Recom m endations for Future Research

Một phần của tài liệu Strengthening concrete structures with prestressed CFRP sheets Laboratory and numerical investigations to field application (Trang 351 - 370)

A lthough m any topics have been investigated in this thesis, the application w ith C FR P sheets still requires further research. T he follow ing should be investigated:

• M ore accurate FEA m odels should be dev elo p ed to p redict the full load-deflection response o f concrete structures. A fracture m echanics concept including stress-softening o f concrete should be included in the m aterial m odelling.

318 Y ail J. K im , P .E ng., P h.D . T hesis

C h ap ter 10: C onclusions and R ecom m endations

• T he com bined effect o f p restress levels in C FR P sheets and environm ental loads, such as freezing and thaw ing, low tem perature, and w et-d ry cycles, should be investigated to predict the long-term perfo rm an ce o f strengthened structures w ith prestressed C FR P sheets.

• A novel m echanical an ch o r sy stem should be developed to prestress C F R P sheets.

A lthough the currently used an chorage pro v id ed good perform ance, a m ore p ractical anchor system is necessary. M ech an ical bo n d o f C FR P sheets should b e consid ered to provide rapid execution o f p restressin g C FR P sheets com pared to the currently used chem ical bond, follow ed by the application o f non-m etallic anchor system d eveloped in this thesis.

• F atigue p erfo rm an ce on the develo p ed non-m etallic an ch o r system should be investigated. A po ssib le em pirical design equation should be proposed. T he cum ulative dam age theory m ay p rovide the n ecessary theoretical background for such research.

• T w o-w ay slabs w ith continuous spans should be studied to pro v id e a b etter understanding o f the actual b eh a v io u r in buildings. E xperim ental w o rk should be conducted u n d e r un ifo rm ly d istrib u ted load; rath er than concentrated load, considering practical aspects. O ptim um strengthening m ethods should be investigated such as the best zone to be strengthened w ith C FR P sheets. A p aram etric study based on calibrated F E A m odels should be cond u cted to p ro v id e design charts for various b o undary conditions o f tw o-w ay slabs.

319 Yail J. K im , P .E ng., P h.D . T hesis

F R P s should be prop o sed for practicin g engineers. A m ore practical stren g th en in g m ethod for prestressing C FR P sheets should be d eveloped w ithout drillin g the slab itself. A m ovable m echanical anchor system could be a p o ssible solution.

• A full-scale n o n lin ear solid F E A m odel should be developed to p re d ic t the b eh a v io u r o f an actual bridge. D etailed cracking b eh a v io u r and actual load-carrying capacity could be investigated. A m ore advanced co m puter system w ould b e n ecessary to solve the nonlin ear iterative solution.

• Intensive study based on calib rated F E A should be cond u cted to provide better predictio n o f live load d istributions on various bridge superstructures, resu ltin g in p ossible code revisions. L ive load d istributions on dam aged and repaired bridges should be studied to p ropose d esign equations.

320 Y ail J. K im , P .E ng., Ph.D . T hesis

Appendices

A ppendix A. M aterial P roperties

A ppendix B. In n o v ativ e F lexural S trengthening for R einforced C oncrete B eam s A ppendix C. R ep air o f B ridge G irder D a m ag ed b y Im pact L oads

A ppendix D. M odelling P ro p erties for F E A A ppendix E. P erm ission to P u b lish Form s

T he follow ing m aterial pro p erties are reported by the m anufacturer.

T able A .l M aterial properties o f W abo'8' M B race C F 160 P hysical P roperties

F ibre M aterial H igh S trength C arbon

A rial W eight 600 g/m 2 (0.124 lb /ft2)

F abric W idth 610 m m (24 in.)

