Good morning,
I am trying to analyze a 2D four-level frame structure that is formed by concrete columns and concrete beams. The original building from where I obtained the frame is a university structure here in Perú. I considered the sections and reinforcements according to constrution plans.
I used user defined hinges that were created by a moment-rotation analysis considerating concrete and steel models. I consider a certain level of axial load in order to obtain moment-rotation diagrams in columns. I didn´t use any automatic hinge definition (ASCE or FEMA) because I would like to obtain results acordding to my own constituve models. I created different hinges for columns and beams and I placed them in every extreme side in columns and beam and in the middle of beams.
The seismic record is Lima 1974 earthquake and I scaled it to a 0.45g aceleration that belong to the maximun aceleration in peruvian seismic resistant norm. The original unit of the seismic record is cm/seg2. I think this is a good level of earthquake in order to generated an inelastic response in the hinges. For that reason I used a scale factor of 0.0247 that means to convert the units cm/seg2 to m/seg2 (x 0.01) and I also considered the value of 2.47 to scale the maximun aceleration of the seismic record to the value of 0.45g. At the end, the scale factor results in 0.01 x 2.47 = 0.0247.
In the nonlinear time history case I also used a initial nonlinear case in order to obtain more degradation (Gravity loads). I also defined geometric nonlinearity parameters in order to obtain more displacements.
The problem is that I didn't obtain a good strength degradation of the hinges and they seem to have a elastic degradation response. For that reason, I ask for your help because I don´t find the problem in the model definition. I check my moment-rotation diagrams and don't have any problem or error.
I would apreciated some help and I share the model definition with all the things that I defined in the analysis.
Thanks.
The use of the Interaction hinge PMM in spa2000 is not recommended in the nonlinear dynamic analysis because of the convergence problems, so its limited to the nonlinear static analysis, so try the fiber hinges its possible in sap2000, it has no problem with the variation of the axial loads during the calculation of the moment-curvature, in both dynamic and static nonlinear analysis.
- Badges
- Science topic
- Similar topics
- Engineering
- Civil Engineering