CN111851251A - Box girder bottom plate reinforcing structure and construction method thereof, box girder and box girder bridge - Google Patents

Abstract

The invention relates to a box girder bottom plate reinforcing structure which comprises an anchoring crossbeam and an external prestressed plate, wherein the length direction of the anchoring crossbeam is parallel to the transverse direction of a box girder, the bottom of the anchoring crossbeam is fixedly connected with the box girder bottom plate and/or two ends of the anchoring crossbeam are fixedly connected with two box girder web plates respectively, and the external prestressed plate is tensioned and anchored on the anchoring crossbeam through an anchor rope. In addition, the box girder adopting the box girder bottom plate reinforcing structure, a box girder bridge adopting the box girder and a construction method of the box girder bottom plate reinforcing structure are also provided. According to the invention, the anchoring cross beam is arranged in the box chamber, so that the structural integrity of the box girder and the transverse rigidity of the bottom plate of the box girder can be increased, and the anchoring cross beam is vertical to the bottom plate longitudinally, so that the occurrence and the expansion of longitudinal cracks of the bottom plate can be inhibited; by arranging the external prestressed plates and stretching and anchoring the external prestressed plates on the anchoring cross beam through the anchor cables, transverse pre-stress can be provided for the bottom plate, and the occurrence and the expansion of longitudinal cracks of the bottom plate can be reduced and restrained.

Description

Box girder bottom plate reinforcing structure and construction method thereof, box girder and box girder bridge

Technical Field

The invention belongs to the technical field of civil engineering, and particularly relates to a box girder bottom plate reinforcing structure, a box girder adopting the box girder bottom plate reinforcing structure, a box girder bridge adopting the box girder and a construction method of the box girder bottom plate reinforcing structure.

Background

The large-span prestressed concrete variable cross-section box girder bridge is a bridge type widely adopted at present, and is most common in terms of continuous beams and continuous rigid frame bridges. As shown in fig. 1-4, the large-span prestressed concrete variable cross-section box girder bridge with the downward bending arrangement of the bottom plate cables has the following technical characteristics and accompanying common defects of the bottom plates:

(1) as shown in fig. 3 and 4, the currently common cross section of the variable cross-section box girder bridge is a single-box single-chamber cross section, and due to stress requirements, the height of the girder is continuously increased from the midspan cross section to the fulcrum cross section, so that the elevation of the lower edge of the bottom plate 101 is arched, the elevation of the bottom plate cable 103 is also arched due to the structural arrangement, and the bottom plate cable 103 is arranged in a downward bending manner. Because the bottom plate cable 103 is tensioned and both ends of the bottom plate cable 103 are anchored on the sawtooth blocks 104, the tensioned bottom plate cable 103 inevitably generates downward radial force, and the downward radial force has adverse side effects on the bridge, which easily causes the bottom plate 101 to crack.

(2) As shown in FIG. 4, the bottom plate cables 103 are generally arranged in a single layer, and when the span is increased, the usage amount of the bottom plate cables 103 is increased sharply, and the hollowing rate on the horizontal line section at the center of the bottom plate cables is increased sharply. When the span is increased, the downward radial force of the bottom plate cable 103 is increased, and the effective bearing section area is reduced, so that the bottom plate 101 is more prone to cracking or bursting damage. At present, the problem that the lower surface of the bottom plate 101 cracks along the bridge direction exists in the field of a plurality of continuous beams and continuous rigid frame bridges. Most bridges have large hollowing rate from the midspan section to the L/4 section, and the problem that the lower surface of the bottom plate 101 cracks along the bridge direction is more serious.

(3) As shown in figures 2 and 3, when the span is increased, the amount of the bottom plate cable 103 is increased, the bottom plate cable 103 near the transverse center line of the box girder needs to be bent flatly to the joint of the web plate 102 and the bottom plate 101 for anchoring so as to shorten the force transmission path, and the horizontal force pulling force generated by excessive flat bending also easily and directly causes the cracking of the bottom plate 101. At present, a plurality of long-span continuous beams and continuous rigid frame bridges in the field have serious cracking problems of the lower surface of a bottom plate 101 along the bridge direction.

The box girder bottom plate 101 cracks, so that the overall rigidity of the bridge is reduced, the downwarp of the bridge is too large, the reinforcing steel bar is corroded, and the durability of the structure is affected. The box girder bottom plate 101 is provided with a bottom plate cable 103, and the durability of the bottom plate cable 103 is affected when the bottom plate 101 is cracked seriously, and further the bridge safety can be endangered.

In the prior art, most of methods for treating the cracking of the bridge bottom plate adopt measures such as sealing the cracks by using epoxy resin glue and pasting FRP cloth for reinforcement on the cracks of the bottom plate, and the measures have small improvement effect on the problem of rigidity reduction of the bridge after the cracking of the bottom plate.

Disclosure of Invention

The invention relates to a box girder bottom plate reinforcing structure, a box girder adopting the box girder bottom plate reinforcing structure, a box girder bridge adopting the box girder and a construction method of the box girder bottom plate reinforcing structure, which can at least solve part of the defects in the prior art.

The invention relates to a box girder bottom plate reinforcing structure which comprises an anchoring crossbeam and an external prestressed plate, wherein the length direction of the anchoring crossbeam is parallel to the transverse direction of a box girder, the bottom of the anchoring crossbeam is fixedly connected with the box girder bottom plate and/or two ends of the anchoring crossbeam are fixedly connected with two box girder web plates respectively, and the external prestressed plate is tensioned and anchored on the anchoring crossbeam through an anchor rope.

As one embodiment, two sets of reaction frames are arranged on the external prestressed plate, the two sets of reaction frames are respectively close to two ends of the anchoring beam, an anchor cable is stretched on each set of reaction frame, and the anchor cable is stretched and anchored on the end part of the adjacent anchoring beam.

