Footing Flexural Reinforcement - Effective Steel Area Calculation

RE: Footing Flexural Reinforcement - Effective Steel Area Calculation

Vinay mysore — Wed, 19 Apr 2023 12:51:51 GMT

I tested your file and I agree with your findings that the program is showing red flags for As effective in the X direction.

In the X direction I see that the footing is not extending beyond the Abutment and there is no space to Develop the rebar.

The solution for this issue is to increase length of the footing in X direction by at least 1ft so that the rebars can be fully effective.

Once the length is increased the red flags are gone.

If you are unable to extend the length of the footing then user has to manually calculate the development and As effective as this is a limitation in the program.

RE: Footing Flexural Reinforcement - Effective Steel Area Calculation

Vinay mysore — Tue, 18 Apr 2023 05:26:01 GMT

Please email me the file so that i can test this issue.

RE: Footing Flexural Reinforcement - Effective Steel Area Calculation

Justin Nguyen — Mon, 17 Apr 2023 20:40:59 GMT

any solution from this? I am having the same issues as Travis.

RE: Footing Flexural Reinforcement - Effective Steel Area Calculation

Vinay mysore — Tue, 31 May 2022 08:36:47 GMT

Plea.se email me the file to "vinay.Mysore@Bentley.com" so that i can test this issue

RE: Footing Flexural Reinforcement - Effective Steel Area Calculation

Travis Stump — Thu, 26 May 2022 16:36:43 GMT

I am having a similar issue. I have designed a wall pier with a spread footing on piles. The Z-direction reinforcing is all considered effective, however none of the X-direction reinforcing is effective. The above solution did not resolve my issue did not resolve the issue. I have tried increasing the number of bars, increasing the size of bars, increasing the length of the footing in that direction, hooking the bars 90deg and 180deg, and adjusting the depth of the bars in footing. In every effort , none of the x-direction bars were considered effective. I even tried the auto design feature with no luck. Is there another possible solution? Or a setting in LEAP that can be adjusted? Thank you for your help.

RE: Footing Flexural Reinforcement - Effective Steel Area Calculation

Vinay mysore — Thu, 30 Aug 2018 07:43:34 GMT

The solution for this issue was to hook the bar by 90 degree and the Effective Steel Area red flags will go away.

RE: Footing Flexural Reinforcement - Effective Steel Area Calculation

Daniel — Wed, 29 Aug 2018 12:59:34 GMT

What was the result of this? I am having the same issue.

RE: Footing Flexural Reinforcement - Effective Steel Area Calculation

Alsharif — Fri, 10 Nov 2017 16:12:14 GMT

Adam,

Did you get an explanation for your question above after sending Vinay the file?

Thank you

RE: Footing Flexural Reinforcement - Effective Steel Area Calculation

Vinay mysore — Thu, 06 Apr 2017 13:57:29 GMT

Please email me you file and let me know which version you are working on.
My email ID is--- vinay.mysore@Bentley.com

RE: Footing Flexural Reinforcement - Effective Steel Area Calculation

Adam Oberholtzer — Thu, 06 Apr 2017 13:46:05 GMT

Vinay,

Thank you for your response. Using the equations you provided I get the following for the reinforcement in the Z-Direction:

Development of #8 Bar per AASHTO 5.11.2.1.1 & 5.11.2.1.2:
= 25.26" (Basic Development) x 1.4 (Top Bar) = 35.36" / 12 = 2.95'

Available Development Length:
= (Half of Footing "Hf(Z)" Dimension) - (Distance to Critical Section) - (End Clear Cover)
= (9' / 2) - 1.55' - 0.25' = 2.70'

Effective Area:
= (Steel Area Provided) x (Available Development) / (Required Development Length)
= 12.64 x (2.70') / (2.95') = 11.57 sq in effective (~9% reduction in steel area)

The program is calculating a ~45% reduction in steel area from provided to effective (see my previous post). This is a significant difference from what I have calculated. Is there another factor that the program applies to calculate Effective Steel Area or is there something else that I am missing?

Thank you,

Adam Oberholtzer

RE: Footing Flexural Reinforcement - Effective Steel Area Calculation

Vinay mysore — Thu, 06 Apr 2017 05:56:12 GMT

The Area is reduced linearly.

For example :
At the end of development length(ld), rebar is fully developed and so 100% Ast-provided is available.
At a location X' from the end of rebar, which is < development length, Aeff will be ( X * Rebar area / ld).

The Development length is designed based on AASHTO article 5.11.2 and the AsT/b eff is calculated as follows.

Example: At any location, if development length is 4' and location is 1'

The Ast/b eff=Ast_provided* (1’ or 2’) /4.

Ast_eff = Ast prov *( min (L/ld , 1) )

Ast-eff : Effective top steel area, after considering development length

If As-t eff is < than As-t req you will get a flag

Area Provided may be larger than required but at the same time the effective may be less than required within development length.

By providing additional rebar or increasing the length of the footing in that particular direction or trying to hook the bar will help in getting rid of the red flags.

I hope it helps.