U.S. patent application number 15/741134 was filed with the patent office on 2018-07-05 for carbon fiber reinforcement polymer and its respective application technique for the strengthening of concrete structures.
This patent application is currently assigned to Clever Reinforcement Iberica- Materiais de Construcao LDA. The applicant listed for this patent is CLEVER REINFORCEMENT IBERICA-MATERIAIS DE CONSTRUCAO LDA, UNIVERSIDADE DO MINHO. Invention is credited to Filipe Nuno FERRAZ MARQUES DOURADO, Joaquim Antonio OLIVEIRA DE BARROS.
Application Number | 20180187439 15/741134 |
Document ID | / |
Family ID | 56997514 |
Filed Date | 2018-07-05 |
United States Patent
Application |
20180187439 |
Kind Code |
A1 |
OLIVEIRA DE BARROS; Joaquim Antonio
; et al. |
July 5, 2018 |
CARBON FIBER REINFORCEMENT POLYMER AND ITS RESPECTIVE APPLICATION
TECHNIQUE FOR THE STRENGTHENING OF CONCRETE STRUCTURES
Abstract
The present invention consists of a carbon fiber reinforcement
polymer (CFRP) laminate matrix and its application technique on the
reinforcement of concrete structures. The present carbon fiber
reinforcement polymer (CFRP) laminate matrix comprises a clip or
cane shape and it is comprised by two or three rectilinear segments
connected by one or two transition areas. This product is meant to
be applied on the civil construction area.
Inventors: |
OLIVEIRA DE BARROS; Joaquim
Antonio; (Guimaraes, PT) ; FERRAZ MARQUES DOURADO;
Filipe Nuno; (Elvas, PT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
CLEVER REINFORCEMENT IBERICA-MATERIAIS DE CONSTRUCAO LDA
UNIVERSIDADE DO MINHO |
Elvas
Braga |
|
PT
PT |
|
|
Assignee: |
Clever Reinforcement Iberica-
Materiais de Construcao LDA
Elvas
PT
Universidade Do Minho
Braga
PT
|
Family ID: |
56997514 |
Appl. No.: |
15/741134 |
Filed: |
June 29, 2016 |
PCT Filed: |
June 29, 2016 |
PCT NO: |
PCT/IB2016/053897 |
371 Date: |
December 29, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
E04G 23/0218 20130101;
E04C 5/073 20130101; E04G 2023/0251 20130101; E04C 5/07
20130101 |
International
Class: |
E04G 23/02 20060101
E04G023/02; E04C 5/07 20060101 E04C005/07 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 30, 2015 |
PT |
108611 |
Claims
1. A carbon fiber reinforcement polymer matrix laminate with a clip
or cane shape and comprising slots for the insertion of carbon
fiber sheets, high fluidity adhesive material, armed concrete
structure--beam, pillar, slab and foundation, T section beam,
embedment on the interior section, stirrups, coating concrete and
two or three rectilinear segments connected by one or two
transition areas (Tz).
2. A carbon fiber reinforcement polymer matrix laminate according
to claim 1, presented with a constant through-cut section with a
width between 10 and 20 mm and a thickness of 1.4 mm.
3. A carbon fiber reinforcement polymer matrix laminate according
to claim 1, in which the inclination of the extremities can range
between 30 to 90 degrees regarding the beam axis or the slab
plane.
4. Laminate reinforcement method for the carbon fiber reinforcement
polymer matrix laminates described in claim 1, comprising the
following steps: Opening a slot on the element of coating concrete
from the armed concrete to be reinforced; Puncture opening with a
diameter equal to the maximum dimension of the laminates
through-cut section plus between 1.0 and 3.0 mm; cleaning of the
slot and punctures with compressed air; cleaning of the laminate
with a degreasing agent; adhesive execution and its application
throughout the length of the slot, and application of a thin layers
of said adhesive on the sides of the laminate; introduction of the
laminate part for reinforcement to flexing through the slot, and
the parts of the laminates extremity; after curing the adhesive,
fill the spaces between the external parts of the laminate and the
puncture walls with high fluidity adhesive.