N om inal T h ick n e ss1, tf 0.33 m m /ply (0.013 in./ply) F unctional P roperties

C TE -0.38 x 10'6 /°C (-0.21 x 10"6 /°F)

0° T ensile P roperties

U ltim ate T ensile S trength, /#, 3,800 M Pa (550 ksi)

T ensile M odulus, E f 227 G P a (33,000 ksi)

U ltim ate T ensile S trength p er U nit W idth,./#, tf 1.25 k N /m m /ply (7.14 kips/in./ply) T ensile M odulus p er U nit W idth, E f t f 76 k N /m m /ply (430 kips/in./ply)

U ltim ate R up tu re Strain, 1 .6 7 %

90° T ensile Pro perties

U ltim ate T ensile Strength 0

T ensile M odulus 0

U ltim ate R upture Strain N /A

T able A .2 M aterial properties o f Wabo® M B race C F 130 P hysical P roperties

F ibre M aterial H ig h S trength C arbon

A rial W eight 300 g/m 2 (0.062 lb /ft2)

F abric W idth 610 m m (24 in.)

N om inal T h ic k n e ss1, tf 0.165 m m /ply (0.0065 in./ply) F unctional P roperties

CTE -0.38 x 10'6 /°C (-0.21 x 10‘6 /°F)

0° T en sile P roperties

U ltim ate T ensile S trength, /#, 3,800 M Pa (550 ksi)

T ensile M odulus, E f 227 G Pa (33,000 ksi)

U ltim ate T ensile Strength p e r U nit W idth, /#, tf 0.625 k N /m m /ply (3.57 kips/in./ply) T ensile M odulus p er U nit W idth, E f t f 38 k N /m m /ply (215 kips/in./ply)

U ltim ate R upture Strain, e#, 1.67 %

90° T ensile Pro perties

U ltim ate T ensile Strength 0

T ensile M odulus 0

U ltim ate R up tu re Strain N /A

1: T he n om inal fabric thickness is based on the total area o f fibres (only) in a unit w idth.

F rom experience, the actual cured thickness o f a single ply lam inate (fibres plus saturating resins) is larger

322 Y ail J. K im , P .E ng., P h.D . T hesis

A ppendix A: M aterial P roperties

T able A .3 M aterial properties o f W abo* M B race S aturant P hysical P roperties

D ensity 983 k g /m 3 (61.3 pcf)

T en sile P roperties

Y ield S trength 54 M P a (7,900 psi)

Strain at Y ield 2.5 %

E lastic M odulus 3,034 M P a (440 ksi)

U ltim ate Strength 55.2 M P a (8,000 psi)

R upture Strain 3.5 %

P o isso n ’s R atio 0.40

C om pressive P roperties

Y ield Strength 86.2 M P a (12,500 psi)

Strain at Y ield 5.0 %

E lastic M odulus 2,620 M P a (380 ksi)

U ltim ate S trength 86.2 M P a (12,500 psi)

R upture Strain 5.0 %

F le x u ra li Properties

Y ield Strength 138 M P a (20,000 psi)

Strain at Y ield 3.8 %

E lastic M odulus 3,724 M P a (540 ksi)

U ltim ate S trength 138 M P a (20,000 psi)

R upture Strain 5.0 %

F unctional P roperties

CTE 35 x 10'6 /°C (20 x 10"6 /°F)

T herm al C onductivity 0.2 lW /m °K ( 1.45 B tu in./hr ft2 °F) G lass T ran sitio n T em perature 71 °C (163 °F)

323 Y ail J. K im , P .E ng., P h.D . T hesis

A ppendix B com plem ents the contents d iscussed in Ch. 4: In n o va tive F lex u ra l S tren g th en in g f o r R C B eam s w ith P restresse d C F R P S heets U sing a N o n -m e ta llic A n c h o r System . D etailed anchorage and typical test proced u res are show n in Figs. B .l and B .2, respectively.

