8/10/2019 Ubdt Eqrds Beamer
1/92
Response Spectrum MethodAs Per IS 1893 (Part 1):2002
Satish A. Annigeri
Civil Engineering DepartmentB.V.B. College of Engineering & Technology
Hubli 580 [email protected]
10 May, 2007
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 1 / 27
http://find/8/10/2019 Ubdt Eqrds Beamer
2/92
Objectives
Discuss thephilosophy of design of Earthquake Resistant Structures
Understand the concept of Response Spectrum Method
Understand thegeneral provisions of IS 1893(Part 1):2002
Understand the procedure for implementing Response SpectrumMethod as per IS 1893 (Part 1):2002
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 2 / 27
http://find/8/10/2019 Ubdt Eqrds Beamer
3/92
Objectives
Discuss thephilosophy of design of Earthquake Resistant Structures
Understand the concept of Response Spectrum Method
Understand thegeneral provisions of IS 1893(Part 1):2002
Understand the procedure for implementing Response SpectrumMethod as per IS 1893 (Part 1):2002
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 2 / 27
http://find/8/10/2019 Ubdt Eqrds Beamer
4/92
Objectives
Discuss thephilosophy of design of Earthquake Resistant Structures
Understand the concept of Response Spectrum Method
Understand thegeneral provisions of IS 1893(Part 1):2002
Understand the procedure for implementing Response SpectrumMethod as per IS 1893 (Part 1):2002
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 2 / 27
http://find/8/10/2019 Ubdt Eqrds Beamer
5/92
Objectives
Discuss thephilosophy of design of Earthquake Resistant Structures
Understand the concept of Response Spectrum Method
Understand thegeneral provisions of IS 1893(Part 1):2002
Understand the procedure for implementing Response SpectrumMethod as per IS 1893 (Part 1):2002
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 2 / 27
I t d ti
http://find/8/10/2019 Ubdt Eqrds Beamer
6/92
Introduction
Categories of Earthquake Resistant Structures
Engineered Structuress
Structures which are explicitly analysed and designed to ensure thatthey are earthquake resistant
Examples of Engineered Structures
Multistorey buildings
BridgesTowers, Water tanksNuclear reactors
Non-engineered Structuress
Structures which arenotexplicitly analysed and designed to ensure
that they are earthquake resistant
Earthquake resistance is ensured throughgood materials ofconstructionandgood construction practices
Examples of Non-engineered Structures
Masonry structuresSatish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 3 / 27
Introduction
http://find/8/10/2019 Ubdt Eqrds Beamer
7/92
Introduction
Categories of Earthquake Resistant Structures
Engineered Structuress
Structures which are explicitly analysed and designed to ensure thatthey are earthquake resistant
Examples of Engineered Structures
Multistorey buildings
BridgesTowers, Water tanksNuclear reactors
Non-engineered Structuress
Structures which arenotexplicitly analysed and designed to ensure
that they are earthquake resistant
Earthquake resistance is ensured throughgood materials ofconstructionandgood construction practices
Examples of Non-engineered Structures
Masonry structuresSatish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 3 / 27
Introduction
http://find/8/10/2019 Ubdt Eqrds Beamer
8/92
Introduction
Categories of Earthquake Resistant Structures
Engineered Structuress
Structures which are explicitly analysed and designed to ensure thatthey are earthquake resistant
Examples of Engineered Structures
Multistorey buildings
BridgesTowers, Water tanksNuclear reactors
Non-engineered Structuress
Structures which arenotexplicitly analysed and designed to ensure
that they are earthquake resistant
Earthquake resistance is ensured throughgood materials ofconstructionandgood construction practices
Examples of Non-engineered Structures
Masonry structuresSatish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 3 / 27
Introduction
http://find/8/10/2019 Ubdt Eqrds Beamer
9/92
Introduction
Categories of Earthquake Resistant Structures
Engineered Structuress
Structures which are explicitly analysed and designed to ensure thatthey are earthquake resistant
Examples of Engineered Structures
Multistorey buildings
BridgesTowers, Water tanksNuclear reactors
Non-engineered Structuress
Structures which arenotexplicitly analysed and designed to ensure
that they are earthquake resistant
Earthquake resistance is ensured throughgood materials ofconstructionandgood construction practices
Examples of Non-engineered Structures
Masonry structuresSatish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 3 / 27
Introduction
http://find/http://goback/8/10/2019 Ubdt Eqrds Beamer
10/92
Introduction
Categories of Earthquake Resistant Structures
Engineered Structuress
Structures which are explicitly analysed and designed to ensure thatthey are earthquake resistant
Examples of Engineered Structures
Multistorey buildings
BridgesTowers, Water tanksNuclear reactors
Non-engineered Structuress
Structures which arenotexplicitly analysed and designed to ensure
that they are earthquake resistant
Earthquake resistance is ensured throughgood materials ofconstructionandgood construction practices
Examples of Non-engineered Structures
Masonry structuresSatish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 3 / 27
Introduction
http://find/http://goback/8/10/2019 Ubdt Eqrds Beamer
11/92
Indian Standard Codes for Engineered Structures
Engineered Structures
IS 1893- Criteria for Earthquake Resistant Design of Structures
Part 1: IS 1893(Part 1):2002General Provisions and BuildingsPart 2: Liquid retaining tanks - Not yet publishedPart 3: Bridges and Retaining Walls - Not yet publishedPart 4: IS 1893(Part 4):2005Industrial structures including stack like
structuresPart 5: Dams and embankments -Not yet published
IS 13920:1993- Ductile Detailing of Reinforced Concrete StructuresSubjected to Seismic Forces - Code of Practice
Important NoteUntil Parts 2, 3 and 5 are ready, design of such structures is governed bythe relevant clauses ofIS 1893:1984
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 4 / 27
Introduction
http://find/8/10/2019 Ubdt Eqrds Beamer
12/92
Indian Standard Codes for Engineered Structures
Engineered Structures
IS 1893- Criteria for Earthquake Resistant Design of Structures
Part 1: IS 1893(Part 1):2002General Provisions and BuildingsPart 2: Liquid retaining tanks - Not yet publishedPart 3: Bridges and Retaining Walls - Not yet publishedPart 4: IS 1893(Part 4):2005Industrial structures including stack like
structuresPart 5: Dams and embankments -Not yet published
IS 13920:1993- Ductile Detailing of Reinforced Concrete StructuresSubjected to Seismic Forces - Code of Practice
Important NoteUntil Parts 2, 3 and 5 are ready, design of such structures is governed bythe relevant clauses ofIS 1893:1984
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 4 / 27
Introduction
http://find/8/10/2019 Ubdt Eqrds Beamer
13/92
Indian Standard Codes for Engineered Structures
Engineered Structures
IS 1893- Criteria for Earthquake Resistant Design of StructuresPart 1: IS 1893(Part 1):2002General Provisions and BuildingsPart 2: Liquid retaining tanks - Not yet publishedPart 3: Bridges and Retaining Walls - Not yet publishedPart 4: IS 1893(Part 4):2005Industrial structures including stack like
structuresPart 5: Dams and embankments -Not yet published
IS 13920:1993- Ductile Detailing of Reinforced Concrete StructuresSubjected to Seismic Forces - Code of Practice
Important NoteUntil Parts 2, 3 and 5 are ready, design of such structures is governed bythe relevant clauses ofIS 1893:1984
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 4 / 27
Introduction
http://find/8/10/2019 Ubdt Eqrds Beamer
14/92
Indian Standard Codes for Engineered Structures
Engineered Structures
IS 1893- Criteria for Earthquake Resistant Design of StructuresPart 1: IS 1893(Part 1):2002General Provisions and BuildingsPart 2: Liquid retaining tanks - Not yet publishedPart 3: Bridges and Retaining Walls - Not yet publishedPart 4: IS 1893(Part 4):2005Industrial structures including stack like
structuresPart 5: Dams and embankments -Not yet published
IS 13920:1993- Ductile Detailing of Reinforced Concrete StructuresSubjected to Seismic Forces - Code of Practice
Important NoteUntil Parts 2, 3 and 5 are ready, design of such structures is governed bythe relevant clauses ofIS 1893:1984
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 4 / 27
Introduction
http://find/http://goback/8/10/2019 Ubdt Eqrds Beamer
15/92
Indian Standard Codes for Non-engineered Structures
Non-engineered Structures
IS 4326:1993Earthquake Resistant Design & Construction ofBuildings - Code of Practice
