Search found 7 matches

by hoseindnn
Fri Dec 23, 2016 7:08 am
Forum: OpenSees.exe Users
Topic: nonlinear time history problem
Replies: 0
Views: 2026

nonlinear time history problem

hi you guys i design a SCBF frame with 3 stories and 4 bays in ETABS and calculate columns axial forces and moment. then i model the design frame in opensees with nonlinear element and run a time history analysis. axial force in column was near to ETABS forces but moment in opensees was 5-10 times m...
by hoseindnn
Tue Dec 29, 2015 3:47 am
Forum: OpenSees.exe Users
Topic: difference in first period
Replies: 11
Views: 10447

Re: difference in first period

reebt wrote: > I had the same problem and as rafal said, ETABS considers the shear > stiffness. Using a shear area of 0 solved the problem. > But now, what if I want to consider the shear stiffness in OpenSees? > Is there a way to add it to a frame model with forcebeamcolumn elements? hi i change sh...
by hoseindnn
Mon Dec 14, 2015 12:13 pm
Forum: OpenSees.exe Users
Topic: difference in first period
Replies: 11
Views: 10447

Re: difference in first period

you mean when i just change element type (forcebeam to elastic) the first period should not change ?
i think type of element ( linear non linear) can change stiffness matrix and period
by hoseindnn
Fri Dec 11, 2015 2:33 pm
Forum: OpenSees.exe Users
Topic: difference in first period
Replies: 11
Views: 10447

Re: difference in first period

it is not about fiber or wsection it is about forceBeamColumn element.
i use elastic element with w section properties (area and moment of inertia) same in etabs. but i have diffrence
by hoseindnn
Fri Dec 11, 2015 5:06 am
Forum: OpenSees.exe Users
Topic: difference in first period
Replies: 11
Views: 10447

Re: difference in first period

hi again tnx for answer i replaced all element with elastic element in opensees and my answer get closer to etabs but there is a diffrence yet. i set shear area modifier zero in etabs and didnt get any changes in period. i have 10% error for nonlinear element and 6 % error for elastic element. is it...
by hoseindnn
Mon Nov 09, 2015 11:30 am
Forum: OpenSees.exe Users
Topic: difference in first period
Replies: 11
Views: 10447

difference in first period

hi. i have a simple model 1 bay 1 story steel frame . opensees give me T1= 0.232 S . i have same model in Etabs with T1= 0.242 S .i want to know where can be this problem ? when i increase number of bay and story this difference is higher.please help me to know why this two software have this differ...
by hoseindnn
Tue Aug 18, 2015 5:03 am
Forum: OpenSees.exe Users
Topic: Time history Analysis problem
Replies: 1
Views: 1793

Time history Analysis problem

hi all i have a very simple 2 Bay 1 story frame and i want perform a time history analysis. when analysis is running in deformed shape windows i see middle column moving left and right and other elements not moving. is it a problem ? because the model is very simple. wipe; model BasicBuilder -ndm 2 ...