AU675602B2

AU675602B2 - Method for strengthening a concrete deck

Info

Publication number: AU675602B2
Application number: AU81504/94A
Authority: AU
Inventors: Yoshinori Ito
Original assignee: Sho Bond Corp
Current assignee: Sho Bond Corp
Priority date: 1994-12-16
Filing date: 1994-12-16
Publication date: 1997-02-06
Anticipated expiration: 2014-12-16
Also published as: AU8150494A

Description

I METHOD FOR STRENGTHENING A CONCRETE DECK BACKGROUND OF THE INVENTION (Field of the Invention) The present invention relates to a method for strengthening a concrete deck of existing bridge structures.

(Prior Art) Generally, in cases of bridge structures such as ai elevated road, etc., concrete decks have structure enough to withstand a dynamic load due to a traffic volume of cars.

Strength of the concrete decks of existing aged bridge structures, however, relatively decreases with rapid increases in the traffic volume of cars after construction thereof and in load and collision load due to heavier weight of vehicles. It 600 is therefore necessary to strengthen such concrete decks.

Recently, on the other hand, noise barriers are .0 0 further fixed on edges of overhang portions of existing bridge structures in order to control the noise of cars to go out of the bridge structures. It is thus necessary to strengthen around overhang supports, sites where tensile strength acts to an upside of decks.

Generally, strengthening of the concrete decks is done by removing an asphalt pavement layer 2 laid on an upper surface of a concrete deck 1 as shown in Fig. 7, newly placing a strengthening concrete layer 3 on the upper surface of the concrete deck 1 to thicken a concrete portion as shown in Fig.

8. Then, the asphalt pavement layer 2 is again applied thereon.

In such a strengthening method, however, connection 1

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between the existing concrete layer and the newly placed strengthening concrete layer is not necessarily sufficient, which of ten causes dissatisfied results from a viewpoint of integral structure of the existing and new concrete layers. In addition, strengthening of a site where tensile strength acts to upside of the deck is not complete in the conventional strengthening method.

see: Further, it is necessary to use large-sized concrete .eo placing facilities in such a method, which would widen a scale of construction.

•e Accordingly, it is an object of this invention to solve conventional problems as described above.

(Means to solve the Problems) SUMMARY OF THE INVENTION So.*: According to the present invention, there is provided a method for strengthening a concrete deck which comprises applying an adhesive on a concrete deck in which a pavement layer has been removed, followed by laying and adhering thereon a plurality of block shaped precast panels made of a material having strength similar to or stronger than that of the concrete deck to form a first strengthening layer, adhering a layer of a material having higher tensile strength than the first strengthening layer at a site where tensile strength acts to an upside of the deck to form a tensile resistant layer, further I applying adhesive on the first strengthening layer and the tensile resistant layer, laying thereon a plurality of the block shaped precast panels made of a material having a strength similar to or stronger than that of the concrete deck, so that joints thereof are not overlapped with those of the first strengthening layer, thus forming a second strengthening layer, and applying the pavement layer.

As the first strengthening layer is formed by applying the adhesive on the upper surface of the concrete deck in which the pavement layer has been removed and laying thereon a plurality of the block shaped precast panels, roughness of the upper surface of the concrete deck can be controlled depending on an extent of the adhesive application and a degree of laying pressure of the first strengthening layer.

While, in the second strengthening layer, as a o* plurality of each block shaped precast panel is laid on that of the first strengthening laying so that joints of each panel of the first and the second strengthening layers are not overlapped each other so as to integrate the second layer with Soo the first one, each of precast panel has a continuity, thereby stress added thereto being transmitted throughout the deck.

As each of the precast panel of the first and the o: second strengthening panels is made of a material having strength similar to or stronger than that of the concrete deck and is firmly integrated each other as well as with the 3 I I IEl concrete deck by means of the adhesive, a sufficient strengthening can be obtained.

As the sheet like stuff made of a material having higher tensile strength is applied between the first and the second strengthening layers at sites where tensile strength acts to the upside of the deck, ie., around the overhang supports or above the girders of the bridge, a sufficient *o *ooo **w 0

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strengthening can be achieved at tensile strength acting sites.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a partially cutaway view in perspective showing an example of main part of the present invention.

Fig. 2 is a transverse axial cross section illustrating a strengthening procedure of a concrete deck to be strengthened.

Fig. 3 is a transverse axial cross section illustrating the next step of the procedure shown in Fig. 2.

Fig. 4 is a transverse axial cross section illustrating the next step of the procedure shown in Fig. 3.

Fig. 5 is a transverse axial cross section illustrating the next step of the procedure shown in Fig. 4.

oooo co. Fig. 6 is a transverse axial cross section illustrating the next step of the procedure shown in Fig. Fig. 7 is a transverse axial cross section illustrating an example of an existing concrete deck to be •:co o o strengthened.

Fig. 8 is a transverse axial cross section oe illustrating an example of conventional method for strengthening an existing concrete deck to be strengthened.

DETAILED DESCRIPTION AND THE PREFERRED EMBODIMENTS eoo Reffering now to drawings, the present invention will be described in the following.

Fig. 1 is a partially cutaway view in perspective of a main part of a bridge structure which concrete deck is strengthened completely according to the present invention.

