SEISMICALLY RETROFITTING AND UPGRADING RCMRF BY USING EXPANDED - - PowerPoint PPT Presentation

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SEISMICALLY RETROFITTING AND UPGRADING RCMRF BY USING EXPANDED METAL PANELS EXPANDED METAL PANELS

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SLIDE 1

SEISMICALLY RETROFITTING AND UPGRADING RCMRF BY USING EXPANDED METAL PANELS

  • EXPANDED METAL PANELS
  • !"
  • #$ % &'%

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SLIDE 2
  • 1. Overview of procedures of seismic retrofit of

reinforced concrete moment resisting frames

  • 2. Expanded Metal Materials and Panels (EMP)
  • 3. Experimental studies on EMP

Outline

  • 3. Experimental studies on EMP
  • 4. Numerical studies on EMP
  • 5. Application of EMP to seismically retrofit RC

MRF

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SLIDE 3

HOW TO SEISMICALLY

Seismic evaluation

Performance levels Seismic hazards Performance

  • bjectives

Deficiencies Tools for evaluation Technical strategies

SEISMICALLY RETROFIT RC MRF

Retrofit strategies

Technical strategies Management strategies

Retrofit systems

Concentric braces Steel restrained buckling braces Steel eccentric braces SPSW – RCSW…

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SLIDE 4

EXPANDED METAL PANELS – Introduction

  • Expanded Metal Material (EM): steel or different alloys and adhesive materials
  • Expanded Metal Panels (EMP): Panels formed by expansively pressing and

simultaneously slitting a plate made of EM to obtain 3D rhombshape stitch sheets; 3D stitch sheets can be cut by the dimensions of ±1,250 x ±2,500m or can be flattened by passing through a coldroll reducing mill and then cutting with the dimensions of ±1,250 x ±2,500m

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SLIDE 5

EXPANDED METAL PANELS – Introduction

Expanded metal → Flattened Type: without overlap between stitches

→ Normal Type: with overlaps between stitches

A rhomb shape stitch

Result: Rhomb shaped stitches with a lot of possible dimensions → Normal Type: with overlaps between stitches → Nonconstantly mechanic properties;

Fields of application

→ storefront protectors, fences …

  • '/0$&$/0/110(&/('/#.'.
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SLIDE 6

FINAL AIM OF THIS STUDY : APPLICATION OF EMP TO RETROFIT RCMRF

Why could EMP be effective to seismically retrofit RC frames?

  • May work as steel plate shear walls SPSW and concentric braces
  • Cost of EM material is relatively low when compared with SPSW.

My study focuses on:

1. Testing EMP loaded in shear: small to large scales to observe the behavior

  • f EMP.

2. Numerically simulating the tests 3. Parametrically studying to propose simplified models for EMP under shear. 4. Characterizing the use of EMP in retrofitting RC frames.

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SLIDE 7

EXPANDED METAL PANELS –Small scale tests

Direction 1 Direction 2

α

α

Glue connections

Spe. LD(mm) CD(mm) A(mm) B(mm) EM type Type of tests Direction 1 51 27 3,5 3,0 Flatten 1-Mono 2-Cyclic 1 2 51 27 3,5 3,0 Flatten 1-Mono 2-Cyclic 2 3 86 46 4,3 3,0 Flatten 1-Mono 2-Cyclic 1 4 86 46 4,3 3,0 Flatten 1-Mono 2-Cyclic 2 5 51 23 3,2 3,0 Normal 1-Mono 2-Cyclic 1 6 51 23 3,2 3,0 Normal 1-Mono 2-Cyclic 2 7 86 40 3,2 3,0 Normal 1-Mono 2-Cyclic 1 8 86 40 3,2 3,0 Normal 1-Mono 2-Cyclic 2

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SLIDE 8

EXPANDED METAL PANELS – Large scale tests

Experimental Procedures: → Monotonic tests: Shear up to complete failure of sheets ⇒ Preparing the data for cyclic tests → Cyclic tests: ECCS 1996

