OUTLINE Introduction Motivation Replaceable shear link in MRFs - - PDF document

٠٩/٠۴/١۴٣۶ ١ FINITE ELEMENT INVESTIGATION OF A NEW STRUCTURAL SHEAR FUSES IN MOMENT RESISTING FRAMES By:

Pouya Rezazadeh (Sharif University of Technology) Kiarash M. Dolatshahi

(Sharif University of Technology)

• M. T. Nikoukalam (Presentor)

(University of Colorado Boulder) June 2015

OUTLINE

• Introduction
• Motivation
• Replaceable shear link in MRFs
• Perforated and slit shear links
• Summary and conclusion

FE INVESTIGATION OF A NEW STRUCTURAL SHEAR FUSES IN MOMENT RESISTING FRAMES

• M. T. Nikoukalam

٠٩/٠۴/١۴٣۶ ٢

Introduction

• M. T. Nikoukalam
• Of the most favorable lateral load resisting systems are Special

Moment Resisting Frames (SMRFs) due to their high ductility and energy dissipation capacity.

• A minimum span-to-depth ratio of 7 in special MRFs and 5 in

intermediate MRFs must be maintained (AISC 358-10)

• The span-to-depth ratio in Framed Tube structures is about

3.4-4.

FE INVESTIGATION OF A NEW STRUCTURAL SHEAR FUSES IN MOMENT RESISTING FRAMES

Motivation

• M. T. Nikoukalam

F F

Vpb1 V M F F

V >V

pb2 pb1

V M

F F

V >V >V

pb3 pb2 pb1

V M

• 2
• FE INVESTIGATION OF A NEW STRUCTURAL SHEAR FUSES IN MOMENT RESISTING FRAMES

٠٩/٠۴/١۴٣۶ ٣

Motivation

• M. T. Nikoukalam

(Photo by M.T.Nikoukalam)

FE INVESTIGATION OF A NEW STRUCTURAL SHEAR FUSES IN MOMENT RESISTING FRAMES

Replaceable shear link in MRFs

• M. T. Nikoukalam

Prefabricated in shop & shipped to site On-site bolting of replaceable link

e Replaceable Shear Link

Bolted End-Plate Connection Stiffener Pls Beam C L

• Replaceable shear link with solid web
• Slit shear link
• Perforated shear link

FE INVESTIGATION OF A NEW STRUCTURAL SHEAR FUSES IN MOMENT RESISTING FRAMES

٠٩/٠۴/١۴٣۶ ۴

Replaceable shear link in MRFs

Methodology

• M. T. Nikoukalam
• 900
• 600
• 300

300 600 900

• 0.15
• 0.10
• 0.05

0.00 0.05 0.10 0.15 Link Shear: V (kN) Inelastic Rotation: γP (rad)

Vn Vn

• 800
• 600
• 400
• 200

200 400 600 800

• 0.15
• 0.10
• 0.05

0.00 0.05 0.10 0.15 Link Shear: V (kN) Inelastic Rotation: γp (rad)

Test ABAQUS

• 2.0
• 1.0

0.0 1.0 2.0

• 8
• 6
• 4
• 2

2 4 6 8 Normalized Moment at Column Face (M/Mpn) Story Drift (%) Test ABAQUS

Okazaki, M.D. Engelhardt (2007) Lee et al. (2005)

• Finite Element Modeling (Abaqus/CAE 6.13-1)

FE INVESTIGATION OF A NEW STRUCTURAL SHEAR FUSES IN MOMENT RESISTING FRAMES

Replaceable shear link concept in MRFs

Design Concept

• M. T. Nikoukalam

θp

1

θ > θ

p p 2 1

Drift Base shear

1 2

Drift

Elastic Rapid return to occupancy Collapse prevention Flexural yielding

Base shear

1 2 Shear yielding

(a)RBS (b)Shear Link Frame (SLF) (a)Hybrid Frame (HF)

