EX. US-6 Prestress and Poststress Loading
This is an example of prestress loading in a plane frame structure.
- From the member on which it is applied, the prestressing effect is transmitted to the rest of the structure through the connecting members (known in the program as
PRESTRESS
load). - The prestressing effect is experienced by the member(s) alone and not transmitted to the rest of the structure (known in the program as
POSTSTRESS
load).
This problem is installed with the program by default to C:\Users\Public\Public Documents\STAAD.Pro 2024\Samples \Sample Models\US\US-6 Prestress and Poststress Loading.STD when you install the program.
Where:
- L1 = 15 ft
- L2 = 20 ft
- L3 = 40 ft
Actual input is shown in bold lettering followed by explanation.
STAAD PLANE FRAME WITH PRESTRESSING LOAD
Every input has to start with the term STAAD
. The term PLANE
signifies that the structure is a plane frame structure and the geometry is defined through X and Y axes.
UNIT KIP FT
Defines the input units for the data that follows.
JOINT COORD
1 0. 0. ; 2 40. 0. ; 3 0. 20. ; 4 40. 20.
5 0. 35. ; 6 40. 35. ; 7 0. 50. ; 8 40. 50.
Joint number followed by X and Y coordinates are provided above. Since this is a plane structure, the Z coordinates need not be provided.
MEMBER INCIDENCE
1 1 3 ; 2 3 5 ; 3 5 7 ; 4 2 4 ; 5 4 6
6 6 8 ; 7 3 4 ; 8 5 6 ; 9 7 8
Defines the members by the joints to which they are connected.
SUPPORT
1 2 FIXED
The supports at joints 1 and 2 are defined to be fixed supports.
MEMB PROP
1 TO 9 PRI AX 2.2 IZ 1.0
Member properties are provided using the PRI (prismatic) attribute. Values of area (AX) and moment of inertia about the major axis (IZ) are provided.
UNIT INCH
DEFINE MATERIAL START
ISOTROPIC CONCRETE
E 3000.
POISSON 0.17
DENSITY 8.7e-005
ALPHA 5e-006
DAMP 0.05
G 1346.15
TYPE CONCRETE
STRENGTH FCU 4
END DEFINE MATERIAL
CONSTANTS
MATERIAL CONCRETE ALL
The DEFINE MATERIAL
command is used to specify material properities and the CONSTANT
command is used to assign the material to all members. Length unit is changed from FT to INCH to facilitate the input.
LOADING 1 PRESTRESSING LOAD
MEMBER PRESTRESS
7 8 FORCE 300. ES 3. EM -12. EE 3.
Load case 1 is initiated along with an accompanying
title. Load 1 contains PRESTRESS
load. Members 7 and 8 have a cable
force of 300 kips. The location of the cable at the start (ES
) and end
(EE
) is 3 inches above the center of gravity while at the middle
(EM
) it is 12 inches below the c.g. The assumptions and facts
associated with this type of loading are explained in G.15.5 Prestress and Poststress Member Load.
LOADING 2 POSTSTRESSING LOAD
MEMBER POSTSTRESS
7 8 FORCE 300. ES 3. EM -12. EE 3.
Load case 2 is initiated along with an
accompanying title. Load 2 is a POSTSTRESS
load. Members 7 and 8 have
cable force of 300 kips. The location of the cable is the same as in load case 1. For a
difference between PRESTRESS loading and POSTSTRESS loading, as well as additional
information about both types of loads, please refer to G.15.5 Prestress and Poststress Member Load.
PERFORM ANALYSIS
This command instructs the program to perform the analysis.
UNIT FT
PRINT ANALYSIS RESULT
The preceding command is an instruction to write joint displacements, support reactions and member forces in the output file. The preceding line causes the results to be written in the length unit of feet.
FINISH
This command terminates the STAAD run.
Input File
STAAD PLANE FRAME WITH PRESTRESSING LOAD
UNIT KIP FT
JOINT COORD
1 0. 0. ; 2 40. 0. ; 3 0. 20. ; 4 40. 20.
5 0. 35. ; 6 40. 35. ; 7 0. 50. ; 8 40. 50.
MEMBER INCIDENCE
1 1 3 ; 2 3 5 ; 3 5 7 ; 4 2 4 ; 5 4 6
6 6 8 ; 7 3 4 ; 8 5 6 ; 9 7 8
SUPPORT
1 2 FIXED
MEMB PROP
1 TO 9 PRI AX 2.2 IZ 1.0
UNIT INCH
DEFINE MATERIAL START
ISOTROPIC CONCRETE
E 3000.