IS 4326:1993deals with Masonry buildings
Size and location ofopenings
Size, location and details ofhorizontal bandsVertical reinforcementin masonry construction
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 5 / 27
Introduction
http://find/8/10/2019 Ubdt Eqrds Beamer
16/92
Indian Standard Codes for Non-engineered Structures
Non-engineered Structures
IS 4326:1993Earthquake Resistant Design & Construction ofBuildings - Code of Practice
IS 4326:1993deals with Masonry buildings
Size and location ofopenings
Size, location and details ofhorizontal bandsVertical reinforcementin masonry construction
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 5 / 27
Introduction
http://find/8/10/2019 Ubdt Eqrds Beamer
17/92
Philosophy of Design of Earthquake Resistant Structures
Characteristics of Earthquake Resistant Structures
1 During amild earthquakeno damage to any structural elements (that is, structure shouldrespond elastically),non-structural elements (such as glazing, infill walls, ceiling) may bedamaged
2 During amoderate earthquake
Structural elements may suffer(repairable) damage, but . . .It must be possible torehabilitate the structureand make it fit for itsintended use
3
During asevere earthquakeStructural elements may suffer irrepairable damage, but . . .The structure shouldnot collapsewithout giving adequate time for theoccupants of the structure to escape with their life
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 6 / 27
Introduction
http://find/http://goback/8/10/2019 Ubdt Eqrds Beamer
18/92
Philosophy of Design of Earthquake Resistant Structures
Characteristics of Earthquake Resistant Structures
1 During amild earthquakeno damage to any structural elements (that is, structure shouldrespond elastically),non-structural elements (such as glazing, infill walls, ceiling) may bedamaged
2 During amoderate earthquake
Structural elements may suffer(repairable) damage, but . . .It must be possible torehabilitate the structureand make it fit for itsintended use
3
During asevere earthquakeStructural elements may suffer irrepairable damage, but . . .The structure shouldnot collapsewithout giving adequate time for theoccupants of the structure to escape with their life
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 6 / 27
Introduction
http://find/http://goback/8/10/2019 Ubdt Eqrds Beamer
19/92
Philosophy of Design of Earthquake Resistant Structures
Characteristics of Earthquake Resistant Structures
1 During amild earthquakeno damage to any structural elements (that is, structure shouldrespond elastically),non-structural elements (such as glazing, infill walls, ceiling) may bedamaged
2 During amoderate earthquake
Structural elements may suffer(repairable) damage, but . . .It must be possible torehabilitate the structureand make it fit for itsintended use
3
During asevere earthquakeStructural elements may suffer irrepairable damage, but . . .The structure shouldnot collapsewithout giving adequate time for theoccupants of the structure to escape with their life
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 6 / 27
Introduction
http://find/8/10/2019 Ubdt Eqrds Beamer
20/92
Implications of the Design Philosophy
How can we achieve all three goals simultaneously?
Correctly estimatethe seismic force on the structure
Analyze the structure for acombination of loads- Dead Load, LiveLoad, Earthquake Load
Design the components of the struture for the most severe load
combinationDetailthe structure for ductility
Understimatingthe seismic force will result in the collapse of thestructure during even a moderate earthquake
Overstimatingthe seismic force will result in an uneconomicalstructure (no damage even during a severe earthquake)
Strengthalone is not enough. Ductility is necessary to satisfy thethird requirement
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 7 / 27
Introduction
http://find/8/10/2019 Ubdt Eqrds Beamer
21/92
Implications of the Design Philosophy
How can we achieve all three goals simultaneously?
Correctly estimatethe seismic force on the structure
Analyze the structure for acombination of loads- Dead Load, LiveLoad, Earthquake Load
Design the components of the struture for the most severe load
combinationDetailthe structure for ductility
Understimatingthe seismic force will result in the collapse of thestructure during even a moderate earthquake
Overstimatingthe seismic force will result in an uneconomicalstructure (no damage even during a severe earthquake)
Strengthalone is not enough. Ductility is necessary to satisfy thethird requirement
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 7 / 27
Introduction
http://find/8/10/2019 Ubdt Eqrds Beamer
22/92
Implications of the Design Philosophy
How can we achieve all three goals simultaneously?
Correctly estimatethe seismic force on the structure
Analyze the structure for acombination of loads- Dead Load, LiveLoad, Earthquake Load
Design the components of the struture for the most severe load
combinationDetailthe structure for ductility
Understimatingthe seismic force will result in the collapse of thestructure during even a moderate earthquake
Overstimatingthe seismic force will result in an uneconomicalstructure (no damage even during a severe earthquake)
Strengthalone is not enough. Ductility is necessary to satisfy thethird requirement
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 7 / 27
Introduction
http://find/http://goback/8/10/2019 Ubdt Eqrds Beamer
23/92
Implications of the Design Philosophy
How can we achieve all three goals simultaneously?
Correctly estimatethe seismic force on the structure
Analyze the structure for acombination of loads- Dead Load, LiveLoad, Earthquake Load
Design the components of the struture for the most severe load
combinationDetailthe structure for ductility
Understimatingthe seismic force will result in the collapse of thestructure during even a moderate earthquake
Overstimatingthe seismic force will result in an uneconomicalstructure (no damage even during a severe earthquake)
Strengthalone is not enough. Ductility is necessary to satisfy thethird requirement
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 7 / 27
Introduction
http://find/http://goback/8/10/2019 Ubdt Eqrds Beamer
24/92
Implications of the Design Philosophy
How can we achieve all three goals simultaneously?
Correctly estimatethe seismic force on the structure
Analyze the structure for acombination of loads- Dead Load, LiveLoad, Earthquake Load
Design the components of the struture for the most severe load
combinationDetailthe structure for ductility
Understimatingthe seismic force will result in the collapse of thestructure during even a moderate earthquake
Overstimatingthe seismic force will result in an uneconomicalstructure (no damage even during a severe earthquake)
Strengthalone is not enough. Ductility is necessary to satisfy thethird requirement
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 7 / 27
Introduction
http://find/8/10/2019 Ubdt Eqrds Beamer
25/92
Implications of the Design Philosophy
How can we achieve all three goals simultaneously?
Correctly estimatethe seismic force on the structure
Analyze the structure for acombination of loads- Dead Load, LiveLoad, Earthquake Load
Design the components of the struture for the most severe load
combinationDetailthe structure for ductility
Understimatingthe seismic force will result in the collapse of thestructure during even a moderate earthquake
Overstimatingthe seismic force will result in an uneconomicalstructure (no damage even during a severe earthquake)
Strengthalone is not enough. Ductility is necessary to satisfy thethird requirement
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 7 / 27
Introduction
http://find/http://goback/8/10/2019 Ubdt Eqrds Beamer
26/92
Implications of the Design Philosophy
How can we achieve all three goals simultaneously?
Correctly estimatethe seismic force on the structure
Analyze the structure for acombination of loads- Dead Load, LiveLoad, Earthquake Load
Design the components of the struture for the most severe load
combinationDetailthe structure for ductility
Understimatingthe seismic force will result in the collapse of thestructure during even a moderate earthquake
Overstimatingthe seismic force will result in an uneconomicalstructure (no damage even during a severe earthquake)
Strengthalone is not enough. Ductility is necessary to satisfy thethird requirement
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 7 / 27
Introduction
http://find/8/10/2019 Ubdt Eqrds Beamer
27/92
Implications of the Design Philosophy
How can we achieve all three goals simultaneously?
