅bt⋅d = 0.0013⋅100⋅44 = 5.72 cm2

or

As,min = 0.26⋅(fctm/fyk)⋅bt⋅d = 0.26⋅0.22/50.00⋅100⋅44 = 5.03 cm2

whichever is greater.

??

Question is simple: Which expression Robot uses to calculate minimum reinforcement of the spread footing?

Mirko Jurcevic M.Eng.
INTELIKA d.o.o.
www.intelika.hr