4. The release of the energy results in vibratory
waves propagating through the surface in all
directions.
Earthquake
Earthquake is a series of vibrations induced in the earth’s
crust by the abrupt rupture and rebound of rocks in which
elastic strain has been slowly accumulating.
6. For the calculation we have considered four storey RCC
building which is located in seismic zone IV.
The type of soil encountered is hard and it is proposed to design
the building with a SMRF.
The intensity of the floors are to cater an LL of 3.5 kN/m2
7. Size of Column-(250X450)mm.
Size of Beam- Longitudinal-(250X400)mm.
Transverse-(250X350)mm.
Depth of Slab- 100mm
Damping-5%
No infill Pannels
9. Zone factor (Z)
Importance Factor (I)
Average Response Acceleration Coefficient (Sa/g)
Response Reduction Factor (R)
10. • It is the indicator of the maximum seismic risk characterized
by Maximum Considered Earthquake (MCE ) in the zone in
which the structure is located.
• According to IS 1893(Part 1)-2002, Seismic Zones are
classified into II, III, IV & V respectively.
11. • It depends on the occupancy category of the building.
• It is obtained from table 6, Clause 6.4.2, IS 1893-2002.
Site Class
• Site Class is determined based on the average properties of the
soil within a certain depth (30 m) from the ground surface.
12. • It depends on the type of rock or soil sites and also the natural
period and damping of the structure.
• It is obtained from, Clause 6.4.5, IS 1893-2002.
13. • It is determined by the type of lateral load resisting system
used.
• It is a measure of the system’s ability to accommodate
earthquake loads and absorb energy without collapse.
• It is obtained from table 7, IS 1893-2002.
14. with infil panels,
Ta=0.09h/√d
where,
h - height of the building
d- Base dimension of the building at the plinth level
• The approximate fundamental natural period of vibration ( Ta ),
of a SMRF building from Clause 7.6,
without brick infil panels,
Ta= 0.075 h0.75 for RC frame building
= 0.085 h0.75 for steel frame building
15. where,
Qi - Design lateral force at floor i
Wi - Seismic weight of floor i
hi - Height of floor i measured from base, and
n - Number of storey's in the building is the number of levels at
which the masses are located.
16. Mass of Column (0.25X10X0.4+0.25X15X0.35)X25
Mass of Beams in Long. & Trans. (0.25x0.45x3.5/2x3x25)
Mass of Slab (0.1X5X10)X25
Mass of Infill (0.25x10x0.35/2)x20+(0.15X15X3
0.5/2)X20
Imposed Load (5x10x3.5x0.5x25)
Total Weight 632.43kN =64.45 Ton
17. Mass of Column (0.25X10X0.4+0.25X15X0.35)X25
Mass of Beams in Long. & Trans. (0.25x.45x3.5/2x3x25)
Mass of Slab (0.1X5X10)X25
Mass of Infill (0.25x10x0.35/2)x20+(0.15X15X3.5
/2)X20
Imposed Load 0
Total Weight 363.82kN =37.087 Ton
For Roof
21. It assumes that the building responds in its
fundamental mode.
The building must be low-rise and must not twist
significantly when the ground moves.
Generally determines the shear acting due to an
earthquake as equivalent static base shear.
STATIC ANALYSIS
22. According to data we have got Zone factor=0.24
Floor area =50 m2
Importance Factor=1
Response Reduction Factor=5
23. Now, fundamental natural period (Ta)
T= 0.075 h0.75
=0.075X140.75=0.5423
For hard soil Type
Sa/g=1.842
Contd...
31. 0
20
40
60
80
100
120
3.5 7 10.5 14
Total Horizontal Shear Force acting on Floors
Total Shear, kN (Manual) Total Shear, kN (STAAD)
0
5
10
15
20
25
30
35
40
45
50
3.5 7 10.5 14
Horizontal Shear force acting on Floors
Storey Shear, kN (Manual) Storey Shear, kN (STAAD)
33. The basic mode superposition method.
Restricted to linearly elastic analysis.
Produces the complete time history response of joint
displacements and member forces.
Involves the calculation of only the maximum values of the
displacements and member forces.
Response Spectrum Techniques
45. Dynamic analysis may be done by other methods.
Structures of nonlinear materials may be introduced for
further analysis and design.
Irregular shaped structure may be introduced for further
analysis and design.
Dynamic analysis may be introduced for further
analysis and design.
Commercial buildings may be introduced for further
Recommendation
46. Static manual method gives more conservative results then
static software method for low storey building.
As the height increases static software method gives more
horizontal shear force , so becomes more conservative then
static manual
In this case static method came more conservative then
dynamic method but whenever we will be finding base shear
for designing any structure we will be using both the methods
and the higher value must be considered as per the IS1893
part1 provisions.
We have got different base shear values for which we can
design shear walls as per IS13920-1993 for earthquake
resistant design of structures
47. Comparison between Manual calculation and Software
calculation of G+3 Building Using Staad Pro. v8i M.A.
Qureshi 1Assistant Professor, Civil Engineering
DepartmChopra AK (1995). “Dynamics of Structures Theory
and Application to Earthquake Engineering”, University of
California at Berkeley, USA.
Duggal S K (2010). “Earthquake Resistance Design of
Structure”, Fourth Edition, Oxford University Press, New
Delhi.
IS 1893 Part 1 (2002). “Indian Standard Criteria for
Earthquake Resistant Design of Structures”, Bureau of Indian
Standards, New Delhi.
48. Jan. T.S, Liu. M.W. and Kao. Y.C. (2004), “An upper-bond
pushover analysis procedure for estimating the seismic
demands of high-rise buildings”, Engineering structures. 117-
128.
Nouredine Bourahla (2013), "Equivalent Static Analysis of
Structures Subjected to Seismic Actions", Encyclopedia of
Earthquake Engineering, Springer- Verlag Berlin Heidelberg.
Pankaj Agarwal and Manish Shrikhande (2014)."Earthquake
Resistant Design of Structures", PHI Learning Private Limited,
Delhi.