CN218492264U

CN218492264U - High-ductility UHPC (ultra high performance polycarbonate) butt strap and seamless bridge head structure thereof

Info

Publication number: CN218492264U
Application number: CN202222786030.2U
Authority: CN
Inventors: 马熙伦; 惠迎新; 杨傲雄; 冀伟; 马伟
Original assignee: Ningxia University
Current assignee: Ningxia University
Priority date: 2022-10-21
Filing date: 2022-10-21
Publication date: 2023-02-17
Anticipated expiration: 2032-10-21

Abstract

The utility model belongs to bridge structures field, concretely relates to high ductility UHPC attachment strap and seamless bridge bridgehead structure thereof. The butt strap comprises a butt strap body and a connecting steel bar, wherein the front end surface of the butt strap body is higher than the rear end surface, the bottom surface of the butt strap body is a horizontal plane, and the connecting steel bar penetrates through the front end surface and the rear end surface; a seamless bridge head structure comprises the UHPC butt strap, a bridge main beam and a ground beam; the front end surface and the rear end surface of the UHPC butt strap are respectively connected with the sections of the main beam and the ground beam of the bridge. Because the rigidity of the UHPC butt strap is smaller than that of the beam body, when the tensile stress of the beam body on the UHPC butt strap is larger than the ultimate tensile strength of the UHPC concrete, a plurality of dense and thin cracks are generated on the butt strap within a certain length range, and the temperature-drop deformation of the beam body is absorbed through the tiny cracks. The high-ductility UHPC has strong crack control capability, the width of the cracks is small, and the cracks cannot be reflected to the road surface to cause the road surface to crack, so that a telescopic device is not needed to be arranged, and the maintenance cost is reduced.

Description

High-ductility UHPC (ultra high performance polycarbonate) butt strap and seamless bridge head structure thereof

Technical Field

The utility model belongs to bridge structures field, concretely relates to high ductility UHPC attachment strap and seamless bridge bridgehead structure thereof.

Background

Because the bridge expansion device is exposed in the natural environment for a long time and directly bears the external effects of temperature effect, automobile load, concrete shrinkage and creep, foundation settlement and the like, the bridge expansion device is extremely easy to damage, so that the plate end, the support and the lower structure are corroded by snow water containing a snow melting agent and the like, and great adverse effects are generated on the driving quality and the driving safety. Meanwhile, expansion and contraction deformation of the bridge causes frequent damage to the expansion device, aggravates the phenomenon of bumping at the bridge head, and needs to consume a large amount of expenses to maintain and replace the expansion device every year. Therefore, a series of problems caused by the bridge expansion device are inevitable.

In order to solve the problem of vulnerability of the telescopic device fundamentally, engineers put forward a concept of a seamless bridge, namely the best expansion joint without the expansion joint. The seamless bridge is a structure which cancels all telescopic devices of the bridge, and for the multi-span bridge, the telescopic devices on the bridge piers can be cancelled by adopting methods of continuous bridge deck, continuous beam, continuous rigid frame and the like; the seamless bridge abutment can be eliminated by adopting three methods of a full integral bridge abutment, a semi-integral bridge abutment and an extended bridge deck bridge abutment. Compared with the common gap bridge, the gap bridge can reduce the construction and maintenance cost of the bridge, simplify the construction of the bridge, improve the driving performance of the bridge and improve the durability and the anti-seismic performance of the bridge.

For the seamed bridge, the longitudinal expansion and contraction deformation of the main beam of the bridge can be completed at the expansion joint, and the butt strap for connecting the bridge and the adjacent road surface is mainly used for overcoming the problem of bumping at the bridge head caused by filling and settling behind the bridge. The seamless bridge has no telescopic device in bridge abutment and has butt strap connected to the main bridge beam, and the longitudinal deformation of partial main bridge beam is transferred to the rigid road or flexible road in the adjacent road. Therefore, the straps are one of the important structures of the seamless bridge structure, and have been paid attention by engineers, and various strap forms have been proposed to adapt to various situations.

According to the transfer mode of the deformation of the longitudinal bridge of the bridge, the method can be divided into two types: delivery and imbibition types.