Rear plate 25 0

2 5 0 x 2 5 0 x 1 2 ^ 150 U pper plate

100 x 162 x (V

S tiffener ' 4 4 x 44 x 6

25 0

70 2 5 0

250

R e a r v ie w T h r e a d e d ro d / ( * = 10)

2 5 0

F ro n t v ie w E n d -c a p a n ch o r

S tiffener Rod

\ / Rear plattT'"'^'

S id e plates 2 5 0 x 2 5 0 x 12

F a b ric a tio n

R ods ' 4 4 x 4 4 x 6 D 1 0 x 5 0

44 Plate

7 0 x 70 x 12

D 10

H ole

$25

J a ck in g a n ch o r

Fig. B .l. D etailed steel anchorage

44

S tiffen er J a c k in g ch a ir (u n its in m m )

324 Y ail J. K im , P.E ng., Ph.D . T hesis

A ppendix B: In n ovative F lexural S trengthening for R C B eam s (C h ap ter 4)

(a) Place the jacking anchor plate bonded with CFRP sheets and prestress the sheets

(c) Cure the strengthening system

(e) To be tested in flexure

fold

<=>

<=>

H

fold

I

r

(b) Apply U-wraps after tightening the nuts

, x s

/

Remove the steel anchorage

...

(d) Remove the steel anchorage by cutting the sheets

Fig. B.2 T ypical test p rocedure

D etailed instrum entation for the b eam testing is show n in Fig. B.3.

325 Y ail J. K im , P .E ng., Ph.D . T hesis

125 1550 125 150 150 400 400 400 150 150

j 00|5p 250 1000 2 50 j q i o p 40 0 x 4 5 0 x 0.33 g i 550 x 80 x 0.33 x 2

(J-l: Control)

0 1 0 - v

! G 2 0 (J-2) 0 2 3

G 1 G ? ■ ■ ■ U J G 8 G 9

• G 4 • i

• a . ( i 5

250 . 225

0 1 3 0 7

275 . 275 225 . 250 1500

150 150 400 400 400 150 150

4 0 0 x 4 5 0 x 0 . 3 3 G 2 5 5 5 0 x 80 x 0.33 x 2

0 1 5 — v -

! G 1 6 (J-3) ..01? A

G 2 0 \ \ G l

" o i l , " !

sd n 2* Si

T ^

G 2 3 - S ? G 2 4

i 3 i 2 , g l

150 100 225 2 7 5 GU 275 225 100 150 1500

G 10 a n d 1 1 a r e r e b a r s t r a i n s g = i n i t i a l l y b o n d e d ; G = b o n d e d a f t e r

1800

375 1050 375

5 5 0 x 80 x 0.33 x 2 layers Support plate 750 x 1 5 0 x 0.33

_ _ .

ITi*- £

g t£ ~

*

30 0 x 100 x 1.2

(J-5)

y 1200 x 150 x 0.33 x 3 layers

232C

V H I

(

7 inm G I 6

(

“ 4 *

G I 4 " “ 4 6 G 1 <

m ’7 m £ glO . g l 1

150 100 225 275 275 225 100 150

1500

G 10 a n d 11 a r e r e b a r s t r a i n s

G 12 a n d 13 w e r e b o n d e d a f t e r p r c s t r c s s i n g d u e t o m a l f u n c t i o n i n i g o f G 6 a n d G 7

1800

G 1 2 a n d 13 a r e r e b a r s t r a i n s g = i n i t i a l l y b o n d e d ; G = b o n d e d a f t e r c u r e

1800

150 150 400 400 4 0 0 150 150

4 0 0 x 4 5 0 x 0.33 c i s 550 x 80 x 0.33 x 2

. " ( J 1)' 1 " V

( J - 4 )

G 12 \ ...

G 8 J . G I O ... ...< 3 1 3 ' \ G 1 S

r I o n G 1 4 , 1

G 5

G l G 7

• G 3 ■

400 2oiY 200 40 0

300 1200 300

Ci 16 a n d 1 7 a r e r e b a r s t r a i n s g = i n i t i a l l y b o n d e d ; G = b o n d e d a f t e r c u r e

1800

375 1050 375

f 550 x 80 x 0.3 3 x 2 layers f

ilEZ * (J-6) 7- 4

M r ~ i

y 1200 X 15 0 x 0.33 x 3 layers / y

,g 5 - g l I g 3 mgs

150 550

g 4

400 250 150 150. 150 150 550

g 4

40 0 250 150 150 150

125„ 175 11 1200 1751'1 2 5 ’1' ' l 7 5 " 1200 " ; 175:125;

