Topic: symmetric building systems

dear sir

1) In order to reduce analysis time, I want to model just half of a symmetric building, I don't know what should I do about beams that are in the middle of building and on the symmetry line.
I tried to attach plane figure here,but I couldn't
would you help me please?

2)how can I model a joint as a hing?

best regards

Re: symmetric building systems

Dear elham_ho64,
1. for reinforcement bars in the symmetry plane, just use 0.5 for "number of bars" or divide the cross section area by 2.
2. Please keep in mind that ATENA is not a beam-based [linear elastic design] program. Point loads, supports, or connections in nonlinear material are usually wrong modelling. Or do you refer to a plastic hinge that develops during the loading/analysis?

You can send your model to our general support address, along with your question and your ATENA User ID (WR). Including a sketch of the structure being modelled is never a bead idea.

Re: symmetric building systems

1)the 6 story official building have axial symmetry,I took the columns,beams and slabs of half of plan,building has seven bays,symmetry line is in the middle of one of bays (forth),I mean what should I do about the beams take place in this bay?should I apply boundary conditions or define spring?or any other suggestion?

2)no,I mean hing joint, witch just transfers axial load and vertical shear.

Re: symmetric building systems

Ad 1: if you apply the symmetry boundary condition to the concrete elements, the bars crossing the symmetry plane do not need any special condition (they are automatically connected to the concrete elements they are embedded in). If bond is defined for a bar, the "no slip at beginning/end" option should be checked for the end on the symm. plane.

Ad 2: please be specific about what is to be connected (e.g., 2 macroelements, 2 reinf. bars, ...), and what is the reality to be modelled.

Re: symmetric building systems

I have the same question !
using the spring element how to make hinge?
if not, is it different methods that can make hinge at boundary

Re: symmetric building systems

Dear Lee Byeong Han,
it is not clear from your question what you like to model:

A. a hinge support, i.e., a point support where displacements are blocked, but rotations free (then I don't understand why you mention "spring element")?
If so, define a normal point support. Please note you may need to include an elastic support plate to prevent unrealistic nonlinear damage localization near the support point.

B. a hinge connecting 2 parts of your structure? Explain what kind of elements are to be connected and what their connection is like in reality.

C. something else - please explain?