FREQUENCY OF RCC BUILDING USING RALEIGH METHOD Data:Building size : 24m x 24m (6 Bays each bay 4m )Height : 21m (7 Bays each bay 3.0m)Column size: 0.40m x 0.40mBeam size : 0.30m x 0.30mConcrete M30 Steel Fe 415

1.Creation of Geometry: New Project Space File: Rayleigh frequency Method Unit :

Length=metre : Force=KN Next Open structure wizard Finish. Change to Frame Models from Truss models Select Bay Frame and

double click on it.

Length (Along X Direction)= 24.0m. No. of bays (Span) =6 Click Bay No.1 =4.0m Bay No.2=4.0m Bay No.3=4.0m; Bay No.4=4.0m Bay No.5=4.0m; Bay No.6=4m.Height (Along Y Direction) =3.0m. No. of bays (Span) =1 Click Bay No.1 =3.0m Width (Along Z Direction) =24.0m. No. of bays (Span) =3 Click Bay No.1 =4.0 ; Bay No.2=4.0 ; Bay No.3=4.0; Bay No.4=4.0m; Bay No.5=4.0m; Bay No.6=4.0m Apply Transfer model Click yes OK.

2. Property: Click General Property Define Rectangular YD=0.40m ZD=0.40m

(column) Add. YD=0.30m ZD=0.30m (Beam) AddClose.

Front view Select all columns by windowing and high light YD=0.40

ZD=0.40 Assign to selected beam Assign Yes.

Highlight YD=0.30 ZD=0.30 and select all beams by windowing Assign to

selected beam Assign Yes.

Select the entire structure. Go to Geometry Translational repeat Y

direction. No. of steps=6 Default spacing=3m Ok.

3. Supports :

Front view Click support Create Fixed Add. Highlight support 2.

Select node cursor and select bottom most nodes by windowing

Assign to selected nodes Assign Yes Close.

De select the nodes and change to beam cursor.

4.Loading :

Click Loads & Definitions Click Load case details Add.

Primary No.1 Loading Type: None

Title: Load in X direction Add.

Number 2 Loading type: none

Title: load in Z direction Add Close.

Click Load case 1 Add.

Self weight X Direction Factor 1 Add.

Click Floor Load Pressure= 6 KN/m2 Global X

Y range mini= 0 m; max=21.0m Add.

Highlight self weight X Assign to view Assign Yes.

Load case 1 Add.

Frequency –Rayleigh Frequency Add.

Click Load case 2 Add.

Self weight Z Direction Factor 1 Add.

Click Floor Load Pressure= 3KN/m2 Global Z

Y range mini= 0 m; max=21.0m Add.

Highlight self weight Z Assign to view Assign Yes.

Load case 2 Add. Frequency – Rayleigh Frequency AddClose.

5. Analysis Type:

Page control Analysis/Print No print Add.

Click post printDefine Commands Analysis ResultsAddClose.

6.Perform Analysis:

Analysis Run Analysis Go to post processing mode Done.

7. Result :

Click output icon. Click result in the post processing mode.

At the end of the result you can see Rayleigh frequency in X =0.68997 cps

Max. Deflection in X =67.65677 cm. GX at Joint 365.

Rayleigh frequency in Z =0.871418 cps

Max. Deflection in Z = 42.35502 cm GZ at Joint 347.

Note:-

1. In Rayleigh frequency Load in X and load in Z has to be created.

2. Self weight in X has to be assigned before adding Rayleigh

Frequency.