1800 k p 1* I* p 1

1800

G 6 a n d 7 a r e r e b a r s t r a i n s

g = i n i t i a l l y b o n d e d ; G = b o n d e d a f t e r c u r e

G 6 a n d 7 a r e r e b a r s t r a i n s

g = i n i t i a l l y b o n d e d ; G :ft b o n d e d a l t e r c u r e

Fig. B .3. D etailed in strum entation for testing: B eam s J-l to J-6

326 Yail J. K im , P .E ng., P h.D . T hesis

A ppendix B: In n ovative F lexural S trengthening for R C B eam s (C h ap ter 4)

375 750 x 1 5 0 x 0.33

1800

1050 375 375

1800

1050 375

550 x 80 x 0.33 x 2 layers Support plate 30 0 x 100 x 1.2

G U 2 S G U I

0 -7 ) S G l i

S G U ‘

mooi

7=h

450 x 80 x 0.33 x 1 layer Support plate 75 0 x_150 x Q-33 55Q x 80 x 0.33 x 1 l a y e / \ 3 0 0 x'TOO x 1.2

$ £ T 0-8)

I Oi:

*

1200 x 1 5 0 x 0.33 x 3 layers / y Y 1200 x 1 5 0 x 0 .3 3 x 3 layers / y

g l - g - g d g 4 - g 5

• g 3 - g 6

150 550 40 0 25 0 150 1 5 0 1 5 0 ,

■I1501 550 40 0 25 0 150 150 150.,

p Tằ

125 175 ^ 1200 2 1 7 5 2 1 2 5 2 .,125, '175. ^ 1200 r

" 175''125'

k

1800 1800 K 1* 1ằ

S G S I a n d S G S 2 a r c r e b a r s t r a i n s g = i n i t i a l l y b o n d e d ; G ~ b o n d e d a f t e r c u r e

, 250 250 45 0 x 150 x 0 .33 CFRP anchor sh eet o n \ \ 2 5 0 x 5 0 x 0.33

~ruur~

S G U 2 C

G 1 a n d 2 a r c r e b a r s t r a i n s

g = i n i t i a l l y b o n d e d ; G = b o n d e d a f t e r c u r e

CFRP rolled-strip anchor

4 5 0 x 150 x 0.33~ CFRP anchor sh eet

G 1 3 1 2 5 0 x 5 0 x 0.33

—r=rsGU6

1_____■?. — I S G U 5

y 1200 x 150 x 0.33 x 3 layers / y

125 175 1200 175 125

1800 — H. -k V -

y 1200 X 150 x 0.33 x 3 layers / y

125 175 . 1200 . 175 .125.

1800

• g 5 , g 6

150 175 550 . 175 150

V — 1200 1*

----*

G I a n d 2 a r e r e b a r s t r a i n s

g = i n i t i a l l y b o n d e d ; G = b o n d e d a l t e r c u r e

■ S G F I ằisGl-l2

• S G F 3

• S G F 4

150 175 550 175 150i

*---

k n

1200 --- *

S G S I a n d S G S 2 a r e r e b a r s t r a i n s g - i n i t i a l l y b o n d e d ; G - b o n d e d a f t e r c u r e

Fig. B.3. D etailed instrum entation for testing (continued): B eam s J-7 to J-10

The strain variations on the C FR P sheets along the loading-span during the prestresin g operation and during the test are show n in F igs. B .4 and B.5, respectively. T he typical load levels w ere selected at 25 % , 50 % , 75 % and 100 % o f the ja c k in g force. N o te that the experim ental fitting curves do no t p ro v id e any inform ation. T he curves are show n to readily distinguish the v ariation o f the experim ental observation.

327 Y ail J. K im , P .E ng., Ph.D . T hesis

3000

500 1000

D istance from the end of CFRP (mm)

600 800 1000 1200 Distance from the end of CFRP (mm)

- J-3 (2 3 .9 kN )

5000 2 4000

3000 .2 2000 E

J-3 (7 1 .5 kN ) J-3 (9 2 .5 kN)

• 3000

1000 !

