EX. UK-7 Modeling Offset Connections in a Frame
This example illustrates modeling of structures with offset connections. Offset connections arise when the center lines of the connected members do not intersect at the connection point. The connection eccentricity behaves as a rigid link and is modeled through specification of MEMBER OFFSETS.
This problem is installed with the program by default to C:\Users\Public\Public Documents\STAAD.Pro 2023\Samples\Sample Models\UK\UK-7 Modeling Offset Connections in a Frame.STD when you install the program.
- L1 = 4.5 m
- L2 = 6 m
- L3 = 178 mm
- L4 = 152 mm
Actual input is shown in bold lettering followed by explanation.
STAAD PLANE TEST FOR MEMBER OFFSETS
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 METER KNS
Defines the input units for the data that follows.
JOINT COORD 1 0. 0. ; 2 6. 0. ; 3 0. 4.5 4 6. 4.5 ; 5 0. 9. ; 6 6. 9.
Joint number followed by X and Y coordinates are provided above. Since this is a plane structure, the Z coordinates need not be provided.
SUPPORT 1 2 PINNED
Pinned supports are specified at joints 1 and 2. The word PINNED signifies that no moments will be carried by these supports.
MEMB INCI 1 1 3 2 ; 3 3 5 4 5 3 4 ; 6 5 6 ; 7 1 4
Defines the members by the joints to which they are connected.
MEMB PROP BRITISH 1 TO 4 TABLE ST UC356X368X129 5 6 TA ST UB305X165X40 7 TA LD UA200X150X12
All member properties are from British steel table. The word ST stands for standard single section. LD stands for long leg back-to-back double angle.
UNIT MMS MEMB OFFSET 5 6 START 178. 0.0 0.0 5 6 END -178. 0.0 0.0 7 END -178.0 -152.0 0.0
The preceding specification states that an OFFSET is located at the START/END joint of the members. The X, Y, and Z global coordinates of the offset distance from the corresponding incident joint are also provided. These attributes are applied to members 5, 6, and 7.
DEFINE MATERIAL START ISOTROPIC STEEL E 210 POISSON 0.3 DENSITY 7.6977e-008 ALPHA 6e-006 DAMP 0.03 TYPE STEEL STRENGTH FY 0.24821 FU 0.399894 RY 1.5 RT 1.2 END DEFINE MATERIAL CONSTANTS MATERIAL STEEL ALL
The DEFINE MATERIAL command is used to specify material properties and the CONSTANT is used to assign the material to all members.
LOADING 1 WIND LOAD
Load case 1 is initiated followed by a title.
JOINT LOAD 3 FX 225.0 ; 5 FX 112.5
Load 1 contains joint loads at nodes 3 and 5. FX indicates that the load is a force in the global X direction.
PERFORM ANALYSIS
The above command is an instruction to perform the analysis.
UNIT METER PRINT FORCES PRINT REACTIONS
The above PRINT commands are instructions for writing the member forces and support reactions to the output file. The preceding line causes the results to be written in the length unit of meters
FINISH
This command terminates a STAAD run.
Input File
STAAD PLANE TEST FOR MEMBER OFFSETS
UNIT METER KNS
JOINT COORD
1 0. 0. ; 2 6. 0. ; 3 0. 4.5
4 6. 4.5 ; 5 0. 9. ; 6 6. 9.
