CN101435185A - Case type closed reinforcing method of reinforced concrete ribbed arch bridge - Google Patents

Abstract

The invention discloses a box type sealed reinforcing method of a reinforced concrete ribbed arch bridge, comprising the following steps: 1. a finite element theoretical model is adopted for determining the optimum segment position, and the length and thickness the optimum sealed back-up coat for the box type sealed reinforcement; 2. bar-planting rubber anchor rods are embedded on the outside surfaces of the arch soffit, the back arch and the arch rib of the optimum segment position, longitudinal bars and transversal stirrups are connected, thus forming a reinforcing steel bar net; 3. lofting locating is carried out at the casting position of a template; and 4. reinforced concrete is cast in situ so as to form the reinforced concrete box type sealed back-up coat. The beneficial effects of the method are that: close contact and deformation compatibility can be realized between the reinforced concrete box type sealed back-up coat and an original arch rib, and single-rib bearing is changed into double-rib bearing, thus effectively improving the bearing capacity of the reinforced concrete ribbed arch bridge.

Description

The case type closed reinforcing method of reinforced concrete ribbed arch bridge

Technical field

The present invention relates to the reinforcement means of reinforced concrete ribbed arch bridge, specially refer to the case type closed reinforcing method in the crucial cross section of reinforced concrete ribbed arch bridge.

Background technology

Bridge is being brought into play very important effect as the important component part of main artey of communications in national economic development and social development.Health with the people is the same, bridge also the time regular meeting pathology takes place, take rational reinforcement means to handle to it and just seem particularly important.Usually, prior art adopts reinforcement means such as increasing section is long-pending, steel concrete cuff sealing main arch circle that Reinforced Concrete Bridge is reinforced.Its basic principle all is the sectional areas that increase Reinforced Concrete Bridge, and the supporting capacity of main arch circle is improved.But, for the reinforced concrete ribbed arch bridge of lightweight structures system, adopt reinforcement means such as increasing section is long-pending, steel concrete cuff sealing main arch circle to reinforce, can too increase the deadweight of bridge, not only can not effectively improve the bearing capacity of reinforced concrete ribbed arch bridge, on the contrary the stressed of arch rib had a negative impact, reduced the supporting capacity of bridge, cause serious potential safety hazard.

Summary of the invention

For solve undue increase bridge deadweight that existing Technology Bridge Strengthening exists in reinforced concrete ribbed arch bridge is reinforced, to problems such as arch rib stressed have a negative impact, the present invention proposes a kind of case type closed reinforcing method of reinforced concrete ribbed arch bridge.The case type closed reinforcing method of reinforced concrete ribbed arch bridge of the present invention adopts the finite element theory model to determine optimal zone fragment position, optimum sealed back-up length and the thickness of case type closed reinforcing, steel mesh reinforcement is set and cast reinforced concrete box type closed reinforcement layer on this steel mesh reinforcement at soffit, hogback and the arch rib outer surface of optimal zone fragment position.

The case type closed reinforcing method of reinforced concrete ribbed arch bridge of the present invention may further comprise the steps:

1, adopt the finite element theory model to determine optimal zone fragment position, optimum sealed back-up length and the thickness of case type closed reinforcing;

2, implant bar planting glue anchor pole at soffit, hogback and the arch rib outer surface of optimal zone fragment position, connect longitudinal reinforcement and lateral tie, form steel mesh reinforcement;

3, cast template position setting-out location;

4, cast-in-site steel concrete forms steel concrete box closed reinforcement layer.

The case type closed reinforcing method of reinforced concrete ribbed arch bridge of the present invention adopts the finite element theory model to determine the optimal zone fragment position of case type closed reinforcing, optimum sealed back-up length and thickness, comprise: be subjected to force mode and bridge strengthening design experiences in the past according to reinforced concrete ribbed arch bridge, tentatively draft the reinforcing position and the back-up coat length of steel concrete box confining bed, set up the model of the case type closed reinforcing of several reinforced concrete ribbed arch bridges, the employing finite element software calculates the cross direction profiles data of aforementioned each model arch rib load and compares, wherein, the average of load cross direction profiles ratio k value $\mathrm{EX}=\underset{i}{\mathrm{\Σ}}{x}_i{p}_i$ Approach 1 and dispersion ratio more $\mathrm{DX}=\underset{i=1}{\overset{\∞}{\mathrm{\Σ}}}{[X_i-\mathrm{EX}]}^2{P}_i$ Approaching 0 the case type closed reinforcing model of bridge more is best Scheme of Strengthening, and the position of the determined arch rib closed reinforcement of this scheme layer is the optimal zone fragment position, and determined closed reinforcement layer length is the best length of reinforcing;