—* - J - 5 (2 2 .6 kN )

* - J - 5 (4 5 .3 k N ) ;

—* — J-5 (6 8 .9 k N ) | - * - J - 5 (9 1 .2 k N ) j

6000 5000

3000 .2 2000 1000

200 400 600 800 1000

D istance from the end of CFRP (mm)

( C )

—♦— J-6 (2 3 .7 k N ) : J-6 (4 2 .5 k N ) :

—* — J -6 (6 5 .3 k N ) [ --*•••• J -6 (9 2 .4 k N )'

200 400 600 800 1000

D istance from the end of C FRP (mm) 1200

(e)

CDC If) 10000

*3(1) E 8000 Q.

6000 'g'

O 4000

£

ro 2000 co

200 400 600 800 1000

Distance from the end of CFRP (mm)

(d)

200 400 600

- J-7 (2 3 .5 k N ).

- J - 7 (4 7 .6 kN ) - J - 7 (7 1 .8 k N ) 1 - J - 7 (95.1 k N ) ;

800 1000 1200 Distance from the end of CFRP (mm)

(f)

F ig . B .4 . S tr a in v a r ia tio n s o n th e C F R P s h e e ts d u r in g p r e s tr e s s in g : (a ) J - l ; (b ) J - 2 ; ( c ) J -3 ; (d ) J - 5 ; (e ) J - 6 ; ( 0 J -7

328 Yail J. K im , P .E ng., Ph.D . T hesis

A pp en d ix B: In n ovative F lexural S trengthening for R C B eam s (C h ap ter 4)

¥ 7000 w$ 6000

| 5000

„ 4000 H 3000

| o 2000

£ 1000

— J- 9 (2 0 .6 2 kN ) -ằ• J -9 (4 7 .9 kN )

J -9 (7 2 .5 kN ) - H - J - 9 (9 5 .6 k N )

_ 7000 CT)

$ 6000 0)

| 5000 0 4000 2 . 3000

2

1 2000

| 1000 if) 0

200 400 600 800 1000

D istance from the end of CFRP (mm) 1200

(g )

- J - 1 0 (2 4 .3 k N ) - J -1 0 (51 .1 kN ) - J - 1 0 (7 2 .5 kN ) - J - 1 0 (9 5 .7 k N )

200 400 600 800 1000

D istance from the end of CFRP (mm)

200 400 600 800 1000

Distance from the end of CFRP (mm)

(h)

(i)

F ig . B .4 . S tra in v a r ia tio n s o n th e C F R P s h e e ts d u r in g p r e s tr e s s in g ( c o n ti n u e d ) : (g ) J -8 ; (h ) J -9 ; (i) J - 1 0

4000

"oi 3500 c jg 3000 . 7 2500 :

£ 2000

'§ 1500 !

| 1000 :

500

0 0

if)

- J - 1 (4 2 .6 kN ) J-1 (8 4 .9 kN ) J-1 (1 2 7 .4 kN ) J-1 (1 6 9 .9 kN )

500 1000

D istance from the end of C FRP (mm)

1600 3 1400 c

ô 1 2 0 0 o tN 1 0 0 0

t 800

■§ 600

■| 400

ô 200

0

ằ— J-2 (28.1 kN)

*— J-2 (5 6 .4 kN) k— J-2 (84.1 kN) x— J-2 (1 1 2 .0 kN )

200 400 600 800 1000

D istance from the end of CFRP (mm)

(a) (b )

F ig . B .5 . S tra in v a r ia tio n s o n th e C F R P s h e e ts d u r in g b e a m te s tin g ( s tr a in s d u e to p r e s tr e s s in g w e r e e x c lu d e d ) : (a ) J - l ; (b ) J -2

329 Y ail J. K im , P .E ng., Ph.D . T hesis

’ 2500

500

• 2000

■ 1500

• 1 0 0 0

500

0

♦— J-3 (3 5 .0 kN )