Specimens LD CD A B Type of EM Type of tests Dimensions(mm) 1-Mono 51 27 3,5 3,0 Flatten Monotonic 2590x2630 2-Mono 86 46 4,3 3,0 Flatten Monotonic 2590x2630 3-Cyclic 51 27 3,5 3,0 Flatten Cyclic 2590x2630 4-Cyclic 86 46 4,3 3,0 Flatten Cyclic 2590x2630

Large scale specimens (dimensions in mm)

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SLIDE 9
  • Hysteretic behaviour
  • f flattened types

EXPANDED METAL PANELS – Test Results

20 40 60 80 100 5 10 15 20 25 Shear forces (kN) Displacements (mm)

Monotonic test A51_27_35_30 small scale

Direction 1 Direction 2 120 80 40 40 80 120 2,5 2 1,5 1 0,5 0,5 1 1,5 2 2,5 Shear Forces(kN) Drift (%)

Hysteric behaviour Monotonic behaviour Monotonic behaviour in the opposite direction

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SLIDE 10
  • Modeling: FINELG code

Material: Material properties of EMP are exploited from tensile tests of bars: steel multilinear relationship with softening and hardening taken into account

EXPANDED METAL PANELS – Simulations of tests

Yield strength (MPa) Ultimate strength (MPa) Yield deformation Maximum deformation Elastic modulus (MPa) Strainhardening modulus (MPa) 337 393 0,0024 0,0290 134000 2139 Elements: Each bar

  • f

a rhomb shape stitch is modeled as a 3D inelastic beam. Buckling

  • f

an individual bar is neglected. 337 393 0,0024 0,0290 134000 2139 3D inelastic beam

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SLIDE 11

EXPANDED METAL PANELS –Tests Model

60 80 100 es (kN)

Comparison of tests and numerical simulations of A51_27_35_30 small scale

Monotonic loading

20 40 5 10 15 20 25 Shear forces Displacements (mm) Test results of direction 1 Numerical simulations of direction 1 Test results of direction 2 Numerical simulations of direction 2

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SLIDE 12

EXPANDED METAL PANELS – Tests Model

20 40 60 80 Forces (kN)

Cyclic loading

A51_27_35_30 direction 1

80 60 40 20 10 8 6 4 2 2 4 6 8 10 Shear Fo Displacement (mm) Test of direction 1 Numerical Simulations

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SLIDE 13

EXPANDED METAL PANELS – Parametric studies – Monotonic shear loading

Conclusion: FINELG describe properly the specimens’ behavior ⇒ Use of FINELG in parametric studies to define a simplified model of the shear resistance of EMP Models in parametric studies

  • Dimensions from small (100mm) to large values (2000mm)
  • Different ratios between widths and heights of panels
  • Initial deformations: 1/250 of the largest dimensions
  • Steps to analyze EMP: linear elastic analysis

critical behavior fully nonlinear analysis

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SLIDE 14

EXPANDED METAL PANELS – Parametric studies – Monotonic shear loading

25 30 35 40 45 50 Loads [kN]

Priortobuckling shear resistance of EMP

5 10 15 20 200 400 600 800 1000 1200 1400 1600 1800 2000 Critical Loa Dimension of square EMS [mm] A.43.23.45.30 A.62.34.45.30 A.51.27.35.30 A.86.46.43.30 A.115.60.45.20 A.62.34.30.20 A.62.34.25.15 A.43.23.25.15 A.31.16.23.15

Critical loads of different square EMP with different profiles subjected to shear.

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SLIDE 15

EXPANDED METAL PANELS – Parametric studies – Monotonic shear loading

40 60 80 100 120 ltim ate shear loads (kN)

60 80 100 120 ltimate shear loads (kN)

Postbuckling shear resistance

20 40 100 200 300 400 500 600 700 800 900 1000 Dimensions of the square EMS Ulti A51-27-35-30 A86-46-43-30 A43-23-45-30 A62-34-45-30 A62-34-30-20 A115-60-45-20 A62-34-25-15 A43-23-25-15

20 40 200 300 400 500 600 700 800 900 1000 Dimensions in short sides of the rectangular EMS ratio 1:2 direction 1 Ultim A51-27-35-30 A86-46-43-30 A43-23-45-30 A62-34-45-30 A62-34-30-20 A115-60-45-20