Again according to aforementioned optimal zone fragment position and the best length of reinforcing, adopt finite element software to calculate the supporting capacity of ribbed arch under the different closed reinforcement layer thickness d conditions, set up the curve map of back-up coat thickness d and arch rib supporting capacity, when this curve ribbed arch bearing capacity turned to the flex point that reduces gradually along with the increase of back-up coat thickness d from improving constantly, the concrete enclosing back-up coat thickness d that flex point characterized was the best thickness d of reinforcing and faces;

Wherein:

K is a load cross direction profiles ratio, $k=\frac{{\mathrm{\σ}}_2}{{\mathrm{\σ}}_1},$ σ wherein ₁And σ ₂Be respectively the maximum stress of No. 1 rib and No. 2 ribs;

$\mathrm{EX}=\underset{i}{\mathrm{\Σ}}{x}_i{p}_i$ Be the average of load cross direction profiles ratio k value, in the formula, x _iBe each cross section load cross direction profiles rate value k, i=1,2,3 ...; p _iBe cross direction profiles ratio weight coefficient, in view of there is not correlation in the cross direction profiles ratio between each cross section, so p _i=1, i=1,2,3 ....

$\mathrm{DX}=\underset{i=1}{\overset{\∞}{\mathrm{\Σ}}}{[X_i-\mathrm{EX}]}^2{P}_i$ Be dispersion ratio, in the formula, x _iBe each cross section load cross direction profiles rate value k, i=1,2,3 ...; EX is the average of load cross direction profiles ratio k value; p _iBe cross direction profiles ratio weight coefficient, in view of there is not correlation in the cross direction profiles ratio between each cross section, so p _i=1, i=1,2,3 ....

The case type closed reinforcing method of reinforced concrete ribbed arch bridge of the present invention is provided with steel mesh reinforcement at soffit, hogback and the arch rib outer surface of optimal zone fragment position, comprise: bar planting glue anchor pole by quincunx implantation certain-length is arranged at soffit, hogback and arch rib outer surface, on anchor pole, connect longitudinal reinforcement and lateral tie formation steel mesh reinforcement, described " by quincunx " is meant according to orthohexagonal form, chooses the bore position that any orthohexagonal six angle points of formation are implanted as anchor pole in anchorage zone.

Adopt welding or hinged mode to connect between bar planting glue anchor pole, longitudinal reinforcement and the lateral tie of the case type closed reinforcing method of reinforced concrete ribbed arch bridge of the present invention.

The steel mesh reinforcement of the case type closed reinforcing method of reinforced concrete ribbed arch bridge of the present invention on bar planting glue anchor pole can be one or more layers.

The bolt diameter of the case type closed reinforcing method of reinforced concrete ribbed arch bridge of the present invention is that 12mm, length are 12～16mm, the diameter of longitudinal reinforcement is 20～28mm, the diameter of lateral tie is 12～20mm, and the height that anchor pole exposes the arch rib surface should lack 2～5cm than the thickness of steel concrete box closed reinforcement layer.

The case type closed reinforcing method of reinforced concrete ribbed arch bridge of the present invention is poured into a mould reinforced concrete box type closed reinforcement layer on this steel mesh reinforcement, comprise: on the steel mesh reinforcement of soffit, hogback and the arch rib outer surface of arch rib, set up and fixed form, cast-in-site steel concrete, the steel concrete box closed reinforcement layer of formation certain-length and thickness.

The case type closed reinforcing method of reinforced concrete ribbed arch bridge of the present invention is pressed ribbed arch concrete surface cutter hair earlier, again according to the order fluid concrete that encircles side, soffit and hogback when the case type closed back-up coat of casting reinforced concrete.

The beneficial effect of the case type closed reinforcing method of reinforced concrete ribbed arch bridge of the present invention is that steel concrete box closed reinforcement layer can be realized closely contacting with former arch rib, compatibility of deformation, single rib carrying is transformed into two rib carryings, has effectively improved the supporting capacity of reinforced concrete ribbed arch bridge.

