A series of cable tips are given as follows:

• Nonlinear analysis – Nonlinear analysis should be performed any time a cable is modeled. Cable behavior is highly nonlinear.

• Modeling cables – Cable geometry is only used to determine cable length. Loading is not added during this stage of modeling. Initial cable geometry should be drawn Perform a nonlinear analysis. Forces in the cable are dependent on its shape; therefore, a nonlinear analysis is required for understanding cable behavior.
• Draw initial cable geometry accurately, as this will affect subsequent behavior.
• Cables over roller or pulley systems – A cable may be modeled with a roller support such that the undeformed length between the roller and adjacent support points remains the same, independent of applied loading, while the roller is free to translate according to load application.

• Loading cables – Cables may then be loaded using either strain load, target force, or by drawing the initial length shorter than the final length. Dead load pattern may be included in the nonlinear analysis to account for self-weight, which is automatically calculated according to cable properties.

• Cables with point loads –

• Load the cables after defining geometry and supports.
• To apply a point load to a cable, multiple cable segments should be modeled such that a point object exists at the location of load application. Similarly,  
• To apply a uniform dead load (UDL) may be applied to a portion of the cable by subdividing the portion subjected to loading such that it is a segment itself.Changing cable location – We recommend cables to be deleted and then redrawn in new locationsload over part of a cable, subdivide the cable into one or more segments where the length of the segment(s) is the length of the uniform load. Then apply the uniform load to the segment(s).

• If a cable location needs to be changed, delete the cable and redraw it in the new location, rather than changing joint coordinates. Cable stiffness will change unless the distance between joints remains exactly the same. This will affect analysis results.

See Also

• CSI Analysis Reference Manual (The Cable Element

  , page 145

  )

• SAP2000 - 16 Cable Objects of the CSI Watch & Learn video series presents a useful demonstration on this topic.