TR.20.2.1 Prismatic Tapered Tube Property Specification
The following commands are used to specify section properties for prismatic tapered tube cross-sections. For the property types shown below, additional information can be obtained from Table 2.1 of the ASCE 72 document, 2nd edition.
General Format
property-spec = { ROUND | HEXDECAGONAL | DODECAGONAL | OCTAGONAL | HEXAGONAL | SQUARE } START D1 END D2 THICK t
Where:
Parameter | Definition |
---|---|
START D1 | Depth of section at start of member. |
END D2 | Depth of section at end of member. |
THICK t | Thickness of section (constant throughout the member length). |
Square |
Hexagonal (6 sides) |
Octagonal (8 sides) |
Dodecagonal (12 sides) |
Hexdecagonal (16 sides) |
Round |
Notes
- Section properties are calculated using the rules applicable for thin-walled sections.
-
Shear deformation is not considered for tapered
I-Beams and tapered poles. This means that the
SET SHEAR
command has no effect on the deformation computed for members with these cross sections.
Example
UNIT …
MEMBER PROPERTY
1 PRIS ROUND STA 10 END 8 THI 0.375
2 PRIS HDC STA 15 END 10 THI 0.375
3 PRIS DOD STA 12 END 12 THI 0.375
Square Tapered Example
STAAD SPACE
START JOB INFORMATION
ENGINEER DATE 31-Jul-14
END JOB INFORMATION
INPUT WIDTH 79
UNIT METER KN
JOINT COORDINATES
2 0 3 0; 3 3 3 0;
MEMBER INCIDENCES
2 2 3;
DEFINE MATERIAL START
ISOTROPIC STEEL
E 2.05e+008
POISSON 0.3
DENSITY 76.8195
ALPHA 1.2e-005
DAMP 0.03
TYPE STEEL
STRENGTH FY 253200 FU 407800 RY 1.5 RT 1.2
END DEFINE MATERIAL
MEMBER PROPERTY
2 PRIS SQUARE STA 0.4 END 0.3 THI 0.125
CONSTANTS
MATERIAL STEEL ALL
SUPPORTS
2 FIXED
LOAD 1 LOADTYPE Dead TITLE LOAD CASE 1
MEMBER LOAD
2 UNI GY -0.5
2 CON GY -10
2 CMOM GZ -50 3
LOAD 2 LOADTYPE Live TITLE LOAD CASE 2
MEMBER LOAD
2 UNI GY -10
2 CON GY -15
2 CMOM GZ -500 3
PERFORM ANALYSIS
SECTION 0.25 0.5 0.916
PRINT MEMBER SECTION FORCES ALL
LOAD LIST 1 2
PARAMETER 1
CODE AISC UNIFIED 2010
METHOD LRFD
TRACK 2 ALL
CHECK CODE ALL
PARAMETER 2
CODE AISC UNIFIED 2010
METHOD ASD
TRACK 2 ALL
CHECK CODE ALL
FINISH
Round Tapered Example
STAAD SPACE
START JOB INFORMATION
ENGINEER DATE 31-Jul-14
END JOB INFORMATION
INPUT WIDTH 79
UNIT METER KN
JOINT COORDINATES
2 0 3 0; 3 3 3 0;
MEMBER INCIDENCES
2 2 3;
DEFINE MATERIAL START
ISOTROPIC STEEL
E 2.05e+008
POISSON 0.3
DENSITY 76.8195
ALPHA 1.2e-005
DAMP 0.03
TYPE STEEL
STRENGTH FY 253200 FU 407800 RY 1.5 RT 1.2
END DEFINE MATERIAL
MEMBER PROPERTY
2 PRIS ROUND STA 0.4 END 0.3 THI 0.125
CONSTANTS
MATERIAL STEEL ALL
SUPPORTS
2 FIXED
LOAD 1 LOADTYPE Dead TITLE LOAD CASE 1
MEMBER LOAD
2 UNI GY -0.5
2 CON GY -10
2 CMOM GZ -50 3
LOAD 2 LOADTYPE Live TITLE LOAD CASE 2
MEMBER LOAD
2 UNI GY -10
2 CON GY -15
2 CMOM GZ -500 3
PERFORM ANALYSIS
SECTION 0.25 0.5 0.916
PRINT MEMBER SECTION FORCES ALL
LOAD LIST 1 2
PARAMETER 1
CODE AISC UNIFIED 2010
METHOD LRFD
TRACK 2 ALL
CHECK CODE ALL
PARAMETER 2
CODE AISC UNIFIED 2010
METHOD ASD
TRACK 2 ALL
CHECK CODE ALL
FINISH