Correctly estimatethe seismic force on the structure
Analyze the structure for acombination of loads- Dead Load, LiveLoad, Earthquake Load
Design the components of the struture for the most severe load
combinationDetailthe structure for ductility
Understimatingthe seismic force will result in the collapse of thestructure during even a moderate earthquake
Overstimatingthe seismic force will result in an uneconomicalstructure (no damage even during a severe earthquake)
Strengthalone is not enough. Ductility is necessary to satisfy thethird requirement
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 7 / 27
IS 1893 (Part 1):2002
( )
http://find/http://goback/8/10/2019 Ubdt Eqrds Beamer
28/92
IS 1893 (Part 1)- General Provisions and Buildings
Load combinations
Seismic Zoning of India (Z)
Design SpectrumSag
Regular and Irregular configuration of buildings
Importance Factor (I
)Response Reduction Factor (R)
Design Imposed Loads for earthquake force calculation
Seismic Weight of Buildings (W)
Methods of estimating seismic design force1 Static Analysis (Equivalent Static Analysis)2 Dynamic Analysis
Response Spectrum AnalysisTime History Analysis
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 8 / 27
IS 1893 (Part 1):2002
C
http://find/8/10/2019 Ubdt Eqrds Beamer
29/92
Load Combinations
Plastic Design of Steel Structures
1 1.7(Dead Load + Imposed Load)2 1.7(Dead Load Earthquake Load)
3 1.3(Dead Load + Imposed Load Earthquake Load)
Limit State Design of Reinforced and Prestressed Concrete Structures
1 1.5(Dead Load + Imposed Load)
2 1.2(Dead Load + Imposed Load Earthquake Load)
3 1.5(Dead Load Earthquake Load)
4
0.9 Dead Load
1.9 Earthquake Load
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 9 / 27
IS 1893 (Part 1):2002
L d C bi i
http://find/8/10/2019 Ubdt Eqrds Beamer
30/92
Load Combinations
Plastic Design of Steel Structures
1 1.7(Dead Load + Imposed Load)2 1.7(Dead Load Earthquake Load)
3 1.3(Dead Load + Imposed Load Earthquake Load)
Limit State Design of Reinforced and Prestressed Concrete Structures
1 1.5(Dead Load + Imposed Load)
2 1.2(Dead Load + Imposed Load Earthquake Load)
3 1.5(Dead Load Earthquake Load)
4
0.9 Dead Load
1.9 Earthquake Load
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 9 / 27
IS 1893 (Part 1):2002
D i E h k L d
http://find/8/10/2019 Ubdt Eqrds Beamer
31/92
Design Earthquake Load
Design Horizontal Earthquake Load
Lateral Load Resisting Elements in Orthogonal DirectionsStructure must be designed for the effects due to full design earthquakeload in one direction at a timeLateral Load Resisting Elements Not in Orthogonal DirectionsStructure must be designed for the effects due to full design earthquake
load in one direction plus 30% of the design earthquake load in theother direction
Design Vertical Earthquake Load
Design acceleration spectrum in vertical direction may be taken as 23 ofthe design horizontal acceleration
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 10 / 27
IS 1893 (Part 1):2002
S i i Z i f I di
http://find/http://goback/8/10/2019 Ubdt Eqrds Beamer
32/92
Seismic Zoning of India
India is divided into4 seismic zones, Zone II to Zone V
Zone II is the least severe seismic zone andZone V is the most severe
Seismic zoning is based on geological investigationsandhistory ofpast earthquakesexperienced by the the location
Seismic zoning is given in Fig. 1 (page 5) of IS 1893(Part 1):2002
Coastal Karnatakalies in Zone III and therest of Karnatakalies inZone II
Zone III: Dharwad, Belgaum, Bijapur, Karwar, Mangalore
Zone II: Bangalore, Mysore, Chitradurga, Gulbarga (See Annexure E,
page 35-36)
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 11 / 27
IS 1893 (Part 1):2002
S i i Z f I di
http://find/8/10/2019 Ubdt Eqrds Beamer
33/92
Seismic Zones of India
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 12 / 27
IS 1893 (Part 1):2002
Z F t f Diff t S is i Z s
http://find/http://goback/8/10/2019 Ubdt Eqrds Beamer
34/92
Zone Fator for Different Seismic Zones
Table: Table 2 Zone Factor Z (page 16)
SeismicZone II III IV V
Seismic
Intensity Low Moderate Severe VerySevere
Z 0.10 0.16 0.24 0.36
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 13 / 27
IS 1893 (Part 1):2002
Response Spectra for Rock and Soil Sites for 5% Damping
http://find/8/10/2019 Ubdt Eqrds Beamer
35/92
Response Spectra for Rock and Soil Sites for 5% Damping
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 14 / 27
IS 1893 (Part 1):2002
Response Spectra from Equations
http://find/http://goback/8/10/2019 Ubdt Eqrds Beamer
36/92
Response Spectra from Equations
Type I - Rock or Hard Soil
Sa
g =
1 + 15 T 0s T 0.1s
2.50 0.1s T 0.4s
1.00/T 0.4s T 4.0s
Type II - Medium Soil
Sa
g =
1 + 15 T 0s T 0.1s
2.50 0.1s T 0.55s
1.36/T 0.55s T 4.0s
Type III - Soft Soil
Sa
g =
1 + 15 T 0s T 0.1s
2.50 0.1s T 0.67s
1.67/T 0.67s T 4.0s
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 15 / 27
IS 1893 (Part 1):2002
Design Spectrum
http://find/8/10/2019 Ubdt Eqrds Beamer
37/92
Design Spectrum
Design Spectrumis a graph of Spectral Acceleration CoefficientSag
versus Period of Vibration (T)There arethreediffrent Spectra, for three differentSoil types
The design spectrum is for5% damping, and must besuitably scaledif the damping ratio is not 5% (See Table 3, page 17)
Design Spectrum has three distinct phases (See Fig. 2, page 16)Linearlry increasingportion from T= 0s upto T = 0.1sConstant portionfrom T = 0.1s to T = 0.4/0.55/0.67sDecreasing curved portionfrom T= 0.4/0.55/0.67s to T= 4s
Maximum Spectral Acceleration is Sa = 2.5g
From the Design Spectrum, we get theMaximum Accelerationexperienced by a SDOF system with a given Natural Period
Design Spectrum gives theDesign Elastic Force
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 16 / 27
IS 1893 (Part 1):2002
Design Spectrum
http://find/8/10/2019 Ubdt Eqrds Beamer
38/92
Design Spectrum
Design Spectrumis a graph of Spectral Acceleration CoefficientSag
versus Period of Vibration (T)There arethreediffrent Spectra, for three differentSoil types
The design spectrum is for5% damping, and must besuitably scaledif the damping ratio is not 5% (See Table 3, page 17)
Design Spectrum has three distinct phases (See Fig. 2, page 16)Linearlry increasingportion from T= 0s upto T = 0.1sConstant portionfrom T = 0.1s to T = 0.4/0.55/0.67sDecreasing curved portionfrom T= 0.4/0.55/0.67s to T= 4s
Maximum Spectral Acceleration is Sa = 2.5g
From the Design Spectrum, we get theMaximum Accelerationexperienced by a SDOF system with a given Natural Period
Design Spectrum gives theDesign Elastic Force
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 16 / 27
IS 1893 (Part 1):2002
Design Spectrum
http://find/8/10/2019 Ubdt Eqrds Beamer
39/92
Design Spectrum
Design Spectrumis a graph of Spectral Acceleration CoefficientSag
versus Period of Vibration (T)There arethreediffrent Spectra, for three differentSoil types
The design spectrum is for5% damping, and must besuitably scaledif the damping ratio is not 5% (See Table 3, page 17)
Design Spectrum has three distinct phases (See Fig. 2, page 16)Linearlry increasingportion from T= 0s upto T = 0.1sConstant portionfrom T = 0.1s to T = 0.4/0.55/0.67sDecreasing curved portionfrom T= 0.4/0.55/0.67s to T= 4s
Maximum Spectral Acceleration is Sa = 2.5g
From the Design Spectrum, we get theMaximum Accelerationexperienced by a SDOF system with a given Natural Period
Design Spectrum gives theDesign Elastic Force
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 16 / 27
IS 1893 (Part 1):2002
Design Spectrum
http://find/8/10/2019 Ubdt Eqrds Beamer
40/92
Design Spectrum