As one embodiment, a set of anchoring splints is arranged between each set of reaction frames and the end of the adjacent anchoring beam, the anchoring splints are fixedly arranged on the external prestressed plate, and the reaction frames are movably arranged on the external prestressed plate and are abutted against the adjacent anchoring splints.

As one embodiment, the anchoring clamping plates comprise two clamping plates which are sequentially arranged along the longitudinal direction of the box girder, and the two clamping plates are fixedly connected and at least one external prestressed plate is clamped between the two clamping plates.

In one embodiment, the plate surface of each external prestressed plate is parallel to the vertical direction.

As one embodiment, the reaction frame comprises two frame bodies sequentially arranged along the longitudinal direction of the box girder, the two frame bodies are fixedly connected and enclose a through hole for allowing the external prestressed plate to pass through, and the anchor cable is tensioned on at least one of the frame bodies.

As an embodiment, one set of the anchor cleats abuts the adjacent anchor beam end, and the other set of anchor cleats is laterally spaced from the adjacent anchor beam end.

In one embodiment, a lead shim plate is interposed between the reaction frame and the adjacent anchor clamping plate.

In one embodiment, the external prestressed plates are arranged along the front side and/or the rear side of the anchoring beam, two ends of the anchoring beam are provided with anchor boxes protruding towards the corresponding sides, and the anchor cables are tensioned on the two sets of anchor boxes on the corresponding sides.

In one embodiment, a plurality of prestressed plate sets are sequentially arranged at intervals from top to bottom along the front side and/or the rear side of the anchoring beam, and each prestressed plate set comprises at least one external prestressed plate.

In one embodiment, the anchor box is a steel anchor box, the box girder bottom plate and/or the box girder web plate on the corresponding side is/are provided with a consolidation reinforcing steel bar, and the anchor box is welded with the adjacent consolidation reinforcing steel bar.

As an embodiment, the external prestressed plate is a CFRP plate.

In one embodiment, the external pre-stressed plate is housed in a GFRP isolation box fixed to a box girder floor.

As one embodiment, the external prestressed plate, the anchor cable and other corresponding anchoring devices are all adhered and coated with GFRP checked cloth;

and/or the upper surface of the box girder bottom plate and the outer surface of the anchoring beam are both pasted and coated with GFRP (glass fiber reinforced plastics) check cloth.

The invention also relates to a box girder which comprises a box girder bottom plate, two box girder web plates and at least one group of box girder bottom plate reinforcing structures; when the box girder bottom plate reinforcing structures are in multiple groups, the anchoring cross beams are sequentially arranged at intervals along the longitudinal direction of the box girder.

In one embodiment, a longitudinal beam is disposed in the box chamber, the longitudinal direction of the longitudinal beam is parallel to the longitudinal direction of the box beam, and the longitudinal beam is connected with each anchoring cross beam in sequence.

In one embodiment, the number of the longitudinal beams is at least two, each longitudinal beam is connected with the box girder bottom plate, and the two longitudinal beams are respectively connected with the two box girder webs.

In one embodiment, the box girder comprises a plurality of box girder segments, and at least some of the box girder segments have a floor cable and the box girder floor reinforcement structure disposed therein.

As an embodiment, the bottom plate cables are anchored on a sawtooth block in the corresponding box girder segment, and a corresponding anchoring cross beam is arranged right above the intersection of the upper slope surface of the sawtooth block and the bottom plate.

In one embodiment, the box girder is a variable cross-section box girder.

The invention also relates to a box girder bridge, wherein at least part of box girders are the box girders.

The invention also relates to a construction method of the box girder bottom plate reinforcing structure, which comprises the following steps:

tensioning the anchor cable at one end of the anchoring beam to a designed tonnage and anchoring, and then tensioning the anchor cable at the other end of the anchoring beam to the designed tonnage; wherein, a surface dynamometer is pasted on the external prestressed plate, and the symmetrical synchronous control tensioning is carried out according to the tension value measured by the surface dynamometer.

The invention has at least the following beneficial effects:

according to the invention, the anchoring cross beam is arranged in the box chamber, so that the structural integrity of the box girder and the transverse rigidity of the bottom plate of the box girder can be increased, and the anchoring cross beam is vertical to the bottom plate longitudinally, so that the occurrence and the expansion of longitudinal cracks of the bottom plate can be inhibited; by arranging the external prestressed plates and stretching and anchoring the external prestressed plates on the anchoring cross beam through the anchor cables, transverse pre-stress can be provided for the bottom plate, and the occurrence and the expansion of longitudinal cracks of the bottom plate can be reduced and restrained.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

Fig. 1 is a schematic structural view of a box girder bridge according to an embodiment of the present invention;

FIG. 2 is a schematic view of the arrangement of the floor cables mentioned in the background art;

FIG. 3 is a cross-sectional view taken along A-A of FIG. 2;

FIG. 4 is a cross-sectional view taken along line B-B of FIG. 2;

FIG. 5 is a schematic side view of a box girder according to an embodiment of the present invention;

fig. 6 is a schematic top view of a box girder according to an embodiment of the present invention;

FIG. 7 is a schematic view of an arrangement structure of an anchoring beam according to an embodiment of the present invention;

FIG. 8 is a schematic view of a box girder bottom plate reinforcing structure provided by an embodiment of the present invention;

fig. 9 is a schematic view of a tension structure of an external prestressed plate at one end of an anchoring beam according to an embodiment of the present invention;

fig. 10 is a schematic view of a tension structure of an external prestressed plate at the other end of the anchoring beam provided by the embodiment of the invention;