5. Reinforcement method regarding the carbon fiber reinforcement
polymer matrix laminate according to claim 4, in which the coating
concrete slot is comprised between 4.5 and 5.5 mm.
6. (canceled)
Description
TECHNICAL FIELD
[0001] The present application describes a carbon fiber laminate
and the respective technique to reinforce concrete structures.
PREVIOUS ART
[0002] In several cases of projects of reinforcement of armed
concrete (AC) structures, the need for reinforcement to flexing
demands additional measures to the cut in order to avoid the
occurrence of this type of rupture which is frail and that,
generally, shows no signs of its occurrence. Thus, for these cases
the rehabilitation practice undergoes the application of two
reinforcement systems, one for flexing and another for cutting. A
similar situation also happens for slabs, where sometimes the need
for reinforcement regarding negative momentum forces a
reinforcement to puncturing.
[0003] The two inventors, Prof. Joaquim Barros from Universidade do
Minho, and Eng. Filipe Dourado, CEO of Clever Reinforcement
Iberica--Materiais de Construcao Lda., have intense collaboration
on the investigation on the laminate area regarding carbon fiber
reinforcement polymers (CFRP--Carbon Fiber Reinforcement Polymer)
applied according to the internationally designated technique for
Near Surface Mounted (NSM), and which in Portuguese can be termed
as "Instalacao proximo da superficie". Since the beginning of the
current century, Eng. Filipe Dourado has collaborated with the
ongoing investigation by Prof. Joaquim Barros on the use of CFRP
laminates applied with the NSM technique towards the reinforcement
of concrete structures, brickwork and wood. The efficiency of this
technique regarding the reinforcement of beams and concrete slabs
(BA) to flexing has been evaluated [1-3] and also regarding BA beam
cutting [4,5], as well as to increase the reinforcement to flexing
and energy dispersion from the BA pillars when applied together
with CFRP mantle strips involving the section of the element being
reinforced, in order to increase the concretes confinement [6]. The
binding conditions of the applied CFRP laminates according to the
NSM technique have been properly investigated [7]. Recently, the
joint use of CFRP systems for reinforcement to flexing and cutting,
either from the experimental investigation [8] or numerical [9]
standpoint was explored, triggering the opportunity for the
laminate concept that it is intended to develop under the present
project. The extraordinary efficiency on the reinforcement to
cutting of rods which were inserted in beams opening run was
recently explored, having been demonstrated that it is possible to
convert fragile cutting failure modes into flexing cuts in ductile
failure modes [10].
[0004] The knowledge heritage acquired by the inventors in the past
fifteen years on the subject of structure reinforcement with
composite materials has allowed a deep understanding of the
advantages and frailties of the current systems. The disadvantages
of the reinforcement techniques which resort to Fiber-Reinforced
Polymers (FRP) are ultimately its early rupture by detachment,
especially when resorting to the externally bonded reinforcement
(EBR) and its susceptibility to high temperatures and acts of
vandalism. When applied according to the NSM technique, the CFRP
laminate reinforcement ability is also not fully mobilized, due to
the premature occurrence by detachment of the recoating concrete
where the laminates are inserted, or by sliding alongside the
substrate.
GENERAL DESCRIPTION
[0005] The present request describes a carbon fiber reinforcement
polymer (CFRP) matrix laminate and its application technique on the
reinforcement of concrete structures. More specifically, the
request describes a CFRP laminate with a clip shape, formed by
three straight segments and two transition areas, or canes,
constituted by two rectilinear segments and a transition area
(elbow), in which the extremity branches ensure reinforcement
towards cutting in beam like elements or puncturing in slabs, while
the rest of the laminate ensures reinforcement towards flexing.
This product is meant to be applied in the construction area.