Description of drawings:

Accompanying drawing 1 is the full-bridge front schematic view of the case type closed reinforcing section of the case type closed reinforcing method of reinforced concrete ribbed arch bridge of the present invention;

Accompanying drawing 2 is schematic cross-sectional view of the case type closed layer of the case type closed reinforcing method of reinforced concrete ribbed arch bridge of the present invention;

Accompanying drawing 3 is longitudinal section schematic diagrames of the case type closed layer of the case type closed reinforcing method of reinforced concrete ribbed arch bridge of the present invention;

Accompanying drawing 4 is the arrangement of reinforcement schematic diagrames in the case type closed layer of the case type closed reinforcing method of reinforced concrete ribbed arch bridge of the present invention cross section;

Accompanying drawing 5 is plane arrangement of reinforcement schematic diagrames of the case type closed layer of the case type closed reinforcing method of reinforced concrete ribbed arch bridge of the present invention;

Accompanying drawing 6 is " blossom type " distribution schematic diagrams of layout bar planting glue anchor pole position of the case type closed reinforcing method of reinforced concrete ribbed arch bridge of the present invention;

Accompanying drawing 7 is bar planting glue anchor pole organigrams of the case type closed reinforcing method of reinforced concrete ribbed arch bridge of the present invention.

Be further described below in conjunction with the case type closed reinforcing method of the drawings and the specific embodiments reinforced concrete ribbed arch bridge of the present invention.

The specific embodiment

Specific embodiment 1:

Accompanying drawing 1 is the full-bridge front schematic view of the case type closed reinforcing section of the case type closed reinforcing method of reinforced concrete ribbed arch bridge of the present invention.Among the figure, the 1st, abut, the 2nd, arch rib, the 3rd, straining beam, the 4th, bearing beam, the 5th, case type closed layer.As seen from the figure, the case type closed reinforcing method of reinforced concrete ribbed arch bridge of the present invention is provided with case type closed back-up coat in arch rib optimal zone fragment position, but not all seal at arch rib, can or not have a negative impact because of closed reinforcement too increases the bridge deadweight to the stressed of arch rib.Tentative calculation obtains according to the finite element theory model and adopt case type closed optimal zone fragment position, best sealing length and best confining bed concrete thickness, can guarantee the actual effect of closed reinforcement.

Accompanying drawing 2 is schematic cross-sectional view of the case type closed layer of the case type closed reinforcing method of reinforced concrete ribbed arch bridge of the present invention, and accompanying drawing 3 is longitudinal section schematic diagrames of the case type closed layer of the case type closed reinforcing method of reinforced concrete ribbed arch bridge of the present invention.Among the figure, the 2nd, arch rib, the 3rd, straining beam, the 5th, case type closed layer.As seen from the figure, the closed reinforcement layer of the case type closed reinforcing method of reinforced concrete ribbed arch bridge of the present invention such as same " box-frame " lock ring are around the ribbed arch outside, on arch side, soffit and the hogback of ribbed arch, the closed reinforcement layer is arranged all, therefore, be referred to as " case type closed back-up coat ".1 as can be known in conjunction with the accompanying drawings, and reinforcement means of the present invention is arranged on described " case type closed back-up coat " requirement distribution according to the optimal zone fragment position on the whole ribbed arch, therefore, is referred to as " case type closed reinforcing method ".

Specific embodiment 2:

Accompanying drawing 4 is the arrangement of reinforcement schematic diagrames in the case type closed layer of the case type closed reinforcing method of reinforced concrete ribbed arch bridge of the present invention cross section, and accompanying drawing 5 is plane arrangement of reinforcement schematic diagrames of the case type closed layer of the case type closed reinforcing method of reinforced concrete ribbed arch bridge of the present invention.Among the figure, the 6th, bar planting glue anchor pole, the 7th, longitudinal reinforcement, the 8th, lateral tie.As seen from the figure, the case type closed reinforcing method of reinforced concrete ribbed arch bridge of the present invention has bar planting glue anchor pole by quincunx implantation certain-length at soffit, hogback and the arch rib outer surface of arch rib optimal zone fragment position, connects longitudinal reinforcement and lateral tie forms steel mesh reinforcement on anchor pole.Accompanying drawing 6 is " blossom type " distribution schematic diagrams of layout bar planting glue anchor pole position of the case type closed reinforcing method of reinforced concrete ribbed arch bridge of the present invention.Among the figure, the 9th, bar planting glue bolthole.As seen from the figure, described " by quincunx " is meant according to orthohexagonal form, chooses the bore position that any orthohexagonal six angle points of formation are implanted as anchor pole in anchorage zone.Because its arrangement form is similar to the shape of plum blossom, so be referred to as the quincuncial arrangement form.According to the punching of quincuncial arrangement anchor pole position distribution, clear hole, then, in anchor hole, inject bar planting glue, will implant anchor hole according to the reinforced anchor bolt that designing requirement is made again, make concrete and anchor pole gluing together.After treating that concrete and anchor pole gluing reach certain intensity, on anchor pole, connect longitudinal reinforcement and lateral tie again, form steel mesh reinforcement.Wherein, the diameter of bar planting glue anchor pole is that 12mm, length are 12～16cm, and the diameter of longitudinal reinforcement is 20～28mm, and the diameter of lateral tie is 12～20mm, and the height that anchor pole exposes the arch rib surface should lack 2～5cm than the thickness of steel concrete box confining bed.

