Seismosoft | Earthquake Engineering Solutions

hi, everyone , my 3D model RC frame (3 stories-2 Bayes) ,i used static pushover analysis , and applied 292 KN as base shear force which is distributed as a triangle uniformly along the structure ,,the result of the capacity curve i get when i used a response control with 250 mm as target displacement is to 230 KN base shear ,i am confused ,how if i applied 292 KN ?,the second question ,the shape of the capacity curve didn't like that i got from SAP 2000 or ETABS which there is a point the structure is started to failure and drop
also how i define the releasing applied load
and if i defined the loading phase as load control the program stop and this message is shown to me
LF= 0.92500, LF_incr= 0.02500 (Iter: 1 => Converg)
LF= 0.92500, LF_incr= (Iter: 2 => fbd_Tol)
LF= 0.92500, LF_incr= (Iter: 4 => fbd_Tol)
-----------------------------------------
Unable to apply the entire phase load. Phase terminated
i tried to listen to a video about solving convergence difficulties and i change a several time this values but it doesn't work with me,please any one help me with this problems i read the seisomsoft manual Repeatedly but nothing worked with the changes i do .
this the link of model
https://www.dropbox.com/s/vlpo7ptxzkwag ... l.spf?dl=0
thanks in advance to any one help me
saso

What type of elements are you using? FB or DB inelastic frame elements? DB elements typically require a fine subdivision, while FB elements typically do not. What is the displacement at which you expect the onset of inelastic behavior on the pushover curve from SAP? Do material properties, reinforcement patterns, diaphragm constraints, support conditions, applied vertical losds, and damping specifications exactly match your SAP model? These are the first things I would check, based on experience in trying to match results between software platforms. Best of luck saso.

dear huff
thank you for concern and reply
the type or elements is inelastic FBPH,secondly the displacement that structure is behavior linear at 50 KN and that offset 5 mm displacement
i want to get the shape of capacity curve to be Converged the one from SAP, so i didn't speak of matching the results,this attach for the paper that i verify from the results of experimental and analytical (SAP)
https://www.dropbox.com/s/ga3yot4gudayu ... c.pdf?dl=0
so if you didn't mind take a look to the model and attached paper and advise me what should i do

Dear SASO,

Have you checked if the assigned information in your model is according to the referred paper?
I took a quick look at your model and realized that some properties were not the same with the paper, for example
• yield strength of the reinforcement steel is not the actual material yield stress provided in the paper.
• I didn't find any additional mass assigned to your model (in the paper there is a value of additional mass assigned on each floor)
• you have assigned T-sections to the beam elements but you have not assigned the beam effective width
• is the value for the cover thickness correct?
I hope that the above help a little.

SASO, in addition to Zoi's excellent advice, you might also double check the plastic hinge length assigned (16.67%). With a story height, and column element length, of 1800mm, this gives plastic hinge lengths of 300mm. This may be correct, but does seem excessive given that the paper you reference suggests a value of half the member depth, which would be 100mm for your columns. Perhaps you have a more exact calculation to justify the larger value however. Best of luck, SASO.

dear huff and zoi
thank you for replying and sorry for late posting
the yield strength that author mention is only average values of samples , that mean some elements is that value or more or less,but i took you advice into account and change Fy=478 MPA
secondly for add.mass the paper is mentioned that is 0.54 ton ? that mean the load is concentrated ,but in fig. of experimental model it is seem like distributed? and how can you modeling it?
thirdly,for t-section i saw a model is formed by seismosoft (verification model -ch4-infill-05) modeling the slab like that with beam
fourthly, for concrete cover he didn't mention it ,so i took the default value 25mm
finally,for length of plastic hinge i really i didn't pay attention for this notice , so i took LP=5.56% as percentage of length of column length (100mm )
am i thinking right or what? i really confused and really i need that model as soon as possible
thank you all for concerning and pursuit
saso

hi ,again
if i increased Fy &Fcu to the elements that reached to the limit of crushing or yielding (performance criteria) is that right ?
is that will make the model continue to finishing the loading and this message will not appear
i really need a help with my model
thanks
saso

Dear Seismosoft, plz reply tome , it seems no one want to answer

Saso, you might try adding a small amount of damping, say 1%. The default is zero. I am not sure if it will make a difference in the type of analysis you are running.

Dear SASO,

For the additional mass, you may distribute it to the beam elements and then assign it in two ways; within the beam section by defining a section additional mass or by applying distributed loads at the beam elements. In both cases you should make the proper modifications in the Gravity & Mass module of the Project Settings for the correct definition of the mass and the loads.