[0006] Analytical and numerical analysis studies, as well as
parametric studies performed with these models provided privileged
information that are the ground for the CFRP laminate now being
presented. Indeed, the developed laminate results of a
transformation of a laminate currently produced by Clever
Reinforcement Iberica--Materiais de Construcao Lda in its Elvas
factory, where a developed mechanism allows to execute the
transition areas (elbows) which grants the laminate with the clip
or cane shape configurations.
[0007] These configurations assure the reinforcement ability to the
laminate to, simultaneously, flexing and cutting of BA beams,
flexing and puncturing of BA slabs, and anchor flexing regarding
pillars, balconies, panels and related elements. The base of the
CFRP laminate has a constant through-cut section, which can range
in width from 10 and 20 mm, with a thickness of 1.4 mm.
[0008] The extremities of the CFRP laminate are introduced in
opened punctures on the section of the element to be reinforced,
similarly to the Embedded Trough Section (ETC), which demonstrated
an extraordinary efficiency on the reinforcement of armed concrete
beams [10]. The laminates inclination and extremity length depend
on the reinforcement being executed, whereby they are presented
with the reinforcement project. The largest and most complete
experimental program performed to date regarding CFRP laminates
applied to the reinforcement to cutting according to the NSM
technique [4] has demonstrated that the efficiency of this
technique regarding the reinforcement of BA beams cutting
significantly depends on the inclination of the laminates, the
quality of the surrounding concrete, the percentage of stirrups on
the beam to be reinforced, and the hardness of the reinforcement
systems. On the other hand, the results on the efficiency
evaluation tests of the ETS technique on the reinforcement to BA
beams cutting has demonstrated that due to the fact that the
reinforcement elements are within the section, a far superior level
of efficiency is guaranteed when compared with the NSM and EBR
techniques. Such is due to the greater confinement offered by
concrete which envelops the reinforcement elements when using the
ETS technique, as well as a bigger fracture surface which is
developed during the removing process of the reinforcement elements
which go through the cutting clefts. These conclusions were also
confirmed by the presented parametric studies [5].
[0009] In order to evaluate the potential of a new type of
laminate, standard CFRP laminates were manually transformed, in
order to be with the intended configuration, namely clip or cane,
and a preliminary experimental exploratory program consisting of
armed concrete beams and slabs was made, where it was possible to
observe the greater efficiency of these new laminates and its
respective reinforcement technique, relatively to laminates and
traditional techniques, as it is shown on FIGS. 7 and 8, as the
clip or cane configuration with the extremity (extremities)
inserted into the section are very efficient on the reinforcement
to cutting/puncturing. Such is due to the increased confinement
that the surrounding concrete gives to the laminate, a bigger
concrete fracture resistant surface during the removing process of
a laminate with a potential cutting slot across, and the anchoring
effect of the center of the laminate used for the reinforcement to
flexing. In turn, the efficiency of the reinforcement to flexing is
far superior to the one achieved with standard CFRP laminates
applied according to the NSM technique, as the extremities of the
new laminate, when introduced in punctures executed inside the
section, assure and extraordinary anchoring effect to the middle
part of the laminate used in the reinforcement to flexing.
Therefore, the laminates critical area is the transition between
the three segments that form this new laminate, two regarding the
cane configuration (elbows). These areas are made through a
mechanism designed to ensure the proper inclination without loss of
rigidity and resistance. These areas are thermo-mechanically
treated, keeping a plait configuration, and being jacketed with a
fiber sleeve.
[0010] Thus, the results of the experimental, analytical and
numerical investigation, along with the already performed
exploratory results, show that the proposed laminate has a superior
efficiency when compared to what is assured by the existing
nowadays. The extremities of this new type of laminate, being
inserted on the section of the part being reinforced, are more
protected against the nefarious action of high temperatures, when
compared with the current marketed FRP systems. Therefore, even
under fire, the new types of laminates work as tendons, in which
its anchoring matches with the extremity areas of the laminate that
are embedded in the concrete according to the ETC technique. This
type of laminate can also be used on the reinforcement to flexing
of pillars and cantilevers/consoles, balcony types and related,
with full mobilization of the CFRP laminate traction resistance. In
this case, the laminate extremities are inserted, with the intended
anchorage inclination and length, in openings made on the pillars
or cantilevers or consoles connecting elements.
