GFRP Engineering (Click to Download)

advertisement
GFRP (Glass-Fiber-ReinforcedPolymer) Composite System for Bridge
Superstructures
“Advanced technology for bridge
superstructures”
Cantat Associates Inc.
Toronto, Ontario, Canada
2010
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 steelreinforced 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)
-
- Strains changes in GFRP equal strain
changes in adjacent wood or steel (SLS –
see § 16.11.2.2)
-
0.005 < [0.006]
-
- 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/m3
2,050 kg/m3
•
•
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 – GFRPcomposite 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 GFRPcomposite 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 reinforcedconcrete 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.
COMPARISON OF SUPERSTRUCTURES FOR DIFFERENT
MATERIALS
CON

DYNAMIC LOAD ALLOWANCE

BENDING MOMENT

DECK mm THICKNESS REQUIRED

FATIGUE STRESSES IN DECK CASING
STEEL - R. CONCRETE
AND REINFORCED
CONCTETE
SUPERSTRUCTURES
STEEL GIRDERS
AND GFRP
COMPOSITE DECK
RESULTS
1.25
1.30
1.17
1.21
6.5% LESS
7.4% LESS
100%
88%
12% LESS
225
204
9.4% LESS
REQUIRE DESIGN
EVALUATION
NOT REQUIRED
-
BENEFITS




Environmental assessment simplified
Lighter deck and girders + smaller dynamic load
allowance reduce project costs
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 –
less number of restrictions shall be used in design of
GFRP composite superstructures
RC – 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-D eflection Relationship
of Bolton Bridge Span structure ( Support D eflection are Subtracted)
LOA DING
BLOCKS
30 min
48
(22.28)
A
DI #1
DI #1
44
(25.30)
DI #5
DI #3
(22.15)
22.26
D I #5
25.29
33.55
D #6
DI #6
DI #4
3120
20.57
3120
DI #7
(15.70)
Span Struc ture Tes ting.
Sc heme of Dial Indic ators
600
24
(13.91)
D #2
D #1
32
C
L
600
(14.09)
13.91
D #3
SP AN = 15800
28
15.70
(
DI #6
27.45
18.16
(13.41)
14.09
21.35
(11.87)
11.76
13.31
DI #5
18.3
DI #7
SE CT IO N
A
7.77
16
8.53
12.2
19.5 mm 1/800L
DI #2
20
7.77
12
3.95
8
4.07
Note: The repeated res ults
s how n in brac kets
6.1
3.95
Service Study LL x (Dynamic
Load Allowance)
11.86
4380
30 min
D #5
3120
(20.60)
(18.17)
18.16
D #4
3120
30 min
(18.17
)
20 min
Service Study LL x (Dynamic
Load Allowance) x 1.297
DI #2
36
D #5
D #4
D #3
DI #7
D #2
40
D #1
4380
22.14
30 min
D I #6
20 min
DIAL INDICATOR #5
DIAL INDICATOR #6
DIAL INDICATOR #7
4
THEORETICAL
DEFLECTION.
0
0
0.00
0.00
0
2.5
5
7.5
10
12.5
15
17.5
20
22.5
25
27.5
30
32.5
35
DISPLA CEMENT
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
Fax:
Alexander Zevin
- +1 (416) 505-7139
Arie Prilik
- +1 (647) 500-2441
Danny Golnik
- +1 (416) 836-4455
647-436-1844
E-mail: cantat@rogers.com
dgolnik@cantat-associates.com
Related documents
Download