Fig. 11 is a schematic view illustrating an installation process of the external prestressed plate, the anchor clamping plate, the reaction frame and the anchor cable according to the embodiment of the present invention;

FIG. 12 is a schematic diagram of an embodiment of the present invention showing an in vitro pre-stressed plate, anchor cleats, reaction frame, and anchor cables installed in place;

FIG. 13 is a cross-sectional view taken along C-C of FIG. 12;

wherein:

1. the steel plate comprises box girders, 2, piers, 101, box girder bottom plates, 102, box girder webs, 103, bottom plate cables, 104, sawtooth blocks, 105, anchoring cross beams, 106, longitudinal girders, 107, anchor boxes, 108, external prestressed plates, 109, anchor ropes, 110, anchor backing plates, 111, clip anchor anchors, 112, extrusion anchor anchors, 113, consolidation reinforcing steel bars, 114, reaction frames, 1141, anchor pulling holes, 115, anchoring clamping plates, 116, counter-pulling clamping screws, 117 and lead backing plates.

Detailed Description

The technical solutions in the embodiments of the present invention are clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example one

As shown in fig. 5 to fig. 8, an embodiment of the present invention provides a box girder bottom plate reinforcing structure, which includes an anchoring beam 105 and an external prestressed plate 108, a length direction of the anchoring beam 105 is parallel to a transverse direction of the box girder, a bottom of the anchoring beam 105 is fixedly connected to a box girder bottom plate 101 and/or two ends of the anchoring beam 105 are fixedly connected to two box girder webs 102, and the external prestressed plate 108 is tension-anchored on the anchoring beam 105 through an anchor cable 109.

When the box girder 1 is applied to a box girder bridge, the box girder is in a transverse direction, i.e., a transverse bridge direction. For a single-chamber box girder 1, it generally comprises a box girder bottom plate 101 and two box girder webs 102; for the multi-chamber box girder 1, the box girder bottom plate 101 and the box girder web plate 102 to which the anchoring beam 105 is fixedly connected can be understood as a bottom plate and two web plates corresponding to each chamber, so that the anchoring beam 105 and the external prestressed plate 108 can be arranged in each chamber.

The reinforcing structure provided by this embodiment is mainly used for reinforcing the bottom plate, so the above-mentioned anchoring beam 105 is preferably and fixedly connected with the box girder bottom plate 101, and more preferably the bottom of the anchoring beam 105 is fixedly connected with the box girder bottom plate 101, and meanwhile, two ends of the anchoring beam 105 are respectively and fixedly connected with the two box girder webs 102, so as to improve the reliability of the reinforcing structure. For the arrangement of the anchoring beam 105, the anchoring beam can be connected with the box girder bottom plate 101 and/or the box girder web 102 through a bar planting method, the connection structure is reliable, specifically, a structural steel bar is arranged in the anchoring beam 105, correspondingly, the anchoring steel bar is arranged on the box girder bottom plate 101 and/or the box girder web 102 through the bar planting method, and the anchoring beam 105 is fixedly connected with the box girder bottom plate 101 and/or the box girder web 102 through welding the structural steel bar in the anchoring beam 105 with the anchoring steel bar at the corresponding position.

The external prestressed plate 108 is preferably a CFRP plate (FRP is an english abbreviation of Fiber Reinforced Polymer, i.e., a Fiber Reinforced composite material; and CFRP is a case where the Fiber is a carbon Fiber). The tensile strength of the carbon fiber plate is about 3500MPa, and the value of the external prestressed plate 108 can adopt about 2100 MPa; the tensile force of the CFRP plate with the width of 50 mm and the thickness of 2 mm can reach 21 tons (the tensile force of 75 percent of prestressed steel strands with the tensile strength of 1860MPa and the diameter of 15.24 is about 20 tons), so that the CFRP plate is adopted, the operation is reliable, and the operation stability and the reliability of the box girder bottom plate reinforcing structure can be ensured.

According to the box girder bottom plate reinforcing structure provided by the embodiment, the anchoring cross beam 105 is arranged in the box chamber, so that the structural integrity of the box girder 1 and the transverse rigidity of the box girder bottom plate 101 can be increased, and the anchoring cross beam 105 is vertical to the bottom plate in the longitudinal direction, so that the occurrence and the expansion of longitudinal cracks of the bottom plate can be inhibited; by arranging the external prestressed plates 108 and tensioning and anchoring the external prestressed plates 108 on the anchoring cross beams 105 through the anchor cables 109, transverse prestress can be provided for the bottom plate, and the occurrence and the expansion of longitudinal cracks of the bottom plate can be reduced and restrained.

Further optimizing the box girder bottom plate reinforcing structure, as shown in fig. 8-10, two sets of reaction frames 114 are arranged on the external prestressed plate 108, the two sets of reaction frames 114 are respectively close to two ends of the anchoring beam 105, an anchor cable 109 is tensioned on each set of reaction frame 114, and the anchor cable 109 is tensioned and anchored on the end portion of the adjacent anchoring beam 105. The external prestressed plate 108 is tensioned and anchored through the reaction frame 114, construction is facilitated, the existing jack tensioning prestressed technology can be adopted, tensioning prestressed accuracy can be guaranteed, and tensioning and anchoring effects of the external prestressed plate 108 and the anchor cable 109 can be improved. Unlike the conventional reaction frame 114 arrangement, in the present embodiment, the reaction frame 114 is mounted on the external prestressed plate 108, which facilitates the arrangement of the reaction frame 114 in the limited space of the cabinet.