Obviously, adopt welding or hinged mode to connect between bar planting glue anchor pole, longitudinal reinforcement and the lateral tie of the case type closed reinforcing method of reinforced concrete ribbed arch bridge of the present invention.

For guaranteeing the quality of box closed reinforcement layer, the case type closed reinforcing method of reinforced concrete ribbed arch bridge of the present invention with ribbed arch concrete surface cutter hair, is poured into a mould according to the order of arch side, soffit and hogback earlier when fluid concrete again.In casting process, want the concrete pouring density of strict control.

When case type closed back-up coat was thicker, for guaranteeing the intensity of closed reinforcement layer, the steel mesh reinforcement of the case type closed reinforcing method of reinforced concrete ribbed arch bridge of the present invention on bar planting glue anchor pole can be one or more layers.

Accompanying drawing 7 is bar planting glue anchor pole organigrams of the case type closed reinforcing method of reinforced concrete ribbed arch bridge of the present invention.Among the figure, the 2nd, arch rib, the 5th, case type closed layer, the 6th, bar planting glue anchor pole, the 7th, longitudinal reinforcement, the 8th, lateral tie.As seen from the figure, the anchor pole of the case type closed reinforcing method of reinforced concrete ribbed arch bridge of the present invention is rooted in the ribbed arch matrix, and distributes rationally, and the steel mesh reinforcement of being made up of longitudinal reinforcement and lateral tie is soldered or be hinged on the anchor pole.Then, on steel mesh reinforcement, set up and fixed form cast-in-site steel concrete, the steel concrete box confining bed of formation certain-length and thickness.Obviously, the steel concrete box confining bed that adopts the inventive method to reinforce can be realized closely contacting with former arch rib, compatibility of deformation, and single rib carrying is transformed into two rib carryings, has improved the supporting capacity of reinforced concrete ribbed arch bridge.

The case type closed reinforcing method of reinforced concrete ribbed arch bridge of the present invention may further comprise the steps at least:

1, adopt the finite element theory model to determine optimal zone fragment position, optimum sealed back-up length and the thickness of case type closed reinforcing, comprising:

(1) is subjected to force mode and bridge strengthening design experiences in the past according to reinforced concrete ribbed arch bridge, tentatively draft the reinforcing position and the back-up coat length of steel concrete box confining bed, set up the model of the case type closed reinforcing of several reinforced concrete ribbed arch bridges, the employing finite element software calculates the cross direction profiles data of aforementioned each model arch rib load and compares, wherein, the average of load cross direction profiles ratio k value $\mathrm{EX}=\underset{i}{\mathrm{\Σ}}{x}_i{p}_i$ Approach 1 and dispersion ratio more $\mathrm{DX}=\underset{i=1}{\overset{\∞}{\mathrm{\Σ}}}{[X_i-\mathrm{EX}]}^2{P}_i$ Approaching 0 the case type closed reinforcing model of bridge more is best Scheme of Strengthening, and the position of the determined arch rib closed reinforcement of this scheme layer is the optimal zone fragment position, and determined closed reinforcement layer length is the best length of reinforcing;

