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Advanced Concrete Performance ENG5224 2021/2022
Dr. Grassl University of Glasgow
1 of 7
Coursework 1
Assigned: Friday 5th February 2021
Due: Thursday, 24th February, 16:00, 2021 Submission via Moodle Page
Text: Lecture notes, ATENA Tutorial, Exercises
Objectives: Understanding of the numerical analysis of the nonlinear behaviour of
reinforced concrete structures
Weight: 25% of overall grade of Advanced Concrete Performance ENG5224
Adopting a two-dimensional plane stress idealisation, use ATENA to analyse the short term
behaviour of the reinforced concrete beam. See page 7 for the geometry and properties of the beam.
This beam is similar to the one used in the ATENA software tutorial. However, the dimensions of
the beam depend on your student number.
Investigate one failure mode. For your failure mode, you should then investigate one set of
parameters. The list containing your failure mode and your set of parameters can be found on the
Moodle page. You have to choose the reinforcement area As to obtain your failure mode. If
required, you can add shear reinforcement to the beam.
Failure mode:
1) Shear failure
2) Bending failure of an under-reinforced beam
3) Bending failure of an over-reinforced beam
If you are not sure how these failure modes are defined, have a look at the information provided at
the beginning of the lectures.
Set of parameters:
1)
l Compressive strength
l Shear retention (part of fixed crack model)
l Solution scheme (displacement, load and arclength control)
2)
l Fracture energy
l Bond-slip of reinforcement (perfect bond, bond slip). Hint: Make sure that symmetry
conditions are enforced for the reinforcement if slip is activated.
l Mesh size
3)
l Size of the load steps
l Tensile strength
l Compressive strength
For these investigations, choose first a base configuration of input parameters. It is suggested that
you start with the tutorial input parameters and change, if required, the reinforcement amount and
arrangement (you might need to add reinforcement), so that you obtain the failure mode that you
want to investigate. Define this then as your base configuration. Next, change only one parameter at
Advanced Concrete Performance ENG5224 2021/2022
Dr. Grassl University of Glasgow
2 of 7
a time, so that you can be sure that the change in structural response that you obtain is really due to
the parameter that you would like to investigate. This sounds easier than it is done. As an example,
imagine that you would like to change the compressive strength. In the tutorial, the cube
compressive strength is used to calculate all concrete material parameters, including fracture
energy, Young’s modulus and tensile strength. By changing this cube compressive strength value,
all these parameters would change. This would not be desirable, since it would not be clear that the
observed changes are due to the changes of the compressive strength or one of the other parameters.
Therefore, it would be better to change only the compressive strength and leave the other
parameters unchanged.
Also, it is suggested to vary the parameters strongly so that you can see a clear influence on the load
displacement curves. For instance, an increase of the fracture energy by 5% compared to the base
value will most likely only have a very slight influence on the load-displacement curve. In this case,
it would be better to use 50% increase. Obtain the response for at least three different values of a
parameter, so that you can observe a trend.
Study the influence of the parameters on the global response of your structure in the form of load-
displacement curves. Explain the trends that you observe by looking at local results, such as contour
plots of stresses or strains, deformed shapes, crack patterns, etc. Not all of these local results might
be meaningful for your failure mode. It very much depends on your parameters and failure mode
which of the local results are most suitable to look at. Remember that for reinforced concrete
structures at the ultimate limit state, the important parameters are maximum load, displacement at
maximum load and ductility.
Compare your finite element results for the base configuration only for your failure mode with the
capacity calculated for your failure mode according to a Concrete Design Code of your choice
(hand calculations). Results of finite element analysis and hand calculation might differ a lot. This
is not a problem. However, if possible, understand why this is the case. Is it a shortcoming of the
method used in the design code or a limitation of the finite element program?
Advanced Concrete Performance ENG5224 2021/2022
Dr. Grassl University of Glasgow
3 of 7
Report
Each student has to produce one report (one report per student). The report must be submitted
online (Moodle) as a pdf-file. This report should summarise the analyses and include observations
and conclusions regarding the influence of the above parameters.
Important: The maximum length of the entire report is calculated as 10 pages (inclusive all
appendices), Times New Roman, 12pt with at least 2cm margins.
The report should contain the following minimum contents:
1) Cover sheet with the name and matriculation. (not part of the 10 page limit)
2) A short description of models and idealisations used to solve it should be provided. Make sure
that you provide enough information so that someone else could reproduce your results. The results
of the base configuration should be compared to the hand calculation. Description of the analyses
carried out. Presentation of the influence of the parameters on the load-displacement curves.
Comparison of hand calculations with finite element results (only for the base configuration of the
failure mode). Discussion of trends observed in load-displacement curves and presentation of more
detailed results, such as deformation patterns and contour plots (if relevant), to explain these trends.
