Time-dependent analysis of concrete with SAP2000

This tutorial shows how to use the non-linear staged construction analysis and the time-dependent properties form, for calculation of creep and shrinkage in a concrete column.

[@engrshafiq1]

Highly appreciate you efforts. Excellent video explaining difficult subject which has very few reference materials especially in ACI....Thanks again from Saudi Arabia.

[@antonioperez2113]

Borja me gusta mucho tus tutoriales , no lo dejes , te animo a que sigas. saludos

[@kaushikkotadiya1398]

your video helped me a lot..

[@Elsa_Jennifer]

Thank you for the video which is very useful

[@BorjaVarona_at_YT]

You are welcome. Thanks for the feedback

[@JFASACM]

Great lesson! Please, don´t forget to send the document.

[@khaledanwar8351]

Thank you for the excellent video... I have a, a question please.. Why no loads are applied in stage 2 although it is mentioned that the load will be applied after 56 days.
Also I can not find the link for the document
Thx

[@BorjaVarona_at_YT]

Stage 2 ends at 56 days and the idea is that there are no loads during that period. Stage 3 starts at the 57th day so technically the sustained load is applied at the 57th day and remains during 4944 days.
The link for the document is here: hdl.handle.net/10045/72907

[@SuperIbza]

thank you soooo much for this amazing video. this helped me so much with my project. Can you please explain what is happening at 8:28. If you load the column and you would like to determine the creep deformations at 7, 56 and 5000 days, how would you set up the data for each stage?

[@BorjaVarona_at_YT]

Thank you for your comment. The definitions of stages and duration of each stage is set up just before 8:28. From that point on, it is the objects and loads that are defined. Since I am asking the software to give results at the en of each stage, I will be able to have the creep results that you want. At 9:46 you can see that I have asked for stage 8 (that corresponds to 5000 days). But I can choose other step. Alternatively, you can click on the arrows at the bottom of the screen (between 'Start animation' and the active coordinate system), to switch the stage and view the results at different ages.

[@BorjaVarona_at_YT]

If you run this exact model in version 17, the following labels and results are defined for each of the 8 steps:
- Step 0: Stage '7 days - 0', Age = 0 days ... U3 = 0
- Step 1: Stage '7 days - 1', Age = 0 days ... U3 = 0
- Step 2: Stage '7 days - 2', Age = 7 days ... U3 = -0.1185 mm
- Step 3: Stage '56 days - 0', Age = 7 days ... U3 = -0.1185 mm
- Step 4: Stage '56 days - 1', Age = 7 days ... U3 = -0.1185 mm
- Step 5: Stage '56 days - 2', Age = 52 days ... U3 = -0.367 mm
- Step 6: Stage '5000 days - 0', Age = 52 days ... U3 = -0.367 mm
- Step 7: Stage '5000 days - 1', Age = 52 days ... U3 = -2.082 mm
- Step 8: Stage '5000 days - 2', Age = 5000 days ... U3 = -6.5037 mm
It seems that at each stage three results are saved: stage '0' from each stage constitutes an initial step importing the results at the end of previous stage. It becomes more or less clear with steps 6, 7 and 8:
- Step 6 imports the results at the end of previous stage
- Step 7 calculates the immediate deformation due to the load added
- Step 8 calculates the final deformation due to the sustained load, creep and shrinkage

[@SuperIbza]

@@BorjaVarona_at_YT Step 0: Stage '7 days - 0', Age = 0 days ... U3 = 0
- Step 1: Stage '7 days - 1', Age = 0 days ... U3 = 0
- Step 2: Stage '7 days - 2', Age = 7 days ... U3 = -0.1185 mm
- Step 3: Stage '56 days - 0', Age = 7 days ... U3 = -0.1185 mm
- Step 4: Stage '56 days - 1', Age = 7 days ... U3 = -0.1185 mm
- Step 5: Stage '56 days - 2', Age = 52 days ... U3 = -0.367 mm
- Step 6: Stage '5000 days - 0', Age = 52 days ... U3 = -0.367 mm
- Step 7: Stage '5000 days - 1', Age = 52 days ... U3 = -2.082 mm
- Step 8: Stage '5000 days - 2', Age = 5000 days ... U3 = -6.5037 mm
how did you output the results like that?

[@BorjaVarona_at_YT]

@@SuperIbza Hi Danny. I just wrote them down like that.

[@SuperIbza]

Hi Borja, if we want the effects of creep at 7,56 and 5000 days, why did you load objects at 5000 days and not at 7 days?

[@BorjaVarona_at_YT]

The load is applied at the third stage. The third stage starts at an age of 57 days (because stages 1 and 2 last for 56 days). Therefore, the load is applied on the 57th day and remains during 4944 days, until the age is 5000 days.
Stages 1 and 2 could have constituted one single stage with a duration of 56 days (or 52 days in terms of adjusted time). However, considering these two stages prior to loading allows us at the end to see the evolution of both creep and shrinkage.

[@user-jn1ms9nc3e]

Do you have an example of shoring and reshoring of slabs using time dependent analysis?

[@BorjaVarona_at_YT]

I do not have examples on that problem. However, it has been studied by professor Yezid Alvarado in his PhD and subsequently in some of his co-authored research papers:
- Load Limiters on Temporary Shoring Structures: Tests on a Full-Scale Building Structure under Construction, in J. of Structural Engineering (2021) DOI 10.1061/(ASCE)ST.1943-541X.0002948
- Maximum loads on shores during the construction of buildings, in Proceedings of the Institution of Civil Engineers: Structures and Buildings (2016) DOI 10.1680/jstbu.15.00089
- Short- and long-term deflections of RC building structures influenced by construction processes, in Structural Engineering and Mechanics (2017) DOI 10.12989/sem.2017.64.2.173

[@enriqueparedes1880]

Muchas gracias por el video, quisiera hacerle una consulta, que es el t0 ajustado?

[@BorjaVarona_at_YT]

El t0 ajustado es un procedimiento analítico que permite generalizar el coeficiente de fluencia calculado para distintos tipos de cemento (ecuación 5.1.73 del Código Modelo) y temperaturas no extremas distintas de la estándar (ecuación 5.1.85 del Código Modelo)

[@hassanmachlab5881]

Muy interesante. Por favor puedes subir enlace de descarga de los cálculos de comprobación. Muchas gracias

[@BorjaVarona_at_YT]

El enlace al documento con el resumen de formulación y cálculos es el siguiente:
hdl.handle.net/10045/72907

[@hassanmachlab5881]

@@BorjaVarona_at_YT Muchas gracias

[@fahimalizada1888]

can we use this method to steel embedded composite column

[@BorjaVarona_at_YT]

I was going to answer that it did not seem possible. One of the main issues with concrete-filled steel columns is that a stress-strain model for confined concrete is then required. One of the most known models is that of Mander et al.. I am not sure that modern versions of SAP2000 include that model. In any case, in this paper (2017.compdyn.org/proceedings/pdf/18163.pdf) you may find that it is possible to manually define the Mander stress-strain model for confined concrete. Confined concrete could potentially sustain a greater compressive stress than unconfined concrete, so creep effects may be affected. And here (www.mdpi.com/1996-1944/14/2/295) you may find information regarding creep of confined concrete. I know that some colleagues of mine have used either Abaqus or OpenSees for confined concrete because these offered some advantages over SAP2000.

[@fahimalizada1888]

I can't reach for the paper that you send their link to me what should I do sir .this is my Gmail [e-mail] can I ask them from you please

[@BorjaVarona_at_YT]

The document which summarises the Model Code 1990 formulation can be accessed in the following link:
hdl.handle.net/10045/72907