(2) again according to aforementioned optimal zone fragment position and the best length of reinforcing, adopt finite element software to calculate the supporting capacity of ribbed arch under the different closed reinforcement layer thickness d conditions, set up the curve map of back-up coat thickness d and arch rib supporting capacity, when this curve ribbed arch bearing capacity turned to the flex point that reduces gradually along with the increase of back-up coat thickness d from improving constantly, the concrete enclosing back-up coat thickness d that flex point characterized was the best thickness d of reinforcing and faces.Wherein: k is a load cross direction profiles ratio, $k=\frac{{\mathrm{\σ}}_2}{{\mathrm{\σ}}_1},$ σ wherein ₁And σ ₂Be respectively the maximum stress (China's reinforced concrete ribbed arch bridge is in the majority with dipleuraltype, and No. 1 of this place and No. 2 arch ribs mainly are at general Reinforced Concrete Double ribbed arch bridge and opinion, and wherein No. 1 rib is the unbalance loading rib, and No. 2 ribs are the underloading rib) of No. 1 rib and No. 2 ribs; $\mathrm{EX}=\underset{i}{\mathrm{\Σ}}{x}_i{p}_i$ Be the average of load cross direction profiles ratio k value, in the formula, x _iBe each cross section load cross direction profiles rate value k, i=1,2,3 ...; p _iBe cross direction profiles ratio weight coefficient, in view of there is not correlation in the cross direction profiles ratio between each cross section, so p _i=1, i=1,2,3 .... $\mathrm{DX}=\underset{i=1}{\overset{\∞}{\mathrm{\Σ}}}{[X_i-\mathrm{EX}]}^2{P}_i$ Be dispersion ratio, in the formula, x _iBe each cross section load cross direction profiles rate value k, i=1,2,3 ...; EX is the average of load cross direction profiles ratio k value; p _iBe cross direction profiles ratio weight coefficient, in view of there is not correlation in the cross direction profiles ratio between each cross section, so p _i=1, i=1,2,3 ....

2, implant bar planting glue anchor pole, connect longitudinal reinforcement and lateral tie, form steel mesh reinforcement, comprising:

(1) according to quincuncial arrangement anchor pole position, the punching that distributes, clear hole;

(2) in anchor hole, inject bar planting glue, will make reinforced anchor bolt according to designing requirement again and implant anchor hole, make concrete and anchor pole gluing together;

(3) on anchor pole, connect longitudinal reinforcement and lateral tie, form steel mesh reinforcement;

Wherein, the diameter of bar planting glue anchor pole is that 12mm, length are 12～16cm, and the diameter of longitudinal reinforcement is 20～28mm, and the diameter of lateral tie is 12～20mm, and the height that anchor pole exposes the arch rib surface should lack 2～5cm than the thickness of steel concrete box confining bed.

3, cast template position setting-out location comprises: set up and fixed form on the steel mesh reinforcement of soffit, hogback and the arch rib outer surface of arch rib.

4, cast-in-site steel concrete forms steel concrete box closed reinforcement layer.

(1) with ribbed arch concrete surface cutter hair,

(2) pour into a mould according to the order of arch side, soffit and hogback,

(3) in casting process, want the concrete pouring density of strict control.

Claims (9)

1, a kind of case type closed reinforcing method of reinforced concrete ribbed arch bridge, it is characterized in that: adopt the finite element theory model to determine optimal zone fragment position, optimum sealed back-up length and the thickness of case type closed reinforcing, steel mesh reinforcement is set and cast reinforced concrete box type closed reinforcement layer on this steel mesh reinforcement at soffit, hogback and the arch rib outer surface of optimal zone fragment position.

2, according to the case type closed reinforcing method of the described reinforced concrete ribbed arch bridge of claim 1, it is characterized in that: described reinforcement means may further comprise the steps:

(1) adopt the finite element theory model to determine optimal zone fragment position, optimum sealed back-up length and the thickness of case type closed reinforcing;

(2) implant bar planting glue anchor pole at soffit, hogback and the arch rib outer surface of optimal zone fragment position, connect longitudinal reinforcement and lateral tie, form steel mesh reinforcement;

(3) cast template position setting-out location;

(4) cast-in-site steel concrete forms steel concrete box closed reinforcement layer.

3, case type closed reinforcing method according to the described reinforced concrete ribbed arch bridge of claim 1, it is characterized in that: adopt the finite element theory model to determine the optimal zone fragment position of case type closed reinforcing, optimum sealed back-up length and thickness, comprise: be subjected to force mode and bridge strengthening design experiences in the past according to reinforced concrete ribbed arch bridge, tentatively draft the reinforcing position and the back-up coat length of steel concrete box confining bed, set up the model of the case type closed reinforcing of several reinforced concrete ribbed arch bridges, the employing finite element software calculates the cross direction profiles data of aforementioned each model arch rib load and compares, wherein, the average of load cross direction profiles ratio k value $\mathrm{EX}=\underset{i}{\mathrm{\Σ}}{x}_i{p}_i$ Approach 1 and dispersion ratio more $\mathrm{DX}=\underset{i=1}{\overset{\∞}{\mathrm{\Σ}}}{[X_i-\mathrm{EX}]}^2{P}_i$ Approaching 0 the case type closed reinforcing model of bridge more is best Scheme of Strengthening, and the position of the determined arch rib closed reinforcement of this scheme layer is the optimal zone fragment position, and determined closed reinforcement layer length is the best length of reinforcing;