The transfer type butt strap transfers part of the longitudinal deformation of the bridge girder to the tail end of the butt strap, and is divided into a panel type and an embedded type. The panel type butt strap is arranged above the filling soil behind the platform, plays a role of a pavement structure and can be used for wiring of a rigid pavement and a flexible pavement. The panel type butt strap is a weak link of the bridge, and an expansion joint capable of adapting to repeated expansion and contraction is required to be arranged at the joint of the butt strap and a wiring road, and a roadbed is required to be prevented from being soaked by rainwater entering the joint. The problems of subgrade settlement and pavement damage still occur when the panel type butt strap tail end is found in a solid bridge. In addition, the rigidity of the horizontal embedded type butt strap in the vertical direction has a more obvious sudden change problem from the bridge girder to the butt strap. The embedded type access panel is generally used for the case that the wiring is a flexible road surface, and can be further divided into a horizontal type and an inclined type. The flat embedded type butt strap is characterized in that the butt strap is completely embedded under the road surface in equal depth, and the embedding depth of the inclined embedded type butt strap is increased along with the approach of the butt strap to the wiring road surface. The embedded type butt strap enables the wiring road and the filling behind the platform to be similar to a large elastic body to absorb deformation, the butt strap embedded under the road surface provides larger rigidity for the road surface on the butt strap, and the transition from a rigid bridge deck to a flexible embankment is facilitated, so that the problem of vehicle jumping caused by filling settlement behind the platform is solved.

The absorption type butt strap mainly absorbs longitudinal bridge deformation transmitted by a main beam of a bridge through crack development within an allowable limit value range. The Hunan university provides a reinforced concrete slab with pre-sawed seams, the width change of micro cracks generated by the pre-arranged dense sawn seams is used for absorbing the longitudinal bridge deformation transmitted from a main beam of the bridge, and the tail end of the slab is provided with a strong ground beam to prevent the transmission of the deformation to a wiring road surface, so that the reinforced concrete slab is applied to a plurality of bridges in China. However, when the bridge is longer, a longer reinforced concrete access slab is needed, which affects the popularization and application of the bridge.

In summary, the research on the access panel in the seamless bridge is very important, and the design of the access panel and the structure of the bridge head including the access panel become one of the key problems affecting the popularization of the seamless bridge construction.

SUMMERY OF THE UTILITY MODEL

The utility model discloses the technical problem that will solve is: provided are a high strain hardening type UHPC bridgehead strap and a bridgehead structure comprising the same.

In order to solve the above problem, the utility model provides a new technical scheme: a high-ductility UHPC butt strap comprises a butt strap body and a connecting steel bar, wherein the front end surface of the butt strap body is higher than the rear end surface, the bottom surface is a horizontal plane, and the connecting steel bar penetrates through the front end surface and the rear end surface;

the front end face is a near abutment end close to the abutment, the rear end face is a far abutment end far away from the abutment, and the whole butt strap body is a wedge-shaped plate with a certain gradient and can be a prefabricated part or a cast-in-place part.

Furthermore, still include the reinforcement reinforcing bar, reinforcement reinforcing bar one end stretches into inside the access board body from the terminal surface, and the other end extends to outside the terminal surface.

Furthermore, the connecting reinforcing steel bars are at least provided with one layer, and the number of the layers of the connecting reinforcing steel bars can be set according to the thickness of the butt strap.

A seamless bridge head structure comprises the UHPC butt strap, a bridge girder and a ground beam;

the front end face and the rear end face of the UHPC butt strap are respectively connected with the end faces of a bridge girder and a ground beam, and are reinforced through connecting reinforcing steel bars and reinforcing steel bars, and the bridge girder and the abutment are seamless, and can be of an integral abutment structure or a split structure of a semi-integral abutment or an extension bridge deck abutment.

Furthermore, the wiring roadbed and the road-filling roadbed are also included, the wiring roadbed covers the UHPC lapping plate, the tail end of the wiring roadbed is connected with the road-filling roadbed, and the ground beam extends into the road-filling roadbed.

Furthermore, a slip layer is arranged between the UHPC butt strap and a soil filling roadbed below the UHPC butt strap, so that the UHPC butt strap is convenient to adapt to the longitudinal deformation of the butt strap.

Further, the slippage layer composition medium comprises a felt and a fine sand layer.

Furthermore, expansion joints are arranged at the connecting positions of the rear parts of the ground beams and the wiring roadbed, and redundant space is provided for the longitudinal extension of the butt straps.

And the wiring road surface is connected with the bridge floor and is continuously paved above the bridge girder, the UHPC butt strap and the wiring roadbed.

