PBPD of Steel MRF: DESIGN CASE STUDY · One Week FDP Fundamentals of Structural Dynamics and...

One Week FDPFundamentals of Structural Dynamics and Application to

Earthquake Engineeringin Sanjay Ghodawat Group of Institute

PBPD of Steel MRF: DESIGN CASE STUDY

Dr. Swapnil B. Kharmale

Assistant Professor, Applied MechanicsGovernment College of Engineering and Research, Avasari

[email protected]

December 11, 2015Dr. Swapnil B. Kharmale Fundamentals of Structural Dynamics and Application to Earthquake Engineering

Nine-storey Steel Moment Resisting Frame

Dr. Swapnil B. Kharmale Fundamentals of Structural Dynamics and Application to Earthquake Engineering

VALIDATION OF DESIGN


Analytical Validation of Design

Modelling

Using Abaqus as generalpurpose finite elementpackage

Beams and Columns as lineelement (B21)

Elastic-perfectly plasticsteel: Fy = 344.74 MPa

Lumped mass model with5% Rayleigh damping

P-Delta and gravity loadingare not considered

Abaqus Modelling


Analytical Validation of Design

Analysis

Eigen value analysis to check whether T ≈ Tassumed

Nonlinear static pushover analysis (NSPA) for θy =Dy

H

Nonlinear response history analysis (NLRHA) for θp = DmH − θy

Design checking

Achieved ductility ratio µa = DmDy

= 1 +θpθy

Effectiveness of design method:Closeness of the achieved ductility ratio (µa) to the target (µt)


Analytical Validation of Design: Eigen Value Analysis

Modal frequency and time periods

Mode 1, ω1 = 3.33 rad/s, T1 = 1.88 s (Note T1 = 1.88 s≈Tassumed = 1.80 s)

Mode 2, ω2 = 7.79 rad/s, T2 = 0.81 s

Mode 3, ω3 = 20.98 rad/s, T3 = 0.30 s


Analytical Validation of Design: NSPA

For calculation of yield drift

Lateral forces as per IS:1893Part I- 2002

Displacement control foranalysis (Monitor nodehighlighted by red)

Pushed upto 4(θy )assumedH


Analytical Validation of Design: NSPA

Bilinearization pushover plot

Red (solid line):- Actualpushover curve

Black (dash line):-Bilinearized pushover curve

Areas under actual curveand bilinearized curve aresame

Yield base shear,Vby = 5100kN

Yield displacement,Dm = 0.300m


Analytical Validation of Design: NLRHA

Nonlinear response historyanalysis to find plastic drift

EQ1:- Kobe Earthquake,EQ2:-NorthridgeEarthquake,EQ3:Loma PrietaEarthquake

5% damping in first twomodes


Analytical Validation of Design: NLRHA

Achieved displacement ductility ratio µaEarthquake Ultimate roof displacement Dm (m) Yield roof displacement Dy Achieved ductility µa

Kobe 1.2 0.3 4.00

Northridge 1.35 0.3 4.50

Loma Prieta 1.4 0.3 4.67

Note:- Achieved ductility is very close to target ductility


Analytical Validation of Design: NSPA:Yield mechanism

Status of MRF at an instant of maximum roof displacement from

NLRHA under Northridge earthquake. Formation of plastic hinges at the

base of column and at the end of floor beams (Fy = 3.445E + 05 kN/m2)


Summary

1 Performance-based plastic design method for steel MRFsystem considering target displacement ductility ratio anda selected yield mechanism is discussed.

2 A case study of a nine-storey MRF for target displacementductility ratio µt = 4 is achieved using PBPD method.

3 PBPD of a nine-storey MRF is analytically tested usingnonlinear static pushover and nonlinear dynamicanalyses.

4 Analytical validation of this design showed that PBPDmethod is very effective in achieving performanceobjectives in terms of target displacement ductility andpre-selected yield mechanism.


References

1 Lee, S.-S. and Goel, S. C. (2001), “Performance-based designof steel moment frames using target drift and yieldmechanism”, Research Report UMCEE 01-07, University ofMichigan, Ann Arbor, USA.

2 Newmark, N. M. and Hall, W. J. (1982), “Earthquake Spectraand Design”, Earhquake Engineering Research Institute,California, USA.

3 Goel, S. C. and Chao, S.-H. (2009), “Performance-BasedPlastic Design: Earthquake-Resistant Steel Structures”,International Code Council, Washington, USA.

4 Kharmale, S. B.(2011) “Inelastic Displacement-Based SeismicDesign of Steel Plate Shear Wall”, Ph.D Thesis, IndianInstitute of Technology Bombay, India


THANK YOU!


PBPD of Steel MRF: DESIGN CASE STUDY · One Week FDP Fundamentals of Structural Dynamics and...

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