Design Spectrumis a graph of Spectral Acceleration CoefficientSag
versus Period of Vibration (T)There arethreediffrent Spectra, for three differentSoil types
The design spectrum is for5% damping, and must besuitably scaledif the damping ratio is not 5% (See Table 3, page 17)
Design Spectrum has three distinct phases (See Fig. 2, page 16)Linearlry increasingportion from T= 0s upto T = 0.1sConstant portionfrom T = 0.1s to T = 0.4/0.55/0.67sDecreasing curved portionfrom T= 0.4/0.55/0.67s to T= 4s
Maximum Spectral Acceleration is Sa = 2.5g
From the Design Spectrum, we get theMaximum Accelerationexperienced by a SDOF system with a given Natural Period
Design Spectrum gives theDesign Elastic Force
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 16 / 27
IS 1893 (Part 1):2002
Design Spectrum
http://find/8/10/2019 Ubdt Eqrds Beamer
41/92
Design Spectrum
Design Spectrumis a graph of Spectral Acceleration CoefficientSag
versus Period of Vibration (T)There arethreediffrent Spectra, for three differentSoil types
The design spectrum is for5% damping, and must besuitably scaledif the damping ratio is not 5% (See Table 3, page 17)
Design Spectrum has three distinct phases (See Fig. 2, page 16)Linearlry increasingportion from T= 0s upto T = 0.1sConstant portionfrom T = 0.1s to T = 0.4/0.55/0.67sDecreasing curved portionfrom T= 0.4/0.55/0.67s to T= 4s
Maximum Spectral Acceleration is Sa = 2.5g
From the Design Spectrum, we get theMaximum Accelerationexperienced by a SDOF system with a given Natural Period
Design Spectrum gives theDesign Elastic Force
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 16 / 27
IS 1893 (Part 1):2002
Design Spectrum
http://find/8/10/2019 Ubdt Eqrds Beamer
42/92
Design Spectrum
Design Spectrumis a graph of Spectral Acceleration CoefficientSag
versus Period of Vibration (T)There arethreediffrent Spectra, for three differentSoil types
The design spectrum is for5% damping, and must besuitably scaledif the damping ratio is not 5% (See Table 3, page 17)
Design Spectrum has three distinct phases (See Fig. 2, page 16)Linearlry increasingportion from T= 0s upto T = 0.1sConstant portionfrom T = 0.1s to T = 0.4/0.55/0.67sDecreasing curved portionfrom T= 0.4/0.55/0.67s to T= 4s
Maximum Spectral Acceleration is Sa = 2.5g
From the Design Spectrum, we get theMaximum Accelerationexperienced by a SDOF system with a given Natural Period
Design Spectrum gives theDesign Elastic Force
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 16 / 27
IS 1893 (Part 1):2002
Design Spectrum
http://find/8/10/2019 Ubdt Eqrds Beamer
43/92
Design Spectrum
Design Spectrumis a graph of Spectral Acceleration CoefficientSag
versus Period of Vibration (T)There arethreediffrent Spectra, for three differentSoil types
The design spectrum is for5% damping, and must besuitably scaledif the damping ratio is not 5% (See Table 3, page 17)
Design Spectrum has three distinct phases (See Fig. 2, page 16)Linearlry increasingportion from T= 0s upto T = 0.1sConstant portionfrom T = 0.1s to T = 0.4/0.55/0.67sDecreasing curved portionfrom T= 0.4/0.55/0.67s to T= 4s
Maximum Spectral Acceleration is Sa = 2.5g
From the Design Spectrum, we get theMaximum Accelerationexperienced by a SDOF system with a given Natural Period
Design Spectrum gives theDesign Elastic Force
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 16 / 27
IS 1893 (Part 1):2002
Response Reduction Factor
http://find/8/10/2019 Ubdt Eqrds Beamer
44/92
p
Designing your structure as per theDesign Spectrumof the code will
ensure that the structure will remain elastic during a severeearthquake
But the structurecost will increaseif we design it to remain elasticeven during a severe earthquake
If we reduce the design force in theright way, we can satisfy the threerequirements for earthquake resistant structures
The proportion by which we can reduce the elastic design force, andstill satisfy the third requirement for earthquake resistant structures iswhat the code callsResponse Reduction Factor (R)
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 17 / 27
IS 1893 (Part 1):2002
Response Reduction Factor
http://find/8/10/2019 Ubdt Eqrds Beamer
45/92
p
Designing your structure as per theDesign Spectrumof the code will
ensure that the structure will remain elastic during a severeearthquake
But the structurecost will increaseif we design it to remain elasticeven during a severe earthquake
If we reduce the design force in theright way, we can satisfy the threerequirements for earthquake resistant structures
The proportion by which we can reduce the elastic design force, andstill satisfy the third requirement for earthquake resistant structures iswhat the code callsResponse Reduction Factor (R)
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 17 / 27
IS 1893 (Part 1):2002
Response Reduction Factor
http://find/8/10/2019 Ubdt Eqrds Beamer
46/92
p
Designing your structure as per theDesign Spectrumof the code will
ensure that the structure will remain elastic during a severeearthquake
But the structurecost will increaseif we design it to remain elasticeven during a severe earthquake
If we reduce the design force in theright way, we can satisfy the threerequirements for earthquake resistant structures
The proportion by which we can reduce the elastic design force, andstill satisfy the third requirement for earthquake resistant structures iswhat the code callsResponse Reduction Factor (R)
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 17 / 27
IS 1893 (Part 1):2002
Response Reduction Factor
http://find/8/10/2019 Ubdt Eqrds Beamer
47/92
p
Designing your structure as per theDesign Spectrumof the code will
ensure that the structure will remain elastic during a severeearthquake
But the structurecost will increaseif we design it to remain elasticeven during a severe earthquake
If we reduce the design force in theright way, we can satisfy the threerequirements for earthquake resistant structures
The proportion by which we can reduce the elastic design force, andstill satisfy the third requirement for earthquake resistant structures iswhat the code callsResponse Reduction Factor (R)
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 17 / 27
IS 1893 (Part 1):2002
Response Reduction Factor in IS 1893 (Part 1):2002
http://find/8/10/2019 Ubdt Eqrds Beamer
48/92
( )
Response Reduction Factor depends on two factors
The type ofLateral Load Resisting SystemThe degree ofDuctility detailing
R varies
From3.0 to 5.0forFrame StructuresandFrom1.5 to 3.0forMasonry Wall Buildings
It is greater if properductility detailingis planned to be doneIt is greater ifadditional lateral load resisting systems, such as, bracesare provided
Guidelines for choosing R for RC frame structures
Ductility Detailing Nomenlature R
IS 456:2000 OMRF 3
IS 13920:1993 SMRF 5
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 18 / 27
IS 1893 (Part 1):2002
Response Reduction Factor in IS 1893 (Part 1):2002
http://find/8/10/2019 Ubdt Eqrds Beamer
49/92
Response Reduction Factor depends on two factors
The type ofLateral Load Resisting SystemThe degree ofDuctility detailing
R varies
From3.0 to 5.0forFrame StructuresandFrom1.5 to 3.0forMasonry Wall Buildings
It is greater if properductility detailingis planned to be doneIt is greater ifadditional lateral load resisting systems, such as, bracesare provided
Guidelines for choosing R for RC frame structures
Ductility Detailing Nomenlature R
IS 456:2000 OMRF 3
IS 13920:1993 SMRF 5
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 18 / 27
IS 1893 (Part 1):2002
Response Reduction Factor in IS 1893 (Part 1):2002
http://find/8/10/2019 Ubdt Eqrds Beamer
50/92
