Solution
In this step we will define the analysis type and its options, apply loads and
initiate the finite element solution. A new, static analysis is the default option,
so we will not need to specify the analysis type for this problem. Moreover,
there are no analysis options for this problem.
13. Define Boundary conditions
We will apply displacement constraints in all supports:
Support 1
Utility Menu: SelectEntities
1
Select nodes by location
Enter X=0.5 and OK
Main Menu: Solution Define Loads Apply Structural
Displacement On Nodes+
3
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Pick All
Chapter 9 Check by EHE a Prestressed Slab Bridge
Choose UY, UZ and ROTX
OK
Utility Menu: SelectEverything
6
Support 2
Utility Menu: SelectEntities
6
Select nodes by location
Enter X=12 and Ok
Main Menu: Solution Define Loads Apply Structural
Displacement On Nodes+
Pick all
Choose UY, UZ
10
Ok
9
10
Utility Menu: SelectEverything
Chapter 9 Check by EHE a Prestressed Slab Bridge
9-45
We do the same with the rest of supports:
Support 3
Utility Menu: SelectEntities
11
Select nodes by location
12
Enter X=41 and Ok
Main Menu: Solution Define Loads Apply Structural
Displacement On Nodes+
13
Pick all
14
Choose UY, UZ
15
Ok
Utility Menu: SelectEverything
Support 4
Utility Menu: SelectEntities
11
Select nodes by location
12
Enter X=53 and Ok
Main Menu: Solution Define Loads Apply Structural
Displacement On Nodes+
13
Pick all
14
Choose UX, UY, UZ, ROTZ
15
Ok
Utility Menu: SelectEverything
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Chapter 9 Check by EHE a Prestressed Slab Bridge
14. Families and Load States Definition
The user may define load families that can be later used in the combination
module. A family is a group of load states, normally of the same topology. For
example, the vehicles load would be a family formed by all loads created when the
vehicles are placed in all the possible positions.
All the load steps belonging to a family are combined into one unique load step
according to their nature
a) Vehicle Load
Utility Menu: File Change Title
1
Enter Vehicle Load
We load and modify properties of a vehicle from the library using the vehicle
editor:
Main Menu: Civil Solution Bridges SoluTraffic Loads Vehicle
2
Vehicle Library
4
3
Select IAP Heavy Vehicle
Ok to define Vehicle 1
Ok to exit vehicle editor
Chapter 9 Check by EHE a Prestressed Slab Bridge
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Chapter 9 Check by EHE a Prestressed Slab Bridge
Main Menu: Civil Solution Bridges Solu Family Define Family
One heavy vehicle in one line: Type INCOMPATIBLE
6
Family number 1001
4
7
Choose Incompatible
6
7
Ok
Ok to define family coefficients
Now we define the family number to which the mobile loads will be assigned
and the identification number of the vehicle that is going to move over the
bridge:
Main Menu: Civil Solution Bridges Solu Traffic Loads Mobile Load
10
Enter Family number 1001
4
11
Enter Vehicle ID 1 and Ok
Chapter 9 Check by EHE a Prestressed Slab Bridge
9-49
10
11
11
Solving of simple start states is carried out through command ~BLSOLVE. This
command performs the analysis of all the start states contained in the family . The
defined mobile load will generate 19 load steps.
Main Menu: Civil Solution Bridges SoluSolve
12
12
Ok
The solution monitoring info is written to a mntr file.
Now we delete forces to continue with next load step:
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Chapter 9 Check by EHE a Prestressed Slab Bridge
Main Menu: Solution Define LoadsDeleteAll Load dataAll
ForcesOn all nodes
13
Ok
13
b) Initial Prestressing
Utility Menu: File Change Title
14
14
Enter Initial Prestressing
We will calculate the immediate losses, they occur once the prestressing
force is applied, after the concrete has been placed and cured, and when the
tendons are anchored.
Main Menu: Civil Solution Prestress Concrete SoluTendons
Calculate Losses
15
Enter 0 as time
16
OK
Chapter 9 Check by EHE a Prestressed Slab Bridge
9-51
15
16
Now we transfer the tendons actions over the finite elements model:
Main Menu: Civil Solution Prestress Concrete Solu Tendons
Load Tendon
17
Enter 0
18
OK
17
18
~CFLSWRT command writes all load and load step option data for the
selected model to a load step file for later use.
Main Menu: Civil Solution Load StateWrite LS file
19
20
19
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Enter Load step number 20
Chapter 9 Check by EHE a Prestressed Slab Bridge
20
OK
In order for CivilFEM to process the results correctly, it is necessary to use
this command to delete the prestressing loads.
Main Menu: Civil Solution Prestress Concrete SoluTendons Delete
Loads
21
20
21
20
Ok to delete all loads
c) Final Prestressing
Utility Menu: File Change Title
22
22
Enter Final Prestressing
We will calculate the long-term losses, they occur after the end of the last
prestressing operation.