SUPPORT
1 2 PINNED
MEMB INCI
1 1 3 2 ; 3 3 5 4
5 3 4 ; 6 5 6 ; 7 1 4
MEMB PROP BRITISH
1 TO 4 TABLE ST UC356X368X129
5 6 TA ST UB305X165X40
7 TA LD UA200X150X12
UNIT MMS
MEMB OFFSET
5 6 START 178. 0.0 0.0
5 6 END -178. 0.0 0.0
7 END -178.0 -152.0 0.0
DEFINE MATERIAL START
ISOTROPIC STEEL
E 210
POISSON 0.3
DENSITY 7.6977e-008
ALPHA 6e-006
DAMP 0.03
TYPE STEEL
STRENGTH FY 0.24821 FU 0.399894 RY 1.5 RT 1.2
END DEFINE MATERIAL
CONSTANTS
MATERIAL STEEL ALL
LOADING 1 WIND LOAD
JOINT LOAD
3 FX 225.0 ; 5 FX 112.5
PERFORM ANALYSIS
UNIT METER
PRINT FORCES
PRINT REACTIONS
FINISH
STAAD Output File
PAGE NO. 1 **************************************************** * * * STAAD.Pro 2023 * * Version 23.00.02.*** * * Proprietary Program of * * Bentley Systems, Inc. * * Date= DEC 15, 2023 * * Time= 15:59:18 * * * * Licensed to: Bentley Systems Inc * **************************************************** 1. STAAD PLANE TEST FOR MEMBER OFFSETS INPUT FILE: D:\Documentation\STAAD.Pro\_Automated_Py\output\2023-12-15\SPro_Output_Input_Files\Sample .. .STD 2. UNIT METER KNS 3. JOINT COORD 4. 1 0. 0. ; 2 6. 0. ; 3 0. 4.5 5. 4 6. 4.5 ; 5 0. 9. ; 6 6. 9. 6. SUPPORT 7. 1 2 PINNED 8. MEMB INCI 9. 1 1 3 2 ; 3 3 5 4 10. 5 3 4 ; 6 5 6 ; 7 1 4 11. MEMB PROP BRITISH 12. 1 TO 4 TABLE ST UC356X368X129 13. 5 6 TA ST UB305X165X40 14. 7 TA LD UA200X150X12 15. UNIT MMS 16. MEMB OFFSET 17. 5 6 START 178. 0.0 0.0 18. 5 6 END -178. 0.0 0.0 19. 7 END -178.0 -152.0 0.0 20. DEFINE MATERIAL START 21. ISOTROPIC STEEL 22. E 210 23. POISSON 0.3 24. DENSITY 7.6977E-008 25. ALPHA 6E-006 26. DAMP 0.03 27. TYPE STEEL 28. STRENGTH FY 0.24821 FU 0.399894 RY 1.5 RT 1.2 29. END DEFINE MATERIAL 30. CONSTANTS 31. MATERIAL STEEL ALL 32. LOADING 1 WIND LOAD 33. JOINT LOAD 34. 3 FX 225.0 ; 5 FX 112.5 35. PERFORM ANALYSIS TEST FOR MEMBER OFFSETS -- PAGE NO. 2 P R O B L E M S T A T I S T I C S ----------------------------------- NUMBER OF JOINTS 6 NUMBER OF MEMBERS 7 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 = 1, TOTAL DEGREES OF FREEDOM = 14 TOTAL LOAD COMBINATION CASES = 0 SO FAR. 36. UNIT METER 37. PRINT FORCES FORCES TEST FOR MEMBER OFFSETS -- PAGE NO. 3 MEMBER END FORCES STRUCTURE TYPE = PLANE ----------------- ALL UNITS ARE -- KNS METE (LOCAL ) MEMBER LOAD JT AXIAL SHEAR-Y SHEAR-Z TORSION MOM-Y MOM-Z 1 1 1 -49.14 -20.23 0.00 0.00 0.00 4.59 3 49.14 20.23 0.00 0.00 0.00 -95.65 2 1 2 337.50 -25.11 0.00 0.00 0.00 0.00 4 -337.50 25.11 0.00 0.00 0.00 -112.99 3 1 3 -30.77 53.79 0.00 0.00 0.00 150.98 5 30.77 -53.79 0.00 0.00 0.00 91.06 4 1 4 30.77 58.71 0.00 0.00 0.00 170.67 6 -30.77 -58.71 0.00 0.00 0.00 93.55 5 1 3 299.02 -18.38 0.00 0.00 0.00 -52.06 4 -299.02 18.38 0.00 0.00 0.00 -51.65 6 1 5 58.71 -30.77 0.00 0.00 0.00 -85.58 6 -58.71 30.77 0.00 0.00 0.00 -88.07 7 1 1 -479.29 -1.96 0.00 0.00 0.00 -4.59 4 479.29 1.96 0.00 0.00 0.00 -9.62 ************** END OF LATEST ANALYSIS RESULT ************** 38. PRINT REACTIONS REACTION TEST FOR MEMBER OFFSETS -- PAGE NO. 4 SUPPORT REACTIONS -UNIT KNS METE STRUCTURE TYPE = PLANE ----------------- JOINT LOAD FORCE-X FORCE-Y FORCE-Z MOM-X MOM-Y MOM Z 1 1 -362.61 -337.50 0.00 0.00 0.00 0.00 2 1 25.11 337.50 0.00 0.00 0.00 0.00 ************** END OF LATEST ANALYSIS RESULT ************** 39. FINISH *********** END OF THE STAAD.Pro RUN *********** **** DATE= DEC 15,2023 TIME= 15:59:19 **** TEST FOR MEMBER OFFSETS -- PAGE NO. 5 ************************************************************ * For technical assistance on STAAD.Pro, please visit * * http://www.bentley.com/en/support/ * * * * Details about additional assistance from * * Bentley and Partners can be found at program menu * * Help->Technical Support * * * * Copyright (c) Bentley Systems, Inc. * * http://www.bentley.com * ************************************************************