Response Reduction Factor depends on two factors
The type ofLateral Load Resisting SystemThe degree ofDuctility detailing
R varies
From3.0 to 5.0forFrame StructuresandFrom1.5 to 3.0forMasonry Wall Buildings
It is greater if properductility detailingis planned to be doneIt is greater ifadditional lateral load resisting systems, such as, bracesare provided
Guidelines for choosing R for RC frame structures
Ductility Detailing Nomenlature R
IS 456:2000 OMRF 3
IS 13920:1993 SMRF 5
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 18 / 27
IS 1893 (Part 1):2002
Response Reduction Factor in IS 1893 (Part 1):2002
http://find/8/10/2019 Ubdt Eqrds Beamer
51/92
Response Reduction Factor depends on two factors
The type ofLateral Load Resisting SystemThe degree ofDuctility detailing
R varies
From3.0 to 5.0forFrame StructuresandFrom1.5 to 3.0forMasonry Wall Buildings
It is greater if properductility detailingis planned to be doneIt is greater ifadditional lateral load resisting systems, such as, bracesare provided
Guidelines for choosing R for RC frame structures
Ductility Detailing Nomenlature R
IS 456:2000 OMRF 3
IS 13920:1993 SMRF 5
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 18 / 27
IS 1893 (Part 1):2002
Response Reduction Factor in IS 1893 (Part 1):2002
http://find/8/10/2019 Ubdt Eqrds Beamer
52/92
Response Reduction Factor depends on two factors
The type ofLateral Load Resisting SystemThe degree ofDuctility detailing
R varies
From3.0 to 5.0forFrame StructuresandFrom1.5 to 3.0forMasonry Wall Buildings
It is greater if properductility detailingis planned to be doneIt is greater ifadditional lateral load resisting systems, such as, bracesare provided
Guidelines for choosing R for RC frame structures
Ductility Detailing Nomenlature R
IS 456:2000 OMRF 3
IS 13920:1993 SMRF 5
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 18 / 27
IS 1893 (Part 1):2002
Response Reduction Factor in IS 1893 (Part 1):2002
http://find/8/10/2019 Ubdt Eqrds Beamer
53/92
Response Reduction Factor depends on two factors
The type ofLateral Load Resisting SystemThe degree ofDuctility detailing
R varies
From3.0 to 5.0forFrame StructuresandFrom1.5 to 3.0forMasonry Wall Buildings
It is greater if properductility detailingis planned to be doneIt is greater ifadditional lateral load resisting systems, such as, bracesare provided
Guidelines for choosing R for RC frame structures
Ductility Detailing Nomenlature R
IS 456:2000 OMRF 3
IS 13920:1993 SMRF 5
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 18 / 27
IS 1893 (Part 1):2002
Importance Factor (I)
http://find/8/10/2019 Ubdt Eqrds Beamer
54/92
Important structureswhich mustcontinue to function even after
occurrence of a severe earthquakemust be made stronger than theordinary structures
Design force for such structures is made more than for ordinarystructures
Importance factor (I) is given in Table 6, page 18
Importance factor for buildings is
1.5forlifeline building structures, and1.0forordinary building structures
Importance factor for structures other than buildings is not given in
IS 1893 (Part 1):2002Importance factor fordamsis3.0, and forcontainers of inflammableliquids, it is2.0, as given inIS 1893:1984(Table 4, page 19)
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 19 / 27
IS 1893 (Part 1):2002
Importance Factor (I)
http://find/8/10/2019 Ubdt Eqrds Beamer
55/92
Important structureswhich mustcontinue to function even after
occurrence of a severe earthquakemust be made stronger than theordinary structures
Design force for such structures is made more than for ordinarystructures
Importance factor (I) is given in Table 6, page 18
Importance factor for buildings is
1.5forlifeline building structures, and1.0forordinary building structures
Importance factor for structures other than buildings is not given in
IS 1893 (Part 1):2002Importance factor fordamsis3.0, and forcontainers of inflammableliquids, it is2.0, as given inIS 1893:1984(Table 4, page 19)
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 19 / 27
IS 1893 (Part 1):2002
Importance Factor (I)
http://find/8/10/2019 Ubdt Eqrds Beamer
56/92
Important structureswhich mustcontinue to function even after
occurrence of a severe earthquakemust be made stronger than theordinary structures
Design force for such structures is made more than for ordinarystructures
Importance factor (I) is given in Table 6, page 18
Importance factor for buildings is
1.5forlifeline building structures, and1.0forordinary building structures
Importance factor for structures other than buildings is not given in
IS 1893 (Part 1):2002Importance factor fordamsis3.0, and forcontainers of inflammableliquids, it is2.0, as given inIS 1893:1984(Table 4, page 19)
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 19 / 27
IS 1893 (Part 1):2002
Importance Factor (I)
http://find/8/10/2019 Ubdt Eqrds Beamer
57/92
Important structureswhich mustcontinue to function even after
occurrence of a severe earthquakemust be made stronger than theordinary structures
Design force for such structures is made more than for ordinarystructures
Importance factor (I) is given in Table 6, page 18
Importance factor for buildings is
1.5forlifeline building structures, and1.0forordinary building structures
Importance factor for structures other than buildings is not given in
IS 1893 (Part 1):2002Importance factor fordamsis3.0, and forcontainers of inflammableliquids, it is2.0, as given inIS 1893:1984(Table 4, page 19)
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 19 / 27
IS 1893 (Part 1):2002
Importance Factor (I)
http://find/8/10/2019 Ubdt Eqrds Beamer
58/92
Important structureswhich mustcontinue to function even after
occurrence of a severe earthquakemust be made stronger than theordinary structures
Design force for such structures is made more than for ordinarystructures
Importance factor (I) is given in Table 6, page 18
Importance factor for buildings is
1.5forlifeline building structures, and1.0forordinary building structures
Importance factor for structures other than buildings is not given in
IS 1893 (Part 1):2002Importance factor fordamsis3.0, and forcontainers of inflammableliquids, it is2.0, as given inIS 1893:1984(Table 4, page 19)
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 19 / 27
IS 1893 (Part 1):2002
Importance Factor (I)
http://find/8/10/2019 Ubdt Eqrds Beamer
59/92
Important structureswhich mustcontinue to function even after
occurrence of a severe earthquakemust be made stronger than theordinary structures
Design force for such structures is made more than for ordinarystructures
Importance factor (I) is given in Table 6, page 18
Importance factor for buildings is
1.5forlifeline building structures, and1.0forordinary building structures
Importance factor for structures other than buildings is not given in
IS 1893 (Part 1):2002Importance factor fordamsis3.0, and forcontainers of inflammableliquids, it is2.0, as given inIS 1893:1984(Table 4, page 19)
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 19 / 27
IS 1893 (Part 1):2002
Design Imposed Loads for Earthquake Force Calculation
http://find/8/10/2019 Ubdt Eqrds Beamer
60/92
The imposed loads to be considered for design of buildings are taken
as perIS 875 (Part 2):1987The natural period of vibration of a building depends on its
Massdue to(i)Dead Loads- Do not vary, and(ii)Imposed Loads- Do vary
Lateral Stiffness- Does not varyIt is therefore important that we correctly estimate theImposed Loadexisting on the buildingduring the earthquake
Thisreduction in the Imposed Loadis only for the purpose ofcomputing the vibration properties of the structure
