STAAD.Pro Help

TR.31.10 Defining Enclosed Zones

This set of commands is used to define an enclosed zone boundary, optional openings, and ignored members for either boundaries or load transfer.

Also referred to as an "enclosed zone load" or "zone load".

General Format

DEFINE ENCLOSED ZONE

Define the enclosed zone name and boundary. Optional ignored members and openings are also included.

ENCLOSED ZONE zone-name
BOUNDARY joint-list
( IGNORE LOAD member-list )
( IGNORE MEMBER member-list )
( OPENING joint-list )

Additional enclosed zones (up to 500 in total) may be added. 

END
ParameterDescription
ZONE zone-name Unique alphanumeric name up to 15 characters in length. This is used as the identifier for the enclosed zone.
BOUNDARY joint-list A list of nodes that the defines the closed boundary for the enclosed zone. This list should be in either clockwise or counter-clockwise order.
IGNORE LOAD member-list Members in this list are assumed to represent a free boundary condition. These members are considered in forming the closed polygon of the enclosed zone but do not carry any load resulting from the enclosed zone loading.
IGNORE MEMBER member-list Members in this list are ignored by the enclosed zone processor. These members are not considered in forming the closed polygon of the enclosed zone nor do they carry any load resulting from the enclosed zone loading.

The total load of the enclosed zone does not change. Thus, the zone load which would have otherwise been applied to an ignored member is added to the adjacent members of the same panel.
OPENING joint-list A list of nodes that defines the closed boundary for an opening within the enclosed zone. This list must be defined in a consecutive sequence. should be in either clockwise or counter-clockwise order (though does not have to be in the same direction used for the boundary joint list).

Notes

  1. Within a single enclosed zone definition, only a single instance of BOUNDARY, IGNORE LOAD, or IGNORE MEMBER each is allowed. However, multiple instances of the OPENING command are allowed.
  2. While defining an enclosed zone, the program requires the joint-list to specify the boundary nodes. The defined boundary must form one closed polygon. It is recommended not to define joint-list in an order such that the defined outer boundary crosses or intersects with itself. Instead define multiple enclosed zones.
  3. The program internally connects the joint-list to form the boundary for enclosed zone and any analytical member falling inside that boundary forms a part of enclosed zone. It is recommended that the boundary formed by traversing through the list of joints is also connected by analytical members.
  4. It is recommended to avoid assigning IGNORE MEMBER to a member that lies on the boundary of enclosed zone as it may lead to an unclosed polygon for enclosed zone leading to enclosed zone integrity failure. Instead redefine zone boundary, or if necessary, utilize IGNORE LOAD.
  5. Joists are internally assigned IGNORE MEMBER specification.
  6. The joint-list and member-list used for BOUNDARY, IGNORE LOAD, IGNORE MEMBER, or OPENING do not support Group name specifications.

Limitations

  • No more than 500 enclosed zones can be included in a model.
  • No more than 400 boundary nodes can be used in a single enclosed zone.
  • No more than 400 openings can be included in a single enclosed zone.
    Note: This limit is dynamic such that the actual maximum is capped at 80% of the total nodes in the model file. If this threshold is met, then it is suggested to redefine the zone boundary for a balance between memory and performance.
  • Enclosed zone loads are not considered for generated mass models, regardless of the load type.
  • Live load reduction is not applied to enclosed zone loads.

Example

DEFINE ENCLOSED ZONE
    
ENCLOSED ZONE FLOOR1
BOUNDARY 1 3 6 8
OPENING 2 11 9 10

ENCLOSED ZONE FLOOR2
BOUNDARY 3 TO 6
IGNORE LOAD 13

END
Parent topic: TR.31 Definition of Load Systems
Related tasksRelated reference