ằ•••• J-3 (7 0 .6 kN ) J-3 (1 0 5 .2 kN ) J-3 (1 4 1 .7 kN )

600 800 1000 1200

400 200

D istance from the end of CFRP (mm)

(c)

- J - 5 (3 8 .4 kN ) - J - 5 (7 6 .4 kN ) - J - 5 (1 1 5 .2 kN ) - J - 5 (1 5 3 7 kN )

200 400 600 800

D istance from the end of C FRP (mm)

(e )

4000 3 3500

ô 3000 B

^ 2500

)

£ 2000

§ 1500 I 1000 55 500

0

3000 05c 2500 a>

to 2000

“ 5

'o' 1500 o JE 1000

c 2 CO 500

- J-4 (3 4 .6 kN ) ! - J - 4 (6 9 .2 kN ) ' - J A (1 0 3 .2 k N ), - J - 4 (1 3 7 .9 k N );

200 400 600 800 1000 1200

D istance from the end of CFRP (mm)

(d)

- J - 6 (6 3 .0 k N ) :

•J -6 (84.1 k N ) - J - 6 (1 2 6 .2 kN ).

- J - 6 (1 2 6 .8 kN ):

200 400 600 800 1000

Distance from the end of C FRP (mm)

(f)

400 s

05c 350 A

toa) 300 250 o' 200

I 150 . —♦— J -7 (2 4 .2 kN )

c

to 100 ••••ằ•••• J-7 (4 8 .2 kN )

(O 50 J-7 (7 2 .3 kN )

J-7 (9 6 .5 kN ) x

0

100 200 300 400

D istance from the end of CFRP (mm)

(g )

2000 a>1800 c 1600 (O B 1400 CO1200

~>

'o 1000 b 800 c 600 co 400 CO

200

J-8 (28 .1 k N )

•••ằ•••• J-8 (56 .1 k N )

— J- 8 (84 .1 k N ) J-8 (1 1 2 .4 kN )

200 400 600

D istance from the end of CFRP (mm)

(h )

F ig . B .5 . S tr a in v a r ia tio n s o n th e C F R P s h e e ts d u r in g b e a m te s tin g ( s tr a in s d u e to p r e s tr e s s in g w e r e e x c lu d e d ) ( c o n tin u e d ) : (c ) J -3 ; (d ) J - 4 ; (e ) J - 5 ; (f) J - 6 ; (g ) J - 7 ; (h ) J -8

330 Y ail J. K im , P .E ng., P h.D . T hesis

A pp en d ix B: In n ovative F lexural S trengthening for R C B eam s (C hap ter 4)

700

- ♦ — J-9 (2 0 .8 k N ).

2500

cn600 • s . . J-9 (4 1 .7 kN ) a>

IZ

\ —* — J -9 (6 2 .7 k N ) ' cn 2000

aj 500 •~ x -~ J -9 (8 3 .6 kN ) i Q>

m

400 n \ O—>1500

g"

o 300 ... _ \ o 'o 1000

[Ec 200 V E,

c

isCO ‘JO 500

if) 100 c5

200 400 600 800

D istance from the end of CFRP (mm)

- ♦ - J - 1 0 (3 2 .4 kN ) -♦ ••••J -1 0 (65.1 kN )

—* — 1-10 (9 7 .5 kN ) j-1 o (1 3 0 .0 k N )

400 600 800 1000

(i)

200

D istance from the end of CFRP (mm)

G)

F ig . B .5 . S tr a in v a r ia tio n s o n th e C F R P s h e e ts d u r in g b e a m te s tin g ( s tr a in s d u e to p r e s tr e s s in g w e r e e x c lu d e d ) ( c o n ti n u e d ) : (i) J - 9 ; (j) J - 1 0

S tr a in v a r ia tio n s b e f o r e a n d a f te r c u t tin g th e p r e s t r e s s e d C F R P s h e e ts a t ty p ic a l lo c a ti o n s a re s h o w n in F ig . B .6 .

