2. Design by Eurocode No.2 a Concrete Building Applicable CivilFEM Product: All CivilFEM Products Level of Difficulty: Easy Interactive Time Required: 30-35 minutes Discipline: Concrete Analysis Type: Linear static Element Type Used: BEAM3 Active Code: Eurocode Nº2 Units System: N, m, s CivilFEM Features Demonstrated: Units selection, code selection, material definition, concrete section definition, reinforcement and postprocessing of stresses Problem Description The objective is to design the necessary reinforcement of a 2 span and two floors building loaded with distributed load as shown in the figure below. It has a rectangular cross-section. B B H H 0.30 m 0.30 m P D D Exercise 2: Concrete Building Design 2-1
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2. Design by Eurocode No.2 a Concrete Building Applicable CivilFEM Product: All CivilFEM Products Level of Difficulty: Easy Interactive Time Required: 30-35 minutes Discipline: Concrete Analysis Type: Linear static Element Type Used: BEAM3 Active Code: Eurocode Nº2 Units System: N, m, s CivilFEM Features Demonstrated: Units selection, code selection, material
definition, concrete section definition, reinforcement and postprocessing of stresses
Problem Description The objective is to design the necessary reinforcement of a 2 span and two floors building loaded with distributed load as shown in the figure below. It has a rectangular cross-section.
B B
H
H
0.30 m
0.30 m
P
D
D
Exercise 2: Concrete Building Design 2-1
Given The geometry and load distribution of the simply supported beam are shown in the previous figure. The following is a list of all the input parameters:
Concrete C25/30
Reinforcing Steel S 500
Geometric dimensions
B = 5 m
H = 3 m
Loads: - Punctual load P of 100 kN located at the middle of diagonal bar.
- Dead load D of 100 kPa located on first floor and roof.
Approach and Assumptions We are going to discretize the beam with a 2D model, using linear beam elements. Model geometry is defined with solid modeling and automatic meshing of elements and nodes.
2-2 Exercise 2: Concrete Building Design
Summary of Steps
Preprocessing 1. Specify title 2. Set code and units 3. Define material 4. Define element type 5. Define solid modeling entities 6. Beam & Shell Properties 7. Define Solid Modeling entities 8. Meshing 9. Save the database
Postprocessing 13. Enter the postprocessor and read results 14. Plot the deformed shape 15. Plot Bending Moment 16. Axial + bending Checking 17. Axial + bending Design 18. Plot Reinforcement Factor 19. Exit the ANSYS program 20. Log File
Exercise 2: Concrete Building Design 2-3
Interactive Step-by-Step Solution
Preprocessing A typical CivilFEM analysis begins with providing data such as the units system, active code, materials, element types, model and section geometry definition
1. Specify title
Although this step is not required for a CivilFEM analysis, we recommend that you make it part of all your analyses.
Utility Menu: File →Change title
Enter the title: “Concrete Building Reinforcement”
OK to define the title and close the dialog box.
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2. Set code and units
Main Menu: − CivilFEM − Civil Setup
Select CivilFEM Setup
Choose Units
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2-4 Exercise 2: Concrete Building Design
Ok to use SI units
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Exercise 2: Concrete Building Design 2-5
3. Define material
Material properties definition is performed with the CivilFEM ~CFMP command. This command automatically defines the ANSYS material properties (density, Young’s modulus, Poisson’s ratio and thermal expansion coefficient) and the CivilFEM material properties necessary for code checking. In this case we will select Fe 510 steel.
The CivilFEM ~CFMP command allows us to define stress-strain diagrams, to define safety coefficients, to control the linear or non-linear behavior of the material and to select the activation time of the material.
Main Menu: − CivilFEM − Civil Preprocessor →Materials
Pick New Material
Choose Materials
Pick on Concrete
Pick on the EC2 icon to choose C25/30
Add
Pick on Reinforcing Steel
Pick on the EC2 icon to choose S 500
Add
Exit
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2-6 Exercise 2: Concrete Building Design
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Ok to exit 10
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Exercise 2: Concrete Building Design 2-7
4. Define element type
Checking and designing according to codes is performed only on CivilFEM supported element types. Although you can use any ANSYS element to define your model, only the CivilFEM supported elements will be checked according to codes. In the element type menu you can see the CivilFEM supported beam elements.
We will use a 2D elastic Beam 3 for this analysis.
The force of 100 kN is divided into FX and FY components:
Select node number 27
Ok
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Exercise 2: Concrete Building Design 2-27
3 Choose FX
Enter value of 85750 N
Apply
Select again node 27
Enter value of -51450 N
Ok
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2-28 Exercise 2: Concrete Building Design
12. Solve
Main Menu: Solution → − Solve − Current LS
Review information in the status window, and then close the window
OK to begin the solution
Close the information window when solution is done
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Exercise 2: Concrete Building Design 2-29
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2-30 Exercise 2: Concrete Building Design
Postprocessing Postprocessing is where you review the analysis results through graphic displays and tabular listings.
13. Enter the postprocessor and read results
You must select the load step from which you want to read the results data, from the CivilFEM results file. This results file contains the calculated forces, moments and stresses.
Main Menu: − CivilFEM − Civil Postprocess →Read Results → By Load Step
Enter 1 in the Load Step number box
OK to read load step 1
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14. Plot the deformed shape
Main Menu: General Postproc →Plot Results →Deformed Shape