Seismic Specific Functionality in Midas Gen_Eurocode

8/12/2019 Seismic Specific Functionality in Midas Gen_Eurocode

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Seismic Specific Functionality

Seismic Design for New Bui ld ings

Seismic Design for Exist ing Bui ld ings

Base Isolators and Dampers

Mass

Damping

Modal Analys is

Fiber Analys is

03

14

20

26

26

29

31

based on Eurocode8


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Seismic Design for New Buildings




Mass

Damping

Modal Analys is

Fiber Analys is

03

14

20

26

26

29

31


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One Stop Solution for Building and General Structures

5

Performance Requirement and Compliance Criteria

Performance Requirement

No-collapse

TNCR=475 year

W/O limitation of collapse

Damage Limitation

TDLR=95 year

W/O limitation of use

Compliance Criteria

Ultimate limit states

Resistance and Energy Dissipation Capacity need to be checked.

Global level verification

OverturningSliding

Member Level

Ductile component: Plastic Rotation

Brittle component: Resistance

Damage limitation states

Global Level: Inter-story drift

Member Level: Resistance (ULS)

Seismic Design Flowchart (New Buildings)Seismic Design


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Ground Conditions



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Combination of Seismic Action

Load Combination of permanent loads and variable loads

100:30 Rule(1.0Ex + 0.3Ey), (0.3Ex + 1.0Ey)

(1.0Ex + 0.3Ey + 0.3Ez ), (0.3Ex + 1.0Ey + 0.3Ez), (0.3Ex + 0.3Ey + 1.0Ez)



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Criteria for Structural Regularity

Structural Regularity

Analysis Method

LateralForcemethod ofAnalysis

ModalResponseSpectrumAnalysis

PushoverAnalysis

InelasticTimeHistoryAnalysis



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Safety Verification

Ultimate Limit States

Resistance condition: MRd>= MEd, VRd>= VEdGlobal and local ductility condition: MRc>= 1.3 MRbEquilibrium condition : overturning or sliding

Resistance of horizontal diaphragm

Resistance of foundations

Seismic joint condition

Damage limitation

Limitation of story drift



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Seismic Design

Ductility Class

DCL (Low ductility)

DCM (Medium ductility)

DCH (High ductility)

Structure Type & Behavior Factor



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Where,MRb: Beam moment resistanceMce: Column member force

due to seismic load case

Capacity design values of

shear forces on beams

Capacity design shear force

in columns

Design Forces of Capacity Design (Beam/Column)



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Design Forces of Capacity Design (Wall)

Fig. 5.3: Design envelope for bending moments in slender walls Fig. 5.4: Design envelope of the shear forces in the walls of a dual system

Wall systems Dual systems



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Seismic Design for Existing Buildings

Seismic Design for New Bui ld ingsSeismic Design for Exist ing Bui ld ings


Mass

Damping

Modal Analys is

Fiber Analys is

03

14

20

26

26

29

31


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Seismic Assessment of Buildings as per Eurocode8 (Existing buildings)


Knowledge Level

Seismic Action

Combination of Seismic Action

Seismic Analysis

Safety Verification

Decision for Structural Intervention

Seismic ZoneRepresentation of seismic action

[Method of Analysis]

Lateral Force method of Analysis

Modal Response Spectrum AnalysisPushover Analysis

Inelastic Time History Analysis

Seismic Design Flowchart (Existing Buildings)Seismic Design


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Performance Requirement and Compliance Criteria


Near Collapse (NC) TNCR=2475years

Significant Damage (SD) TNCR=475years

Damage Limitation (DL) TNCR=225years

Compliance Criteria

Near Collapse (NC)

Ductile: ultimate deformation (plastic rotation)

Brittle: ultimate strength

Significant Damage (SD)Ductile: damage-related deformation

Brittle: conservatively estimated strength

Damage Limitation (DL)