500

0

SJ -500 g -1000

I~ -1500

CO

w -2000 -2500 -3000

0

-10 0 -20 -30 : -40 ■ -50 -60 -70

- E n d Q u a te r-s p a m - M id - s p a n

Time (Firs)

(a )

- Q u a r te r- s p a n : M id -s p a n

V

-90 -100

IV

Time (Firs)

40 20 0 co—> -20 -40 b

£ -60 c -80

CO

CO -100 -120 -140 -160

0

-10 0 -2 0 .

-30

- J -3 -P R E g_ 4 J -3 -P R E _ g _ 5 - J -3 -P R E _ g _ 6

Time (Firs)

(b )

-40 .E -60

co

W -70 -80 -90 -100

Q u a rte r-s p a n M id -s p a n

Time (Firs)

( b ) (d )

F ig . B .6 . S tr a in v a r ia tio n s b e f o r e a n d a f te r c u t tin g th e p r e s tr e s s e d C F R P s h e e ts : (a ) J -2 ( n e a r c u t - o f f p o in t, q u a r te r - s p a n , a n d m id - s p a n ) ; (b ) J -3 ( th re e g a u g e s a t m id - s p a n ) ; (c ) J- 5 ( q u a r te r - s p a n a n d m id - s p a n ) ; ( d ) J - 6 ( q u a r t e r - s p a n a n d m id - s p a n )

331 Y ail J. K im , P .E ng., P h.D . T hesis

0.1 0.2 ; Q.3; 0.4

M id -s p a n -1 M id -s p a n -2

Time (Hrs)

15 10

-0.2 -5 Of 0.2 -10

-15 -20 -25 -30 -35

)

Q u a rte r-s p a n M id -s p a n

— M id -s p a n -2

Time (Hrs)

(f)

80 60 | 9 40 S

I 20 !

£ ;

B 0 | "

CO -20 !***ô, -40 ! -60 '

- Q u a rt e r -s p a n ; M id -s p a n |

0.2 0.4 0.6 0.?

f f l r n F v

150 100

o 50

| - 5 0 ®

• § -1 0 0

■ | -1 5 0 ; CO

-200 -250 : -300

0.1 0.2 0.3 0.4 0.5 0.6

- Q u a te r- s p a n ; M id -s p a n

Time (Hrs)

(g )

Time (Hrs)

(h)

F ig . B .6 . S tr a in v a r ia tio n s b e f o r e a n d a f te r c u t tin g th e p r e s t r e s s e d C F R P s h e e ts ( c o n tin u e d ) : ( e ) J - 7 ( tw o g a u g e s a t m id - s p a n ) ; (f) J -8 ( o n e q u a r te r - s p a n a n d tw o m id ­ s p a n s ) ; ( g ) J -9 ( q u a r te r - s p a n a n d m id - s p a n ) ; (h ) J - 1 0 ( q u a r te r - s p a n a n d m id - s p a n )

S o m e p i c tu r e s d u r in g p r e p a r a tio n o f th e t e s t b e a m s a r e s h o w n in F ig . B .7 .

F ig . B .7 . P r e p a r a ti o n o f th e te s t: ( a ) S te e l c a g e s h o w in g d o u b le r e in f o r c e m e n t; (b ) f a b r ic a te d e n d - c a p a n c h o r

332 Y ail J. K im , P .E ng., Ph.D . T hesis

A ppendix B: In n ovative F lexural S trengthening for R C B eam s (C h ap ter 4)

F ig . B .7 . P r e p a r a ti o n o f th e t e s t ( c o n ti n u e d ) : ( c ) p r e li m in a r y t e s t to in v e s tig a te th e p o s s i b le le v e l o f p r e s tr e s s ; (d ) p r e p a r e d j a c k i n g a n c h o r s ; (e ) s tr a i n g a u g e s b o n d e d o n C F R P s h e e ts a t m id - s p a n ; (f) c u r in g o f th e s t r e n g t h e n in g s y s te m ; ( g ) a p p l ic a tio n o f U - w r a p s w ith s tr a i n g a u g e s ; ( h ) p r e m a tu r e f a il u r e d u e to e x c e s s iv e e c c e n tr ic i ty a t a lo a d o f