[0011] The present FCRP laminate has the ability of,
simultaneously, serve as reinforcement to flexing and cutting
regarding BA beams, and flexing and puncturing regarding BA slabs.
It can also be applied on the reinforcement to pillar, balcony and
console flexing, where the folded extremity, regarding the case of
a laminate with only one folded extremity--named as a cane type
laminate--is inserted in a puncture executed on the concrete
element where the laminate will be anchored. The reinforcement
ability of this laminate is higher than any other FRP system
currently in the market, given that the highest traction extension
possible to be mobilized nears the ultimate traction extension of
the material, being possible in most cases to achieve the final
extension, as observed in the made exploratory experimental assays,
as well as in the performed numerical simulations. The
reinforcement technique for the application of this new type of
laminate also contributed to its biggest reinforcement efficiency,
given that beyond the benefits derived from a good laminate
anchoring, its extremities are protected from the nefarious action
of high temperatures, whereby the laminate, even under fire,
develops a reinforcement ability, as if it is a tendon, much larger
than any existing FRP system. The use of an epoxy (S&P 55)
adhesive which fills the spacing between the laminate and the
substrate on the puncture area by means of its own weight, given
its high fluidity, allows a more complete and quick filling than
the currently existing systems.
[0012] Throughout this request it is considered that an elevated
fluidity equals a viscosity between 850 e 1150 mPa*s.
[0013] The nature of this new type of laminate and the
reinforcement technique is based on the accumulation of solid
knowledge supported by experimental, numerical and analytical
investigation performed during the last 15 years on FRP and
structure reinforcement areas.
[0014] This investigation allowed to demonstrate that the CFRP
laminates of rectangular section, when applied according to the NSM
technique, are more effective on reinforcement to flexing than the
systems applied according to the EBR technique. This comes from the
fact that the laminate is confined within a groove which is on the
coating concrete, whereby its separation by detachment, observed on
systems applied according to the EBR technique, it is not observed
on the laminate applied according to the NSM technique. Beyond
this, the analytical and numerical models have shown that the
bigger the ratio between the perimeter of the laminate and the area
of the through-cut section, the bigger its fixation capacity to the
concrete substrate [2]. However, the high tension concentration on
the extremities of the CFRP laminates applied according to the NSM
technique leads to detachment of the concrete coating, which starts
in those areas and progresses throughout almost the entire
laminate, given that the maximum mobilized extension can be
significantly lower than the last extension on the laminate
traction. Thus, by having folded extremities on the laminate,
inserted into punctures made on the section of the part to be
reinforced, a precocious detachment is avoided, and the critical
areas of the laminate are protected against the nefarious action of
high temperatures typical of a fire.
[0015] On the other hand, the investigation performed on the
reinforcement to cutting with CFRP laminates applied according to
the NSM and ETS techniques has shown that the reinforcement
efficiency is higher when the ETS technique is used, given the
higher confinement assured by the surrounding concrete [10]. By
such fact, in the proposed laminate, its extremities are applied
according to the ETS techniques, but now resorting to the
rectangular section laminate due to the already stated fact of this
geometry assures better fixation conditions than circular section
reinforcement. Besides that, the adhesive to be applied on these
areas, with elevated fluidity, will ensure a faster and more
complete space filling between the laminate and the surrounding
substrate.