ForGravity Load calculation,full Imposed Loadmust be considered
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 20 / 27
IS 1893 (Part 1):2002
Design Imposed Loads for Earthquake Force Calculation
http://find/8/10/2019 Ubdt Eqrds Beamer
61/92
The imposed loads to be considered for design of buildings are taken
as perIS 875 (Part 2):1987The natural period of vibration of a building depends on its
Massdue to(i)Dead Loads- Do not vary, and(ii)Imposed Loads- Do vary
Lateral Stiffness- Does not varyIt is therefore important that we correctly estimate theImposed Loadexisting on the buildingduring the earthquake
Thisreduction in the Imposed Loadis only for the purpose ofcomputing the vibration properties of the structure
ForGravity Load calculation,full Imposed Loadmust be considered
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 20 / 27
IS 1893 (Part 1):2002
Design Imposed Loads for Earthquake Force Calculation
http://find/8/10/2019 Ubdt Eqrds Beamer
62/92
The imposed loads to be considered for design of buildings are taken
as perIS 875 (Part 2):1987The natural period of vibration of a building depends on its
Massdue to(i)Dead Loads- Do not vary, and(ii)Imposed Loads- Do vary
Lateral Stiffness- Does not varyIt is therefore important that we correctly estimate theImposed Loadexisting on the buildingduring the earthquake
Thisreduction in the Imposed Loadis only for the purpose ofcomputing the vibration properties of the structure
ForGravity Load calculation,full Imposed Loadmust be considered
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 20 / 27
IS 1893 (Part 1):2002
Design Imposed Loads for Earthquake Force Calculation
http://find/8/10/2019 Ubdt Eqrds Beamer
63/92
The imposed loads to be considered for design of buildings are taken
as perIS 875 (Part 2):1987The natural period of vibration of a building depends on its
Massdue to(i)Dead Loads- Do not vary, and(ii)Imposed Loads- Do vary
Lateral Stiffness- Does not varyIt is therefore important that we correctly estimate theImposed Loadexisting on the buildingduring the earthquake
Thisreduction in the Imposed Loadis only for the purpose ofcomputing the vibration properties of the structure
ForGravity Load calculation,full Imposed Loadmust be considered
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 20 / 27
IS 1893 (Part 1):2002
Design Imposed Loads for Earthquake Force Calculation
http://find/8/10/2019 Ubdt Eqrds Beamer
64/92
The imposed loads to be considered for design of buildings are taken
as perIS 875 (Part 2):1987The natural period of vibration of a building depends on its
Massdue to(i)Dead Loads- Do not vary, and(ii)Imposed Loads- Do vary
Lateral Stiffness- Does not varyIt is therefore important that we correctly estimate theImposed Loadexisting on the buildingduring the earthquake
Thisreduction in the Imposed Loadis only for the purpose ofcomputing the vibration properties of the structure
ForGravity Load calculation,full Imposed Loadmust be considered
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 20 / 27
IS 1893 (Part 1):2002
Seismic Weight (W) of a Building
http://find/8/10/2019 Ubdt Eqrds Beamer
65/92
Seismic Weight (W)
Seismic weight is the sum ofDead Load, andan appropriate part of Imposed Load, that part which islikelyto bepresent during an earthquake
Part of the Imposed Load to be considered while calculating the
Seismic Weight isFloors
25% of Imposed Loadif Imposed Load 3.0 kN/m2
50% of Imposed Loadif Imposed Load > 3.0 kN/m2
Roof
Nil, as the likelihood of Imposed Load being present on the roofat the time of an earthquake is considered to be extremely low(7.3.2, page 17)
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 21 / 27
IS 1893 (Part 1):2002
Seismic Weight (W) of a Building
http://find/8/10/2019 Ubdt Eqrds Beamer
66/92
Seismic Weight (W)
Seismic weight is the sum ofDead Load, andan appropriate part of Imposed Load, that part which islikelyto bepresent during an earthquake
Part of the Imposed Load to be considered while calculating the
Seismic Weight isFloors
25% of Imposed Loadif Imposed Load 3.0 kN/m2
50% of Imposed Loadif Imposed Load > 3.0 kN/m2
Roof
Nil, as the likelihood of Imposed Load being present on the roofat the time of an earthquake is considered to be extremely low(7.3.2, page 17)
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 21 / 27
IS 1893 (Part 1):2002
Seismic Weight (W) of a Building
http://find/8/10/2019 Ubdt Eqrds Beamer
67/92
Seismic Weight (W)
Seismic weight is the sum ofDead Load, andan appropriate part of Imposed Load, that part which islikelyto bepresent during an earthquake
Part of the Imposed Load to be considered while calculating the
Seismic Weight isFloors
25% of Imposed Loadif Imposed Load 3.0 kN/m2
50% of Imposed Loadif Imposed Load > 3.0 kN/m2
Roof
Nil, as the likelihood of Imposed Load being present on the roofat the time of an earthquake is considered to be extremely low(7.3.2, page 17)
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 21 / 27
IS 1893 (Part 1):2002
Methods of Estimating Seismic Forces
http://find/8/10/2019 Ubdt Eqrds Beamer
68/92
If Dynamic Analysis isnotrequired as per the code, Equivalent Static
Methodcan be usedDynamic Analysismustbe performed under the followingcircumstances
Dynamic Analysismustbe used in the following cases(7.8.1, page 25)
Zones II, III Zones IV, VRegular Buildings h>90m h>40m
Irregular Buildings h>40m h>12m
Dynamic analysis, when required, must be performed either by the
Time History Analysisor by theResponse Spectrum Method (7.8.2,page 25)WhenTime History Analysisis used, the designer must
Choose anappropriate ground motion, andUseaccepted principles of dynamicsfor theanalysis(7.8.3,page23)
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 22 / 27
IS 1893 (Part 1):2002
Methods of Estimating Seismic Forces
http://find/8/10/2019 Ubdt Eqrds Beamer
69/92
If Dynamic Analysis isnotrequired as per the code, Equivalent StaticMethodcan be usedDynamic Analysismustbe performed under the followingcircumstances
Dynamic Analysismustbe used in the following cases(7.8.1, page 25)
Zones II, III Zones IV, VRegular Buildings h>90m h>40m
Irregular Buildings h>40m h>12m
Dynamic analysis, when required, must be performed either by the
Time History Analysisor by theResponse Spectrum Method (7.8.2,page 25)WhenTime History Analysisis used, the designer must
Choose anappropriate ground motion, andUseaccepted principles of dynamicsfor theanalysis(7.8.3,page23)
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 22 / 27
IS 1893 (Part 1):2002
Methods of Estimating Seismic Forces
http://find/8/10/2019 Ubdt Eqrds Beamer
70/92
If Dynamic Analysis isnotrequired as per the code, Equivalent StaticMethodcan be usedDynamic Analysismustbe performed under the followingcircumstances
Dynamic Analysismustbe used in the following cases(7.8.1, page 25)
Zones II, III Zones IV, VRegular Buildings h>90m h>40m
Irregular Buildings h>40m h>12m
Dynamic analysis, when required, must be performed either by the
Time History Analysisor by theResponse Spectrum Method (7.8.2,page 25)WhenTime History Analysisis used, the designer must
Choose anappropriate ground motion, andUseaccepted principles of dynamicsfor theanalysis(7.8.3,page23)
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 22 / 27
IS 1893 (Part 1):2002
Methods of Estimating Seismic Forces
http://find/8/10/2019 Ubdt Eqrds Beamer
71/92
If Dynamic Analysis isnotrequired as per the code, Equivalent StaticMethodcan be usedDynamic Analysismustbe performed under the followingcircumstances
Dynamic Analysismustbe used in the following cases(7.8.1, page 25)
