CN112095449B - Light-weight combined beam pier top longitudinal connection structure and construction method thereof - Google Patents

Abstract

A longitudinal connection structure of a light combined beam pier top and a construction method thereof are disclosed, wherein the connection structure comprises prefabricated units which are oppositely arranged and cast-in-situ components which are arranged between the prefabricated units and the cast-in-situ components; the prefabricated unit comprises a plurality of I-shaped steel beams, a bridge deck arranged on the I-shaped steel beams and a connecting part arranged at the end part of the I-shaped steel beams; the connecting part comprises a first connecting part arranged at the end part of one prefabricated unit and a second connecting part arranged on the other prefabricated unit; the first connecting part comprises first transverse connecting plates and first transverse partition plates, the first transverse connecting plates are connected between the I-shaped steel beams and on two sides of the I-shaped steel beams, and even number of first longitudinal connecting plates are symmetrically arranged on the first connecting part along the center of each I-shaped steel beam; the novel vertical type wall partition is characterized in that a reserved space is arranged between the first longitudinal connecting plate and the bottoms of the first transverse connecting plate and the first transverse partition. The invention also discloses a construction method of the pier top longitudinal connection structure of the light composite beam. The invention has the advantages of convenient installation and construction, reinforced transverse and longitudinal strength, reduced risk of concrete cracking and the like.

Description

Light-weight combined beam pier top longitudinal connection structure and construction method thereof

Technical Field

The invention relates to the technical field of bridge members and construction thereof, in particular to a pier top longitudinal connecting structure of a light composite beam and a construction method thereof.

Background

At present, the assembled steel-concrete composite beam is more and more widely applied because the tensile property of steel and the compression property of concrete can be fully utilized. However, the adverse conditions that concrete is pulled and a steel beam is pressed are generated in the hogging moment area, and in the normal use stage, the concrete bridge deck is easy to crack, so that the rigidity of the composite beam is reduced, and the safety and the durability of the structure are influenced. For the construction performance, in the assembled steel-concrete composite beam, the bridge deck is partially prefabricated, the workload of pouring the joints of the bridge deck is large, and the workload of field construction is large. In addition, in order to solve the problems of concrete tension and steel beam compression in the hogging moment region, the conventional steel-concrete combined continuous beam bridge usually adopts the mode that cast-in-place concrete is arranged at the steel beam position of a pier top compression area, and a pier top tension bridge deck reduces the tensile stress level of a concrete slab through various construction measures (such as tensioning prestress, adjusting the pouring sequence of the concrete bridge deck, adopting temporary support and the like), so that the field operation amount of the combined structure bridge is increased, and the assembly rate is reduced.

The steel-ultrahigh performance concrete light composite beam has the advantages of light dead weight, high strength, good durability, low structural height and high assembly rate, can realize one-step forming, integral prefabrication and hoisting of a main beam, is suitable for the strict clearance requirement of urban bridges, can reduce the interference on the existing traffic under the bridge as far as possible, and has wide application prospect. The ultra-high performance concrete with excellent tensile property (higher tensile strength and stable crack control capability) is used for the concrete bridge deck slab in the tension area, and the problem that the concrete bridge deck slab is easy to crack is hopefully solved.

CN 108385503a discloses a simple-supported variable-structure continuous structure of an assembled light composite beam and a construction method thereof, the structure comprises two-span steel-ultra-high performance concrete light composite beam prefabricated units which are oppositely arranged and a cast-in-situ ultra-high performance concrete pier top beam arranged between the two prefabricated units, wherein each prefabricated unit comprises a plurality of i-shaped steel beams, bridge decks which are arranged on the i-shaped steel beams and connecting parts which are arranged at the end parts of the i-shaped steel beams. The stress situation in the negative moment zone of this construction is improved, however, this solution has the following drawbacks: (1) the beam end of the prefabricated unit comprises longitudinal connecting plates which are arranged in a staggered mode, the part, extending out relative to the second transverse connecting plate, of the second longitudinal connecting plate is clamped between the adjacent first longitudinal connecting plates, the problem that construction cannot be achieved or construction is difficult exists, and the difficulty of installation of the prefabricated unit is increased due to the shear connecting piece welded to the longitudinal connecting plates of the staggered clamping portion; (2) the cast-in-place concrete amount at the upper edge slot of the bridge deck is large, the structural assembly rate is reduced, and the risk of concrete shrinkage cracking is increased; (3) the first longitudinal connecting plate is connected with the bottoms of the first transverse connecting plate and the first transverse partition plate, so that the concrete in the separation area is disconnected, and the compactness of cast-in-place concrete pouring cannot be guaranteed.