Ultimate load in function of the dimensions of square and rectangular EMP

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SLIDE 16

EXPANDED METAL PANELS – Parametric studies – Monotonic shear loading

0.45 0.5 0.55 0.6 0.65 0.7 0.75 ateloads/ldiag/B/fu/(A/lbar) 0.25 0.3 0.35 0.4 100 200 300 400 500 600 700 800 900 1000 Dimensions of the square EMS Ultimate A51-27-35-30 A86-46-43-30 A43-23-45-30 A62-34-45-30 A62-34-30-20 A115-60-45-20 A62-34-25-15 A43-23-25-15

Ultimate load in function of the dimensions of square EMP

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SLIDE 17

EXPANDED METAL PANELS – Parametric studies – Monotonic shear loading

f B l f B W V

dia

. . . . . . α γ = =

  • Monotonic ultimate resistance of EMP – Simplified model: the panels work as one

diagonal tension band. V shear resistance of the sheet; W – effective width of the equivalent band ldia diagonal length of the sheet

2 2

2 2

bar in in

A A l LD LD CD CD α = = − −     +        

B thickness of the sheet f stress generated in the equivalent band influence of rhomb shape γ influence of aspect ratio of panel 0.35 square 0.27 rectangular with ratio 2:1 0.18 rectangular with ratio 3:1

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SLIDE 18

DESIGN OF RCMRF ACCORDING TO EC2EC8

  • Four RC moment resisting frames:

PHUNG NGOC DUNG ARGENCO UNIVERSITY OF LIEGE

2' '* '( (3 ' /"'$ 10// 0)/(' 1/4 ''* 1/ . '" (3# . 0/! #(&5 . 1/3 EC2 Regular 5 m x 3 3,5 + 2x3 0,15 2/6 EC2 Regular 5 m x 3 3,5 + 5x3 0,15 3/3 EC2+EC8 Regular 5 m x 3 3,5 + 2x3 0,15 4/6 EC2+EC8 Regular 5 m x 3 3,5 + 5x3 0,15

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SLIDE 19

DESIGN OF RCMRF ACCORDING TO EC2EC8

/ 0'/ 52. ()0'/ *0''''* 52. 6( 0'/ $& 52.

  • 0/

γ γ γ γ *&5 / *"5 / 5,67 3,002,00 0,900,07 0,15g DCM 1 25 500 Loads and Seismic Actions and Material Characteristics: Dimensions of beams and columns 2' '* '( '0$. . 7/. . Internal External Width Height Flange 1/3

0,35 x 0,35 0,35 x 0,35 0,25 0,35 0,85

2/6

0,35 x 0,35 0,35 x 0,35 0,25 0,35 0,85

3/3

0,35 x 0,35 0,35 x 0,35 0,25 0,35 0,85

4/6

0,4 x 0,4 0,4 x 0,4 0,25 0,35 0,85

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SLIDE 20

DESIGN OF RCMRF ACCORDING TO EC2EC8

First mode periods, weight and effective mass of the original frames and design base shears of frame 3 and 4 Frame/No of Stories/Design Code 1st Periods of cracked frames (s) Design base shear (kN) Total Mass (x103 Kg) Effective Mass 1/3/EC2 0,88 1722 91% 2/6/EC2 1,85 3486 86% 3/3/EC2+EC8 0,88 215 1722 91% 4/6/EC2+EC8 1,50 220 3536 86%

Reinforcement configuration of the four frames

4/6/EC2+EC8 1,50 220 3536 86%

Frame/Number

  • f

Stories/ Code Beams (all stories) Column (number of stories x rebar configuration) Top Bottom Exterior Interior 1/3/EC2 12Φ10+2Φ10 3Φ14 2x8Φ8+1x8Φ14 3x8Φ8 2/6/EC2 12Φ10+2Φ10 3Φ14 1x8Φ12+4x8Φ8+1x8Φ14 1x8Φ22+1x8Φ16+1x8 Φ10+3x8Φ8 3/3/EC2+EC8 12Φ10+2Φ10 3Φ16 3x8Φ20 3x8Φ20 4/6/EC2+EC8 12Φ10+2Φ10 3Φ16 6x8Φ16 1x8Φ22+5x8Φ16