Further preferably, as shown in fig. 9 and 10, a set of anchoring splints 115 is provided between each set of reaction frames 114 and the end of the adjacent anchoring beam 105, the anchoring splints 115 are fixedly installed on the external prestressed plate 108, and the reaction frames 114 are movably arranged on the external prestressed plate 108 and are abutted against the adjacent anchoring splints 115. Based on the structure, the reaction frame 114 and the anchoring clamping plate 115 are matched to be used as a tensioning component of the external prestressed plate 108, the reaction frame 114 can be movably arranged, construction and prestressed tensioning operation are facilitated, and structural damage to the external prestressed plate 108 can be reduced. Optionally, as shown in fig. 12, a lead backing plate 117 is sandwiched between the reaction frame 114 and the adjacent anchor splint 115, so as to ensure the uniformity of the stress on the anchor splint 115, that is, the uniformity of the stress on the external prestressed plate 108.

Continuing with the above structure, as shown in fig. 13, the anchoring clamp plate 115 includes two clamp plates sequentially arranged along the longitudinal direction of the box girder, and the two clamp plates are fixedly connected and at least one external prestressed plate 108 is clamped between the two clamp plates. The plate surfaces of the two clamping plates are preferably parallel to the vertical direction, and the plate surfaces of the outer prestressed plates 108 are also preferably parallel to the vertical direction, namely perpendicular to the longitudinal direction of the box girder, so as to facilitate the arrangement. In one embodiment, as shown in fig. 13, the two clamping plates can be fixed by a plurality of bolts/counter-pulling clamping screws 116, so that the external prestressed plate 108 between the two clamping plates can be clamped, and the bolt assembly mode is convenient to disassemble and assemble, thereby facilitating construction. In an alternative embodiment, as shown in fig. 13, two or more external prestressed plates 108 are sequentially attached and arranged along the longitudinal direction of the box girder, so that the tension prestress can be increased, or the tension prestress can be uniformly distributed to each external prestressed plate 108 when the required tension prestress is reached, thereby improving the stability and reliability of the base plate reinforcing structure.

Continuing the structure, as shown in fig. 13, the reaction frame 114 includes two frame bodies sequentially arranged along the longitudinal direction of the box girder, the two frame bodies are fixedly connected and surrounded by a through hole for allowing the external prestressed plate 108 to pass through, the anchor cable 109 is tensioned on at least one of the frame bodies, the effect of tensioning the anchor cable 109 on the two frame bodies is obviously better, the stress uniformity and the tension stability of the reaction frame 114 and the anchor clamping plate 115 can be improved, especially, in the structure that the anchor clamping plate 115 includes two clamping plates sequentially arranged along the longitudinal direction of the box girder, the two frame bodies are respectively abutted against the two clamping plates, and the tension stability and the stress uniformity of the anchor clamping plate 115 are better; correspondingly, the frame body is correspondingly provided with anchor holes 1141 for tensioning the anchor cables 109, the anchor holes 1141 are generally circular holes, and a plurality of anchor cables 109 can be tensioned on each frame body, so that the number of the anchor holes 1141 is correspondingly set, and more preferably, a plurality of anchor cables 109 are sequentially tensioned on each frame body from top to bottom. It should be noted that the through holes can allow the corresponding external prestressed plates 108 to pass through, and when two or more external prestressed plates 108 are longitudinally clamped between the anchoring splints 115 along the box girder, the through holes can allow the two or more external prestressed plates 108 to pass through together; meanwhile, the through holes are suitable for preventing the anchor clamping plate 115 from passing through, for example, the through holes are rectangular holes, for example, the plate surface of the external prestressed plate 108 is arranged parallel to the vertical direction, the height of the rectangular holes is greater than or equal to the height of the external prestressed plate 108 and smaller than the height of the anchor clamping plate 115, and the width of the rectangular holes (i.e. the size along the longitudinal direction of the box girder) is greater than or equal to the sum of the thicknesses of the external prestressed plates 108 clamped by the anchor clamping plate 115 and smaller than the width of the anchor clamping plate 115. Similarly, the two frame bodies can be fixed by a plurality of bolts/opposite-pulling clamping screws 116, and the assembling mode of the bolts is convenient to disassemble and assemble, so that the construction is convenient.

Further optimizing the above structure, as shown in fig. 6, the external prestressed plates 108 are disposed along the front side and/or the rear side of the anchoring beam 105, the two ends of the anchoring beam 105 protrude toward the corresponding sides to form anchor boxes 107, and the anchor cables 109 are tensioned on the two sets of anchor boxes 107 on the corresponding sides. Preferably, the external prestressed plates 108 are arranged on both the forward-to-bridge side and the backward-to-bridge side of the anchoring cross beam 105, so that the structural integrity of the box girder 1 and the transverse rigidity of the box girder bottom plate 101 are further improved, and the stress uniformity of the anchoring cross beam 105 in the front and back directions can be improved; meanwhile, the arrangement and construction of the external prestressed plates 108, the reaction frames 114 and the like are facilitated by utilizing the space of the forward side and/or the rear side of the anchoring beam 105 along the bridge. The anchor box 107 is preferably a steel anchor box 107, and when the anchor box 107 is provided only on one side of the anchoring beam 105, the steel anchor box 107 is preferably buried in the anchoring beam 105; when the anchor boxes 107 are arranged on the front side and the rear side of the anchoring beam 105, the steel anchor boxes 107 are preferably of an integrated structure, and the front end and the rear end of each steel anchor box respectively extend out of the anchoring beam 105, so that the front end and the rear end of each steel anchor box 107 are stressed cooperatively, and the stress uniformity of the steel anchor boxes 107 on the two sides of the anchoring beam 105 is improved. It can be understood that, two sets of anchor boxes 107 are arranged along the front side or the back side of the anchoring beam 105, the two sets of anchor boxes 107 on each side respectively protrude out of two ends of the anchoring beam 105, and the external prestressed plates 108 on each side are respectively tensioned and anchored on the two sets of anchor boxes 107 on the corresponding side through anchor cables 109.

