TR.28.1 Control/Dependent Specification
This set of commands may be used to model specialized linkages (displacement
tying, rigid links) through the specification of control
and dependent
joints. Please read the notes for restrictions.
General Format
Dependent *{ XY | YZ | ZX | RIGID | FX | FY | FZ | MX | MY | MZ } CONTROL j JOINT joint-spec
where:
joint-spec = { joint-list | *{ XRANGE | YRANGE | ZRANGE } f1 f2 }
Description
The control/dependent option provided in STAAD.Pro allows you to model specialized linkages (displacement tying, rigid
links) in the system. For example, DEPENDENT FY …
connects the two
joints such that the Y displacement at the dependent will be the sum of Y
displacement at the control plus the rigid rotation,
Note that instead of providing a joint list for the dependent joints, a
range of coordinate values (in global system) may be used. All joints whose
coordinates are within the range are assumed to be dependent joints. For
convenience, the coordinate range specified for dependent joints in this entry may
include the control joint for this entry. However, control and dependent joints of
other entries must not be included in the coordinate range. All 2 or 3
ranges can be entered to form a tube
or box
for selecting joints in the tube or box region.
Fx, Fy etc. are the directions in which they are dependent (any combination may be entered).
If two or more entries have the same control, the dependent lists will be merged. Please ensure that the same direction specs are used.
The direction specifiers (XY, YZ, ZX) are combinations of the basic
directions, XY is the same as entering FX, FY, MZ; etc. Any combination of direction
specifiers may be entered. An example of the use of this format is: a rigid
diaphragm floor that still retains bending flexibility entered as SLA ZX
…
.
If RIGID
or if all directions are provided, the joints
are assumed to be rigidly connected as if SLA DIA RIG
were entered,
even if DIA
is omitted.
Restrictions
-
Solid elements may not be connected to dependent joints.
-
Control joints may not be control or dependent in another entry.
-
Dependent joints may not be control or dependent in another entry.
-
Dependent directions at joints may not be supported directions or have displacements imposed.
-
Control and/or dependent joints may not be inclined supports.
-
The control/dependent specification is only intended for linear static and dynamic analysis.
-
Multilinear springs are not permitted.
- Control/dependent joints may not be specified when rigid floor diaphragms are used (refer to TR.28.2 Floor Diaphragm).
- If a
command is specified, then any control/dependent joints must be
re-specified if they are intended to be used after the change. Further, any
support commands must also be re-specified after the
CHANGE
command and immediately prior to the control/dependent command.
The internal processing of any control/dependent command includes an automatic bandwidth reduction.
Example
Fully Rigid and Rigid Floor Diaphragm
DEPENDENT RIGID CONTROL 22 JOINT 10 TO 45
DEPENDENT RIGID CONTROL 70 JOINT YRANGE 25.5 27.5
DEP ZX CON 80 JOINT YR 34.5 35.5