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General FAQ

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Are solid objects with less than

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eight nodes available?

Answer: Yes, SAP2000 does support the degenerate solids are available, where nodes which are solid objects with collapsed (duplicated) to make nodes. These solids have less than eight nodes, and are useful for modeling wedges and tetrahedra. The joints can Joints may be collapsed in any way as long as the operation does not create a variety of ways. An error message will report any creation of an illegal solid object.

How

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are solid objects drawn in SAP2000?

Answer: Solid elements can be created either by extruding area objects via the "Edit > Extrude" menu command, or they can be defined via interactive database editing. To use interactive database editing to define solid elements, open the interactive database editing via "Edit > Interactive Database Editing" and then edit the "MODEL DEFINITION objects may be created in SAP2000 through one of the following two methods:

• Extrude area objects by using Edit > Extrude; or

• Define solid objects directly by using interactive database editing to modify the Connectivity - Solid table, available through Edit > Interactive Database Editing > Model Definition > Connectivity Data > Object Connectivity > Table: Connectivity - Solid

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Why are red springs automatically generated on

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my solid

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objects?

The red-Answer: Red springs are typically generated for solid objects with edge constraints. They are used to restraint the joints of the solid object to restrain their joints from rotation.

Solid elements objects activate only three translational degrees of freedom (DOF) at each of their joints. However, the implementation of the edge constraint activates three additional rotational degrees of freedom. Since the solid element does not provide any rotational stiffness at it joints, the program generates internal rotational springs at the affected joints to prevent local numerical instabilities due to zero rotational stiffness provided by the solid elements.joint location. Edge-constraint implementation then activates the three rotational DOF. Since solid objects do not provide rotational stiffness, internal rotational springs are generated at affected joints to provide rotational stiffness such that local numerical instabilities do not occur.

Without these internal rotational springs, warning messages in the output log would report zero stiffness at affected DOF. These warnings may either be ignored or eliminated by providing rotational springsIf these internal rotational springs were not generated, you would see warnings in the output log for zero stiffness at the affected DOFs. These warning could be ignored, but providing rotational springs eliminates them altogether.