POISSON 0.17
DENSITY 8.7e-005
ALPHA 5e-006
DAMP 0.05
G 1346.15
TYPE CONCRETE
STRENGTH FCU 4
END DEFINE MATERIAL
CONSTANTS
MATERIAL CONCRETE ALL
LOADING 1 PRESTRESSING LOAD
MEMBER PRESTRESS
7 8 FORCE 300. ES 3. EM -12. EE 3.
LOADING 2 POSTSTRESSING LOAD
MEMBER POSTSTRESS
7 8 FORCE 300. ES 3. EM -12. EE 3.
PERFORM ANALYSIS
UNIT FT
PRINT ANALYSIS RESULT
FINISH
PAGE NO. 1
****************************************************
* *
* STAAD.Pro 2023 *
* Version 23.00.03.** *
* Proprietary Program of *
* Bentley Systems, Inc. *
* Date= JUL 4, 2024 *
* Time= 11:29: 8 *
* *
* Licensed to: Bentley Systems Inc *
****************************************************
1. STAAD PLANE FRAME WITH PRESTRESSING LOAD
INPUT FILE: D:\Documentation\STAAD.Pro\_Automated_Py\output\2024-07-04\SPro_Output_Input_Files\Sample .. .STD
2. UNIT KIP FT
3. JOINT COORD
4. 1 0. 0. ; 2 40. 0. ; 3 0. 20. ; 4 40. 20.
5. 5 0. 35. ; 6 40. 35. ; 7 0. 50. ; 8 40. 50.
6. MEMBER INCIDENCE
7. 1 1 3 ; 2 3 5 ; 3 5 7 ; 4 2 4 ; 5 4 6
8. 6 6 8 ; 7 3 4 ; 8 5 6 ; 9 7 8
9. SUPPORT
10. 1 2 FIXED
11. MEMB PROP
12. 1 TO 9 PRI AX 2.2 IZ 1.0
13. UNIT INCH
14. DEFINE MATERIAL START
15. ISOTROPIC CONCRETE
16. E 3000.
17. POISSON 0.17
18. DENSITY 8.7E-005
19. ALPHA 5E-006
20. DAMP 0.05
21. G 1346.15
22. TYPE CONCRETE
23. STRENGTH FCU 4
24. END DEFINE MATERIAL
25. CONSTANTS
26. MATERIAL CONCRETE ALL
27. LOADING 1 PRESTRESSING LOAD
28. MEMBER PRESTRESS
29. 7 8 FORCE 300. ES 3. EM -12. EE 3.
30. LOADING 2 POSTSTRESSING LOAD
31. MEMBER POSTSTRESS
32. 7 8 FORCE 300. ES 3. EM -12. EE 3.
33. PERFORM ANALYSIS
FRAME WITH PRESTRESSING LOAD -- PAGE NO. 2
P R O B L E M S T A T I S T I C S
-----------------------------------
NUMBER OF JOINTS 8 NUMBER OF MEMBERS 9
NUMBER OF PLATES 0 NUMBER OF SOLIDS 0
NUMBER OF SURFACES 0 NUMBER OF SUPPORTS 2
Using 64-bit analysis engine.
SOLVER USED IS THE IN-CORE ADVANCED MATH SOLVER
TOTAL PRIMARY LOAD CASES = 2, TOTAL DEGREES OF FREEDOM = 18
TOTAL LOAD COMBINATION CASES = 0 SO FAR.
