Example: Seismic Analysis and Design of a Five Storey Building

PLAN

ELEVATION

1. Enter into STAAD.Pro Program.

a. Select Global Design Codes b. Advanced Analysis Engine

c. Select New Project

2. File Name and Units

a. Select space

b. Type the File Name

c. Choose Location

d. Type the title (optional)

e. Click Length Unit as Meter

f. Click Force Unit as Kilo Newton

g. Click Next

3. To create the geometry

a. Select Open Structure Wizard

b. Click Finish

c. Select Model Type as Frame Models

d. Double click on Bay Frame

e. Type the Length as 12m since the total length is 4m+4m+4 m.

f. Type No. of bays along length as 3

g. Type Height as 18m since the total height is 2m+4m+3m+3m+3m+3 m

h. Type No. of bays along height as 6

i. Click the icon … near the no. of bays along height to give individual bay

heights ( bay 1 as 2m, bay 2 as 4m , bay 3 as 3m, bay 4 as 3m, bay 5 as 3m

and bay 6 as 3m)

j. Type Width as 20m

k. Type No. of bays along width as 4

l. Click Apply

m. Click File

n. Click Merge Model with STAAD.Pro. Model

o. Click Yes

p. Click Ok

q. Click the Front View icon.

r. Click the symbols and labels icon

s. Check the boxes which are to be displayed in the screen

t. Check Node Numbers, Node Points, Beam Numbers etc.,

u. Click Apply

v. Click Ok (Now the points, node numbers, beam numbers shall be seen on

screen

4. To Assign Member Property

The size of columns are assumed to be 230mm x 600mm

The size of beams are assumed to be 230mm x 450mm

So, first these properties are needed to be added and then assigned to appropriate

members. To do this,

a. Click Commands

b. Click Member Property

c. Click Prismatic

d. Click Rectangle

e. Type YD as 0.45m and ZD as 0.23m

f. Click Add

g. Type YD as 0.6m and ZD as 0.23m

h. Click Add

i. Click Close

j. Click on 1Rect 0.45 x 0.23 CONCRETE to select this property

k. Click select beams parallel to X

l. Click select beams parallel to Z

m. Click Assign, Click Yes

n. Click on 2 Rect 0.6 x 0.23 CONCRETE to select this property

o. Click select beams parallel to Y

p. Click Assign, Click Yes

q. Click Close

5. To Assign Support Conditions

a. Click Cut Section icon (left icon of symbols and labels icon)

b. Select X-Z plane with node #1

c. Click ok

d. Take the nodes cursor from left

e. Select all nodes in that level

f. Click Commands

g. Click Support Specifications

h. Click Fixed

i. Click Assign

j. Click Close

6. Torsional release (IS 456 cl 41.1)

a. Click specification page icon

b. Click beam & default in start

c. Click partial moment release (in order to avoid more no of degree freedom

in nodes)

d. Click MPX and enter 0.99

e. Click add

f. Select all the members

g. Click assign

h. Click yes

i. Click beam

j. Click end

k. Click partial moment release

l. Select MPX and enter 0.99

m. Click add

n. Assign to all members

o. Click yes

p. Click close

MASTER SLAVE (IS 1893 cl 7.7.2.11)

Drift or displacement of members in each and every floor is uniform

a. Click specification page icon

b. Click node

c. Give master node number For ex:104

d. Click ZX and add

e. Click node cursor

f. Select all ground floor level nodes

g. Click assign

h. Click yes

Loads calculation:

Member load:

For plinth beams,

Brick load (230mm wall) = 0.23x(4-0.45)x20 = 16.33 =17 kN/m

For floor beams,

Brick load (230mm wall) = 0.23x(3-0.45)x20 = 11.73 =12 kN/m

For roof beams, ( only periphery beams carries the parapet load)

Brick load (230mm wall) = 0.23x1x20 = 4.6 =5 kN/m

Floor load:

For floor slab:

Self-weight of the slab = 0.125x25 = 3.125 kN/m2

Floor finish = 0.025x24 = 0.6 kN/m2

Partition load = 1.96 kN/m2

Total dead load = 5.685 kN/m2

Live load (typical) = 2 kN/m2

Roof slabs:

Self wt of slab+ 0.125x25 = 3.125 kN/m2

Floor finish = 0.6 kN/m2

Water proofing = 1.5 kN/m2

Dead load = 5.225 kN/m2

Live load = 1.5kN/m2

For seismic analysis:

Reference load 1 – for all dead loads

Reference load 2- for live loads less than or equal to 3kN/m2

Reference load 3- for live loads greater than 3kN/m2

Reference load 4- for roof live loads

a. Click commands

b. Click loading

c. Click definition

d. Click reference load

e. Select loading type as dead and add

REFERENCE LOAD CASE1:

Self wt:

a. Click R1.REF LOAD CASE 1 in load page

b. Click add

c. Click self-weight

d. Click add

e. Click self-weight Y-1

f. Select all members

g. Click assign

Member load:

a. Click R1: REF LOAD CASE 1

b. Click add

c. Click member load

d. Enter w1= -12kN/m

e. Click add and close

f. Select all beams except roof beams and plinth beams

g. Select UNI GY-12 kN/m

h. Click assign to selected beams and assign

Similarly, give parapet load -5kN/m and assign only roof periphery

beams

Similarly assign brick load(17 kN/m) for plinth beams

Floor load:

a. Click R1:REF LOAD CASE 1

b. Click add

c. Click floor load

d. Enter pressure -5.685 kN/m2

e. Enter Y range minimum 3m and maximum 15m

R1: REF LOAD CASE 1 => Add => Floor load => Enter -5.225 kN/m2 => Put min &

max Y range 18m

REFERENCE LOAD 2:

a. Click reference load definition in load page

b. Click add

c. Click loading type as live and add

d. Click close

e. Now, click R2: REF LOAD CASE 2

f. Click add

g. Click floor add

h. Enter pressure -2 kN/m2

i. Enter Y range minimum=3m maximum=15m

j. Click add

REFERENCE LOAD 3:

There is no live load greater than 3kN/m2

Therefore in this problem, ref load 3 will contain roof live load only

a. Click reference and definitions in load page

b. Click add

c. Click R3: REF LOAD CASE 3

d. Click add

e. Click floor load

f. Enter pressure -1.5kN/m2 and put Y range min:18m max:18m

g. Click add

Seismic load:

Parameters definition:

Click definition in load page

a. Click seismic definition

b. Click add

c. Select type: IS1893-2002 code

d. Click generate

e. Zone factor: Select Madurai

f. Response reduction: Select “Ordinary RC Moment Resisting Frame”

OMRF

g. Importance Fi: All general buildings

h. Other parameters

i. Rock soil type => hard soil

j. Structure type RC frame building

k. Enter damping ratio as 5%

T = 0.09 X h

√d Enter period X (sec) =

0.09 X 18

√12 = 0.468

Period Z (sec) =0.09 X 18

√20 = 0.362

l. Click add

m. Click reference load

n. Pick ref load 1 and ref load 2 to right hand side

o. Put 1 factor as 1 to R1

a. 0.25 factor as 2 to R2

p. Click add and close.

Creation of seismic load and load combination:

a. Click “load case details” in load page

b. Click new

c. Click load case

d. Select “seismic” type for load case 1,2,3,4 and add

e. Select “dead” type for load case 5 and add

f. Select “live” type for load case 6 and add

Load case 1: seismic +X direction

Load case 2: seismic -X direction

Load case 3: seismic +Z direction

Load case 4: seismic -Z direction

Load case 5: Dead load

Load case 6: full live load

Load case 7: reduced live load

g. Click load case 1 in load case page

Click add

Click seismic loads (direction default in X direction)

Enter 1 as factor

Click add and close

h. Click load case 2 in load case details

Click add

Click seismic loads

Enter -1 as factor

Click add and close

i. Click load case 3

Click add

Click seismic loads

Select Z direction

Enter 1 as factor

Click add and close

j. Click load case 4

Click add

Click seismic loads

Select Z direction

Enter -1 as factor

Click add and close

k. Click load case 5

Click repeat load

Click reference load

l. Take R1: Ref load case 1 into right hand side & enter 1 as factor (default

value is 1)

