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General assumptions

Distributed ground displacements can be assigned to any pipe or frame object with distributed supports.

(1) Distributed ground displacement loads will get applied only to distributed supports and will not impose any load on discrete supports that may be connected to the pipe to which distributed ground displacement loads are applied. If the user wishes to apply matching point displacement load to discrete support, such load would need to be applied separately. This may be offered as an option in the future.

(3) Distributed supports internally generate two sets of springs at a common joint, so it is straightforward to independently apply displacement loads from each pipe and thereby account for displacement discontinuity at the common joint. No averaging is needed.

(3) Point displacement loads applied to discrete support are applied independently from distributed ground displacement loads.

(4) Since distributed ground displacement loads do not have impact on discrete supports at a common joint, no special consideration are needed for discrete supports at the common joint (i.e. no averaging of distributed ground displacement loads is needed at the common joint).

Applying ground displacements

Figure 1: Form for applying distributed ground displacements

Internal modeling

When distributed supports are assigned to pipe or frame element, analysis model for the ground displacement loads is created as follows:

(1) Identify location of discrete supports representing the distributed support.

(2) Use interpolation of the ground displacement load to calculate its values at the locations of discrete supports.

(3) Apply the ground displacement load to the fixed end of links internally representing each discrete support.

Figure 2: Internal modeling of distributed ground displacements

Various scenarios

Figure 3: Distributed ground displacements applied to single pipe

Figure 4: Distributed ground displacements applied to two adjacent pipes