TR.22.3 Element Ignore Stiffness
Structural units like glass panels or corrugated sheet roofs are subjected to loads like wind pressures or snow loads. While these units are designed to carry those loads and transmit those loads to the rest of the structure, they are not designed to provide any additional stiffness to the structure. One way to handle the situation is to not input the unit as part of the structural model, and apply the load using load generation techniques like AREA LOAD
or FLOOR LOAD
.
STAAD provides another way of handling such units. This is through the help of the ELEMENT IGNORE STIFFNESS
command. To use this feature, the glass panel or roof unit must be defined using plate elements. The IGNORE STIFFNESS
command enables one to consider the unit just for the purpose of application of ELEMENT LOAD
commands, while its stiffness will not be considered during the assembly of the stiffness matrix. In other words, it is like an INACTIVE
member which is active for ELEMENT LOAD
command application but INACTIVE
for stiffness. Like the INACTIVE
command, the plates listed here will become active at the next CHANGE
command. To keep them inactive, re-enter this data after each CHANGE
.
The SELFWEIGHT
, ELEMENT WEIGHT
, TEMPERATURE
, and mass of the plates listed here will still be ignored.
General Format
IGNORE STIFFNESS {ELEMENT} element-list
Example
IGNORE STIFFNESS ELEMENT 78 TO 80