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TECHNICAL PAPER

5.7.3 Shear force 5.7.5 Base shear

The Shear force based on variation of flexural rigidity under La03 The Base shear drift based on the variation of flexural rigidity
earthquake is recorded in Table-11 under La03 earthquake is recorded in Table-13

table 13: variation in base shear for M 1 under LA03
table 11: variation in shear for M 1 under LA03
earthquake
earthquake
β sheAR foRce (mn) β bAse sheAR (mn)
With
WithoUt With ReDUction WithoUt DAmPeR DAmPeR ReDUction
(%)
DAmPeR DAmPeR (%)
0.25 18.72 8.22 56.09
0.25 19.22 9.73 49.38
0.50 8.31 5.40 35.02
0.50 16.95 5.61 66.90 0.75 5.77 4.85 15.95
0.75 13.81 4.93 64.30 1 5.23 4.36 16.63
1 10.62 4.61 56.59 1.25 5.48 3.99 27.19
1.25 8.47 4.21 50.30 1.50 5.63 4.29 23.80
1.50 7.11 3.82 46.27 1.75 5.51 4.35 21.05
1.75 5.92 3.57 39.70 2 5.27 4.19 20.49
2 4.95 3.27 33.94 Observations:
Table-13 shows the reduction in base shear with the variation of
Observations:
flexural rigidity ratio. It can be observed that there is reduction
From the Table-11 it is observed that the performance of the of 56.09% of base shear for the flexural rigidity ratio of 0.25
structure with the dampers is efficient for the flexural rigidity and 35.02% reduction for 0.50 flexural rigidity ratio but with the
ratio of 0.50 with a reduction in shear force of 66.90%. increase in flexural rigidity ratio there is not much reduction of
base shear is observed.
5.7.4 Inter-story drift 6. CONCLUsIONs

The Inter-story drift based on variation of flexural rigidity under Following conclusions are drawn from the results of analysis
La03 earthquake is recorded in Table-12 based on one and two outrigger system with dampers and
performance of the structural system with varying flexural
rigidity.
table 12: variation in inter-story drift for M 1 under
LA03 earthquake • The results obtained from the analysis signifies that the
β inteR-stoRy DRift e-3 performance of the outrigger structure with dampers
efficiently reduces the responses of the structure with a
WithoUt With ReDUction maximum reduction of 52.11% in lateral deflection, 52.80%
DAmPeR DAmPeR (%) in bending moment, 40.54% in shear force, 73.05% in
0.25 4.26 1.34 68.55 story drift and 36.59% in base shear for structure with one
outrigger for 15% damping when compared to outrigger
0.50 4.35 1.16 73.33
structure without dampers.
0.75 4.02 1.02 74.63 • The performance of the structure is also observed to
1 3.88 1.29 66.71 improve further with two outriggers for a damping of 15%
with the maximum reduction of 55.28% in lateral deflection,
1.25 4.34 1.62 62.67 62.02% in bending moment, 50.38% in shear force, 63.26%
1.50 4.68 1.89 59.62 in story drift, 52.54% in base shear.
• From the results of analysis of the structure by varying
1.75 4.93 2.08 57.82
the flexural rigidity it is observed that the responses of
2 5.07 2.18 57 the structure is reduced significantly between the flexural
rigidity ratio 0.25 to 1.
Observations:

From the above Table-12 it is observed that there is a reduction Acknowledgement
of 74.63% of story drift when the flexural rigidity is 0.75. Further The results reported in this paper are based on the investigation
there is a reduction in drift for flexural rigidity ratio greater than carried out in the CAD laboratory of Adichunchanagiri Institute
0.75 but for the ratio 0.75 the performance of the structure is of Technology, Chikmagalur, Karnataka State. The authors
efficient. thankfully acknowledge Principal and Management of the
Institute for the support extended.

The IndIan ConCreTe Journal | november 2019 21