Disclosure of Invention

The invention aims to overcome the defects in the prior art and provide a pier top longitudinal connecting structure of a light combined beam and a construction method thereof, wherein the pier top longitudinal connecting structure has the advantages of strong compactness, convenience in installation and construction, transverse and longitudinal strength enhancement and capability of reducing the cracking risk of concrete.

The technical scheme of the invention is as follows:

the invention relates to a pier top longitudinal connection structure of a light combined beam, which comprises prefabricated units arranged oppositely and a cast-in-place component arranged between the prefabricated units and the cast-in-place component; the prefabricated units comprise a plurality of I-shaped steel beams, bridge decks arranged on the I-shaped steel beams and connecting parts arranged at the end parts of the I-shaped steel beams; the connecting part comprises a first connecting part arranged at the end part of one prefabricated unit and a second connecting part arranged on the other prefabricated unit; the first connecting part comprises first transverse connecting plates and first transverse partition plates, the first transverse connecting plates are connected between the I-shaped steel beams and on two sides of the I-shaped steel beams, and even number of first longitudinal connecting plates are symmetrically arranged on the first connecting part along the center of each I-shaped steel beam; and a reserved space is arranged between the first longitudinal connecting plate and the bottoms of the first transverse connecting plate and the first transverse partition plate.

Furthermore, a reserved space with a height of 80-120 mm is arranged between the first longitudinal connecting plate and the bottoms of the first transverse connecting plate and the first transverse partition plate.

Furthermore, the second connecting part comprises second transverse connecting plates and second transverse partition plates which are connected between the I-shaped steel beams and on two sides of the I-shaped steel beams, and odd second longitudinal connecting plates are symmetrically arranged on the second connecting part along the center of each I-shaped steel beam; the cast-in-place ultrahigh-performance concrete between the first connecting part and the second connecting part forms a longitudinal integral structure.

Further, the cast-in-place part extends out 50-120 mm along the bottom of the I-shaped steel beam.

Furthermore, the upper edge of the bridge deck is provided with upper edge longitudinal embedded steel bars; and a steel plate strip is welded on the upper edge of the longitudinal embedded steel bar.

Further, the steel plate strip extends out relative to the first diaphragm plate or the second diaphragm plate; the transverse clear distance between the steel plates is 50-90 mm, the longitudinal clear distance between the steel plates of the adjacent prefabricated units is 90-120 mm, and the steel plates are connected with the steel plates below the longitudinal embedded steel bars on the upper edge of the bridge deck of the other prefabricated unit through the lapping steel bars to form an integral stress structure; the length of the lap joint steel bar is 120-180 mm; and the steel plate strips are welded with shear connectors.

Furthermore, shear connectors are arranged on the first longitudinal connecting plate and the second longitudinal connecting plate, and longitudinal steel bars are bound on the shear connectors.

Further, the length of the longitudinal steel bar is 250-450 mm, the distance between the end of the longitudinal steel bar and the first transverse partition plate or the second transverse partition plate is 15-35 mm, and the vertical distance between the end of the longitudinal steel bar and the first transverse partition plate or the second transverse partition plate is 60-90 mm; the longitudinal steel bars bound with the shear connectors become U-shaped steel bars with one open end, and the concrete surrounded by the longitudinal steel bars bound on the shear connectors on the first longitudinal connecting plate facing the web plate of the I-shaped steel beam and the longitudinal steel bars bound on the shear connectors on the adjacent second longitudinal connecting plate form a core concrete column.

The invention relates to a construction method of a pier top longitudinal connecting structure of a light composite beam, which comprises the following steps:

s1: prefabricating a steel-ultrahigh performance concrete light composite beam prefabricating unit in a factory;

s2: erecting prefabricated units obtained by prefabricating the S1 and arranged oppositely on a construction site, and arranging two prefabricated units for connecting the first connecting part and the second connecting part oppositely;

s3: connecting the steel plate strips below the longitudinal embedded steel bars at the upper edges of the two adjacent prefabricated units in a lap steel bar spot welding mode, keeping the longitudinal embedded steel bars at the lower edges of the two prefabricated units in a staggered arrangement, and pouring ultrahigh-performance concrete in situ between the first connecting part and the second connecting part to form a longitudinal integral structure;

s4: and maintaining the cast-in-place ultrahigh-performance concrete part to reach the design strength, and finishing the construction of the longitudinal connection of the pier tops of the light composite beam.