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SLIDE 21

SEISMIC EVALUATION OF THE ORIGINAL FRAMES

Pushover analysis (N2 method) is first used to assess the existing frames. Then NLTH is used to check the results of pushover analysis, and to assess the real behaviour of the original structures. To perform nonlinear analyses of the frames, estimation of actual values of material strengths is considered, instead of the design strength in order to reflect the expected real overstrength of the structures. The seismic excitation is represented by a set of four artificial accelerograms, with γI x S x agR=1 x 1,15 x 0,15g = 0,1725g

  • 2
  • 1,5
  • 1
  • 0,5

0,5 1 1,5 2 3 6 9 12 15 Acceleration(m/s2) Time(s) Accelerogram 1 - Soil C - type 1 - 0,15g

  • 2
  • 1,5
  • 1
  • 0,5

0,5 1 1,5 2 3 6 9 12 15 Acceleration(m/s2) Time(s) Accelerogram 2 - Soil C - type 1 - 0,15g

  • 2
  • 1,5
  • 1
  • 0,5

0,5 1 1,5 2 3 6 9 12 15 Acceleration(m/s2) T ime(s) Accelerogram 3 - Soil C - type 1 - 0,15g

  • 2
  • 1,5
  • 1
  • 0,5

0,5 1 1,5 2 3 6 9 12 15 Acceleration(m/s2) T ime(s) Accelerogram 4 - Soil C - type 1 - 0,15g

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SLIDE 22

SEISMIC RESPONSE OF THE ORIGINAL FRAMES

Modelling and analyses:

  • Nonlinear code: SAP 2000 and SEISMOSTRUCT – a full nonlinear code
  • Concrete: a uniaxial nonlinear constant confinement model (Mander et al. [1998]).

Confinement : fcc/fc = 1,2 for the concrete core.

  • Steel: elasticperfectly plastic steel stressstrain diagram
  • Seismic performance criteria: FEMA356 with three levels of plastic deformations of

beams or columns: beams or columns: Immediate Occupancy IO, Life Safety LS and Collapse Prevention CP.

  • Failure modes: (1) softstory mechanism

(2) local failure (3) the structure is 20% below the maximum strength attained.

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SLIDE 23
  • Response of the original frames

SEISMIC RESPONSE OF THE ORIGINAL FRAMES

Frame Load Pattern Vb

1y

(kN) ∆b

1y

(m) Vb

m

(kN) ∆b

m

(m) E (kNm) Criteria of failure ∆t

0,15gSC

(m) Vb

0,15gsC

(kN) Max PGA 1 ‘Modal’ 274,9 0,112 297,1 0,148 030,1 Soft-story 0,100 261 0,22g ‘Uniform’ 308,4 0,104 344,3 0,152 036,1 Soft-story 0,090 286 0,25g 2 ‘Modal’ 147,7 0,096 219,7 0,204 028,9 Local failure 0,164 244 0,18g ‘Uniform’ 170,0 0,090 256,2 0,204 034,6 Local failure 0,164 291 0,18g ‘Uniform’ 170,0 0,090 256,2 0,204 034,6 Local failure 0,164 291 0,18g 3 ‘Modal’ 347,0 0,100 505,5 0,340 133,0 Global 0,100 347 0,48g ‘Uniform’ 398,5 0,100 563,7 0,290 122,0 Global 0,090 336 0,50g 4 ‘Modal’ 158,0 0,090 265,2 0,256 047,7 Local failure 0,160 244 0,23g ‘Uniform’ 183,7 0,084 318,0 0,246 054,2 Local failure 0,130 273 0,28g

Response of the original frames by pushover analyses

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SLIDE 24
  • Response of the original frames