3) Conclusions clearly stating the trends observed.
4) References (if required)
Advanced Concrete Performance ENG5224 2021/2022
Dr. Grassl University of Glasgow
4 of 7
Marking
The marking will consider in equal weights the presentation of the results and the understanding.
Concerning the presentation, aim for the following:
• Arguments are well presented
• Major findings are clear and easily accessible
• The writing is accurate
• Good English
• All references to figures and equations are correct
• Enough information is provided to allow others to reproduce your results
Concerning the understanding, provide sufficient discussion to show that you have understood the
underlying models/theory, which give you the presented results.
Advanced Concrete Performance ENG5224 2021/2022
Dr. Grassl University of Glasgow
5 of 7
Please note that standard penalties for late submission apply:
Reduction of two subgrades (e.g. B1 to B3) for each working day late, up to a maximum of 5 days.
Zero mark if more than 5 days late.
It is essential that you still submit any late coursework, even if you are going to get zero marks for it
(otherwise you cannot obtain any credits for this course).
Advanced Concrete Performance ENG5224 2021/2022
Dr. Grassl University of Glasgow
6 of 7
ATENA
You can access ATENA via the Glasgow Anywhere Desktop
(https://www.gla.ac.uk/myglasgow/anywhere/desktop/) , which is the preferred route. No need to
install it. Simply connect to a Science and Engineering Desktop and then choose ATENA2D in the
folder Cervenka Consulting.
You can also use it from your personal computer at home. (Only Windows. See it support page
below.)
First, you will need to install VPN: http://www.gla.ac.uk/services/it/flexaccess/vpn/
Once VPN is working you can visit this webpage for instructions to install ATENA:
http://web.eng.gla.ac.uk/wiki/general/index.php/Atena
Should you have problems with this, please contact the IT Support at eng-itsupport@glasgow.ac.uk.
Advanced Concrete Performance ENG5224 2021/2022
Dr. Grassl University of Glasgow
7 of 7
Concrete beam
The dimensions of the beam depend on your student number. You need to determine the
parameter d as the sum of the digits of your student number. For instance, for student
number 7654321, the sum of the digits is 7+6+5+4+3+2+1 = 28. Therefore, the parameter d for
this student number would be 28.
Figure 1: Elevation of the reinforced concrete beam.
Figure 2: Cross-section of the beam.
Dr. Grassl University of Glasgow
1 of 7
Coursework 1
Assigned: Friday 5th February 2021
Due: Thursday, 24th February, 16:00, 2021 Submission via Moodle Page
Text: Lecture notes, ATENA Tutorial, Exercises
Objectives: Understanding of the numerical analysis of the nonlinear behaviour of
reinforced concrete structures
Weight: 25% of overall grade of Advanced Concrete Performance ENG5224
Adopting a two-dimensional plane stress idealisation, use ATENA to analyse the short term
behaviour of the reinforced concrete beam. See page 7 for the geometry and properties of the beam.
This beam is similar to the one used in the ATENA software tutorial. However, the dimensions of
the beam depend on your student number.
Investigate one failure mode. For your failure mode, you should then investigate one set of
parameters. The list containing your failure mode and your set of parameters can be found on the
Moodle page. You have to choose the reinforcement area As to obtain your failure mode. If
required, you can add shear reinforcement to the beam.
Failure mode:
1) Shear failure
2) Bending failure of an under-reinforced beam
3) Bending failure of an over-reinforced beam
If you are not sure how these failure modes are defined, have a look at the information provided at
the beginning of the lectures.
Set of parameters:
1)
l Compressive strength
l Shear retention (part of fixed crack model)
l Solution scheme (displacement, load and arclength control)
2)
l Fracture energy
l Bond-slip of reinforcement (perfect bond, bond slip). Hint: Make sure that symmetry
conditions are enforced for the reinforcement if slip is activated.
l Mesh size
3)
l Size of the load steps
l Tensile strength
l Compressive strength
For these investigations, choose first a base configuration of input parameters. It is suggested that
you start with the tutorial input parameters and change, if required, the reinforcement amount and
arrangement (you might need to add reinforcement), so that you obtain the failure mode that you
want to investigate. Define this then as your base configuration. Next, change only one parameter at
Advanced Concrete Performance ENG5224 2021/2022
Dr. Grassl University of Glasgow
2 of 7
a time, so that you can be sure that the change in structural response that you obtain is really due to
the parameter that you would like to investigate. This sounds easier than it is done. As an example,
imagine that you would like to change the compressive strength. In the tutorial, the cube
compressive strength is used to calculate all concrete material parameters, including fracture
energy, Young’s modulus and tensile strength. By changing this cube compressive strength value,
all these parameters would change. This would not be desirable, since it would not be clear that the
observed changes are due to the changes of the compressive strength or one of the other parameters.