[0016] Intervals and Possible Variations
[0017] The efficiency and profitability of the reinforcement
technique depends on the rigor assured for the required length and
inclination of the laminate, as well as the quality and rigor on
the execution of the transition areas. However, an error below 10%
whether on the inclination or the length of the extremities does
not affect significantly the performance of the new type of
laminate and the respective reinforcement technique, as well as the
quickness of execution of such technique. An equal error level is
admitted regarding the execution of a puncture for the laminate
extremities, as well as its diameter. These relatively high
tolerances are justified by the adequate flexibility of the
laminates transition area, which allows for some work adjustment
regarding the laminates extremity inclination. The extremity
inclination of the laminate can range from 30 to 90 degrees with
the beam axis (or the slab plane, and it should be the closest from
orthogonal regarding the cutting slots (beams) or puncturing
(slabs). Considering the cutting and puncturing rupture modes
observed on armed concrete beams and slabs, respectively, the
laminates extremities inclination should be close to 45 degrees,
but a variation of +/-15 degrees is perfectly acceptable
(inclinations of 30 to 60 degrees), and the assumption of vertical
extremities (orthogonal regarding the beam axis or the slab plane)
can still be an effective alternative when difficulties on the
execution of inclined puncturing are a considerable obstacle for
technical/economic reasons. The length of each of the parts that
make up for the laminate, will be completely dependent on the
conditions of the reinforcement project, but a 10% error does not
compromise its efficacy. However, the higher the length of the
laminates embedment on the BA element section to be reinforced, the
greater the efficiency of the reinforcement to
cutting/puncturing.
BRIEF DESCRIPTION OF FIGURES
[0018] To better understand the technique, the figures are present
in annex, which represent preferable embodiments which, however,
are not intended to limit the object of the present disclosure.
[0019] FIG. 1 shows a clip type of CFRP laminate.
[0020] FIG. 2 shows a cane type of CFRP laminate.
[0021] FIG. 3 shows a clip type laminate application for the
reinforcement to flexing and cutting of armed concrete beams.
[0022] FIG. 4 shows a clip type laminate application for the
simultaneous reinforcement to flexing and puncturing of armed
concrete slabs.
[0023] FIG. 5 shows a clip type laminate application for the
simultaneous reinforcement to flexing of armed concrete pillars
with laminate extremity anchoring.
[0024] FIG. 6 shows a cane type laminate application for the
reinforcement the negative momentum of swinging armed concrete
structures, with the example of a balcony.
[0025] FIG. 7 shows a beam reinforcement.
[0026] FIG. 8 shows an exploratory assay on the use of the new
types of laminates for reinforcement to BA slabs flexing and
puncturing: a) laminate configuration; b) reference slab rupture by
cutting; c) reinforced slab rupture by flexing with a 30% increase
on the cargo capacity and 33% on the straining ability, using a
small percentage, executed by a manual process of laminate
transformation.
DESCRIPTION OF THE EMBODIMENTS
[0027] Hereafter, some embodiments will be described in a more
detailed manner, which however are not intended to limit the scope
of the present disclosure.
[0028] The present disclosure describes CFRP laminates as the ones
shown on FIGS. 1 and 2, as well as the concrete structures
reinforcement technique using these laminates.
[0029] Types of Laminates
[0030] The laminates shown of FIGS. 1 e 2 are elaborated from
transverse section laminates 1.4.times.10 mm.sup.2 or 1.4.times.20
mm.sup.2. The transformation, executed by an automatism, introduces
the transition areas (Tz), elbows, presented on the referred
figures, being the laminate able to take a clip shape (FIG. 1) or a
cane shape (FIG. 2). The transition area is executed by a
thermo-mechanical treatment, in which by temperature rise, with an
oven existing in the mechanism, the adhesive becomes viscous, in a
way that it becomes possible to assure the required inclination to
the laminates extremity. This process is followed by application of
a rotational movement to the parte formed by the transition area
and its corresponding laminate extremity, while the other part of
the laminate is kept fixated, being this way introduced a plait
configuration to the transition area. This area is then dipped in
an adhesive and jacketed by a fiber sleeve in order to achieve the
intended hardness, being the process finalized by curing of this
area.