FE INVESTIGATION OF A NEW STRUCTURAL SHEAR FUSES IN MOMENT RESISTING FRAMES

٠٩/٠۴/١۴٣۶ ۵

Replaceable shear link concept in MRFs

Frames with shear fuse

• M. T. Nikoukalam

(a) L/d=4 (b) L/d=5 (c) L/d=7

FE INVESTIGATION OF A NEW STRUCTURAL SHEAR FUSES IN MOMENT RESISTING FRAMES

Replaceable shear link concept in MRFs

Analysis results

• M. T. Nikoukalam

(I) Cyclic load-displacement curves (II) Dissipated energy (a) L/d=4 (b) L/d=5 (c) L/d=7

• 2000
• 1500
• 1000
• 500

500 1000 1500 2000

• 6.0
• 4.0
• 2.0

0.0 2.0 4.0 6.0 Base Shear (kN) Story Drift (%) Shear Link RBS

• 2000
• 1500
• 1000
• 500

500 1000 1500 2000

• 6.0
• 4.0
• 2.0

0.0 2.0 4.0 6.0 Base Shear (kN) Story Drift (%) Shear Link RBS

• 2000
• 1500
• 1000
• 500

500 1000 1500 2000

• 6.0
• 4.0
• 2.0

0.0 2.0 4.0 6.0 Base Shear (kN) Story Drift (%) Shear Link RBS 2 4 6 8 10 12 14 0.0 1.0 2.0 3.0 4.0 5.0 6.0 Accumulative Energy Dissipation (kN.mm)

x 100000

Story Drift (%) Shear Link RBS 2 4 6 8 10 12 0.0 1.0 2.0 3.0 4.0 5.0 6.0 Accumulative Energy Dissipation (kN.mm)

x 100000

Story Drift (%) Shear Link RBS 2 4 6 8 10 12 0.0 1.0 2.0 3.0 4.0 5.0 6.0 Accumulative Energy Dissipation (kN.mm)

x 100000

Story Drift (%) Shear Link RBS

0.0 1.0 2.0 3.0 4.0 5.0 0.0 1.0 2.0 3.0 4.0 5.0 (SLF)PE / (RBS)PE Story Drift (%) L/D = 4 L/D = 5 L/D = 7

• Shear Link Frame (SLF)

FE INVESTIGATION OF A NEW STRUCTURAL SHEAR FUSES IN MOMENT RESISTING FRAMES

• 2000
• 1500
• 1000
• 500

• 6.0
• 4.0
• 2.0

• 2000
• 1500
• 1000
• 500

500 1000 1500 2000

• 6.0
• 4.0
• 2.0

0.0 2.0 4.0 6.0 Base Shear (kN) Story Drift (%) Shear Link RBS

• 2000
• 1500
• 1000
• 500

• 6.0
• 4.0
• 2.0

٠٩/٠۴/١۴٣۶ ۶

Replaceable shear link concept in MRFs

Analysis results

• M. T. Nikoukalam
• Hybrid Frame (HF)

(I) Load-displacment curves (II) Cumulative dissipated energy (a) L/d=4 (b) L/d=5 (c) L/d=7

• 2500
• 2000
• 1500
• 1000
• 500

500 1000 1500 2000 2500

• 6.0
• 4.0
• 2.0

0.0 2.0 4.0 6.0 Base Shear (kN) Story Drift (%) RBS Hybrid Frame

• 2500
• 2000
• 1500
• 1000
• 500

500 1000 1500 2000 2500

• 6.0
• 4.0
• 2.0

0.0 2.0 4.0 6.0 Base Shear (kN) Story Drift (%) RBS Hybrid Frame

• 2500
• 2000
• 1500
• 1000
• 500

500 1000 1500 2000 2500

• 6.0
• 4.0
• 2.0

0.0 2.0 4.0 6.0 Base Shear (kN) Story Drift (%) 2 4 6 8 10 12 14 0.0 1.0 2.0 3.0 4.0 5.0 Accumulative Energy Dissipation (kN.mm)

x 100000

Story Drift (%) RBS Hybrid Frame Link Beam 2 4 6 8 10 12 0.0 1.0 2.0 3.0 4.0 5.0 Accumulative Energy Dissipation (kN.mm)

x 100000

Story Drift (%) RBS Hybrid Frame Link Beam 2 4 6 8 10 12 0.0 1.0 2.0 3.0 4.0 5.0 Accumulative Energy Dissipation (kN.mm)

x 100000

Story Drift (%) RBS Hybrid Frame Link Beam

FE INVESTIGATION OF A NEW STRUCTURAL SHEAR FUSES IN MOMENT RESISTING FRAMES

Slit and perforated links

• M. T. Nikoukalam

Model name Perf 1 Perf 2 Perf 3 Perf 4 D/S 0.24 0.34 0.39 0.6 V

y(MPa)