The utility model has the advantages that: after the scheme is adopted, the UHPC butt strap is closely connected with the ground beam at the far platform end, the near platform end is closely connected with the main beam of the bridge, the bottom of the butt strap is provided with the sliding layer, and the deformation of the beam body is absorbed by the high-ductility UHPC butt strap within a certain length range. Because the sliding layer at the bottom of the butt strap has the function of friction stress, the UHPC butt strap is made into a wedge-shaped plate with a certain gradient, and the uniform stress of the butt strap can be ensured when the butt strap is pulled. When the outside temperature rises, the beam body stretches, and the UHPC butt strap and the ground beam are extruded; when the outside temperature is reduced, the beam body contracts, and the UHPC lapping plate and the ground beam are pulled to contract towards the temperature center of the beam body together. Because the rigidity of the UHPC butt strap is smaller than that of the beam body, when the tensile stress of the beam body on the UHPC butt strap is larger than the ultimate tensile strength of the UHPC concrete, a plurality of dense and thin cracks are generated on the butt strap within a certain length range, and the temperature-drop deformation of the beam body is absorbed through the tiny cracks. The high-ductility UHPC has strong crack control capability, the width of the cracks is small, and the cracks cannot be reflected to the road surface to cause the road surface to crack, so that a telescopic device is not needed to be arranged, and the maintenance cost is reduced.

Drawings

Fig. 1 is a side view structural diagram of a first embodiment of the present invention;

fig. 2 is a schematic perspective view of a first embodiment of the present invention;

fig. 3 is a schematic view of two layers of connecting steel bars according to the first embodiment of the present invention;

fig. 4 is a front view of a second embodiment of the present invention;

fig. 5 is a schematic perspective view of a second embodiment of the present invention.

In the figure: 1. a strap body; 2. a bridge girder; 3. a ground beam; 4. connecting reinforcing steel bars; 5. reinforcing steel bars; 6. expanding the seam; 7. a slip layer; 8. wiring the road surface; 9. a wiring roadbed; 10. filling a soil roadbed; 11. an abutment.

Detailed Description

In order to explain the technical contents, the objects and the effects of the present invention in detail, the following description is made with reference to the accompanying drawings in combination with the embodiments.

The first embodiment is as follows:

as shown in fig. 1 to fig. 3, a high-ductility UHPC strap comprises a strap body 1 and a connecting reinforcement 4, wherein the front end surface is higher than the rear end surface, the bottom surface is a horizontal plane, and the connecting reinforcement 4 penetrates through the front end surface and the rear end surface; the front end face is a near abutment end close to the abutment 11, the rear end face is a far abutment end far away from the abutment 11, and the whole butt strap body 1 is a wedge-shaped plate with a certain gradient and can be a prefabricated part or a cast-in-place part.

Still including consolidating reinforcing bar 5, consolidating reinforcing bar 5 and setting up in the upper strata of hookup reinforcing bar 4, consolidating reinforcing bar 5 one end and stretching into from the front end face inside the access board body 1, the other end extends to the front end off-plate, and the rear end face can set up same reinforcing bar 5.

The connecting reinforcing steel bars 4 are provided with at least one layer, referring to fig. 1-2, the number of layers of the connecting reinforcing steel bars 4 can be set according to the size of the bridge body, and fig. 3 is two layers of the connecting reinforcing steel bars 4.

Example two:

as shown in fig. 4-5: a bridge head structure of a seamless bridge comprises a high-strain strengthening type UHPC butt strap, a bridge girder 2, a ground beam 3, a wiring road surface 8, a wiring roadbed 9 and the like. Wherein:

the near platform end of the high strain strengthening UHPC butt strap is connected with a main beam 2 of the bridge, the far platform end of the butt strap body 1 is provided with a ground beam 3 of common concrete connected with the ground beam, and the ground beam 3 extends into a post-platform filling subgrade 10.

The high-strain-strengthening UHPC butt strap is a wedge-shaped plate with a certain gradient, and can be a prefabricated member or a cast-in-place member.

At least one layer of connecting reinforcing steel bars 4 are arranged in the UHPC butt strap, the connecting reinforcing steel bars 4 respectively extend into the bridge main beam 2 at the near platform end and the ground beam 3 at the far platform end, and the UHPC butt strap is connected with the bridge main beam 2 and the ground beam 3 in a reinforcing way through reinforcing steel bars 5.