[0031] In FIG. 1 it is precisely shown a representation of the CFRP
laminate with a clip shape with both of its extremities folded,
being able to yield two different inclinations (.THETA.1 and
.THETA.2). The laminate is formed with three branches: central with
a length of Lb, which has the fundamental function of guaranteeing
a reinforcement to flexing of the BA element to be reinforced; both
extremities, whose behavior can be different, LS1 and LS2, which
have as the main objective of reinforcement to cutting. These
branches are connected by a transition area (TZ), that arises from
a complementary thermo-mechanical treatment with a fiber jacket in
order to assure the required resistance and hardness to avoid
precocious ruptures as a consequence of a development of tension
gradient caused by the variation on the orientation on the parts of
the laminate and the existence of different anchoring conditions on
the laminates parts.
[0032] In FIG. 2 a representation of a cane type CFRP laminate with
a folded extremity is shown, being able to take the intended
orientation. The laminate is formed by two branches, one with a Lb
length for reinforcement to flexing, and another with a Ls length
which can serve as a reinforcement to cutting and/or to assure an
adequate anchoring from the reinforcement laminate to flexing.
These branches are connected by a transition area (TZ).
[0033] Reinforcement Techniques
[0034] The reinforcement technique consists of installing the
laminate part destined to the reinforcement to flexing (Lb on FIGS.
1 e 2) in a slot made on the BA concrete element coating to be
reinforced (area with a L1 and L2 length as shown on FIG. 3a) and
on the installation of the extremity (extremities) of the laminate
in previously opened punctures on the section of the element to be
reinforced (FIGS. 3a, 3e and 3f). After the execution of the slot
and puncture, they are cleaned by compressed air or an equivalent
technique. The slot should have a width (ag) between 4.5 and 5.5 mm
(FIG. 3g) and a height (bg) equal to the added laminate from 1.0 to
3.0 (FIG. 3g). On the other hand, the punctures diameter should be
equal to the largest dimension of the added laminate section from
1.0 to 3.0 mm (FIG. 3f). Before introducing the laminate in the
slot and punctures, the laminate is cleaned with a degreasing
agent. The adhesive for fixation on the concrete of the Lb part of
the laminate, S&P 220, is produced according to the
recommendation of the adhesives manufacturer, although another
adhesive can be used as long as it is demonstrated by detachment
assays that the equal or superior conditions on the fixation of the
laminate to concrete are achieved, and applied with spatula, tube
or other nozzle mechanism in order to completely fill the slot with
the adhesive, throughout the length Lb and part of the transition
area in order to seal the lower part of the punctures. On the
laminates sides (10 or 20 mm wide), throughout the Lb length, a
thin adhesive layer is applied, and the laminate is immediately
introduced on the slot and their punctures. After the laminates are
applied, and while assuring a curing period for the adhesive of at
least 24 hours, a high fluidity adhesive is introduced by gravity,
on the top of the punctures, in order to fixate the laminate
extremities to the surrounding concrete (FIGS. 3e, 3f and 3h). The
curing period for the two types of used adhesives should be the one
stated by the manufacturer of such adhesives.
[0035] The clip shaped laminates are especially suited for the
simultaneous reinforcement of beams flexing and cutting. In the
example shown on FIG. 3a, a beam with a T section and reinforced
for positive momentum and transverse effort, resorting to a clip
laminate (L1) disposed along the longitudinal symmetry plane of the
beam, as shown on FIG. 3c, and by two clip laminate (L2) disposed
along the beam, near the beams sides, as shown on FIG. 3b.