Further, the prefabrication method of the prefabrication unit comprises the following steps:

s11: welding a web plate, an upper edge wing and a lower edge wing in a factory to form an I-shaped steel beam, or directly processing the I-shaped steel by adopting a market finished product hot rolled I-shaped steel to form the I-shaped steel beam;

s12: arranging and temporarily fixing the two I-shaped steel beams in parallel, and connecting and fixing the first connecting part or the second connecting part at the end parts of the two I-shaped steel beams;

s13: welding shear connectors at corresponding positions of the upper edge wing, the first connecting part and the second connecting part of the I-shaped steel beam;

s14: binding longitudinal steel bars at corresponding positions of the shear connectors of the first longitudinal connecting plate and the second longitudinal connecting plate;

s15: erecting a formwork above the I-shaped steel beam, firstly binding a steel mesh at the lower edge of the bridge deck, then placing a steel plate strip welded with the shear connector on the steel mesh, then binding the steel mesh at the upper edge of the bridge deck, connecting the upper surface of the steel plate strip with the steel bar in a spot welding manner, then pouring ultrahigh-performance concrete, and timely maintaining;

s16: and when the poured ultrahigh-performance concrete meets the design requirement, removing the template, and storing to a specified position to form the prefabricated assembly type steel-ultrahigh-performance concrete light composite beam prefabricated unit.

The invention has the beneficial effects that:

(1) according to the invention, the longitudinal connection is enhanced by arranging the longitudinally pre-embedded steel plate strips in the pier top negative bending moment area, so that the cast-in-place part only needs to cast the middle area of the prefabricated unit I-shaped steel beam without T-shaped casting, the cast-in-place amount of concrete is greatly reduced, the shrinkage cracking of the concrete is reduced, and the transverse connection performance of the structure is enhanced;

(2) the cast-in-place component extends out of the bottom of the I-shaped steel beam by a section of height, so that the height of the cast-in-place component is increased, the leveling is convenient, the pier top can be directly cast with a support wedge block, and the installation and construction of the support are convenient;

(3) a reserved space is arranged between the first longitudinal connecting plate and the bottoms of the first transverse connecting plate and the first transverse partition plate, so that concrete in different partition areas is connected into a whole through the reserved area in the process of casting the ultra-high performance concrete in situ, and the casting compactness of the cast-in-situ concrete is guaranteed.

(4) Longitudinal steel bars are arranged on two sides of the first longitudinal connecting plate and two sides of the second longitudinal connecting plate, and the longitudinal steel bars are bound with shear connectors on the adjacent longitudinal connecting plates, so that concrete surrounded by the longitudinal steel bars on the first longitudinal connecting plate and the longitudinal steel bars on the adjacent second longitudinal connecting plate forms a core concrete column, the stress of the longitudinal connecting plates is enhanced, the bearing capacity of wet joints is improved, and the cracking risk of the concrete is reduced.

Drawings

FIG. 1 is an elevation view of a steel structure section of this embodiment without longitudinal web reinforcement;

FIG. 2 is a schematic cross-sectional view at C-C in FIG. 1;

FIG. 3 is a schematic cross-sectional view taken at A-A in FIG. 1;

FIG. 4 is a schematic cross-sectional view at B-B in FIG. 1;

FIG. 5 is a schematic view of the arrangement of shear connectors on the front and back sides of the first and second longitudinal connecting plates;

FIG. 6 is a schematic elevation view of the binding of reinforcing bars at the longitudinal connecting plates of the steel structural portion in the embodiment;

FIG. 7 is a schematic cross-sectional view at C-C in FIG. 6;

FIG. 8 is a schematic cross-sectional view taken at A-A in FIG. 6;

FIG. 9 is a schematic cross-sectional view at B-B in FIG. 6;

FIG. 10 is an elevation view of the concrete portion of the present embodiment;

FIG. 11 is a schematic cross-sectional view at C-C of FIG. 10;

FIG. 12 is a schematic cross-sectional view taken at A-A in FIG. 10;

FIG. 13 is a schematic cross-sectional view at B-B in FIG. 10;

fig. 14 is a schematic cross-sectional view at D-D in fig. 10.

