Depending on the model being designed, you may have to change some or all of the parameter default values. Some parameters are unit dependent and when altered, the n setting must be compatible with the active "unit" specification.

The follow table lists all the relevant EC3 parameters together with description and default values.

Notes

1. CAN, DJ1, and DJ2 – Deflection

   1. When performing the deflection check, you can choose between two methods. The first method, defined by a value 0 for the CAN parameter, is based on the local displacement. Refer to TR.44 Printing Section Displacements for Members for details on local displacement..

      If the CAN parameter is set to 1, the check will be based on cantilever style deflection. Let (DX1, DY1, DZ1) represent the nodal displacements (in global axes) at the node defined by DJ1 (or in the absence of DJ1, the start node of the member). Similarly, (DX2, DY2, DZ2) represent the deflection values at DJ2 or the end node of the member.

      Compute  Delta = SQRT((DX2 - DX1)² + (DY2 - DY1)² + (DZ2 - DZ1)²)

      Compute Length = distance between DJ1 & DJ2 or, between start node and end node, as the case may be.

      Then, if CAN is specified a value 1, dff = L/Delta

      Ratio due to deflection = DFF/dff

   2. If CAN = 0, 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.

      PARAMETERS
      DFF 300. ALL
      DJ1 1 ALL
      DJ2 4 ALL

   3. If DJ1 and DJ2 are not used, "Deflection Length" will default to the member length and local deflections will be measured from original member line.

   4. If a serviceability load envelope is specified under "LOAD LIST ENV" before a parameter block, the default value of DFF 360 is used for deflection calculations. If DFF 0 is specified for any member, then the deflection check is skipped for that member.

   5. The above parameters may be used in conjunction with other available parameters for steel design.

2. The values of CMM for various loading and support conditions are as given below:

   Table 2. Values for the CMM Parameter

   CMM Value	Loading and Support Conditions
   1
   2
   3
   4
   5
   6
   7	varying end moments and uniform loading
   8	varying end moments and central point load

3. Checking beam deflection

   With the TRACK parameter set to 4, the members included in a BEAM CHECK command will be checked for the local axis deflection rather than for the stress capacity using the current LOAD LIST.

   If LOAD LIST ENV is used, then serviceability envelope must be present to check for deflections. If only strength load cases are given in LOAD LIST ENV, only strength checks will be performed and TRACK 4 is treated as TRACK 2.
   Note: While both sets of code checks will be reported in the output file, only the last code check results are reported in the STAAD.Pro graphical interface.

4. The values of CMT for various loading and support conditions are as given below:

   Table 3. Loading and Support Conditions represented by CMT Parameter Values

   CMT Value	Description	Diagram
   1	(Default) : Concentrated Torque at Ends. Ends Torsion fixed and Warping fixed
   2	Concentrated Torque along length of member. Ends Torsion fixed and Warping free
   3	Concentrated Torque along length of member. Ends Torsion fixed and Warping fixed
   4	Uniform Torque in member. Ends Torsion fixed and Warping free
   5	Uniform Torque in member. Ends Torsion fixed and Warping fixed
   6	Concentrated Torque in cantilever. End Torsion fixed and Warping fixed
   7	Uniform Torque in cantilever. End Torsion fixed and Warping fixed

   Note: For CMT = 2 and CMT = 3, you have the option of specifying the distance at which the concentrated torque acts, measured from the start of the member. This can be done by using the ALH design parameter. The ALH parameter indicates the ratio of the distance of the point torque (from the start of the member) to the length of the member. This parameter will have a default value of 0.5 (i.e., the torque acts at the center of the span) and will accept values ranging from 0 to 1.