Throughout the L1 length, the beam is reinforced to flexing with 3
laminates, as shown on FIGS. 3a and 3d, while on the L2 lengths the
beam has only 2 laminates for reinforcing to flexing, as shown on
FIGS. 3a and 3c. The central part of the laminates (Lb) assures
reinforcement to flexing, and offers resistance against the
propagation against flexing clefts (Crf), while the laminates
extremity parts (Ls) assure reinforcement to cutting (Crs). The
side parts of the laminate, while inclined, are inserted into
opened punctures on the beams section, with a diameter equal to the
bigger side of the laminate section, bf, as shown on FIG. 3e. After
the laminate is installed, the puncture is filled with high
fluidity adhesive in order to fill by gravity the existing spaces
between the laminate and the puncture wall, as shown in FIGS. 3h
and 3f.
[0036] The clip laminates, as shown of FIG. 4, are also proposed
for the simultaneous reinforcement to flexing and puncturing of BA
slabs. The central branches are used towards reinforcement to
flexing but also assure anchoring to the extremity branches, while
such extremity branches have the main function of reinforcement to
puncturing and anchoring to the central branch of reinforcement to
flexing. The central branches offer a resistance to flexing cleft
propagation (CRf), while the extremity branches offer resistance to
cutting clefts opening and sliding (CRs).
[0037] The clip or cane laminates, as shown on FIG. 5, can also be
used for the reinforcement to flexing of pillars, whereas the
non-inclined part has the function of reinforcement to flexing and
the extremity (extremities) to assure the needed anchoring in order
to an effective reinforcement to flexing, avoiding a precocious
detachment.
[0038] The cane laminates, as shown on FIG. 6, are indicated
particularly for the reinforcement of negative swing momentum, as
it is in the case of the balconies shown in the figure. The
laminates horizontal part assures the intended reinforcement to
flexing, with a La length, assuring the intended laminate
anchoring.
[0039] FIG. 7 shows the BA beams reinforcement configuration
adopted for the current experimental program.
[0040] FIG. 8 shows the BA slabs reinforcement configuration
adopted for the current experimental program--FIG. 8a, brittle
rupture by registered puncturing on the reference slab, as shown on
FIG. 8b and ductile rupture by flexing of the reinforced slab with
the new types of CFRP laminates, as shown on FIG. 8c.
REFERENCES
[0041] 1. Sena-Cruz, J. M.; Barros, J. A. O.; Coelho, M.; Silva, L.
F. F. T., "Efficiency of different techniques in flexural
strengthening of RC beams under monotonic and fatigue loading",
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[0042] 2. Barros, J. A. O.; Dias, S. J. E.; Lima, J. L. T.,
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strengthening of concrete beams", Cement and Concrete Composites
Journal, 29(3), 203-217, March 2007.
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of concrete beams with CFRP laminates bonded into slits", Cement
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RC beams with NSM CFRP laminates: experimental research and
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[0045] 5. Bianco, V., Barros, J. A. O., Monti, G., "Three
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[0046] 6. Perrone, M., Barros, J. A. O., Aprile, A., "CFRP-based
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[0048] 8. Costa, L G., Barros, J. A. O., "Flexural and shear
strengthening of RC beams with composites materials--the influence
of cutting steel stirrups to install CFRP strips", Cement and
Concrete Composites Journal, 32, 544 553, 2010.
[0049] 9. Barros, J. A. O.; Costa, I. G.; Ventura-Gouveia, A.,
"CFRP flexural and shear strengthening technique for RC beams:
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[0050] 10. Barros, J. A. O.; Dalfre, G. M., "Assessment of the
effectiveness of the embedded through-section technique for the
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49(1), 75-93, 2013.
[0051] The present technology is not, naturally, in any way
restricted to the embodiments described in this document and a
person skilled in the art could predict many technology
modification possibilities without straying from the general idea,
such as defined on the embodiments.
[0052] All embodiments above described are obviously
interchangeable. The following claims define additional preferred
embodiments.
[0053] The present technology is not, naturally, in any way
restricted to the embodiments described in this document and a
person skilled in the art could predict many technology
modification possibilities without straying from the general idea,
such as defined on the embodiments.
[0054] All embodiments above described are obviously
interchangeable. The following claims define additional preferred
embodiments.
* * * * *