316 291 278 221

Model name SL 1 SL 2 SL 3 SL 4 b (mm) 28.13 27.73 27.50 27.72 l0 (mm) 36.54 39.06 40.44 51.34 V

y(MPa)

316 291 278 221

b l0

FE INVESTIGATION OF A NEW STRUCTURAL SHEAR FUSES IN MOMENT RESISTING FRAMES

٠٩/٠۴/١۴٣۶ ٧

Slit and perforated links

• M. T. Nikoukalam
• Damage Index (DI) Model
• exp 1.5max
• PEEQ = equivalent plastic strain,

T = triaxiality ratio of hydrostatic stress to Mises stress) (Chao, Khandelwal et al. (2006))

FE INVESTIGATION OF A NEW STRUCTURAL SHEAR FUSES IN MOMENT RESISTING FRAMES

Slit and perforated links

Verification of model

• M. T. Nikoukalam
• 35
• 25
• 15
• 5

5 15 25 35

• 0.15
• 0.1
• 0.05

0.05 0.1 0.15 Link Shear: V (kN) Link Rotation: γ (rad)

test Pre-DI=1.0 Post-DI=1.0 0.084 rad (DI = 1.51) DI = 1.3 DI = 1.0

DI exceeding 1 at the cycle with maximum rotation of 0.07 rad (10cm)

Damage Index

0.000 0.126 0.252 0.378 0.503 0.629 0.755 0.881 1.007 1.133 1.259 1.384 1.510

(picture by courtesy of F. Albermani)

FE INVESTIGATION OF A NEW STRUCTURAL SHEAR FUSES IN MOMENT RESISTING FRAMES

٠٩/٠۴/١۴٣۶ ٨

Slit and perforated links

Verification of model

• M. T. Nikoukalam

Damage Index

0.000 0.084 0.167 0.251 0.335 0.418 0.502 0.586 0.669 0.753 0.837 0.920 1.004

DI exceeding 1 at the cycle with maximum inelastic rotation of 0.09 rad

• 800
• 600
• 400
• 200

200 400 600 800

• 0.15
• 0.1
• 0.05

0.05 0.1 0.15 Link Shear: V (kN) Inelastic Rotation: γ (rad)

Damage Index

0.000 0.132 0.265 0.397 0.530 0.662 0.795 0.927 1.060 1.192 1.324 1.457 1.589

DI at the point of test failure (inelastic rotation = 0.12 rad) (picture by courtesy of T. Okazaki)

FE INVESTIGATION OF A NEW STRUCTURAL SHEAR FUSES IN MOMENT RESISTING FRAMES

Slit and perforated links

Results

• M. T. Nikoukalam

Vy/Vys = 0.83 Vy/Vys = 0.76 Vy/Vys = 0.73 Vy/Vys = 0.58 Rotation Perf1 SL1 Ra Ratio Perf2 SL2 Ra Ratio Perf3 SL3 Ra Ratio Perf4 SL4 Ra Ratio 0.006 006 0.006 0.061 0.102 0.008 0.061 0.129 0.009 0.082 0.115 0.007 0.075 0.093 0.015 015 0.022 0.167 0.129 0.028 0.171 0.163 0.029 0.230 0.127 0.023 0.241 0.095 0.046 046 0.080 0.621 0.128 0.098 0.638 0.153 0.107 0.850 0.126 0.090 0.895 0.100 0.080 080 0.165 1.020 0.161 0.190 1.043 0.182 0.204 1.357 0.150 0.177 1.496 0.118 0.129 129 0.299 1.404 0.213 0.331 1.413 0.234 0.359 1.830 0.196 0.401 2.018 0.199

• Link over-strength comparison

Why???? Why so low in perf?

