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Hi Frank, As per your suggestion I used truss elements for the 3 supports that I am using in my problem of 2 equal span structure. While the case of a structure with I = 3.9e-6 for the beam elements (representing a rigid case) is producing the same period as I have got in other programs, I am not ge...

Thanks Frank. I have validated a single span structure (that i was asking questions earlier) and a two span with no pin connection at the mid-span. I have got Opensees, SAP give same results (modal analysis). The only change in the above problem is the pin connection at the mid-span, and I am not to...

Still no joy

I have also tried with an zerolength element connecting Node 16 (dummy node @mid-span) and 7 (beam node @ mid-span) with a high rotational stiffness. I am getting 0.773s as the period. Below is the code for this case. Without the element b/w Nodes 16 and 7 I am getting 1.036s. The target period that...

Thanks Frank. Node 16 is the dummy node at the mid-span. Node 7 is the mid-span node on the beam. I saw in some of the forum questions, and the suggestion was to have this dummy node (Node 16). Node 14 and 15 define the zero length element section for the central spring at the same mid-span. P.S- No...

Thanks Frank, and I am sorry to keep bugging you with stupid questions. The node 1 is fixed and is connected to node 2 by Element 1, as above. Element 11 (for central spring) is connecting nodes 14 (fixed) and 15, defined by section tag 2. ******* I have 2 equal spans, with end supports modelled as ...

Can I get some help for the above please? Thanks.

Hello Frank; I am having some trouble getting the below code to run properly. The example below is a 2 span single storey structure having supports modelled by springs. I want to have a pinned connection at the centre (defined by Node 7). I was hoping the below code was correct, but it looks like th...

Thanks Frank. I have answered my questions myself - was really tired and a night's sleep helped me the next morning



I have used Rayleigh damping, but is there an option for providing constant damping for all the modes?

Hi Frank, Thanks for your reply. I have modified my code by defining the beam in Y direction and the spring in X direction. The below code gave me 0.5s as fundamental period. I am trying to do dynamic time-history analysis and I have couple of questions. Could you please answer these for me: 1. Does...

Can somebody help with the above please?

Hi FMK, Thanks for your comments. Sorry for not providing more details. I have also posted another query under subject "Distributed-mass model" with some details about the problem. I am still awaiting your response for that problem :-) I am modelling a single storey, single bay structure. ...

Hi fmk, Instead of modelling the beam as a continuous system I used the lumped mass model in this below example. The storey stiffnesses and total structure weight have been calculated to give a natural period of 0.5s. I have verified this in SAP, but I am not able to get the same period in Opensees....

Hi fmk, I am working on a 1 storey high problem where I am modelling columns as springs and the diaphragm as a beam. I have assumed mass and storey stiffness values to get a fundamental period of 0.5s. I checked this in SAP too and I am getting 0.5s. I am trying the same example in Opensees and not ...

Thanks fmk. I have posted the same query in the other forum (feedback/suggestions) to remind you..