Drift of the original frames by pushover analysis (%) at PGA = 0.15g soil C

SEISMIC RESPONSE OF THE ORIGINAL FRAMES

Frame 1 (Average of two load patterns) Frame 2 (Average of two load patterns) Story1 Story2 Story3 Story1 Story 2 Story3 Story 4 Story 5 Story 6 1,140 1,200 1,000 0,910 1,100 0,832 1,100 0,970 0,890 Frame 3 (Average of two load patterns) Frame 4 (Average of two load patterns) patterns) 0,900 1,100 1,000 0,760 0,890 0,930 0,904 1,100 0,780 Frame 1 (Average) Frame 2 (Average) Frame 3 (Average) Frame 4 (Average) Period Base shear Period Base shear Period Base shear Period Base shear 0,6s 184,3kN 1,1s 233,9kN 0,52s 233,3kN 1s 252,3kN

Fundamental periods and maximum base shear of the original frames from NLTH due to Earthquake type 1 with PGA of 0.15g soil C

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SLIDE 25
  • Response of the original frames

Max story drift (%) and top displacements (m) of the original frames by NLTH due to Earthquake type 1 with PGA of 0.15g soil C

SEISMIC RESPONSE OF THE ORIGINAL FRAMES

Frame 1 (Average) Frame 2 (Average) Story1 Story2 Story3 Top Displ Story1 Story2 Story3 Story4 Story5 Story6 Top Displ 0,70% 0,75% 0,71% 0,07m 0,70% 0,8% 0,8% 0,77% 0,72% 0,66% 0,124m Frame 3 (Average) Frame 4 (Average) 0,51% 0,66% 0,64% 0,064m 0,63% 0,71% 0,74% 0,72% 0,69% 0,64% 0,118m 0,51% 0,66% 0,64% 0,064m 0,63% 0,71% 0,74% 0,72% 0,69% 0,64% 0,118m

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SLIDE 26

SEISMIC RESPONSE OF THE ORIGINAL FRAMES

  • Response of the original frames: Pushover and target displacements of frame 1 and 3

250 300 350 400 450 500 550 600 se shear (kN)

EC2 EC8

50 100 150 200 250 0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 Base s Top displacements(m)

'Modal' Frame 1 Target Displ 'Modal' Frame 1 0,15gsoilC Max Displ 'Modal' Frame 1 0,22g soilC 'Modal' Frame 3 Target Disp 'Modal' Frame 3 0,15g soilC Max Displ 'Modal' Frame 3 0,47g soilC Design base shear for Frame 3 Max base shear of Frame 1 NLTH Max base shear of Frame 3 NLTH

EC2

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SLIDE 27

SEISMIC RETROFIT OF RCMRFS BY USING EMP

Selecting the EMP to retrofit the original frames:

  • Approach: Direct Displacement Based Design
  • Equivalent Viscous Damping: Rules for Takeda Thin model
  • EMP to carry the seismic forces. Depending on the deficiencies of the
  • riginal frames, types and distribution of the EMP are selected.
  • Because all frames are symmetric with three bays, EMP are put in the

intermediate bay.

  • In frame 1 and 3 (3story frames), the EMPs are put in the first and second
  • In frame 1 and 3 (3story frames), the EMPs are put in the first and second

stories, while the EMP are put in the first to fourth stories in frame 2 and 4 (6story frames). Because there is no hinge appeared at the upper stories, no EMP is put there.

  • EMP is modelled as an axial tension strut with a bilinear forcedisplacement

relationship for pushover analysis and pivot model for NLTH.

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SLIDE 28

Response of the retrofitted frames by pushover analysis

SEISMIC RETROFIT OF RCMRFS BY USING EMP

Frame Load Pattern Vb

1y

(kN) ∆b

1y

(m) Vb

m

(kN) ∆b

m

(m) E (kNm) Criteria of failure ∆t

0,15gSC

(m) Max PGA 1 ‘M’ 291,5 0,052 476,0 0,208 073,6 Softstory 0,080 0,365g ‘U’ 365,7 0,056 483,8 0,144 050,2 Softstory 0,070 0,300g 2 ‘M’ 268,1 0,090 445,4 0,253 072,2 Local failure 0,150 0,245g ‘U’ 347,7 0,083 535,6 0,235 089,2 Local failure 0,120 0,265g ‘U’ 347,7 0,083 535,6 0,235 089,2 Local failure 0,120 0,265g 3 ‘M’ 352,1 0,060 656,0 0,340 175,0 Beamsway 0,085 0,610g ‘U’ 415,0 0,060 738,3 0,300 172,0 Beamsway 0,070 0,620g 4 ‘M’ 288,2 0,090 444,9 0,271 088,0 Local failure 0,140 0,285g ‘U’ 351,3 0,083 549,1 0,259 104,0 Local failure 0,120 0,320g

