D8.E.3 Design Parameters
Parameter Name | Default Value | Description |
---|---|---|
CODE | - |
Must be specified as
Design code to follow. See TR.53.2 Concrete Design-Parameter Specification. |
BRACING | 0.0 |
Column bracing condition:
|
CLB | 25 mm | The clear cover for the bottom stirrups or ties in beams.
When specified, the clear cover to the main reinforcement is
the CLB + stirrup diameter.Tip: If you want to
specify the clear distance to ties or stirrups, include the full
diameter of those in this value. For example, beams with 25 mm clear
and 8 mm ties should use
CLB 33 . If both See also Note e below. |
CLEAR |
30 mm (beams) 40 mm (columns) |
The clear distance between to the main member reinforcement.
Tip: If
you want to specify the clear distance to ties or stirrups, include
the full diameter of those in this value. For example, columns with
35 mm clear and 8 mm ties should use
CLEAR 43 . See also Note e below. |
CLT | 25 mm | The clear cover for the top stirrups or ties in beams. When
specified, the clear cover to the main reinforcement is the
CLT + stirrup diameter.Tip: If you want to
specify the clear distance to ties or stirrups, include the full
diameter of those in this value. For example, beams with 25 mm clear
and 8 mm ties should use
CLT 33 . See also Note e below. |
DEPTH | YD | Total depth to be used for design.
This value defaults to
YD as provided under
MEMBER PROPERTIES .
|
EFACE | 0.0 |
Face of support location at end of beam. The parameter can also be used to check against shear at any point from the end of the member. Note: Both
SFACE and
EFACE are input as positive numbers.
|
ELZ | 1.0 | Ratio of effective length to actual length of column about major axis. See Note b below. |
ELY | 1.0 | Ratio of effective length to actual length of column about minor axis. See Note b below. |
ENSH | 0.0 |
Perform shear check against enhanced shear strength as per Cl. 40.5 of IS456:2000.
If default value (0.0) is used the program will calculate Length to Overall Depth ratio. If this ratio is greater than 2.5, shear strength will be enhanced at sections (<2d) close to support otherwise ordinary shear check will be performed. |
FC | 30 N/mm2 | Concrete Yield Stress. |
FYMAIN | 415 N/mm2 | Yield Stress for main reinforcing steel. |
FYSEC | 415 N/mm2 | Yield Stress for secondary reinforcing steel. |
MINMAIN | 10 mm | Minimum main reinforcement bar size. |
MAXMAIN | 60 mm | Maximum main reinforcement bar size. |
MINSEC | 8 mm | Minimum secondary reinforcement bar size. |
MAXSEC | 12 mm | Maximum secondary reinforcement bar size. |
METHOD | 0 | Consider minimum eccentricity one axis at a time:
|
MFACE | 0 |
Design beam for flexure at any point along the
length of the beam as specified by
Note: If
SFACE and
EFACE sections are not previously
defined, then the output will present a warning and no flexure design will be
performed (i.e., the MFACE parameter is ignored).
|
RATIO | 4.0 | Maximum percentage of longitudinal reinforcement in columns. |
REINF | 0.0 | Tied column. A value of 1.0 will mean spiral reinforcement. |
RENSH | 0.0 | Distance of the start or end point of the member from its nearest support. This parameter is used only when a span of a beam is subdivided into two or more parts. (Refer note) |
RFACE | 4 |
|
SFACE | 0.0 | Face of support location at start of beam. It is used to check against shear at the face of the support in beam design. The parameter can also be used to check against shear at any point from the start of the member. |
SPSMAIN | 25 mm | Minimum clear distance between main reinforcing bars in beam and column. For column center to center distance between main bars cannot exceed 300 mm. |
TORSION | 0.0 |
|
TRACK | 0 |
Specify the level of detail in the output:
|
ULY | 1.0 | Ratio of unsupported length to actual length of column about minor axis. See Note c below. |
ULZ | 1.0 | Ratio of unsupported length to actual length of column about major axis. See Note c below. |
WIDTH | ZD | Width to be used for design. This
value defaults to
ZD as provided under
MEMBER PROPERTIES .
|
Notes
- You may
specify reinforcing bar combinations through the
BAR COMBINATION
command. Refer to D8.E.7 Bar Combination for details. -
ELY
andELZ
parameters are used to calculate effective length of column to find whether it is a short or long column. Please refer CL 25.1.2 of IS456:2000.In CL 25.1.2 of IS456:2000, you will find two term, lex and ley, which STAAD.Pro calculates as:
- lex =
ELZ
multiplied by the member length (distance between the two nodes of the member) - ley =
ELY
multiplied by the member length (distance between the two nodes of the member)
For the term "D" in CL 25.1.2 of IS456:2000, STAAD.Pro uses the
YD
dimension of the column.For the term "b" in CL 25.1.2 of IS456:2000, STAAD.Pro uses the
ZD
dimension of the column. - lex =
-
ULY
andULZ
parameters are used to calculate unsupported length of column to find minimum eccentricity. Please refer CL 25.4 of IS456:2000.In CL 25.4 of IS456:2000, you will find an expression "unsupported length of column". This term is calculated as
-
ULZ
multiplied by the member length for the Z axis -
ULY
multiplied by the member length for the Y axis
-
-
The value of the
ENSH
parameter (other than 0.0 and 1.0) is used only when the span of a beam is subdivided into two or more parts. When this condition occurs, theRENSH
parameter is also to be used.The span of the beam is subdivided four parts, each of length L meter. The shear strength will be enhanced up to X meter from both supports. The input should be the following:
Steps:
-
ENSH L MEMB 1
=> Shear strength will be enhanced throughout the length of the member 1, positive sign indicates length measured from start of the member -
ENSH (X-L) MEMB 2
=> Shear strength will be enhanced up to a length (X-L) of the member 2, length measured from the start of the member -
ENSH –L MEMB 4
=> Shear strength will be enhanced throughout the length of the member 4, negative sign indicates length measured from end of the member -
ENSH –(X-L) MEMB 3
=> Shear strength will be enhanced up to a length (X-L) of the member 3, length measured from the end of the member -
RENSH L MEMB 2 3
=> Nearest support lies at a distance L from both the members 2 and 3. -
DESIGN BEAM 1 TO 4=>
This will enhance the shear strength up to length X from both ends of the beam consisting of members 1 to 4 and gives spacing accordingly.
At section = y1 from start of member 1 av = y1
At section = y2 from the start of member 2 av = y2+L
At section = y3 from the end of member 3 av = y3+L
At section = y4 from end of member 4 av = y4
where tc, enhanced = 2dtc/av
At section 0.0, av becomes zero. Thus enhanced shear strength will become infinity. However for any section shear stress cannot exceed tc, max. Hence enhanced shear strength is limited to a maximum value of tc, max.
-
- The values from
CLB
,CLEAR
, andCLT
parameters will be rounded up to the nearest multiple of 5 mm for use in the design.