PROBLEM ON NATURAL FREQUENCY OF A STEEL FRAME ON SAP 2000

[AP92]

Problem : continuous frame with shell element . heigh and wide 4000 mm , bases of coloumn 400 mm . shell thickness 5 mm. original weight 180 Kgf. density 8036.56 kg / m3 . steel elemnt. E = 200 GPa.
according to a literature its 7th , 8th and 9th mode natural frequency is 4.14 Hz , 4.64 Hz, 6.69 Hz.
But when I am doing its , I am getting 7th mode result same ..but nt getting same result on 8th mode and 9 th mode.
please help me out ....
here I am giving my analysis .... 9 th mode - 7.47 Hz
8 th mode - 5.04 Hz

 

[Sannyboy]

@ AP92 : If possible please share your SAP File. i would like to check

 

[AP92]

Here is my file link( this is SAP 2000 File )... you please check it and please help me.. thank you ....

 

[stressed]

AP92, are your textbook result values based on dimensions using frame elements? If so, the dimensions may be slightly different than those used in your SAP shell element model. For example, is the 4000mm width based on column centerline to centerline? Because your model uses 4000mm from outer edge to outer edge. Matching exact modal results through the first 7 periods with relatively minor discrepancies in subsequent periods seems pretty good.

 

[AP92]

OK ...STILL i m giving you the the paper what they are telling ,,... if you check it would be helpfull...
And one problem ...I have modelled a cantilever beam with shell element , beam is 2 m long , 60 mm wide and 40 mm deep... here i am getting correct result compare to my analytical result.. but when i modelled using frame element with same material type i am getting different result... why is this so... You please help me i am facing problem very badly... density is 2800kg/m3 . E= 78 GPa . poison's ratio 0.3 .