Click add and close

Click load case 6

Click repeat load

Click reference load

Take R2 & R3 ref load case into right hand side. Enter 1 for both load case

(default value is 1)

Click add and close

Click load case 7

Click add

Click repeat load

Click reference load

m.Take R2: Ref load case 2 into right hand side and enter 0.25 for that load

Load combination:

8 1.5(DL+LL) 1.5(load case 5+load case 6)

9 1.5(DL+ELX) 1.5(load case 5+load case 1)

10 1.5(DL-ELX) 1.5(load case 5+load case 2)

11 1.5(DL+ELZ) 1.5(load case 5+load case 3)

12 1.5(DL-ELZ) 1.5(load case 5+load case 4)

13 0.9DL+1.5ELX 0.9 load case 5+1.5 load case 1

14 0.9DL-1.5ELX) 0.9 load case 5+1.5 load case 2

15 0.9DL+1.5ELZ 0.9 load case 5+1.5 load case 3

16 0.9DL-1.5ELZ 0.9 load case 5+1.5 load case 4

17 *1.2(DL+LL+ELX) 1.2(load case 5+ load case 7+load case 1)

18 *1.2(DL+LL-ELX) 1.2(load case 5+ load case 7+load case 2)

19 *1.2(DL+LL+ELZ) 1.2(load case 5+ load case 7+load case 3)

20 *1.2(DL+LL-ELZ) 1.2(load case 5+ load case 7+load case 4)

NOTE*: Reduced live load as per IS 1893 cl 7.3.1

Load combination:

a. Click load case details in load page

b. Click new

c. Click load case

d. Click combination

e. Take load case 5 & 6 into right hand left

f. Enter 1.5 for both load case

g. Similarly create all load cases,

h. Click comment

i. Click loading

j. Click load list

k. Select load combination 8 to 20 as load list

To Analyse the beam

a. Click Commands

b. Click Analysis

c. Click Perform Analysis

d. Click All

e. Click Ok

8. To Design the beam

Selection of Parameters for Design

a. Select all the members

b. Click Commands

c. Click Design

d. Click Concrete Design

e. Select Current Code as IS456

f. Click Select Parameters

g. Click << button to bring all the parameters to Available Parameters side

h. Click Fc, Fymain, Fysec, Maxmain, Maxsec, Minmain, Minsec by pressing

Ctrl button

i. Click > button to bring Fc, Fymain, Fysec, Maxmain, Maxsec, Minmain,

Minsec to Selected Parameters side

j. Click Ok

ii. To Define Parameters

( First ensure whether all the members are selected. If not, select the

members by clicking on them by pressing Ctrl button or by window

selection (rubber banding) for defining the parameters)

a. Click Define Parameters

b. Click Fc

c. Type Fc value as 25000 kN/m2 and click Assign ( for M25 grade concrete)

d. Click Fymain

e. Type Fymain value as 500000 kN/m2 and click Assign ( for Fe500 grade

steel – main reinforcement)

f. Click Fysec

g. Type Fysec value as 500000 kN/m2 and click Assign (for Fe500 grade steel

– secondary reinforcement)

h. Click Maxmain

i. Select maximum size of main reinforcement as 20mm and click Assign

j. Click Minmain

k. Select minimum size of main reinforcement as 8mm and click Assign

l. Click Maxsec

m. Select maximum size of secondary reinforcement as 12mm and click

Assign

n. Click Minsec

o. Select minimum size of secondary reinforcement as 8mm and click Assign

p. Click Close

iii. To give Design Beam and Design Column Commands

(Since all the members are selected initially, click outside to deselect all

the members and then click on all the beams first to assign design beam

command )

a. Click Commands

b. Click Design Beam

c. Click Assign

Now, select the columns by clicking on them pressing Ctrl button

d. Click Commands

e. Click Design Column

f. Click assign

g. Click Close

h. Click Close on Concrete Design Window

9. To Run Analysis

a. Click Analyse

b. Click Run Analysis

c. Select the Analysis option as STAAD Analysis or Stardyne Advanced

Analysis

d. Click Run Analysis