The attached drawings indicate the following:

the steel plate comprises 1 prefabricated unit, 2 cast-in-place part, 3I-shaped steel beam, 3-1 upper edge wing, 3-2 web plate, 3-3 lower edge wing, 4 bridge deck, 5 first connecting part, 5-1 first transverse connecting plate, 5-2 first transverse partition plate, 5-3 first longitudinal connecting plate, 5-4 reserved space, 6-second connecting part, 6-1 second transverse connecting plate, 6-2 second transverse partition plate, 6-3 second longitudinal connecting plate, 7 shear connecting part, 8 steel plate strip, 8-1 lap-joint steel bar, 9 hole and 10 longitudinal steel bar.

Detailed Description

The invention will be described in further detail below with reference to the drawings and specific examples.

As shown in FIGS. 1-14: a longitudinal connection structure of a lightweight composite beam pier top comprises prefabricated units 1 which are oppositely arranged and cast-in-place components 2 which are arranged between the prefabricated units 1 and the cast-in-place components; each prefabricated unit 1 comprises two I-shaped steel beams 3, a bridge deck 4 arranged on the I-shaped steel beams 3 and a connecting part arranged at the end part of the I-shaped steel beam 3; the connecting parts comprise a first connecting part 5 arranged at the end part of one prefabricated unit 1 and a second connecting part 6 arranged on the other prefabricated unit 1; the first connecting part 5 and the second connecting part 6 are matched to form a pouring area, and the cast-in-place ultrahigh-performance concrete is cast in place to form the cast-in-place component 2.

The cast-in-place component in the embodiment is cast-in-place pier top ultrahigh-performance concrete, the excellent compression resistance of the ultrahigh-performance concrete and the tensile resistance of steel can be fully exerted, the problems that a concrete bridge deck in a hogging moment area is easy to tension and crack and a steel beam is easy to stabilize under compression are solved on the whole stress, great convenience is brought to the construction performance, the field operation amount is reduced as far as possible, and the assembly rate of the assembled steel-ultrahigh-performance concrete light combined beam is improved. The connecting parts of the I-shaped steel beam, the bridge deck and the end part of the prefabricated unit are all formed in one step in a factory and are integrally prefabricated, the structure has better integrity, the steel consumption is saved, the field operation amount in the construction process is greatly reduced, the manufacturing quality of the component is ensured, and further the stress performance of the pier top longitudinal connecting structure of the light combined beam is ensured. The first connecting part and the second connecting part can strengthen the transverse connection of two adjacent I-shaped steel beams and are used as a side mold and a bottom mold of the pier top longitudinal connecting structure of the light combined beam to facilitate construction. The first connecting portion and the second connecting portion are preferably connected to the end portion of the I-shaped steel beam in a welding mode.

In this embodiment, the standard span of the prefabricated unit 1 is preferably 30m, the height is 1.0m, the width is 3.0m, and the longitudinal bridge thickness of the cast-in-place part 2 is 0.4 m. The I-shaped steel beam 3 comprises a web plate 3-2, an upper edge wing 3-1 arranged at the upper part of the web plate 3-2 and a lower edge wing 3-3 arranged at the lower part of the web plate 3-2, and is formed by welding, the height of the I-shaped steel beam 3 is 750mm, the thickness of the web plate 3-2 is 16mm, the height is 718mm, the thickness of an upper flange is 12mm, the width is 300mm, the thickness of a lower flange is 20mm, the width is 500mm, and the center distance between the two I-shaped steel beams 3 of the same prefabricating unit 1 is 1600 mm.

In this embodiment, the cast-in-place part extends 100mm along the bottom of the i-beam. The cast-in-place part extends out of the bottom of the I-shaped steel beam by a section of height, so that the height of the cast-in-place part is increased, the leveling is facilitated, the pier top can be directly poured with the support wedge block, and the installation and construction of the support are facilitated.

