Bentley 2006 User Manual

Section 5 

 

 
With this mode, the support joint displacement is modeled as an 
imposed joint displacement.  The joint directions where 
displacement may be specified must be defined (same for all cases) 
in the SUPPORT command, see section 5.27.1. Any beam 
members, springs or finite elements will be considered in the 
analysis.  Other loading, inclined supports, and master/slave are all 
considered.  Any number of cases may have displacements entered.  
However, all cases will have zero displacements at the enforced 
directions if no displacement values are entered for that case.  At 
inclined supports the displacement specification is assumed to be 
in the inclined direction.  Displacements may not be specified at 
slave directions. 
 
If some cases are to have spring supports and others enforced 
displacements at the same joint directions, then two PERFORM 
ANALYSES must be used with the CHANGE command in 
between.  The first perform analysis could have the SUPPORTS 
with springs, no enforced directions, and with the load cases 
without displacements.  The second perform analysis would then 
have SUPPORTS without springs but with enforced directions and 
the cases with displacements. 

 

 
The Support Displacement command may be entered only once per 
case. Spring directions and Enforced directions may not both be 
specified at the same joint direction in the same Perform Analysis 
step. 
 

 
With this mode, the support joint displacement is modeled as a 
load.  Only beam members (not springs or finite elements) are 
considered in computing the joint load distribution necessary to 
cause the displacement.  Other loading, inclined supports, and 
master/slave are also not considered.  These unconsidered factors, 
if entered, will result in displacements other than those entered