20121127 gen advanced webinar time history analysis

7/29/2019 20121127 Gen Advanced Webinar Time History Analysis

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midas Gen

midas Gen

Advanced Webinar

Dynamic Analysis Time History


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MIDAS Information Technology Co., Ltd. 2

Integrated Design System for buildings and General StructuresWhy midas Gen

Stadiums

Power Plants

Hangar

Airport

Transmission

Towers

Cranes

Pressure Vessels

Machine Structures

Underground

Structures

Versatility

Specialty Structures Applications

Beijing National Stadium Beijing National Aquatic Center Beijing Olympic Basketball Gymnasium

Seoul World Cup Stadium JeonJu World Cup Stadium DeaJeon World Cup Stadium

USA Pavilion China Pavilion German Pavilion


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midas Gen

Contents

1. Seismic Design for New Buildings

2. Seismic Design for Existing Buildings

3. Base Isolators and Dampers

4. Mass

5. Damping

6. Modal Analysis

7. Fiber Analysis


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One Stop Solution for Building and General Structures

4

Seismic Design for New Buildings

Seismic Design Process as per Eurocode8 (New buildings)

Seismic Design

Performance Requirement

Ground Condition

Seismic Action

Combination of Seismic Action

Criteria for Structural Regularity

Seismic Analysis

Safety Verification

Capacity Design & Detailing

Seismic Zone

Representation of seismic action

[Method of Analysis]

Lateral Force method of Analysis

Modal Response Spectrum Analysis

Pushover Analysis

Inelastic Time History Analysis


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Performance Requirement and Compliance Criteria


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 for New BuildingsSeismic Design


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Ground Conditions



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Seismic action

I II III IV

T=475 year 0.8 1.0 1.2 1.4

Importance Factor

Representation of Seismic Action

a. Response Spectrum- Horizontal elastic response spectrum

- Vertical elastic response spectrum

- Horizontal design response spectrum (Behavior factor, q, is considered.)

- Vertical design response spectrum (Behavior factor, q, is considered.)

b. Time history

[Horizontal Elastic Spectrum]

Seismic Design Seismic Design for New Buildings


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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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Capacity Design

Ductility Class

DCL (Low ductility)

DCM (Medium ductility)

DCH (High ductility)

Structure Type & Behavior Factor



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Design Procedure

Capacity Design Feature

structures to provide the appropriate amount of ductility in the corresponding ductility classes. Automatic capacity design capability for beam, column, wall and beam-column joint EN 1998-1: 2004 (DCM/DCH), NTC2008 (CD B, CD A), ACI318-05 Design action effects are calculated in accordance with the capacity design rule. Special provision for

ductile primary seismic walls is considered. Detailing for local ductility is considered.

- max/min reinforcement ratio of the tension zone- the spacing of hoops within the critical region- mechanical volumetric ratio of confining hoops with the critical regions

Capacity design shear forces on beams

Define ductility class and check design results Design envelope moments in walls



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Design Procedure

Design member forces (Design moments)

Where,MRb: Beam moment resistance

Mce: column member force due to seismic load case



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Design Procedure

Design member forces (Design shear forces)

Capacity design values of shear forces on beams

Capacity design shear force in columns

Where, MRb: Beam moment resistance

MRc: Column moment resistance

(calculated using same axial forceratio in PM interaction curve)

Mce: Bending moment of column due to

seismic load case



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Design Procedure

Design envelope for bending moments in slender walls Design envelope of the shear forces in the walls of a dual system

Design member forces (Wall design forces)

Wall systems Dual systems



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Seismic Assessment of Buildings as per Eurocode8 (Existing buildings)


Knowledge Level

Seismic Action


Seismic Analysis

Safety Verification

Decision for Structural Intervention

Seismic Zone

Representation of seismic action

[Method of Analysis]

Lateral Force method of Analysis

Modal Response Spectrum AnalysisPushover Analysis

Inelastic Time History Analysis

Seismic Design for Existing BuildingsSeismic 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 strengthDamage Limitation (DL)

Ductile: yield strength

Brittle: yield strength

Infills: story drift

Seismic Design Seismic Design for Existing Buildings


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Knowledge Levels



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Pushover Analysis

Why Pushover Analysis?

a) To verify or revise the over strength ratio values (alpha_u/alpha_1)

b) To estimate the expected plastic mechanisms and the distribution of damage

c) To assess the structural performance of existing or retrofitted buildings

d) As an alternative to the design based on linear-elastic analysis which uses the

behavior factor, q

alpha_u

alpha_1

Hinge status for alpha_uHinge status for alpha_1

PushoverGlobal Control

Define LateralLoads

Define HingeProperties

Assign HingesPerformAnalysis

Check PushoverCurve and

Target Disp.

Check Hinge

Status

Safety

Verification

Process in midas Gen



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Safety Verification



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Base Isolators and Dampers

Base Isolators and Dampers

Dynamics

Objectives of Seismic Isolation Systems

Enhance performance of structures at all hazard levels by:

Minimizing interruption of use of facility (e.g., Immediate

Occupancy Performance Level)

Reducing damaging deformations in structural and

nonstructural components

Reducing acceleration response to minimize contents relateddamage

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 1st story and 3rd story]


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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

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 mod

al response will be calculated based on the user defined da

mping ratios.

Mass & Stiffness Proportional

Damping coefficients are computed for mass proportional d

amping and stiffness proportional damping.

Strain Energy Proportional

Damping ratios for each mode are automatically calculated u

sing the damping ratios specified for element groups and bo

undary groups in Group Damping, which are used to formul

ate the damping matrix.

DampingDynamics


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Modal Analysis

Eigen Vectors

Subspace IterationThis method is effectively used when performing eigenvalue analysis for a finite element system of any scale and

commonly used among engineers.

LanczosTri-diagonal Matrix is used to perform eigenvalue analysis. It is particularly useful for finding decompositions of

very large sparse matrices. The performance of Lanczos method is superior to that of the Subspace Iteration.

Ritz VectorsUnlike 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

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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20121127 gen advanced webinar time history analysis

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