FE INVESTIGATION OF A NEW STRUCTURAL SHEAR FUSES IN MOMENT RESISTING FRAMES

٠٩/٠۴/١۴٣۶ ٩

Slit and perforated links

Results

• M. T. Nikoukalam

200 400 600 800 1000 0.05 0.1 0.15 0.2 Energy (kJ) Link Rotation: γ (rad)

Slit 2 Perf 2

• 800
• 600
• 400
• 200

200 400 600 800

• 0.2
• 0.1

0.1 0.2 Link Shear: V (kN) Link Rotation: γ (rad)

Slit 2 Perf 2

• Dissipated energy comparison

Why????

Vy/Vys = 0.83 Vy/Vys = 0.76 Vy/Vys = 0.73 Vy/Vys = 0.58 Rotation Perf1 SL1 Ratio Perf/SL Perf2 SL2 Ratio Perf/SL Perf3 SL3 Ratio Perf/SL Perf4 SL4 Ratio Perf/SL 0.005 2.28 2.13 1.07 2.08 2.08 1.00 1.96 2.08 0.94 1.43 1.89 0.76 0.014 17.25 17.67 0.98 15.71 17.31 0.91 14.74 17.36 0.85 10.94 15.91 0.69 0.047 114.43 121.68 0.94 104.97 119.71 0.88 98.67 119.85 0.82 74.66 112.38 0.66 0.128 480.00 523.55 0.92 440.78 512.94 0.86 402.70 516.07 0.78 254.57 480.47 0.53 Total 878.82 1022.97 0.86 793.26 1006.47 0.79 677.97 1013.90 0.67 431.02 955.59 0.45

FE INVESTIGATION OF A NEW STRUCTURAL SHEAR FUSES IN MOMENT RESISTING FRAMES

Slit and perforated links

Results

• M. T. Nikoukalam
• DI comparison

Why???? So high in SLIT?????!!!!!!

Vy/Vys = 0.83 Vy/Vys = 0.76 Vy/Vys = 0.73 Vy/Vys = 0.58 Rotation Perf1 SL1 Ratio Perf/SL Perf2 SL2 Ratio Perf/SL Perf3 SL3 Ratio Perf/SL Perf4 SL4 Ratio Perf/SL 0.005 0.04 0.14 0.25 0.02 0.15 0.17 0.03 0.15 0.17 0.02 0.17 0.14 0.014 0.26 1.00 0.26 0.21 1.05 0.20 0.21 1.05 0.20 0.22 1.39 0.16 0.047 1.32 6.00 0.22 1.23 6.40 0.19 1.27 6.30 0.20 1.47 8.30 0.18 0.090 2.52 11.55 0.22 2.46 12.33 0.20 2.55 11.96 0.21 4.38 16.81 0.26 0.128 5.67 19.78 0.29 4.78 21.11 0.23 8.74 20.11 0.43 11.96 29.42 0.41

5 10 15 20 25 30 35 0.05 0.1 0.15 0.2 DI Link Rotation: γ (rad)

Slit 2 Perf 2

FE INVESTIGATION OF A NEW STRUCTURAL SHEAR FUSES IN MOMENT RESISTING FRAMES

٠٩/٠۴/١۴٣۶ ١٠

Summary

• A new replaceable structural shear fuse is introduced and studied

as an alternative to the traditional flexural fuse in moment resisting frames (MRFs)

• The new proposed shear fuse provides a high ductility capacity for

MRFs, especially with low span-to-depth ratios.

• Comparing the results of RBS models revealed that frames with

lower span-to-depth ratio have higher equivalent plastic strains (PEEQ) and shorter plastic hinges.

• Perforated and slit shear links are introduced as two alternative

details for the shear link.

• Slit links showed higher over-strength, more energy dissipation, and

higher damage index.

• M. T. Nikoukalam

FE INVESTIGATION OF A NEW STRUCTURAL SHEAR FUSES IN MOMENT RESISTING FRAMES

Thank You!