Figs. 2 to 6 are transverse axial cross sections illustrating a 4 strengthening procedure of a concrete deck according to the present invention. Fig. 7 is a cross section illustrating an example of an existing concrete deck to be strengthened.

In Fig. 7, a concrete deck 1 to be strengthened is put on the girders 4 and a pavement layer 2 is applied on an upper surfce of the concrete deck.

An example of a strengthening procedure of the concrete deck 1 required to strengthen will be described in the following.

First of all, as shown in Fig. 2, the pavement layer 2 applied on the upper surface of the concrete deck 1 shown in Fig. 7 is removed. If a degraded portion la exists on the concrete deck 1, the portion la is removed or repaired as shown eeoc in Fig. 1.

An adhesive is then applied on the upper surfce of the concrete deck 1 as shown in Fig. 1 to form an adhesive layer A plurality of block shaped precast panels 6 are laid thereon eooe to adhere and integrate the concrete deck and the precast panels 6, thereby forming first strengthening layer 7.

A sheet like stuff 8 is then adhered with the adhesive around an overhang supports of the overhang portions lb and above the of girders 4 of the first strengthening layer 7 formed by laying a plurality of the block shaped precast panels 6, as shown in Fig. 4. When sites where tensile strength acts to upside of the deck are only around the overhang supports, the sheet like stuff 8 may be applied merely therearound.

Further, the adhesive is applied both on the upper surface of the first strengthening layer 7 comprising the block 5 shaped precast panels adhered and integrated with the concrete deck 1 and on the upper surface of the sheet like stuff 8 to form an adhesive layer 9, as shown in Fig. 5. A plurality of block shaped precast panels 10 are laid thereon similarly as in the case of formation of the first strengthening layer 10 so that joints 13 of neighboring each precast panel 10 are not overlapped to joints 12 of each precast panel 6 of the first strengthening layer 7, thereby forming second strengthening layer 11. The first strengthening layer 7 and the second one 11 are thus adhered and integrated.

Finally, the pavement layer 2 is again formed to complete the strengthening method, as shown in Fig. 6.

The bridge structure wherein concrete deck is completely strengthened comprises the pavement layer 2, the second strengthening layer 11 consisting of the precast panels 1 0, the adhesive layer 9, the sheet like stuff 8, the first strengthening layer 7 consisting of the precast panels 6, the adhesive layer 5 and the concrete deck 1, as shown in Fig. 1.

Epoxy resin mortar was used as the adhesive in the example. Other adhesives which can securely adhere the concrete deck and the precast panels may also be used. An example of particularly preferable adhesives includes an epoxy resisn adhesive.

Non-asbest slate boards were used as the precast panels. The precast panels should be made of a material having strength similar to or stronger than that of the concrete deck, including such materials as glass-fiber reinforced cement, cement mortar, ceramics and the like other than the slate 6

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boards described above. Although the dimension of the precast panels is not particularly restricted, panels of 300 mm to 400 mm x 400 mm x 500 mm are preferable from a viewpoint of appliability, Carbon fiber was used as the sheet like stuff. Other materials useful herein and having higher tensile strength include, for example, glass fiber, aramid fiber, or if necessary, thin steel plate and the like.

As is described above, the present invention has following favorable effects.

As the first strengthening layer is formed by applying the adhesive on the upper surface of the concrete deck in which the pavement layer has been removed and laying thereon a plurality of the block shaped precase panels, it is possible to lay these panels evenly without any affection of roughness of the concrete deck nor formation of foam on the adhesive surface.

0.00 e As the second strengthening layer is formed by laying a plurality of each block shaped precast panel so that oe 00 0 neighboring joints thereof are not overlapped to those of the first layer, the precast panels have a continuity each other, thereby stress being transmitted smoothly.

000000 As each of the precast panel of the first and the second strengthening panels is made of a material having strength similar to or stronger than that of the concrete deck and is firmly integrated each other as well as with the concrete deck by means of the adhesive, a sufficient strengthening can be obtained.

7 -s I 0 1 As the sheet like stuff made of a material having higher tensile strength is applied between the first and the second strengthening layers at sites where tensile strength acts to the upside of the deck, a similar effect as steel reinforcing results in, thereby the tensile strength acting sites such as around the hangover portions of the bridge or above the girders being strengthened.

Further, as large-sized facilities are not required in the present strengthening method, the construction can be done effectively.

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Claims

2. A method for strengthening a concrete deck, substantially as hereinbefore described with reference to figures 1 to 6 of the accompanying drawings. dated this 8th October 1996 Sho-Bond Corporation by their Patent Attorneys Paul R. Taylor Associates ABSTRACT In order to strengthen existing concrete decks, there is provided a method for strengthening a concrete deck which comprises applying an adhesive on a concrete deck in which a pavement layer has been removed, followed by laying and adhering thereon a plurality of block shaped precast panels made of a material having strength similar to or stronger than that of the concrete deck to form first strengthening layer, adhering sheet like stuff made of a material having higher tensile strength on the first strengthening layer at a site where tensile strength acts to an upside of the deck to form a ~o tensile resistant layer, further applying the adhesive on the first strengthening layer and the tensile resistant layer, r e S laying thereon a plurality of the block shaped precast panels made of the material having the strength similar to or stronger than that of the concrete deck so that joints thereof are not overlapped with those of the first strengthening layer to form second strengthening layer, and applying the pavement layer. Se
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