Main Menu: Civil Solution Prestress Concrete SoluTendons
Calculate Losses
23
Enter time 1,000,000 and OK
Chapter 9 Check by EHE a Prestressed Slab Bridge
9-53
24
24
Now we transfer the tendons actions over the finite elements model:
Main Menu: Civil Solution Prestress Concrete SoluTendons Load
Tendon
25
26
25
Enter 0
26
OK
~CFLSWRT command writes all load and load step option data for the
selected model to a load step file for later use.
Main Menu: Civil Solution Load StateWrite LS file
27
28
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Chapter 9 Check by EHE a Prestressed Slab Bridge
27
Enter Load step number 21
28
Ok
In order for CivilFEM to process the results correctly, it is necessary to use
this command to delete the prestressing loads.
Main Menu: Civil Solution Prestress Concrete SoluTendons Delete
Loads
29
29
Ok to delete all loads
d) Self Weight
Utility Menu: File Change Title
30
30
Enter Self Weight
We specify the linear acceleration of the structure:
Main Menu: Solution Define Loads Apply
StructuralInertiaGravityGlobal
31
4
Enter 9.81 as ACELZ and OK
Chapter 9 Check by EHE a Prestressed Slab Bridge
9-55
31
~CFLSWRT command writes all load and load step option data for the
selected model to a load step file for later use.
Main Menu: Civil Solution Load StateWrite LS file
32
33
32
Enter Load step number 22
33
Ok
Now we delete this load by entering zero gravity:
Main Menu: Solution Define Loads Apply
StructuralInertiaGravity
34
34
34
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Enter 0 as ACELZ and Ok
Chapter 9 Check by EHE a Prestressed Slab Bridge
e) Dead Load
Utility Menu: File Change Title
35
36
35
Enter Dead Load
36
OK
We specify a surface load on all beam elements:
Main Menu: Solution Define Loads Apply Structural
PressureOn Beams+
38
39
40
37
37
Pick all
38
Enter 2 as load key
39
Enter pressure value= 33200
40
OK
Chapter 9 Check by EHE a Prestressed Slab Bridge
9-57
~CFLSWRT command writes all load and load step option data for the
selected model to a load step file for later use.
Main Menu: Civil Solution Load StateWrite LS file
41
42
41
Enter Load step number 23
42
Ok
Now we delete the surface loads from all elements:
Main Menu: Solution Define Loads Delete All Load dataAll
Surface Ld On all Elems
43
43
Ok
f) Surface Load
Utility Menu: File Change Title
44
44
44
49
9-58
Enter Surface Load an Ok
Chapter 9 Check by EHE a Prestressed Slab Bridge
We specify a surface load on all beam elements:
Main Menu: Solution Define Loads Apply Structural
PressureOn Beams+
46
47
48
45
45
Pick all
46
Enter 2 as Load key
47
Enter pressure value = 40000
48
Ok
~CFLSWRT command writes all load and load step option data for the selected
model to a load step file for later use.
Main Menu: Civil Solution Load StateWrite LS file
49
50
49
Enter 24
Chapter 9 Check by EHE a Prestressed Slab Bridge
9-59
50
Ok
Now we delete the surface loads from all elements:
Main Menu: Solution Define Loads Delete All Load dataAll
Surface Ld On all Elems
51
51
Ok
g) Thermal Gradient
Utility Menu: File Change Title
52
52
52
Enter Thermal gradient and Ok
Now we apply temperature on all elements:
Main Menu: Solution Loads Apply Structural
TemperatureOn Elements
53
Pick all
54
Starting location at location 1
55
VAL1=0, VAL2=0, VAL3=5, VAL4=5
56
Apply
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Chapter 9 Check by EHE a Prestressed Slab Bridge
54
55
56
57
53
57
Pick all again
58
Starting location at node 5
59
VAL1=0, VAL2=0, VAL3=5, VAL4=5
60
Ok
58
59
60
~CFLSWRT command writes all load and load step option data for the selected
model to a load step file for later use.
Chapter 9 Check by EHE a Prestressed Slab Bridge
9-61
Main Menu: Civil Solution Load StateWrite LS file
61
62
61
Enter 25
62
Ok
We finally delete element body force loads:
Main Menu: Solution Define Loads Delete All Load dataAll
Body loads On all Elems
63
63
Ok
To finish we must read and solve multiple load steps taking into account the
construction process:
64
We type this in the ANSYS command window:
~CFLSSLV, 20,25,1
Range of load step files to be read and solved, from LS20 to LS25 in steps of 1
64
These are all the load steps and start states created :
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Chapter 9 Check by EHE a Prestressed Slab Bridge
Load Steps
Start
States
Vehicle Load
LS1:19
Initial Prestressing
LS20
Final Prestressing
LS21
Self Weight
LS22
Dead Load
LS23
Surface Load
LS24
Thermal Gradient
LS25
Chapter 9 Check by EHE a Prestressed Slab Bridge
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