34. UNIT FT
35. PRINT ANALYSIS RESULT
ANALYSIS RESULT
FRAME WITH PRESTRESSING LOAD -- PAGE NO. 3
JOINT DISPLACEMENT (INCH RADIANS) STRUCTURE TYPE = PLANE
------------------
JOINT LOAD X-TRANS Y-TRANS Z-TRANS X-ROTAN Y-ROTAN Z-ROTAN
1 1 0.00000 0.00000 0.00000 0.00000 0.00000 0.00000
2 0.00000 0.00000 0.00000 0.00000 0.00000 0.00000
2 1 0.00000 0.00000 0.00000 0.00000 0.00000 0.00000
2 0.00000 0.00000 0.00000 0.00000 0.00000 0.00000
3 1 0.07698 0.00000 0.00000 0.00000 0.00000 0.00039
2 0.00000 0.00000 0.00000 0.00000 0.00000 0.00000
4 1 -0.07698 0.00000 0.00000 0.00000 0.00000 -0.00039
2 0.00000 0.00000 0.00000 0.00000 0.00000 0.00000
5 1 0.07224 0.00000 0.00000 0.00000 0.00000 0.00087
2 0.00000 0.00000 0.00000 0.00000 0.00000 0.00000
6 1 -0.07224 0.00000 0.00000 0.00000 0.00000 -0.00087
2 0.00000 0.00000 0.00000 0.00000 0.00000 0.00000
7 1 -0.00059 0.00000 0.00000 0.00000 0.00000 0.00015
2 0.00000 0.00000 0.00000 0.00000 0.00000 0.00000
8 1 0.00059 0.00000 0.00000 0.00000 0.00000 -0.00015
2 0.00000 0.00000 0.00000 0.00000 0.00000 0.00000
FRAME WITH PRESTRESSING LOAD -- PAGE NO. 4
SUPPORT REACTIONS -UNIT KIP FEET STRUCTURE TYPE = PLANE
-----------------
JOINT LOAD FORCE-X FORCE-Y FORCE-Z MOM-X MOM-Y MOM Z
1 1 -6.71 0.00 0.00 0.00 0.00 58.62
2 0.00 0.00 0.00 0.00 0.00 0.00
2 1 6.71 0.00 0.00 0.00 0.00 -58.62
2 0.00 0.00 0.00 0.00 0.00 0.00
FRAME WITH PRESTRESSING LOAD -- PAGE NO. 5
MEMBER END FORCES STRUCTURE TYPE = PLANE
-----------------
ALL UNITS ARE -- KIP FEET (LOCAL )
MEMBER LOAD JT AXIAL SHEAR-Y SHEAR-Z TORSION MOM-Y MOM-Z
1 1 1 0.00 6.71 0.00 0.00 0.00 58.62
3 -0.00 -6.71 0.00 0.00 0.00 75.67
2 1 0.00 0.00 0.00 0.00 0.00 0.00
3 0.00 0.00 0.00 0.00 0.00 0.00
2 1 3 0.00 13.92 0.00 0.00 0.00 90.81
5 -0.00 -13.92 0.00 0.00 0.00 117.98
2 3 0.00 0.00 0.00 0.00 0.00 0.00
5 0.00 0.00 0.00 0.00 0.00 0.00
3 1 5 0.00 2.34 0.00 0.00 0.00 38.31
7 -0.00 -2.34 0.00 0.00 0.00 -3.16
2 5 0.00 0.00 0.00 0.00 0.00 0.00
7 0.00 0.00 0.00 0.00 0.00 0.00
4 1 2 -0.00 -6.71 0.00 0.00 0.00 -58.62
4 0.00 6.71 0.00 0.00 0.00 -75.67
2 2 0.00 0.00 0.00 0.00 0.00 0.00
4 0.00 0.00 0.00 0.00 0.00 0.00
5 1 4 -0.00 -13.92 0.00 0.00 0.00 -90.81
6 0.00 13.92 0.00 0.00 0.00 -117.98
2 4 0.00 0.00 0.00 0.00 0.00 0.00
6 0.00 0.00 0.00 0.00 0.00 0.00
6 1 6 -0.00 -2.34 0.00 0.00 0.00 -38.31
8 0.00 2.34 0.00 0.00 0.00 3.16
2 6 0.00 0.00 0.00 0.00 0.00 0.00
8 0.00 0.00 0.00 0.00 0.00 0.00
7 1 3 304.85 -37.50 0.00 0.00 0.00 -241.48
4 -304.85 -37.50 0.00 0.00 0.00 241.48
2 3 297.65 -37.50 0.00 0.00 0.00 -75.00
4 -297.65 -37.50 0.00 0.00 0.00 75.00
8 1 5 286.07 -37.50 0.00 0.00 0.00 -231.29
6 -286.07 -37.50 0.00 0.00 0.00 231.29
2 5 297.65 -37.50 0.00 0.00 0.00 -75.00
6 -297.65 -37.50 0.00 0.00 0.00 75.00
9 1 7 -2.34 0.00 0.00 0.00 0.00 3.16
8 2.34 -0.00 0.00 0.00 0.00 -3.16
FRAME WITH PRESTRESSING LOAD -- PAGE NO. 6
MEMBER END FORCES STRUCTURE TYPE = PLANE
-----------------
ALL UNITS ARE -- KIP FEET (LOCAL )
MEMBER LOAD JT AXIAL SHEAR-Y SHEAR-Z TORSION MOM-Y MOM-Z
2 7 0.00 0.00 0.00 0.00 0.00 0.00
8 0.00 0.00 0.00 0.00 0.00 0.00
************** END OF LATEST ANALYSIS RESULT **************
36. FINISH
*********** END OF THE STAAD.Pro RUN ***********
**** DATE= JUL 4,2024 TIME= 11:29:10 ****
FRAME WITH PRESTRESSING LOAD -- PAGE NO. 7
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