I have started using OpenSees very recently and find some difficulties when I do a 3d dynamic analysis of reinforced concrete framework. These are important to me. Can anyone help me.
1. What is the differences between MultipleSupport and UniformExcitation? Both of them
can be used to do a time-history analysis ,so if I use the acceleration series which should I choose.
2. Slab were omitted in the analytical model but their participation to the beam stiffness
was accounted. If the beams are elastic, this can be done by enlarging their second moment of area, but if I use the nonlinear beam column element, how can I account for it.
3. How to calculate the length of plastic hinge when use the beam with hinge element.
4. The command that used to define plane stress material is “nDMaterial PlaneStress $matTag $threeDtag” . This should define a three-dimensional material previously, so how can I define a three-dimensional material, for example “shear wall”.
5. Should I concentrate the mass at the node where columns and beams meet or at the centre of the diaphragm like example 5. Especially if I want to account for the torsional effect, how should I do.
6. In the example 5, there are some commands to define the section of columns:
# Column torsional stiffness
set GJ 1.0e10;
# Linear elastic torsion for the column
uniaxialMaterial Elastic 10 $GJ
# Attach torsion to the RC column section
# tag uniTag uniCode secTag
section Aggregator 2 10 T -section 1
Why the GJ is set to 1.0E10, it means the torsional effect were neglected or not ?
When do a 3d analysis, if the aggregator section is essential?
Thank you!
