E2

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

Solution 10. Apply displacement constraints 11. Apply pressure load 12. Solve

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


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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Ok to use SI units

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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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3 6

74

5 8 9

Ok to exit 10

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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.

Main Menu: − CivilFEM − Civil Preprocess →Element Types →Civil Beams

Select 2D Elastic Beam 3

OK to define element type

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5. Define concrete cross section

Main Menu: − CivilFEM − Civil Preprocessor →Cross Sections

Click Concrete button 1


Select Rectangular shape

Enter Ywidth = 0.3 and Zdepth = 0.3

OK to define concrete cross section

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Modify 4

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Go to Edit Reinforcement Groups 5

Pick on New Reinforcement button to define group 1 6


7 Select Material 2

Enter Geometrical cover Gc= 0.03 m 8

Choose Face 2 9

10 Select 0: Scalable

Amount by number of bars 11

Enter 3 as number of bars 12

Choose Fi = 20 mm 13

Select 4: Bars at both end at MC 14

Ok 13 15


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12 11

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Pick on New Reinforcement to define group 2 16


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17 Select Material 2

Enter Geometrical cover Gc= 0.03 m 18

Choose Face 4 19

20 Select 0: Scalable

Amount by number of bars 21

Enter 3 as number of bars 22

Choose Fi = 20 mm 23 23

Select 4: Bars at both end at MC 24

Ok 13 25


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Ok again and exit 26


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6. Beam & Shell Properties

CivilFEM command ~BMSHPRO will be used to define ANSYS real constants.


Main Menu: − CivilFEM − Civil Preprocessor →Beam & Shell pro

Click the New Beam button 1

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2 Select cross section number 1

3 Enter “Concrete Beam” as name for the Beam property

Select element type BEAM3 4


5 4 3

2

5 Apply

6 Exit Beam & Shell Properties

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7. Define solid modeling entities

Now we create keypoints.

Main Menu: Preprocessor → − Modeling − Create →Keypoints →In Active CS

Enter 1 for first keypoint

Enter x=0, y=0 for coordinates of keypoint 1

Apply to create the first keypoint

Enter 2 for second keypoint

Enter x=5, y=0 for coordinates of keypoint

Ok

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Follow the same procedure in point 3 ( x=10, y=0)

Now we copy all these points :

Main Menu: Preprocessor → −Modeling− Copy → Keypoints

7 Pick alll

8 Enter 2 copies

9 Enter 3m as Y offset


10 Ok

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9

Now we create lines joining these keypoints


Main Menu: Preprocessor → −Modeling− Create →Lines → Straight Line

Floor:

7 Pick keypoint 4 and then keypoint 5 .

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8 Pick keypoint 5 and then keypoint 6

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9 Pick keypoint 4 and then keypoint 7


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Follow the same procedure to create lines for the roof between keypoints 7-8

Now for first column:

10 Line between keypoint 1 & 4

Now for second column:



And for third column




12 14

10 11 13

8. Meshing

Main Menu: Preprocessor →Meshing→Mesh Tool

In Size Controls: Pick on Global Set

Enter 10 as number of element divisions

Ok

Mesh

Pick all

Close Mesh Tool

5 1

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5 4

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Select everything: Utility Menu: Select →Everything

9. Save the database

Toolbar: CFSAVE


Solution

10. Apply displacement constraints

Main Menu: Solution → − Define Loads − Apply → – Structural – Displacement →On Nodes

Pick the three nodes at supports

Ok

Choose ALL DOF

Ok

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11. Apply pressure load

Main Menu: Solution → − Loads − Apply→ − Structural − Pressure →On Beams

Pick floor & roof elements : 11 to 20 and 31 to 40 to select them ( a total of 20)

Enter 1 for Load key

Enter 100000 for VAL I

OK to apply pressure and close dialog box

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12. Apply punctual load

Main Menu: Solution → − Loads − Apply→ − Structural − Force/Moment →On Nodes

The force of 100 kN is divided into FX and FY components:

Select node number 27

Ok

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3 Choose FX

Enter value of 85750 N

Apply

Select again node 27

Enter value of -51450 N

Ok

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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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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

Choose Def + undef edge

OK

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15. Plot Bending Moment

Main Menu: − CivilFEM − Civil Postprocess →Code Design →Eurocode No.2: Beam Results→Beams Utilities→Graph Results→Forces & Moments

Choose Bending Mom Z

OK

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16. Axial + Bending Checking

Main Menu: − CivilFEM − Civil Postprocess →Code Checking →Eurocode No.2: Check by code→Beams & Solid: 2D Axial + Bend

Ok

We plot results:

Main Menu: − CivilFEM − Civil Postprocess →Code Checking →Eurocode No.2: Beam Results→ Plot results

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Ok to plot Eurocode No.2 checking criterion. 1

17. Bending and Axial Design

The CivilFEM ~DIMCON command design reinforced concrete cross sections.

Main Menu: − CivilFEM − Civil Postprocess →Code Design →Eurocode No.2: Design by code→Beams & Solid: 2D Axial + Bend

Enter 0.5 and 70 as minimum & maximum amount of allowable reinforcement

Ok

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18. Plot Reinforcement factor

Main Menu: − CivilFEM − Civil Postprocess →Code Design →Eurocode No.2: Beam Results→ Plot results

Choose Reinfact and Ok

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Reinforcement factor is plotted, the total reinforcement area must be multiplied by this factor to design by Eurocode No.2.


19. Exit the ANSYS program

ANSYS Toolbar: Quit

Choose to save everything

OK

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20. Log File

FINISH

~CFCLEAR,,1

/TITLE,CONCRETE BUILDING REINFORCEMENT

~UNITS,SI

FINISH

/PREP7

! ELEMENT TYPE

ET,1,BEAM3

! MATERIALS

~CFMP,1,LIB,CONCRETE,EC2,C25/30,0,0,0

~CFMP,2,LIB,REINF,EC2,S500,0,0,0

! CROSS SECTION

~CSECDMS,1,REC,1,0.3,0.3,

! BENDING REINFORCEMENT

~RNFDEF,1,1,2,2,0,0.03,,,20,3,,,4

~RNFDEF,1,2,2,4,0,0.03,,,20,3,,,4

! BEAM & SHELL PROPERTY

~BMSHPRO,1,BEAM,1,1,,,3,1,0,CONCRETE BEAM

! MODEL

K,1, 0,0

K,2, 5,0

K,3,10,0

KGEN,2,ALL,,,,3,,0,0


K,7, 5,6

K,8,10,6

L,4,5 $ L,5,6 ! 1ST FLOOR

L,4,7 $ L,7,8 ! ROOF

L,1,4 ! 1ST COLUMN

L,2,5 $ L,5,7 ! 2ND COLUMN

L,3,6 $ L,6,8 ! 3RD COLUMN

! MESHING

ESIZE,,10

LMESH,ALL

/SOLU

! BOUNDARY CONDITIONS

NSEL,S,LOC,Y,0

D,ALL,ALL

ESEL,S,ELEM,,11,20

ESEL,A,ELEM,,31,40

SFBEAM,ALL,1,PRES,100000

ALLSEL,ALL

F,27,FX,85750

F,27,FY,-51450

ALLSEL,ALL

SOLVE

/POST1

~CFSET,,1,1


! BENDING MOMENT

~PLLSFOR,M,Z,-1,

! DEFORMED SHAPE

PLDISP,2

~CHKCON,2DB

~PLLSCON,ELM_OK,1,

~PLLSCON,CRT_TOT,1,

! BENDING+AXIAL DESIGN

~DIMCON,2DB,,,0.5,70

~PLLSCON,REINFACT ! REINFORCEMENT FACTOR


E2

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