GFRP (Glass-Fiber-Reinforced- Polymer) Composite System for Bridge Superstructures

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GFRP (Glass
-
Fiber
-
Reinforced
-
Polymer) Composite System for Bridge
Superstructures


2010





“Advanced technology for bridge
superstructures



Cantat Associates Inc.

Toronto, Ontario, Canada




1. How did it happen?


As it is known, the actual lifespan for steel, reinforced concrete and
steel
-
reinforced concrete SS’s everywhere in the world is no longer
than 35 to 50 years, which is much shorter than Canadian, American,
or European Bridge Design Code requirements. The causes for such
a dramatic mismatch, in our analysis, are:

1. Acid rains, occurring with increasing frequency over the last several
decades.

2. De
-
icing salts widely used to prevent traffic sliding.

3. Contaminating debris, increasingly being brought on deck wearing
surface by truck wheels.

4. Damage to structural elements due to fatigue.


The cause for such a short lifespan cannot be blamed on the growing
weight of heavy trucks. In our opinion during the last 60 years, the
average weight of heavy trucks has increased by no more than 20%.
Within the Bridge Design Codes, this problem is solved by using
conditional live loads (i.e. conditional heavy trucks, much heavier than
real trucks) and a significant magnitude of live load factor in
calculations, as well as much better than theoretical live load
redistribution in real superstructures. The precise space calculations
of a superstructure’s cross
-
sections and test results are confirming
this statement theoretically as well as practically.


To summarize:

the unanticipated changes in environment and
material properties over time are the primary causes for dramatic
reduction in the service life of bridges. The secondary cause in the
SS’s degradation is insufficient funding for proper maintenance.

2. What to do?


The obvious conclusion for the Engineers was to seek alternatives to the
materials conventionally used in bridge construction and rehabilitation. The
solution would involve using materials that are not vulnerable to
environmental damage and would increase service life, which means
durability of bridge SS’s. On the other hand, the life cycle and maintenance
costs would have to be competitive with traditional materials, because of the
limited resources available for maintaining those bridges. Such alternative
material was found. It is FRP (Fiber
-
Reinforced
-
Polymer)
-
composite
product.


In the mid 1930s as a part of experiment FRP was used for a boat hulls.
From that point on and during the following 50 years, FRP
-
composite was
used in marine, chemical processing, aerospace, for military items and
transportation. Now, the worldwide attention is focusing on the
opportunities offered by structural composites and structural industry.



Composite FRP material is formed by using high strength artificial fibers (for
example E
-
Glass, Carbon
-
Fibers, Basalt
-
Fibers and so on) and Resin
(vinyl
-
ester, polyester and Epoxy) and offers many advantages:



It is very strong and durable material, not sensitive to environment;


It is much lighter than concrete or steel.


According to Canadian official information, reinforced concrete and steel
-
reinforced concrete structures during their lifetime of 35 to 45 years required
an additional investment for their maintenance and rehabilitation of at least
40
-
50% of their initial construction costs. FRP
-
composite structures on the
other hand do not require maintenance, or require minimal investment for
painting of their open surfaces.



There are three main methods for production of composite structures:


Molding (mostly for small structural elements);


Pultrusion (mostly for extensive elements, relatively with conditionally small
cross
-
sections);


Infusion (mostly for big structural elements).



Cantat Associates Inc. selected GFRP composite material using infusion
method for production, high strength E
-
Glass Fiber and Epoxy Resin.

3. How did we solve it?

GFRP
-
composite system for bridge superstructures



To meet time and situation challenges, Cantat Associates Inc. have
developed a composite system for bridge SS’s in which steel, wood and
GFRP are working together. Steel and wood are totally encapsulated by
GFRP casing and are protected against corrosion and degradation.



In our R&D we tested thousands GFRP samples based mostly on American
Standards ASTM:

Average Statistical test
result

Taken in consideration for
design

-

Tensile strength and

1,000 MPa

800 MPa


corresponding Modulus of Elasticity

45,000 MPa

35,000 MPa

-

Compression strength and

900 MPa

700 MPa


corresponding Modulus of Elasticity

42,000 MPa

35,000 MPa

-

Flexural strength and

1,000 MPa

800 MPa


Modulus of Elasticity

46,000 MPa

35,000 MPa

-

Shear strength

50 MPa

20 MPa


Shear Modulus

3,600 MPa

2,400 MPa

-

Coefficient of linear Expansion

0.000011 /
°
C

0.000011 /
°
C

-

Acceptable max value of the strain in GFRP
(ULS


see
§

13.11.2.3, CHBDS)

-

0.005 < [0.006]

-

Strains changes in GFRP equal strain
changes in adjacent wood or steel (SLS


see
§

16.11.2.2)

-

-

-

Durability test (UV
-
test with changing “t”
from 130
°
C to
-
130
°
C)
-

5600 cycles


lost 1 micron

~ 150 year

~ 150 year

-

Mass density

2,050 kg/m
3

2,050 kg/m
3


Glue
-
nailed Laminated timber core shell conform to CAN/CSA
-
0122
(Spruce
-
Pine
-
Fir selected wood or #1)


Plywood shall be CANPly Exterior Canadian Softwood Plywood (CSP)
certified by CSA
-
0151 (thickness shall not be less than 25.5 mm, number of
plies shall not be more than 9, not less than 7)



From year 2002 up until today we made a long way to get considerably
adjusted GFRP material:



To find the most efficient sections of our Hybrid GFRP composite structures;


To efficiently include GFRP composite deck in combine operation with steel
girders;


To elaborate efficient details for deck fixation, to steel girders, barriers, the
deck fixation to the steel frame;


To attach elements of the deck to each other



We already tested in full size GFRP
-
wooden composite beams 3m in
length. We designed, tested and installed nine different superstructures
from 11m simple span up to 90m one span, including a Hybrid


GFRP
-
composite deck and a Skew bridge. All those bridges had been designed
and successfully used for the last 4
-
7 years under Truck Live Load 625 kN,
one of those bridges is a pedestrian bridge over HWY 10, with continuous
SS’s (scheme 24+36+24m). Another bridge was installed under a highway
in Nova Scotia.