For the arrangement of the anchor box 107, it is further preferable that the anchor box 107 is further connected with the box girder bottom plate 101 and/or the adjacent box girder web plate 102, so as to improve the working reliability of the anchor box 107, for example, for the steel anchor box 107, the steel anchor box 107 may be welded with the corresponding steel bar 113 by setting the steel bar 113 on the box girder bottom plate 101 and the adjacent box girder web plate 102; furthermore, epoxy resin glue can be arranged at the bottom of the steel anchor box 107 to be adhered with the bottom plate. In addition, epoxy concrete is filled in the anchor box 107, so that the working reliability and the service life of the anchor box 107 are further improved; in one embodiment, the anchor cable 109 penetrates into the anchor box 107 from the transverse bridge of the anchor box 107 to one side, and then penetrates out of the anchor box 107 from the transverse bridge of the anchor box 107 to the other side for anchoring, and the epoxy concrete filled in the anchor box 107 can perform a consolidation action on the anchor cable 109, so that the stability and reliability of the tension structure of the anchor cable 109 can be improved.

Further optimizing the above structure, as shown in fig. 9 to 12, a plurality of prestressed plate sets are sequentially arranged at intervals from top to bottom along the front side of the bridge and/or along the rear side of the bridge of the anchoring beam 105, and each prestressed plate set includes at least one external prestressed plate 108. Based on the above structure, the structural integrity of the box girder 1 and the lateral rigidity of the box girder bottom plate 101 can be further increased. In an alternative embodiment, each external prestressed plate 108 on each side is clamped by the same anchoring clamp plate 115, specifically, a plurality of clamping holes are sequentially formed on the anchoring clamp plate 115 from top to bottom, the number of the clamping holes is the same as that of the prestressed plate groups, the clamping holes are arranged in a one-to-one correspondence, and each external prestressed plate 108 of each prestressed plate group is clamped in the corresponding clamping hole; when there are two or more external prestressed plates 108 for each prestressed plate group, it is preferable that the external prestressed plates 108 are sequentially arranged along the longitudinal direction of the box girder. Similarly, each external prestressed plate 108 on each side is preferably tensioned by the same reaction frame 114, that is, the reaction frame 114 is correspondingly provided with a plurality of through holes, the number of the through holes is the same as that of the prestressed plate groups and the through holes are arranged in a one-to-one correspondence manner, and each external prestressed plate 108 of each prestressed plate group is arranged in the corresponding through hole. By adopting the same anchoring splint 115 and reaction frame 114 to tension and anchor the external prestressed plates 108 on the same side, not only is construction convenient, but also the external prestressed plates 108 on the same side are stressed cooperatively, and meanwhile, the stress uniformity of the anchoring splint 115 and the reaction frame 114 is improved.

In a preferred embodiment, as shown in fig. 12, the anchor cables 109 are anchored to the reaction frame 114 by clip anchor devices 111, and in the case of multiple anchor cables 109 on each frame from top to bottom, the integral clip anchor devices 111 may be used to anchor the anchor cables 109 on the frame; lead backing plates 117 can be arranged between the clip anchor 111 and the reaction frame 114 to ensure the stress uniformity of the reaction frame 114. As shown in fig. 9-12, for anchoring of the anchor lines 109 on the anchor boxes 107, squeeze anchor anchors 112 may be used; the plurality of anchor lines 109 on each frame may also be anchored using an integral extruded anchor 112; an anchor backing plate 110 can be arranged between the extrusion anchor 112 and the anchor box 107 to ensure the stress uniformity of the anchor box 107. Obviously, other conventional anchoring means for the anchor cable 109 are also suitable for use in this embodiment.

As a preferred solution of this embodiment, as shown in fig. 9 and 10, one set of the anchor cleats 115 abuts the end of the adjacent anchor beam 105, and the other set of the anchor cleats 115 has a lateral spacing from the end of the adjacent anchor beam 105. In the structure in which the anchor boxes 107 are correspondingly arranged at the end portions of the anchor beams 105, one set of anchor clamping plates 115 abut against the adjacent anchor boxes 107, so that the stability and reliability of the anchor structure can be improved; the other set of anchor cleats 115 is laterally spaced from the adjacent anchor boxes 107. The transverse distance should not be smaller than a set distance, which is a critical distance required by the deformation of the external prestressed plate 108 and is determined by calculation according to specific working conditions by those skilled in the art. Based on the arrangement of the transverse distance, the effect of tensioning and anchoring the external prestressed plate 108 and the working reliability can be ensured.

Continuing the reinforcement structure, the external prestressed plate 108 is accommodated in a GFRP (fiber reinforced composite material in glass fiber, often referred to as glass fiber reinforced plastic) insulation box, which is fixed on the box girder bottom plate 101. Through the GFRP isolation box, the external prestressed plate 108 can be well protected, the external prestressed plate 108 is prevented from being influenced by external construction, the service life of the external prestressed plate 108 is prolonged, and the scheme is particularly suitable for the condition that the CFRP external prestressed plate 108 is adopted. In this embodiment, the GFRP isolation box is a single-chamber box body, which encloses the corresponding external pre-stressed plate 108, and the anchor cable 109 extends out of the GFRP isolation box. In the above-described structure in which a plurality of prestressed plate groups are sequentially arranged from top to bottom at intervals along the bridge-wise front side and/or along the bridge-wise rear side of the anchoring beam 105, each external prestressed plate 108 on each side can be accommodated in the same GFRP isolation box.