Ductile: yield strength

Brittle: yield strength

Infills: story drift


Operat ionalDamage

Limi tat ion

Signi f icant

Damage

Near

Col lapse


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Knowledge Levels



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Safety Verification



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Mass

Damping

Modal Analys is

Fiber Analys is

03

14

20

26

26

29

31


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Dynamics

Objectives of Seismic Isolation Systems

Enhance performance of structures at all hazard levels by:

Minimizing interruption of use of facility

Reducing damaging deformations in structural and

nonstructural components

Reducing acceleration response to minimize contents related

damage

Characteristics of Well-Designed Seismic Isolation Systems

Flexibility to increase period of vibration and thus reduce

force response

Energy dissipation to control the isolation system

displacement

Rigidity under low load levels such as wind and minor

earthquakes


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Base Isolators and DampersDynamics

Base Isolators:

Lead Rubber Bearing Isolator

Friction Pendulum System Isolator

Applicable Base Isolators in midas Gen


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[Viscoelastic Damper] [Hysteretic System Damper]

Applicable Dampers in midas Gen



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Analysis Results (Graph & Text output)


[Hysteretic Graph of Friction pendulum system isolator]

[Hysteretic Graph of Lead rubber bearing isolator]

[Time History Graph at 1ststory and 3rdstory]


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[Without Isolators]

[With Isolators]

Shear force at 1ststory column Displacement - Frequency

Displacement - FrequencyShear force at 1ststory column


Analysis Results (Time History Graph)


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Mass & Damping Ratio




Mass

Damping

Modal Analys is

Fiber Analys is

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14

20

26

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29

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Mass

Nodal Masses Floor Diaphragm Masses

Loads to Masses

Consistent Mass

Self-weight to Mass

[Lumped Mass and Consistent Mass]

Lumped Mass

Consistent Mass

MassDynamics

210 0 0 0 0 0 1

0 210 0 0 0 0 1

0 0 210 0 0 0 1

0 0 0 210 0 0 2420

0 0 0 0 210 0 2

0 0 0 0 0 210 2

L

u

ALI

u

2 2

2 2

140 0 0 70 0 0 1

0 156 22 0 54 13 1

0 22 4 0 13 3 1

70 0 0 140 0 0 2420

0 54 13 0 156 22 2

20 13 3 0 22 4

c

u

L L

L L L LALI

u

L L

L L L L

1 2

u1 u2

1 2

1 2


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Damping

ModalUser defines the damping ratio for each mode, and the modal

response will be calculated based on the user defined damping

ratios.

Mass & Stiffness Proportional

Damping coefficients are computed for mass proportional

damping and stiffness proportional damping.

Strain Energy Proportional

Damping ratios for each mode are automatically calculated using

the damping ratios specified for element groups and boundary

groups in Group Damping, which are used to formulate the

damping matrix.

DampingDynamics


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Modal Analysis




Mass

Damping

Modal Analys is

Fiber Analys is

03

14

20

26

26

29

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Modal Analysis

Eigen Vectors

Subspace Iteration

This method is effectively used when performing eigenvalue analysis for a finite element system of a large scale

(large matrix system) and commonly used among engineers.

Lanczos

Tri-diagonal Matrix is used to perform eigenvalue analysis. This method is effectively used when performing

eigenvalue analysis for lower modes.

Ritz Vectors

Unlike the natural eigenvalue modes, load dependent Ritz vectors produce more reliable results in dynamic analyses

with relatively fewer modes. The Ritz Vectors are generated reflecting the spatial distribution or the characteristics of the

dynamic loading.

Modal AnalysisDynamics


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Fiber Analysis




Mass

Damping

Modal Analys is

Fiber Analys is

03

14

20

26

26

29

31


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Fiber Analysis

Fiber Cell Result PlottingSection division for Fiber Model definition

Kent & Park Model Menegotto-Pinto Model

Inelastic Material Properties (Stress-strain curve)

Fiber AnalysisDynamics


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Seismic Specific Functionality in Midas Gen_Eurocode

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