D8.C.4 Design Parameters

The following table contains the input parameters for specifying values of design variables and selection of design options.

Note: Once a parameter is specified, its value stays at that specified number until it is specified again. This is the way STAAD.Pro works for all codes.

Table 1. IS 801: Indian cold formed steel design parameters
Parameter Name	Default Value	Description
CODE	-	Must be specified as `IS801` Design code to follow. See TR.48.1 Parameter Specifications.
BEAM	1.0	When this parameter is set to 0) the 13 location check is not conducted, and instead, checking is done only at the locations specified by the SECTION command (see TR.41 Section Specification for details) For TRUSS members only start and end locations are designed. 1) the adequacy of the member is determined by checking a total of 13 equally spaced locations along the length of the member.
CAN	0	Beam type used for deflection checks: 0) general member 1) cantilever member Used only when `DFF` parameter is also specified.
CB	0	Bending coefficient Cb used for bending checks. By default (value of 0), this is calculated by the program.
CMY	calculated	Coefficient Cm as per Cl. 6.7 for bending about the member Y axis. See IS:801-1975, 6.7. Used for Combined axial load and bending design. Values range from 0.4 to 1.0.
CMZ	calculated	Coefficient Cm as per Cl. 6.7 for bending about the member Z axis. See IS:801-1975, 6.7. Used for Combined axial load and bending design. Values range from 0.4 to 1.0.
CWY	0	Specifies whether the cold work of forming strengthening effect should be included in resistance computation. See IS:801-1975, 6.1.1 0) effect should not be included 1) effect should be included
DFF	0	"Deflection length"/ maximum allowable local deflection. 0) Deflection check is not performed Any other value is used as the deflection check ratio It is recommended to use `DJ1` and `DJ2` parameters along with `DFF` for deflection results.
DJ1	Start Joint of member	Joint No. denoting starting point for calculation of "Deflection Length" (See Note a)
DJ2	End Joint of member	Joint No. denoting end point for calculation of "Deflection Length" (See Note a)
FLX	0	Specifies whether the member has torsional-flexural buckling restraints that will in turn determine whether the member is susceptible to flexural-torsional bucking mode. See IS:801-1975, 6.6.1 0) No Torsional restraints provided and the section subject to torsional flexural buckling 1) Torsional restraints provided and the section is not subject to torsional flexural buckling
FU	450 MPa (4588.72 kg/cm²)	Ultimate tensile strength of steel in current units.
FYLD	353.04 MPa (3600.0 kg/cm²)	Yield strength of steel in current units.
KX	1.0	Effective length factor for torsional buckling. It is a fraction and is unit-less. Values can range from 0.01 (for a column completely prevented from buckling) to any user specified large value. It is used to compute the KL/R ratio for twisting for determining the capacity in axial compression.
KY	1.0	Effective length factor for overall buckling about the local Y-axis. It is a fraction and is unit-less. Values can range from 0.01 (for a column completely prevented from buckling) to any user specified large value. It is used to compute the KL/R ratio for determining the capacity in axial compression.
KZ	1.0	Effective length factor for overall buckling in the local Z-axis. It is a fraction and is unit-less. Values can range from 0.01 (for a member completely prevented from buckling) to any user specified large value. It is used to compute the KL/R ratio for determining the capacity in axial compression.
LX	Member length	Unbraced length for twisting. It is input in the current units of length. Values can range from 0.01 (for a member completely prevented from torsional buckling) to any user specified large value. It is used to compute the KL/R ratio for twisting for determining the capacity in axial compression.
LY	Member length	Effective length for overall buckling in the local Y-axis. It is input in the current units of length. Values can range from 0.01 (for a member completely prevented from buckling) to any user specified large value. It is used to compute the KL/R ratio for determining the capacity in axial compression.
LZ	Member length	Effective length for overall buckling in the local Z-axis. It is input in the current units of length. Values can range from 0.01 (for a member completely prevented from buckling) to any user specified large value. It is used to compute the KL/R ratio for determining the capacity in axial compression.
NSF	1.0	Net section factor for tension members. The net area is calculated as `NSF`×gross area.
RATIO	1.0	Permissible ratio of actual to allowable stresses
TRACK	0	This parameter is used to control the level of detail in which the design output is reported in the output file. The allowable values are: 0) Prints only the member number, section name, ratio, and PASS/FAIL status. 1) Prints the design summary including allowable stress in addition to that printed by `TRACK 0`. 2) Prints member, material properties, and stress check table in addition to that printed by `TRACK 1`.
TSA	0	Specifies whether transverse web stiffeners have been provided to check for the requirements of IS:801-1975, 5.2.4. 0) Web stiffeners not provided 1) Web stiffeners provided
UNL	Member length	Unsupported length (in current units) for calculating the allowable bending stress.

Notes

"Deflection Length" is defined as the length that is used for calculation of local deflections within a member. It may be noted that for most cases the "Deflection Length" will be equal to the length of the member. However, in some situations, the "Deflection Length" may be different. A straight line joining DJ1 and DJ2 is used as the reference line from which local deflections are measured.
For example, refer to the figure below where a beam has been modeled using four joints and three members. The "Deflection Length" for all three members will be equal to the total length of the beam in this case. The parameters DJ1 and DJ2 should be used to model this situation. Thus, for all three members here, DJ1 should be 1 and DJ2 should be 4.

D = Maximum local deflection for members 1, 2, and 3.
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PARAMETERS
DFF 300. ALL
DJ1 1 ALL
DJ2 4 ALL
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