Further optimizing the reinforcing structure, the external prestressed plate 108, the anchor cable 109 and other corresponding anchoring devices are all pasted and coated with GFRP check cloth; and/or GFRP (glass fiber reinforced plastics) check cloth is pasted and coated on the upper surface of the box girder bottom plate 101 and the outer surface of the anchoring cross beam 105. Specifically, each external pre-stress plate 108, each anchor clamping plate 115, each reaction frame 114, bolts/screws and nuts for fastening the anchor clamping plates 115, bolts and nuts for fastening the reaction frames 114, the anchor boxes 107, the anchor lines 109, the clip anchor 111, the extrusion anchor 112, the lead plate 117, and the like are coated with GFRP checkerboard, and the adhesive used may be, but is not limited to, epoxy resin. GFRP check cloth has the guard action to each part, carries out the structure to each part simultaneously and strengthens, further improves the reinforcing effect to box girder bottom plate 101. Further preferably, when the box girder bottom plate 101 has cracks, after the cracks on the lower surface of the box girder bottom plate 101 are sealed by injecting epoxy resin glue, a layer of GFRP check cloth is adhered on the lower surface of the box girder bottom plate 101; the GFRP (glass fiber reinforced plastic) check cloth is pasted to have a complete waterproof effect on the box girder bottom plate 101, meanwhile, the box girder bottom plate 101 is strengthened, and further expansion of cracks on the lower surface of the box girder bottom plate 101 along the bridge direction can be restrained. In an optional scheme, a layer of GFRP chopped strand mat can be respectively stuck on two side cloth surfaces of the GFRP check cloth, the structural strength and the use performance of the GFRP check cloth are further optimized, and the adhesive can be epoxy resin but is not limited to the epoxy resin.

Further optimizing the above-mentioned reinforced structure, anchor rope 109 stretches out the working length section of drawing end and is provided with the GFRP protection casing, and this GFRP protection casing intussuseption is filled with rust-resistant butter, can protect anchor rope 109 better, avoids anchor rope 109 corrosion. For the case that a plurality of anchor cables 109 are arranged in sequence in the vertical direction, the tensioning ends of each vertical row of anchor cables 109 can be accommodated in the same GFRP shield. The GFRP shield may be a rectangular box structure secured to an adjacent tension member, such as by adhesive attachment to the reaction frame 114.

Example two

Referring to fig. 5 and 6, an embodiment of the present invention provides a box girder 1, which includes a box girder bottom plate 101 and two box girder web plates 102, and further includes at least one set of box girder bottom plate reinforcing structures provided in the first embodiment; when the box girder bottom plate reinforcing structure has a plurality of groups, the anchoring cross beams 105 are sequentially arranged at intervals along the longitudinal direction of the box girder.

The box girder 1 provided in the present embodiment is preferably a concrete box girder 1; the box girder bottom plate 101 and the box girder web 102 are of a reinforced concrete structure.

The box girder 1 provided by the present embodiment is preferably a box girder 1 arranged with a floor cable 103, and specifically, the box girder 1 includes a plurality of box girder segments, and at least some of the box girder segments are arranged with a floor cable 103 and a reinforcement structure of the box girder floor. The arrangement structure of the bottom cable 103 is conventional in the art, and is not described herein; the damage to the box girder bottom plate 101, which may be caused by the arrangement of the bottom plate cables 103, can be avoided and solved by the box girder bottom plate reinforcing structure. In particular, when the box girder 1 is the variable cross-section box girder 1, the damage of the box girder bottom plate 101 due to the arrangement of the bottom plate cables 103 in the variable cross-section box girder 1 can be solved well based on the box girder bottom plate reinforcing structure. In one embodiment, as shown in fig. 5 and 6, the floor cables 103 are anchored to sawtooth blocks 104 in the corresponding box girder segments, and respective anchoring beams 105 are arranged right above the intersection of the sloping upper surface of the sawtooth blocks 104 and the floor; for the variable cross-section box girder 1, the anchoring cross beam 105 is also arranged at the front end of the corresponding box girder segment, wherein the front end of the box girder segment is the end of the box girder segment far away from the top of the pier of the adjacent pier 2; the anchoring cross beam 105 is arranged in the base plate damage prone area of the corresponding box girder segment, and obviously, the reinforcing effect on the box girder base plate 101 is better.

The box girder bottom plate reinforcing structure can be formed when the box girder 1 is manufactured, and can also be a structural improvement on the existing box girder 1, namely a later-stage structure formed in the existing box girder 1.

As shown in fig. 6 to 10, the longitudinal beams 106 are further arranged in the box chamber, the longitudinal direction of the longitudinal beams 106 is parallel to the longitudinal direction of the box girder, the longitudinal beams 106 are sequentially connected with the anchoring cross beams 105, and the anchoring cross beams 105 are connected into a whole, so that the cooperative stress of the anchoring cross beams 105 is improved, and the method is favorable for inhibiting the occurrence and development of longitudinal cracks of the box girder bottom plate 101. Further preferably, the number of the longitudinal beams 106 is at least two, each longitudinal beam 106 is connected with the box girder bottom plate 101, and two of the longitudinal beams 106 are respectively connected with the two box girder webs 102, so that each longitudinal beam 106 connects the box girder bottom plate 101, the box girder webs 102 and each anchoring cross beam 105 into a whole, which not only can significantly improve the structural integrity of the box girder 1, but also can increase the longitudinal rigidity of the box girder bottom plate 101. As shown in fig. 7 to 10, in the above-described structure in which the anchor boxes 107 are provided, each anchor box 107 is preferably embedded in the corresponding longitudinal beam 106, and the anchor box 107 may be indirectly fixed to the adjacent box beam web 102 by the longitudinal beam 106 without being connected to the adjacent box beam web 102.