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SLIDE 29

Comparison of behaviour between original and retrofitting frames by pushover analyses

SEISMIC RETROFIT OF RCMRFS BY USING EMP

Frame 1 Frame 2 Frame 3 Frame 4 No EMP With EMP No EMP With EMP No EMP No EMP No EMP With EMP 0,85s 0,71s 1,53s 1,28s 0,85s 0,71s 1,53s 1,28s

Periods of all frames with and without EMP

Frame 1(Average) Frame 2(Average) Story1 Story2 Story3 Story1 Story2 Story3 Story4 Story5 Story6 0,74 0,77 0,79 0,66 0,76 0,78 0,79 0,78 0,73 Frame 3(Average) Frame 4(Average) 0,80 0,86 0,79 0,64 0,72 0,75 0,75 0,74 0,70

Drift of the retrofitted frames by pushover analyses (%)

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SLIDE 30

COMPARISON OF SEISMIC RESPONSE OF THE ORIGINAL AND RETROFITTED FRAMES

Pushover and target displacements of frame 1: before and after retrofitted

200 250 300 350 400 450 500 ar (kN) FRAME 1

EC2NoEMP EC2+EMP

50 100 150 200 0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14 0.16 0.18 0.20 0.22 Base shear ( Top displacements(m)

Pushover 'Modal' NoEMP Target Displ 'Modal' NoEMP 0,15gsoilC Maximum Displ 'Modal' NoEMP 0,22g soilC Pushover Modal pattern with EMP 0,15g soilC Target Disp With EMP Modal pattern 0,15g soiC Maximum Displ With EMP Modal pattern 0,36g soilC

EC2NoEMP

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SLIDE 31
  • Comparison of behaviour between original and retrofitting frames:

Capacity curves and target displacements of Frame 3 before and after retrofitting

SEISMIC RETROFIT OF RCMRFS BY USING EMP

400 500 600 700 800 se shear (kN)

EC8NoEMP EC8+EMP

100 200 300 0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 Base s Top displacements(m)

Pushover 'Modal' NoEMP Target Displ 'Modal' NoEMP 0,15gsoilC Max Displ 'Modal' NoEMP 0,47g soilC 'Modal' with EMP 0,15g soilC Target Disp With EMP Modal 0,15g soiC Max Displ With EMP Modal 0,6g soilC

slide-32
SLIDE 32
  • Comparison of behaviour between original and retrofitting frames:

Story Drifts of Frame 3 before and after retrofitting

SEISMIC RETROFIT OF RCMRFS BY USING EMP

4,0 5,0 6,0 7,0 8,0 9,0

  • ry Heights (m)

0,0 1,0 2,0 3,0 4,0 0,4 0,8 1,2 1,6 Story Story Drifts (%)

Frame 1 before retrofitting Frame 1 after retrofitting Frame 3 before retrofitting Frame 3 after retrofitting

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SLIDE 33

SEISMIC RETROFIT OF RCMRFS BY USING EMP Conclusions

The application of the proposed retrofitting system results in an increase of strength, stiffness and ductility. The energy dissipated by EMP is considerable, reaching about 20% of the total energy. This results in an increase of the level of earthquake that the structures can sustain. Although EMP cannot change the failure mechanism of the structures, it can reduce the demand of seismic actions thanks to increases of strength and reduce the demand of seismic actions thanks to increases of strength and stiffness and ductility of the structures. NLTH points out that pushover analysis is successfully in capturing the behaviour of low and medium rise buildings.

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SLIDE 34

FURTHER WORKS

Model more different types of RCMRF with and without EMP by both pushover and NLTH. Characterise the use of EMP to retrofit RCMRF and suggest the design or retrofit procedures. Make suggestions for the connections between the EMP and RCMRF.

slide-35
SLIDE 35

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