Zones II, III Zones IV, VRegular Buildings h>90m h>40m
Irregular Buildings h>40m h>12m
Dynamic analysis, when required, must be performed either by the
Time History Analysisor by theResponse Spectrum Method (7.8.2,page 25)WhenTime History Analysisis used, the designer must
Choose anappropriate ground motion, andUseaccepted principles of dynamicsfor theanalysis(7.8.3,page23)
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 22 / 27
IS 1893 (Part 1):2002
Equivalent Static Method
http://find/8/10/2019 Ubdt Eqrds Beamer
72/92
Design Sesimic Base Shear, VB=AhW (7.5.3, page 24)
Distribute VB to different floor levels, Qi =VBWih
2
i
nj=1Wjh
2j (7.7.1,
page 24)
Apply the floor loads Qialong one directionand compute the seismicdesign forces
Apply the same floor loads Qiin a direction perpendicular to the firstCombine the seismic design forces with other design forces, as per theload combinations required
Design the structural membersfor the most severe load combination
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 23 / 27
IS 1893 (Part 1):2002
Equivalent Static Method
http://find/8/10/2019 Ubdt Eqrds Beamer
73/92
Design Sesimic Base Shear, VB=AhW (7.5.3, page 24)
Distribute VB to different floor levels, Qi =VBWih
2
i
nj=1Wjh
2j (7.7.1,
page 24)
Apply the floor loads Qialong one directionand compute the seismicdesign forces
Apply the same floor loads Qiin a direction perpendicular to the firstCombine the seismic design forces with other design forces, as per theload combinations required
Design the structural membersfor the most severe load combination
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 23 / 27
IS 1893 (Part 1):2002
Equivalent Static Method
http://find/8/10/2019 Ubdt Eqrds Beamer
74/92
Design Sesimic Base Shear, VB=AhW (7.5.3, page 24)
Distribute VB to different floor levels, Qi =VBWih
2
i
nj=1Wjh
2j (7.7.1,
page 24)
Apply the floor loads Qialong one directionand compute the seismicdesign forces
Apply the same floor loads Qiin a direction perpendicular to the firstCombine the seismic design forces with other design forces, as per theload combinations required
Design the structural membersfor the most severe load combination
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 23 / 27
IS 1893 (Part 1):2002
Equivalent Static Method
( )
http://goforward/http://find/http://goback/8/10/2019 Ubdt Eqrds Beamer
75/92
Design Sesimic Base Shear, VB=AhW (7.5.3, page 24)
Distribute VB to different floor levels, Qi =VBWih
2
i
nj=1Wjh
2j (7.7.1,
page 24)
Apply the floor loads Qialong one directionand compute the seismicdesign forces
Apply the same floor loads Qiin a direction perpendicular to the firstCombine the seismic design forces with other design forces, as per theload combinations required
Design the structural membersfor the most severe load combination
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 23 / 27
IS 1893 (Part 1):2002
Equivalent Static Method
D i S i i B Sh V A W ( 3 2 )
http://find/8/10/2019 Ubdt Eqrds Beamer
76/92
Design Sesimic Base Shear, VB=AhW (7.5.3, page 24)
Distribute VB to different floor levels, Qi =VBWih
2i
nj=1Wjh
2j (7.7.1,
page 24)
Apply the floor loads Qialong one directionand compute the seismicdesign forces
Apply the same floor loads Qiin a direction perpendicular to the firstCombine the seismic design forces with other design forces, as per theload combinations required
Design the structural membersfor the most severe load combination
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 23 / 27
IS 1893 (Part 1):2002
Equivalent Static Method
D i S i i B Sh V A W (7 5 3 24)
http://find/8/10/2019 Ubdt Eqrds Beamer
77/92
Design Sesimic Base Shear, VB=AhW (7.5.3, page 24)
Distribute VB to different floor levels, Qi =VBWih
2i
nj=1Wjh
2j (7.7.1,
page 24)
Apply the floor loads Qialong one directionand compute the seismicdesign forces
Apply the same floor loads Qiin a direction perpendicular to the firstCombine the seismic design forces with other design forces, as per theload combinations required
Design the structural membersfor the most severe load combination
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 23 / 27
IS 1893 (Part 1):2002
Steps for Equivalent Static Procedure
Z F t (Z ) (T bl 2 16)
http://find/8/10/2019 Ubdt Eqrds Beamer
78/92
Zone Factor (Z)(Table 2, page 16)
Height of building, hCheck if Equivalent Static Method can be usedClause 7.8.1, page 25
Importance Factor (I),(Table 6, page 18)
Response Reduction Factor (R),(Table 7, page 23)
Soil Type - One of Type I(Rock or Hard Soil), Type II(Medium Soil)or type III(Soft Soil)
Damping Ratio - Usually 5% for Reinforced Concrete and 2% forSteel(7.8.2.1, page 25)
Multiplying Factor for
Sa
g for damping ratios other than 5%(Table 3,page 17)
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 24 / 27
IS 1893 (Part 1):2002
Steps for Equivalent Static Procedure
Z F t (Z ) (T bl 2 16)
http://find/8/10/2019 Ubdt Eqrds Beamer
79/92
Zone Factor (Z)(Table 2, page 16)
Height of building, hCheck if Equivalent Static Method can be usedClause 7.8.1, page 25
Importance Factor (I),(Table 6, page 18)
Response Reduction Factor (R),(Table 7, page 23)
Soil Type - One of Type I(Rock or Hard Soil), Type II(Medium Soil)or type III(Soft Soil)
Damping Ratio - Usually 5% for Reinforced Concrete and 2% forSteel(7.8.2.1, page 25)
Multiplying Factor for
Sa
g for damping ratios other than 5%(Table 3,page 17)
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 24 / 27
IS 1893 (Part 1):2002
Steps for Equivalent Static Procedure
Zone Factor (Z ) (Table 2 page 16)
http://find/8/10/2019 Ubdt Eqrds Beamer
80/92
Zone Factor (Z)(Table 2, page 16)
Height of building, hCheck if Equivalent Static Method can be usedClause 7.8.1, page 25
Importance Factor (I),(Table 6, page 18)
Response Reduction Factor (R),(Table 7, page 23)
Soil Type - One of Type I(Rock or Hard Soil), Type II(Medium Soil)or type III(Soft Soil)
Damping Ratio - Usually 5% for Reinforced Concrete and 2% forSteel(7.8.2.1, page 25)
Multiplying Factor for Sag
for damping ratios other than 5%(Table 3,page 17)
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 24 / 27
IS 1893 (Part 1):2002
Steps for Equivalent Static Procedure contd...
Fundamental Natural Period (7 6 page 24)
http://find/8/10/2019 Ubdt Eqrds Beamer
81/92
Fundamental Natural Period(7.6, page 24)
Ta = 0.075h
0.75
RC frames without brick infill panelsTa = 0.085h0.75 Steel frames without bracings
Ta = 0.09h
d All other buildings
Average Response Acceleration CoefficientSag
(Fig. 2, page 16)
using (i) Soil type, (ii) Fundamental Natural Period and (iii) DampingRatio
Design Horizontal Seismic Coefficient Ah = ZI2R
Sag
Design Seismic Base Shear VB=AhW (7.5.3, page 24)
Design lateral load at Floor i, Qi=VBWih
2
inj=1Wjh
2j (7.7.1, page 24)
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 25 / 27 IS 1893 (Part 1):2002
Steps for Equivalent Static Procedure contd...
Fundamental Natural Period (7 6 page 24)
http://find/8/10/2019 Ubdt Eqrds Beamer
82/92
Fundamental Natural Period(7.6, page 24)
Ta = 0.075
h0.75
RC frames without brick infill panelsTa = 0.085h0.75 Steel frames without bracings
Ta = 0.09h
d All other buildings
Average Response Acceleration CoefficientSag
(Fig. 2, page 16)
using (i) Soil type, (ii) Fundamental Natural Period and (iii) DampingRatio
Design Horizontal Seismic Coefficient Ah = ZI2R
Sag
Design Seismic Base Shear VB=AhW (7.5.3, page 24)
Design lateral load at Floor i, Qi=VBWih
2
inj=1Wjh
2j (7.7.1, page 24)
Satish A. Annigeri (BVBCET, Hubli) Response Spectrum Method 10 May, 2007 25 / 27 IS 1893 (Part 1):2002
Steps for Equivalent Static Procedure contd...