EXAMPLE III

Referring to fig. 1, an embodiment of the present invention provides a box girder bridge, and at least a portion of a box girder 1 uses the box girder 1 provided in the second embodiment.

Example four

The embodiment of the invention relates to a construction method of a box girder bottom plate reinforcing structure provided by the first embodiment, which comprises the following steps:

tensioning the anchor cable 109 at one end of the anchoring beam 105 to a designed tonnage and anchoring, and then tensioning the anchor cable 109 at the other end of the anchoring beam 105 to the designed tonnage; wherein, a surface dynamometer is pasted on the external prestressed plate 108, and symmetrical synchronous control tensioning is carried out according to the tension value measured by the surface dynamometer, so as to achieve the required external prestressed tensioning and anchoring effect and ensure the reliable reinforcement of the box girder bottom plate 101.

The implementation method can adopt a single-cable jack tensioning prestress technology, and is convenient to construct; the accuracy of the tension force can be improved by sticking the surface dynamometer on the external prestressed plate 108, and the symmetry, synchronization and accuracy of the tension prestress can be ensured by triple control of the surface dynamometer, the oil pressure of the jack and the elongation of the external prestressed plate 108.

Specifically, the construction method comprises the following steps:

the method comprises the following steps: installing an anchor box 107, an anchor cable 109 and a pouring anchor beam 105 on the box girder bottom plate 101, wherein the anchor beam 105 is fixedly connected with the box girder bottom plate 101 and/or two ends of the anchor beam 105 are fixedly connected with two box girder webs 102 respectively, and the anchor box 107 protrudes towards the front side and/or the rear side of the anchor beam 105 along the bridge; the anchor line 109 is mounted at one end to the anchor housing 107.

Step two: and installing the external prestressed plates 108, the reaction frame 114, the anchoring clamping plates 115 and the clip anchoring anchors 111 of the anchor cables 109 at designed positions in the box girder 1. A surface dynamometer is attached to the external prestressed plate 108.

Step three: and tensioning the anchor cable 109 at one end of the anchoring beam 105 to a designed tonnage for anchoring, and tensioning the anchor cable 109 at the other end of the anchoring beam 105 to the designed tonnage. Wherein, the symmetrical synchronous control tensioning is carried out according to the tension value measured by the surface dynamometer on the external prestressed plate 108; in one embodiment, surface force meters are adhered to both side plate surfaces of the external prestressed plate 108, and the difference between the tensile values of a pair of surface force meters on the external prestressed plate 108 is less than ± 2% and the maximum difference between the tensile values of the external prestressed plates 108 is less than ± 5% during the tensioning process. Preferably, the final tensile values of the surface dynamometers deviate by less than ± 2%; the deviation between the sum of the final tension values of the surface dynamometers and the design total tensile force is less than +/-1.5%. Further, the stretching amount of the external prestressed plate 108 is measured, and the reliable and effective tensioning control of the external prestressed plate 108 is achieved by combining the control mode of the surface dynamometer.

Further preferably, when the longitudinal beam 106 is further arranged in the box girder 1, the pouring operation of the longitudinal beam 106 is further performed in the first step.

It should be understood that the above-mentioned methods can be applied in concert with the box girder bottom plate reinforcing structure provided in the first embodiment and the box girder 1 provided in the second embodiment, that is, the corresponding structural contents in the box girder bottom plate reinforcing structure provided in the first embodiment and the box girder 1 provided in the second embodiment are also applicable to the present embodiment, for example, the relative connection structures between the anchoring cross beam 105, the external prestressed plate 108, the anchoring clamping plate 115, the reaction frame 114, and the like, which are not described in detail herein.

In the step one, for the installation of the anchor box 107, reinforcing bars 113 may be formed by planting reinforcing bars on the box girder bottom plate 101 and/or the box girder web plate 102 on the corresponding side, and the anchor box 107 is welded with the reinforcing bars 113 during the installation. Meanwhile, in the first step, roughening cleaning work of a joint surface between the anchoring cross beam 105 and the box girder bottom plate 101, a joint surface between the anchoring cross beam 105 and the box girder web plate 102, a joint surface between the longitudinal beam 106 and the box girder bottom plate 101, a joint surface between the longitudinal beam 106 and the box girder web plate 102 and the like can be correspondingly completed; the steel bars can be planted on the box girder bottom plate 101 and/or the box girder web plate 102 on the corresponding side to form anchoring steel bars, the welding of the structural steel bars of the anchoring cross beam 105 and the corresponding anchoring steel bars is firstly completed, and then the pouring of the anchoring cross beam 105 is carried out; the longitudinal beam 106 may also adopt a corresponding construction method, which is not described herein. In the first step, a structure in which the anchor box 107 is filled with epoxy concrete can be completed together.

Further preferably, in the step one, after the strength of the reducing concrete in the steel anchor box 107, the concrete of the anchoring cross beam 105 and the concrete of the longitudinal beam 106 is reached, a layer of GFRP check cloth is adhered to the upper surface of the box girder bottom plate 101, the outer wall of the anchoring cross beam 105 and the outer wall of the longitudinal beam 106. Optionally, after the cracks on the lower surface of the bottom plate are sealed by injecting epoxy resin glue, a layer of GFRP check cloth is adhered on the lower surface of the bottom plate.

Further refining the method, after the anchor cable 109 is tensioned, GFRP (glass fiber reinforced plastics) checkered cloth is pasted on the surface of the external prestressed plate 108 and the surfaces of all the iron members of the related anchoring system. Optionally, a rust prevention cover is installed over the working length section of the tensioning end of the anchor line 109.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.

