Dear All,
I am trying to model a beam resting over another. I have couple of option i can utilize but not certain which will be more realistic and recommended
1. Provide offset to raise beam to rest over other.
2. Provide new point over in Z- direction and connect it through Master-Slave.
3. Provide new point over in Z- direction and connect it through Steel column with negligible density and higher modulus of elasticity.
4. Provide new point over in Z- direction and connect it through Dummy joints.
I would appreciate if someone can shed some light on these options as I am seeing difference in results.
1. Offsets introduce a rigid link between the end of the offset element to the node. This will handle the transformation of any moments and loads to the new position of the element.
2. Retained-Constrained (formerly Master-Slave) nodes connect the degrees of freedom of the two nodes. This does not transform the moments and loads to the new position. Any linked degrees of freedom are applied directly to the constrained node.
3. This method is similar to using offsets (1) except that the connection will never truly be rigid.
4. Dummy joints are intended to transfer loading to Keep joints. The elements connected to the Dummy joints are not considered when constructing the stiffness matrix.
As a side note, if you expect the elements to act as a composite section, none of these methods truly model the behavior. You can use a prismatic section with the composite properties of the section to model the combined section. Note that code checking will not be accurate so a hand calculation would be required for those sections.
Regards,
Geoff
Thanks Geoff for your response. So what do you think is most ideal for beam resting over a beam to be modelled as?