Fundamental Natural Period (7 6 page 24)
http://find/8/10/2019 Ubdt Eqrds Beamer
83/92
Fundamental Natural Period(7.6, page 24)
Ta = 0.075
h0.75
RC frames without brick infill panelsTa = 0.085h0.75 Steel frames without bracings
Ta = 0.09h
d All other buildings
Average Response Acceleration CoefficientSag
(Fig. 2, page 16)
using (i) Soil type, (ii) Fundamental Natural Period and (iii) DampingRatio
Design Horizontal Seismic Coefficient Ah = ZI2R
Sag
Design Seismic Base Shear VB=AhW (7.5.3, page 24)
Design lateral load at Floor i, Qi=VBWih
2
i
nj=1Wjh
2j (7.7.1, page 24)
Satish A. Annigeri (BVBCET Hubli) Response Spectrum Method 10 May 2007 25 / 27 IS 1893 (Part 1):2002
Steps for Equivalent Static Procedure contd...
Fundamental Natural Period (7 6 page 24)
http://find/8/10/2019 Ubdt Eqrds Beamer
84/92
Fundamental Natural Period(7.6, page 24)
Ta = 0.075
h0.75
RC frames without brick infill panelsTa = 0.085h0.75 Steel frames without bracings
Ta = 0.09h
d All other buildings
Average Response Acceleration CoefficientSag
(Fig. 2, page 16)
using (i) Soil type, (ii) Fundamental Natural Period and (iii) DampingRatio
Design Horizontal Seismic Coefficient Ah = ZI2R
Sag
Design Seismic Base Shear VB=AhW (7.5.3, page 24)
Design lateral load at Floor i, Qi=VBWih
2
i
nj=1Wjh
2j (7.7.1, page 24)
Satish A. Annigeri (BVBCET Hubli) Response Spectrum Method 10 May 2007 25 / 27 IS 1893 (Part 1):2002
Steps for Equivalent Static Procedure contd...
Fundamental Natural Period (7 6 page 24)
http://find/8/10/2019 Ubdt Eqrds Beamer
85/92
Fundamental Natural Period(7.6, page 24)
Ta
= 0.075h0.75 RC frames without brick infill panelsTa = 0.085h
0.
75 Steel frames without bracings
Ta = 0.09h
d All other buildings
Average Response Acceleration CoefficientSag
(Fig. 2, page 16)
using (i) Soil type, (ii) Fundamental Natural Period and (iii) DampingRatio
Design Horizontal Seismic Coefficient Ah = ZI2R
Sag
Design Seismic Base Shear VB=AhW (7.5.3, page 24)
Design lateral load at Floor i, Qi=VBWih
2
i
nj=1Wjh
2j (7.7.1, page 24)
Satish A. Annigeri (BVBCET Hubli) Response Spectrum Method 10 May 2007 25 / 27 IS 1893 (Part 1):2002
Response Spectrum Method (7.8.4, page 25)
Undamped free vibration of the entire building using established
http://find/8/10/2019 Ubdt Eqrds Beamer
86/92
Undamped free vibration of the entire building using establishedmethods of mechanics
Number of modes to be considered must be such that thesum totalof modal masses of all modes considered is at least 90% of the totalseismic massPeak response quantities, such as, member design forces,
displacements, storey forces, storey shears and base reactions shall becombined as perComplete Quadratic Combination (CQC)methodModal Mass Mkof mode kis given as follows
Mk=[n
i=1 Wiik]2
gni=1 Wi
2ik
Implementing Response Spectrum Method by hand is tedious anderror prone as thecomputations required are complexIt is better to use a computer program for Response SpectrumMethod
Satish A Annigeri (BVBCET Hubli) Response Spectrum Method 10 May 2007 26 / 27 IS 1893 (Part 1):2002
Response Spectrum Method (7.8.4, page 25)
Undamped free vibration of the entire building using established
http://find/8/10/2019 Ubdt Eqrds Beamer
87/92
p g gmethods of mechanics
Number of modes to be considered must be such that thesum totalof modal masses of all modes considered is at least 90% of the totalseismic massPeak response quantities, such as, member design forces,
displacements, storey forces, storey shears and base reactions shall becombined as perComplete Quadratic Combination (CQC)methodModal Mass Mkof mode kis given as follows
Mk=[n
i=1 Wiik]2
gni=1 Wi
2ik
Implementing Response Spectrum Method by hand is tedious anderror prone as thecomputations required are complexIt is better to use a computer program for Response SpectrumMethod
Satish A Annigeri (BVBCET Hubli) Response Spectrum Method 10 May 2007 26 / 27 IS 1893 (Part 1):2002
Response Spectrum Method (7.8.4, page 25)
Undamped free vibration of the entire building using established
http://find/8/10/2019 Ubdt Eqrds Beamer
88/92
p g gmethods of mechanics
Number of modes to be considered must be such that thesum totalof modal masses of all modes considered is at least 90% of the totalseismic massPeak response quantities, such as, member design forces,
displacements, storey forces, storey shears and base reactions shall becombined as perComplete Quadratic Combination (CQC)methodModal Mass Mkof mode kis given as follows
Mk=[n
i=1 Wiik]2
gni=1 Wi
2ik
Implementing Response Spectrum Method by hand is tedious anderror prone as thecomputations required are complexIt is better to use a computer program for Response SpectrumMethod
Satish A Annigeri (BVBCET Hubli) Response Spectrum Method 10 May 2007 26 / 27 IS 1893 (Part 1):2002
Response Spectrum Method (7.8.4, page 25)
Undamped free vibration of the entire building using established
http://find/8/10/2019 Ubdt Eqrds Beamer
89/92
p g gmethods of mechanics
Number of modes to be considered must be such that thesum totalof modal masses of all modes considered is at least 90% of the totalseismic massPeak response quantities, such as, member design forces,
displacements, storey forces, storey shears and base reactions shall becombined as perComplete Quadratic Combination (CQC)methodModal Mass Mkof mode kis given as follows
Mk=[n
i=1 Wiik]2
gni=1 Wi
2ik
Implementing Response Spectrum Method by hand is tedious anderror prone as thecomputations required are complexIt is better to use a computer program for Response SpectrumMethod
Satish A Annigeri (BVBCET Hubli) Response Spectrum Method 10 May 2007 26 / 27 IS 1893 (Part 1):2002
Response Spectrum Method (7.8.4, page 25)
Undamped free vibration of the entire building using established
http://find/8/10/2019 Ubdt Eqrds Beamer
90/92
methods of mechanics
Number of modes to be considered must be such that thesum totalof modal masses of all modes considered is at least 90% of the totalseismic massPeak response quantities, such as, member design forces,
displacements, storey forces, storey shears and base reactions shall becombined as perComplete Quadratic Combination (CQC)methodModal Mass Mkof mode kis given as follows
Mk=[n
i=1 Wiik]2
gni=1 Wi
2ik
Implementing Response Spectrum Method by hand is tedious anderror prone as thecomputations required are complexIt is better to use a computer program for Response SpectrumMethod
Satish A Annigeri (BVBCET Hubli) Response Spectrum Method 10 May 2007 26 / 27 IS 1893 (Part 1):2002
Response Spectrum Method (7.8.4, page 25)
Undamped free vibration of the entire building using established
http://find/8/10/2019 Ubdt Eqrds Beamer
91/92
methods of mechanics
Number of modes to be considered must be such that thesum totalof modal masses of all modes considered is at least 90% of the totalseismic massPeak response quantities, such as, member design forces,
displacements, storey forces, storey shears and base reactions shall becombined as perComplete Quadratic Combination (CQC)methodModal Mass Mkof mode kis given as follows
Mk=[n
i=1 Wiik]2
gni=1 Wi
2ik
Implementing Response Spectrum Method by hand is tedious anderror prone as thecomputations required are complexIt is better to use a computer program for Response SpectrumMethod
Satish A Annigeri (BVBCET Hubli) Response Spectrum Method 10 May 2007 26 / 27 IS 1893 (Part 1):2002
http://find/8/10/2019 Ubdt Eqrds Beamer
92/92
Thank You
Questions?!
Satish A Annigeri (BVBCET Hubli) Response Spectrum Method 10 May 2007 27 / 27
http://find/