Sunday, January 10, 2016
We are running the first cyclic model using 160109_M2.sdb. the models produces conservative estimates of the base shear force vs displacement at the roof behavior. the actual force capacity is about 55kips, but this model produces 29 Kips. which is 55% of the max capacity only. This explains why I was trying to make the bottom part of the building a bit stronger the first time I conducted the analysis. The model needs more axial load so that the capacity gets increased at the bottom. Check 160110_F-D_plots.xlsx. On the positive side, the models exhibits strength degradation, in good agreement to the experiment.
Shall we run the model using the weight from the flanges and increase the initial axial load to estimate the cyclic behavior? not sure if we got enough time....remember we still need to run the other walls, run the linear procedure using only equations, maybe run Chapter 15 analysis?.
Lets run the model using only the controlling Plastic hinge in each pier, which means we have to eliminate the rocking hinges and sliding hinges from certain walls. Use model 160110_M1. sdb.
Check 160110_F-D_plots.xlsx. It is basically the same!!!! so the influence of removing the additional hinges is negligible. Does this mean that the model can only fail in this way? Or the failure mode will change given a different loading pattern, dynamic loading? I guess it depends of the relationship between rocking and sliding capacity.
Lets implement the nonlinear model using shell elements in SAP2000., then we will compare LSP, using EFM, shell elements, NSP, using EFM, and Shell elements.
Use Model 160110_M2.sdb with shell elements.