A slip layer 7 is arranged between the UHPC lapping plate and a post-platform filling roadbed 10 below the UHPC lapping plate, and the slip layer 7 can be composed of an asphalt felt and a fine sand layer.

And an expansion joint 6 is arranged at the joint of the rear part of the ground beam 3 and the wiring roadbed 9.

The wiring road surface 8 is connected with the bridge floor and is continuously paved above the bridge girder 2, the UHPC butt strap and the wiring roadbed 9.

After the structure is adopted, the UHPC butt strap and the bridge girder 2 at the near platform end are connected together through the reinforcing steel bars and the connecting reinforcing steel bars, so that the UHPC butt strap can deform along with the bridge girder 2, and the ground beam 3 at the far platform end of the UHPC butt strap can also firmly fix the butt strap in the wiring roadbed 9 and the post-platform fill roadbed 10. Therefore, when the bridge girder 2 expands due to heating, the UHPC butt strap and the ground beam 3 are extruded, the deformation is transmitted to the tail end of the ground beam 3, and the expansion joint 6 at the joint of the rear part of the ground beam 3 and the wiring roadbed 9 absorbs the deformation of the expansion. When the bridge girder 2 is shortened due to cold contraction, due to the anchoring effect of the ground beam 3 and the effect of the sliding layer 7, the UHPC butt strap is longitudinally stretched, and the contraction deformation of the bridge girder 2 is absorbed by a large amount of microcracks generated by the UHPC butt strap. The UHPC butt strap is set to be a wedge-shaped plate with a certain gradient, and aims to ensure that the UHPC butt strap is uniformly stressed in the plate under the action of axial tension due to the friction action of the bottom edge plate length of the butt strap body 1. The high-ductility UHPC has strong crack control capability, the width of the micro-cracks is very small, and the micro-cracks cannot be reflected to the road surface to cause the road surface to crack, so that a telescopic device is not required to be arranged, and the maintenance cost is reduced.

The above description is only for the preferred embodiment of the present invention and should not be construed as limiting the scope of the present invention, and the equivalent modifications and variations made by those skilled in the art according to the spirit of the present invention or directly or indirectly applied to the related technical fields shall fall within the scope of the present invention.

Claims

1. A high-ductility UHPC butt strap comprises a butt strap body (1) and a connecting steel bar (4), and is characterized in that the front end face of the butt strap body (1) is higher than the rear end face, the bottom face is a horizontal plane, and the connecting steel bar (4) penetrates through the front end face and the rear end face.

2. A high ductility UHPC strap as claimed in claim 1, characterised in that it further comprises reinforcing steel bars (5), said reinforcing steel bars (5) extending from said front end surface into the interior of said strap body (1) at one end and out of said front end surface at the other end.

3. A high-ductility UHPC strap as claimed in claim 1, characterised in that the coupling reinforcement (4) is provided with at least one layer.

4. A seamless bridge head structure, characterized in that it comprises the UHPC decking of claim 3, the main beam (2) of the bridge, the ground beam (3);

the front end face and the rear end face of the UHPC butt strap are respectively connected with the end faces of a main beam (2) and a ground beam (3) of the bridge, the connecting reinforcing steel bars (4) are respectively anchored into the main beam (2) and the ground beam (3), and the two ends of the UHPC butt strap are reinforced through reinforcing steel bars (5).

5. A seamless bridge head structure according to claim 4, further comprising a wiring subgrade (9) and a soil-filling subgrade (10), wherein said wiring subgrade (9) covers said UHPC floorboards and said earth beams (3), and the ends thereof engage said soil-filling subgrade (10), and said earth beams (3) extend into said soil-filling subgrade (10).

6. A seamless bridge head structure according to claim 5, characterized in that a slip layer (7) is arranged between said UHPC butt strap and said road-fill foundation (10) therebelow.

7. A seamless bridge bridgehead structure according to claim 6, characterised in that the said glide layer (7) composition media comprises felt and fine sand.

8. A seamless bridge pier structure according to claim 5, wherein expansion joints (6) are provided behind the ground beams (3) at the connection with the wiring foundations (9).

9. A seamless bridge head structure according to any of claims 4-8, further comprising a wiring pavement (8), said wiring pavement (8) being contiguous with the deck and being laid continuously over the bridge girders (2), UHPC shingles and wiring subgrade (9).