Again according to aforementioned optimal zone fragment position and the best length of reinforcing, adopt finite element software to calculate the supporting capacity of ribbed arch under the different closed reinforcement layer thickness d conditions, set up the curve map of back-up coat thickness d and arch rib supporting capacity, when this curve ribbed arch bearing capacity turned to the flex point that reduces gradually along with the increase of back-up coat thickness d from improving constantly, the concrete enclosing back-up coat thickness d that flex point characterized was the best thickness d of reinforcing _Face

Wherein:

K is a load cross direction profiles ratio, $k=\frac{{\mathrm{\σ}}_2}{{\mathrm{\σ}}_1},$ σ wherein ₁And σ ₂Be respectively the maximum stress of No. 1 rib and No. 2 ribs;

$\mathrm{EX}=\underset{i}{\mathrm{\Σ}}{x}_i{p}_i$ Be the average of load cross direction profiles ratio k value, in the formula, x _iBe each cross section load cross direction profiles rate value k, i=1,2,3 ...; p _iBe cross direction profiles ratio weight coefficient, in view of there is not correlation in the cross direction profiles ratio between each cross section, so p _i=1, i=1,2,3 ....

$\mathrm{DX}=\underset{i=1}{\overset{\∞}{\mathrm{\Σ}}}{[X_i-\mathrm{EX}]}^2{P}_i$ Be dispersion ratio, in the formula, x _iBe each cross section load cross direction profiles rate value k, i=1,2,3 ...; EX is the average of load cross direction profiles ratio k value; p _iBe cross direction profiles ratio weight coefficient, in view of there is not correlation in the cross direction profiles ratio between each cross section, so p _i=1, i=1,2,3 ....

4, according to the case type closed reinforcing method of the described reinforced concrete ribbed arch bridge of claim 1, it is characterized in that: soffit, hogback and arch rib outer surface in the optimal zone fragment position are provided with steel mesh reinforcement, comprise: bar planting glue anchor pole by quincunx implantation certain-length is arranged at soffit, hogback and arch rib outer surface, on anchor pole, connect longitudinal reinforcement and lateral tie formation steel mesh reinforcement, described " by quincunx " is meant according to orthohexagonal form, chooses the bore position that any orthohexagonal six angle points of formation are implanted as anchor pole in anchorage zone.

5, according to the case type closed reinforcing method of claim 1 or 4 described reinforced concrete ribbed arch bridges, it is characterized in that: adopt welding or hinged mode to connect between bar planting glue anchor pole, longitudinal reinforcement and the lateral tie.

6, according to the case type closed reinforcing method of claim 1 or 4 described reinforced concrete ribbed arch bridges, it is characterized in that: the steel mesh reinforcement on bar planting glue anchor pole can be one or more layers.

7, according to the case type closed reinforcing method of claim 1 or 4 described reinforced concrete ribbed arch bridges, it is characterized in that: bar planting glue bolt diameter is that 12mm, length are 12～16cm, the diameter of longitudinal reinforcement is 20～28mm, the diameter of lateral tie is 12～20mm, and the height that anchor pole exposes the arch rib surface should lack 2～5cm than the thickness of steel concrete box closed reinforcement layer.

8, according to the case type closed reinforcing method of the described reinforced concrete ribbed arch bridge of claim 1, it is characterized in that: cast reinforced concrete box type closed reinforcement layer on steel mesh reinforcement, comprise: on the steel mesh reinforcement of soffit, hogback and the arch rib outer surface of ribbed arch, set up and fixed form, cast-in-site steel concrete, the steel concrete box closed reinforcement layer of formation certain-length and thickness.

9, according to the case type closed reinforcing method of the described reinforced concrete ribbed arch bridge of claim 1, it is characterized in that: when the case type closed back-up coat of casting reinforced concrete, earlier ribbed arch concrete surface cutter hair is pressed, again according to the order fluid concrete that encircles side, soffit and hogback.

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