The main advantages of our GFRP
-
composite SS’s are:

1. Extremely long expected durability: over 100 years

2. Light weight: increases superstructure's capacity or reduces volume of
the material(s) (e.g. steel)

3. Quick installation: usually installed and opened to public traffic in 2
-
3
hours

4. Environment
-
friendly: prefabricated, eliminating scaffolding and
contaminating debris

5. Maintenance free life cycle: not sensitive to the environment does not
corrode or deteriorate and only requires painting of deck
(superstructure) open surfaces once in a decade

6. Year
-
round construction: suitable for construction in both cold
-

and
warm
-
weather conditions

7. Final costs now is approximately 5
-
10% lower than steel or reinforced
-
concrete SS’s and no costs or minimal costs for their maintenance


The primary reason for using GFRP
-
composite SS’s is their unique long
-
term
durability.
There are no alternatives

to this product anywhere in the world.

The Ministries of Transportation of both Ontario and Nova Scotia have already
recognized and adopted this system.

COMPAR
ISON
OF
SUPERSTRUCTURES
FOR

DIFFERENT
MATERIAL
S



CON

STEEL
-
R. CONCRETE
AND
REINFORCED

CONCTETE

SUPERSTRUCTURES

STEEL GIRDERS
AND GFRP

COMPOSITE DECK

RESULTS




DYNAMIC LOAD ALLOWANCE



1.25

1.30

1.17

1.21

6.5% LESS

7.4% LESS



BENDING MOMENT



100%

88%

12% LESS



DECK mm THICKNESS REQUIRED



225

204

9.4
% LESS



FATIGUE STRESSES IN DECK
CASING



REQUIRE DESIGN
EVALUATION

NOT REQUIRE
D

-


BENEFIT
S




Environmental assessment
simplified



Lighter deck and girders + smaller dynamic load
allowance
reduce project cos
ts



Superstructure
height, reduces project costs



Better navigable water fit, reduces project costs


BENEFIT




CHBDC does not require fatigue analysis
when

stresses

in material
are
less than 30%
, it means


les
s number of restrictions shall be used in design of
GFRP composite superstructures


R
C

steel structures
require fatigue analysis

Tests conducted


Type of tests conducted


coupons


Beam sections,


Deck sections,


Results: MOE, Shear, etc.



Testing conducted by


Cantat Associates Inc.


University of Western Ontario


Triodem


Integrity Testing Lab



Results


Product in conformance



CHBDC CL 625 Truck Loading

Testing and Theoretical Load-Deflection Relationship
of Bolton Bridge Span structure ( Support Deflection are Subtracted)
3.95
7.77
3.95
7.77
4.07
8.53
13.31
15.70
20.57
25.29
12.2
18.3
21.35
27.45
33.55
22.14
0.00
11.86
14.09
18.16
18.16
0.00
13.91
11.76
22.26
0.00
6.1
0
0
4
8
12
16
20
24
28
32
36
40
44
48
0
2.5
5
7.5
10
12.5
15
17.5
20
22.5
25
27.5
30
32.5
35
LOADING
BLOCKS
DISPLACEMENT
(mm)
DIAL INDICATOR #5
DIAL INDICATOR #6
DIAL INDICATOR #7
THEORETICAL
DEFLECTION.
D #1
D #2
D #3
D #4
D #5
D #6
DI #1
DI #2
DI #5
DI #6
DI #7
DI #3
DI #4

Span Structure Testing.

Scheme of Dial Indicators
D #1
D #2
D #3
D #4
D #5
D #6
3120
3120
3120
DI #1
DI #2
DI #5
DI #6
DI #7
DI #3
DI #4
SPAN = 15800
4380
3120
A
C
L
4380
DI #5
DI #6
DI #7
600
600
A
SECT ION
19.5 mm 1/800L
Service Study LL x (Dynamic
Load Allowance)
Service Study LL x (Dynamic
Load Allowance) x 1.297
20 min
30 min
20 min
30 min
30 min
30 min
Note: The repeated results
show n in brackets
(13.41)
(11.87)
(
(15.70)
(20.60)
(14.09)
(18.17)
(13.91)
(18.17
)
(25.30)
(22.28)
(22.15)
Test every bridge

Load at plant

Load at site

See page 194 CHBDC and provide test report to owner

9.13m long x 8.7m wide

Typical Prefab bridge panel

Typical Deck to steel girder connection

Typical Diaphragm Connection

Typical Panel to Panel Connection

Stage 1

Stage 2

Stage 3


Contact information:


Cantat Associates Inc.

Toronto, Ontario, Canada


Alexander Zevin

-

+1 (416) 505
-
7139

Arie Prilik



-

+1 (647) 500
-
2441

Danny Golnik


-

+1 (416) 836
-
4455



Fax:

647
-
436
-
1844


E
-
mail:

cantat@rogers.com


dgolnik@cantat
-
associates.com