Claims (22)

1. The utility model provides a case roof beam bottom plate reinforced structure which characterized in that: including anchor crossbeam and external prestressing force board, the length direction of anchor crossbeam is horizontal in the case roof beam, the bottom of anchor crossbeam links firmly with the case roof beam bottom plate and/or the both ends of anchor crossbeam link firmly with two case roof beam webs respectively, external prestressing force board passes through anchor rope stretch-draw anchor and is in on the anchor crossbeam.

2. A box girder bottom plate reinforcing structure according to claim 1, wherein: and two groups of reaction frames are arranged on the external prestressed plate, the two groups of reaction frames are respectively close to two ends of the anchoring cross beam, an anchor cable is stretched on each group of reaction frames, and the anchor cable is stretched and anchored on the end part of the adjacent anchoring cross beam.

3. A box girder bottom plate reinforcing structure according to claim 2, wherein: and a group of anchoring clamping plates are arranged between each group of reaction frames and the end part of the adjacent anchoring cross beam, the anchoring clamping plates are fixedly arranged on the external prestressed plate, and the reaction frames are movably arranged on the external prestressed plate and are tightly propped against the adjacent anchoring clamping plates.

4. A box girder floor reinforcement structure according to claim 3, wherein: the anchoring clamping plate comprises two clamping plates which are sequentially arranged along the longitudinal direction of the box girder, and the two clamping plates are fixedly connected and at least one external prestressed plate is clamped between the two clamping plates.

5. A box girder floor reinforcement structure according to claim 4, wherein: the plate surface of each external prestressed plate is parallel to the vertical direction.

6. A box girder floor reinforcement structure according to claim 3, wherein: the reaction frame comprises two frame bodies which are sequentially arranged along the longitudinal direction of the box girder, the two frame bodies are fixedly connected and surrounded to form a through hole for accommodating the external prestressed plate to pass through, and the anchor cable is stretched on at least one of the frame bodies.

7. A box girder floor reinforcement structure according to claim 3, wherein: one group of the anchoring clamping plates is abutted with the end part of the adjacent anchoring beam, and the other group of the anchoring clamping plates has a transverse distance with the end part of the adjacent anchoring beam.

8. A box girder floor reinforcement structure according to claim 3, wherein: and a lead base plate is clamped between the reaction frame and the adjacent anchoring clamping plate.

9. A box girder floor reinforcement structure according to any one of claims 1 to 8, wherein: the front side of the anchoring beam is arranged along the bridge and/or the rear side of the anchoring beam is arranged along the bridge, the external prestressed plates are arranged at the two ends of the anchoring beam and protrude towards the corresponding side to form anchor boxes, and the anchor cables are stretched and pulled on the two groups of anchor boxes at the corresponding side.

10. A box girder floor reinforcement structure according to claim 9, wherein: a plurality of prestress plate groups are sequentially arranged at intervals from top to bottom along the front side and/or the rear side of the anchoring beam along the bridge, and each prestress plate group comprises at least one external prestress plate.

11. A box girder floor reinforcement structure according to claim 9, wherein: the anchor box is a steel anchor box, consolidation reinforcing steel bars are arranged on a box girder bottom plate and/or a box girder web plate on the corresponding side, and the anchor box is welded with the adjacent consolidation reinforcing steel bars.

12. A box girder bottom plate reinforcing structure according to claim 1, wherein: the external prestressed plate is a CFRP plate.

13. A box beam floor reinforcement structure as defined in claim 12, wherein: the external prestressed plate is contained in a GFRP isolation box, and the GFRP isolation box is fixed on a box girder bottom plate.

14. A box girder bottom plate reinforcing structure according to claim 1, wherein: the external prestressed plate, the anchor cable and other corresponding anchoring devices are all stuck and coated with GFRP check cloth;

and/or the upper surface of the box girder bottom plate and the outer surface of the anchoring beam are both pasted and coated with GFRP (glass fiber reinforced plastics) check cloth.

15. The utility model provides a box girder, includes box girder bottom plate and two box girder webs, its characterized in that: further comprising at least one set of box girder floor reinforcement structures according to any one of claims 1 to 14; when the box girder bottom plate reinforcing structures are in multiple groups, the anchoring cross beams are sequentially arranged at intervals along the longitudinal direction of the box girder.

16. A box beam as defined in claim 15 wherein: and a longitudinal beam is arranged in the box chamber, the length direction of the longitudinal beam is parallel to the longitudinal direction of the box beam, and the longitudinal beam is sequentially connected with the anchoring cross beams.

17. A box beam as defined in claim 16 wherein: the number of the longitudinal beams is at least two, each longitudinal beam is connected with the box girder bottom plate, and the two longitudinal beams are respectively connected with the two box girder webs.

18. A box beam as defined in claim 15 wherein: the box girder comprises a plurality of box girder sections, and at least part of the box girder sections are internally provided with bottom plate cables and the box girder bottom plate reinforcing structure.

19. A box beam according to claim 18 wherein: the bottom plate cable is anchored on a sawtooth block in a corresponding box girder segment, and a corresponding anchoring cross beam is arranged right above the intersection of the upper slope surface of the sawtooth block and the bottom plate.

20. A box beam as defined in claim 19 wherein: the box girder is a variable cross-section box girder.

21. A box girder bridge which characterized in that: at least part of the box girder is the box girder as claimed in any one of claims 15-20.

22. A construction method of a box girder floor reinforcement structure according to any one of claims 1 to 14, comprising:

tensioning the anchor cable at one end of the anchoring beam to a designed tonnage and anchoring, and then tensioning the anchor cable at the other end of the anchoring beam to the designed tonnage; wherein, a surface dynamometer is pasted on the external prestressed plate, and the symmetrical synchronous control tensioning is carried out according to the tension value measured by the surface dynamometer.

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