Modelling of 25 storey building with the specified properties using ETABS
Challenge 6 – ETABS modelling of a 25 storey building
Model a 25 storey building on ETABS with structural properties as specified below. Ground floor or plinth floor level can be taken at a height of 1.5 metres from the base. Each of the successive 25 storeys has a storey height of 3 metres.
Structural Element Sizes
- Beams : 300 × 400 mm
- Columns : 800 × 800 mm
- Slab : 150 mm thick
Material Properties
- Grade of Concrete : M30
- Grade of Steel Reinforcement Bars : Fe 415
Loading
- Dead Load on beams from infill wall : 10 kN/m (Let us assume the same for roof floor in view of parapet)
- Live load on floor : 3 kN/m2 (Let us assume the same for roof floor)
a) Buildings are assumed to be pinned at the base
b) All columns in all storey are of the same size
c) All beams in all storeys are of the same size
d) Building is located on Soil type-II and in Zone-III. Assume other factors if required.
Carry out the following exercises:
- Check if the translational fundamental natural period of vibration in both the x and y direction is approximately: Tx1">Tx1Tx1= 4.4 second Ty1">Ty1Ty1= 4.2 second
This check will help confirm if modelling is done correctly. Some deviations from the above values is possible (± 2%). But any major deviation will suggest an error in modelling.
- Check if the following provision in Table 5 of IS 1893 (part 1) – 2016, on torsional irregularity satisfied:
The natural period corresponding to the torsional mode of oscillation must be less than the two fundamental translational modes of oscillation along each principal plan directions.
- Check if the two provisions of clause 7 in Table 6 (shown below) of IS 1893 (part 1) – 2016, regarding vertical irregularity is satisfied
- Check if provision on inter-storey drift limitations in clause 7.11.1.1 satisfied. Please note that this check is for Serviceability Limit State and hence is for situation when stucture is subjected to unfactored seismic base shear
AIM- TO MODEL A 25 STOREY BUILDING ON ETABS WITH STRUCTURAL PROPERTIES
PROCEDURE-
OPEN THE ETABS SOFTWARE.
CLICK ON LEFT CORNER AND CLICK ON NEW MODEL.
CLICK ON USER BUILT IN SETTINGS
SELECT DISPLAY SETTINGS AS METRIC SI
SELECT STEEL SECTION DATABASE AS INDIAN STEEL DESIGN CODE AS IS 800:2007 AND CONCRETE DESIGN CODE AS IS 456:2000
THEN CLICK OK
MODEL TEMPLATE WILL OPEN
NOW SELECT CUSTOM GRID SPACING AND COSUTOM STORY DATA
CLICK ON EDIT GRID DATA
INSERT THE NUMBER OF GRIDS AS 0 4 8 12 AND 16 IN X-DIRECTION AND 0 4 8 12 IN Y-DIRECTION
ADD THE STORY BY RIGHT CLICKING
ENTRE THE HEIGHT OF PLINTH AS1.5M ABD MAKE ALL THE STORY SIMILAR TO STORY 1ST EXCEPT PLINTH
NEXT THE PLAN VIEW AND 3D VIEW CAN BE SEEN IN THE ETABS ALONG WITH MODEDL EXOLRER
NOW CLOSE ALL WINDOW EXPECT FOR PLAN
AND NOW DEFINE THE MATERIAL PROPERTIES BY CLICKING ON DEFINE
CLICK ON ADD NEW MATERIAL
AFTER CLICKING OK
MATERIAL PROPERTY DATA APPEARS
ADD NEW MATERAIL HYSD 500 FOR LONGITUDNAL BARS
AFTER CLICKING OK
MATERIAL PROPERTY DATA APPEARS
ADD NEW MATERAL FOR SHEAR TIES HYSD 415
AFTER CLICKING OK
MATERIAL PROPERTY DATA APPEARS
NOW TO ADD SLAB
GOI TO DEFINE THEM SELECT PROPERTIES
AND THEN SELECT SLAB SECTION
ADD NEW PROPERTY
CREATE RECTANGULAR SECTION
ADD BEAM OF 300X 400 MM
ADD COLUMN OF SIZE 800 X 800 MM
SLAB OF THICKNESS 150 MM IS ADDED
SELECT FOR ALL STOREY
DEAW COLUMN TO GRID SELCT QUICK COLUMN DRAW
QUICK BEAM DRAW
SELECT FLOOR AND ADD SLAB
SEE IN 3D VIEW
TO ADD LOAD PATTERNS
ADD LOADS SUCH AS
BRICK WALL AS SUPER DEAD
EQX,EQX+,EQX- THEN EQY,EQ+,EQ-
NOW WE SELECT MASS SOURCE AS SHOWN BELOW
AFTER SELECTING DAIPHGRAMS D1 WILL APPPEAR
NOW WE CHAECK THE MODEL
SEELCT ALL THE OPTION ALL FOR CHECK
MODEL HAS BEEN CHECKED. NO WARNING MESSAGE WERE GENERATED
NOW WE SELECT THE SHOW DEFOREMD SHAPE OPTION FOR DIFFRENT LOAD CASES
NOW FROM DISPLAY OPTION WE SELECT THE SHOWE TABLES OPTION
NOW SELCET THE MODAL PARTICIPATING MASS RATIO AS SHOWN BELOW
NEXT MODAL PARTICIPATIONG MASS RARIOS TABLE WILL BE VISIBLE
RESULT- THE 25 STOREY HAS BEEN MODELLED SUSSECFULLY USING ETABS