Therefore, it would be better to change only the compressive strength and leave the other
parameters unchanged.
Also, it is suggested to vary the parameters strongly so that you can see a clear influence on the load
displacement curves. For instance, an increase of the fracture energy by 5% compared to the base
value will most likely only have a very slight influence on the load-displacement curve. In this case,
it would be better to use 50% increase. Obtain the response for at least three different values of a
parameter, so that you can observe a trend.
Study the influence of the parameters on the global response of your structure in the form of load-
displacement curves. Explain the trends that you observe by looking at local results, such as contour
plots of stresses or strains, deformed shapes, crack patterns, etc. Not all of these local results might
be meaningful for your failure mode. It very much depends on your parameters and failure mode
which of the local results are most suitable to look at. Remember that for reinforced concrete
structures at the ultimate limit state, the important parameters are maximum load, displacement at
maximum load and ductility.
Compare your finite element results for the base configuration only for your failure mode with the
capacity calculated for your failure mode according to a Concrete Design Code of your choice
(hand calculations). Results of finite element analysis and hand calculation might differ a lot. This
is not a problem. However, if possible, understand why this is the case. Is it a shortcoming of the
method used in the design code or a limitation of the finite element program?
Advanced Concrete Performance ENG5224 2021/2022
Dr. Grassl University of Glasgow
3 of 7
Report
Each student has to produce one report (one report per student). The report must be submitted
online (Moodle) as a pdf-file. This report should summarise the analyses and include observations
and conclusions regarding the influence of the above parameters.
Important: The maximum length of the entire report is calculated as 10 pages (inclusive all
appendices), Times New Roman, 12pt with at least 2cm margins.
The report should contain the following minimum contents:
1) Cover sheet with the name and matriculation. (not part of the 10 page limit)
2) A short description of models and idealisations used to solve it should be provided. Make sure
that you provide enough information so that someone else could reproduce your results. The results
of the base configuration should be compared to the hand calculation. Description of the analyses
carried out. Presentation of the influence of the parameters on the load-displacement curves.
Comparison of hand calculations with finite element results (only for the base configuration of the
failure mode). Discussion of trends observed in load-displacement curves and presentation of more
detailed results, such as deformation patterns and contour plots (if relevant), to explain these trends.
3) Conclusions clearly stating the trends observed.
4) References (if required)
Advanced Concrete Performance ENG5224 2021/2022
Dr. Grassl University of Glasgow
4 of 7
Marking
The marking will consider in equal weights the presentation of the results and the understanding.
Concerning the presentation, aim for the following:
• Arguments are well presented
• Major findings are clear and easily accessible
• The writing is accurate
• Good English
• All references to figures and equations are correct
• Enough information is provided to allow others to reproduce your results
Concerning the understanding, provide sufficient discussion to show that you have understood the
underlying models/theory, which give you the presented results.
Advanced Concrete Performance ENG5224 2021/2022
Dr. Grassl University of Glasgow
5 of 7
Please note that standard penalties for late submission apply:
Reduction of two subgrades (e.g. B1 to B3) for each working day late, up to a maximum of 5 days.
Zero mark if more than 5 days late.
It is essential that you still submit any late coursework, even if you are going to get zero marks for it
(otherwise you cannot obtain any credits for this course).
Advanced Concrete Performance ENG5224 2021/2022
Dr. Grassl University of Glasgow
6 of 7
ATENA
You can access ATENA via the Glasgow Anywhere Desktop
(https://www.gla.ac.uk/myglasgow/anywhere/desktop/) , which is the preferred route. No need to
install it. Simply connect to a Science and Engineering Desktop and then choose ATENA2D in the
folder Cervenka Consulting.
You can also use it from your personal computer at home. (Only Windows. See it support page
below.)
First, you will need to install VPN: http://www.gla.ac.uk/services/it/flexaccess/vpn/
Once VPN is working you can visit this webpage for instructions to install ATENA:
http://web.eng.gla.ac.uk/wiki/general/index.php/Atena
Should you have problems with this, please contact the IT Support at eng-itsupport@glasgow.ac.uk.
Advanced Concrete Performance ENG5224 2021/2022
Dr. Grassl University of Glasgow
7 of 7
Concrete beam
The dimensions of the beam depend on your student number. You need to determine the
parameter d as the sum of the digits of your student number. For instance, for student
number 7654321, the sum of the digits is 7+6+5+4+3+2+1 = 28. Therefore, the parameter d for
this student number would be 28.
Figure 1: Elevation of the reinforced concrete beam.
Figure 2: Cross-section of the beam.