1 0 0 k N ;

333 Y ail J. K im , P.E ng., Ph.D . T hesis

F ig . B .8 . F a ilu r e m o d e s o f te s te d b e a m s : (a ) c o m p le t e r u p tu r e o f te s te d b e a m ( J - l ) ; (b ) s tr o n g b o n d o f e p o x y r e s in ( J - l ) ; (c ) d e b o n d i n g f a il u r e o f U - w r a p (J - 2 ) ; ( d ) d e l a m i n a ti o n f a ilu re o f U - w r a p (J -3 ) ; (e ) e v e n - d e la m in a tio n o f U - w r a p (J -4 ) ; (f) in it ia t io n o f s h e a r - o f f c r a c k s ( J -5 )

334 Yail J. K im , P .E ng., P h.D . T hesis

A ppendix B: In n ovative F lexural S trengthening for R C B eam s (C h ap ter 4)

F ig . B .8 . F a ilu r e m o d e s o f te s te d b e a m s ( c o n ti n u e d ) : (h ) r u p tu r e o f m e c h a n ic a lly a n c h o r e d U - w r a p s ( J - 7 ) ; (i) b r o k e n r o d a t w e l d e d r e g io n (J -8 ); (j) d e b o n d i n g f a il u r e o f C F R P - a n c h o r e d U -w r a p s ; (k ) S h e a r - o f f c r a c k s p a s s in g th r o u g h th e s id e s h e e ts ( J -1 0 ) ; (1) s p a ll o f c o n c r e te a f te r c r u s h in g ( J - 1 0 )

335 Yail J. K im , P .Eng., P h.D . T hesis

( 2 0 0 4 ), a s s h o w n in F ig . B .9 . .

( a ) (b )

F ig . B .9 . T h e f in ite e l e m e n t a n a ly s i s f o r th e e n d - c a p a n c h o r : (a ) ty p ic a l m e s h g e n e r a tio n w ith o u t b o tto m p la te ; (b ) e l e m e n t s o lu t io n s w ith b o tto m p la te

• R e f e r e n c e

A N S Y S , 2 0 0 4 , A N S Y S o n lin e m a n u a l, A N S Y S In c .

336 Y ail J. K im , P .E ng., P h.D . T hesis

A ppendix C: R ep air o f B ridge G irder D am ag ed by Im p act L oads

Appendix C: Repair o f Bridge G irder D am aged by Im pact Loads

T h is s e c ti o n p r e s e n ts a d d i tio n a l in f o r m a ti o n o n C h a p te r s 8 a n d 9. T h is a p p e n d ix in c lu d e s th e d e t a il e d d e s ig n a n d a n a ly s i s w o r k c o n d u c te d f o r s tr e n g t h e n in g th e M a in S tr e e t B r id g e .

► Bridge inform ation

N a m e : T h e M a in S tr e e t B r id g e ( O v e r p a s s N o .4 ) , W i n n ip e g , M a n i t o b a ( F ig . C . l ) L e n g t h = 5 6 ,2 0 0 m m ( 1 4 ,0 2 0 m m @ 4 s p a n ) in c lu d in g m e tr ic c o n v e r s i o n e r r o r W i d th = 1 3 ,4 5 5 m m x 2 = 2 6 ,9 1 0 m m in to ta l ( tw o s e p a r a te b r id g e d e c k s ) A n g le o f s k e w = 5° 4 5 ’

G ir d e r s p a c in g = 1 ,2 1 9 m m

► Applied M om ent

T o c a lc u la t e th e a p p l ie d m o m e n t o n th e e x t e r io r g ir d e r , th e f o llo w in g a p p r o a c h e s w e r e c o n d u c te d .

Một phần của tài liệu Strengthening concrete structures with prestressed CFRP sheets Laboratory and numerical investigations to field application (Trang 351 - 370)

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