In the embodiment, the first connecting part 5 comprises a first transverse connecting plate 5-1 and a first transverse clapboard 5-2 which are connected between the I-shaped steel beams 3 and at two sides of the I-shaped steel beams 3, and an even number of first longitudinal connecting plates 5-3 are symmetrically arranged on the first connecting part 5 along the central position of each I-shaped steel beam; the first longitudinal connecting plate 5-3 does not extend to the bottom of the first transverse connecting plate 5-1 and the first transverse partition plate 5-2, namely a reserved space 5-4 is arranged between the first longitudinal connecting plate 5-3 and the bottom of the first transverse connecting plate 5-1 and the bottom of the first transverse partition plate 5-2. By arranging the reserved spaces 5-4, concrete in different partition areas is connected into a whole through the reserved areas in the process of casting the ultra-high performance concrete in situ, so that the compactness of cast-in-situ concrete is ensured. Preferably, the height of the headspace 5-4 is 100 mm.

In this embodiment, the second connecting portion 6 includes a second transverse connecting plate 6-1 and a second transverse partition plate 6-2 connected between the i-shaped steel beams 3 and at two sides of the i-shaped steel beams 3, and odd number second longitudinal connecting plates 6-3 are symmetrically arranged on the second connecting portion 6 along the center of each i-shaped steel beam. The cast-in-place ultrahigh-performance concrete between the first connecting part 5 and the second connecting part 6 forms a longitudinal integral structure.

In this embodiment, the lower edge wing 3-3 of one prefabricated unit 1 extends, the first diaphragm plate 5-2 is welded to the end of the i-beam 3, and the first transverse connecting plate 5-1 includes a plate extending along the lower edge wing 3-3, a plate welded between the lower edge wings 3-3 of the two i-beams, and plates on both sides of the lower flange of the i-beam. The first diaphragm plate 5-2 is perpendicular to the second transverse connecting plate 5-1, and divides the first transverse connecting plate 5-1 into an inner side part facing the I-shaped steel beam 3 and an outer side part far away from the I-shaped steel beam 3. Two groups of first longitudinal connecting plates 5-3 which are arranged in parallel are fixedly welded on the first transverse partition plate 5-2, the number of the first longitudinal connecting plates 5-3 in each group is two, and the first longitudinal connecting plates are symmetrically arranged along the joint of the web plate 3-2 of the I-shaped steel beam and the first transverse partition plate 5-2. The ends of the first longitudinal webs 5-3 are flush with the ends of the outer portions of the first transverse webs 5-1.

The web plate 3-2 and the lower edge wing 3-3 of the other prefabricated unit 1 extend out, and the second diaphragm plate 6-2 is welded between the web plates 3-2 of the two I-shaped steel beams and outside the web plates 3-2. The second longitudinal connecting plate 6-3 is a part of the web 3-2 which extends out relative to the second diaphragm 6-2; holes 9 are formed in the bottoms of the second diaphragm plates 6-2 on the left side and the right side of the extending portion of the web plate, and the radius of each hole 9 is preferably 50 mm. The second transverse connecting plate 6-1 comprises a plate extending out along the lower edge wing 3-3, a plate welded between the lower edge wings 3-3 of the two I-shaped steel beams and a plate outside the lower edge wing 3-3; the second diaphragm plate 6-2 is perpendicular to the second transverse connecting plate 6-1, and divides the second transverse connecting plate 6-1 into an inner side portion facing the I-shaped steel beam 3 and an outer side portion far away from the I-shaped steel beam 3. The ends of the second longitudinal webs 6-3 extend beyond the ends of the outer portions of the second transverse webs 6-1.

The thickness of the first diaphragm plate 5-2 and the second diaphragm plate 6-2 is 16mm, and the height is consistent with the height of the web plate 3-2.

In the embodiment, the first diaphragm plate 5-2 and the second diaphragm plate 6-2 are provided with the shear connecting piece 7 at the side far away from the i-shaped steel beam 3, the shear connecting piece 7 is in the form of a cylindrical head welding nail, the height of the cylindrical head welding nail is preferably 120mm, and the distance between every two adjacent cylindrical head welding nails is preferably 200 mm. Shear connectors 7 are welded on two sides of the first longitudinal connecting steel plate and two sides of the second longitudinal connecting plate 6-3, the shear connectors 7 are cylindrical head welding nails which are arranged in a staggered mode, the height of each cylindrical head welding nail is preferably 60mm, and the distance between every two adjacent cylindrical head welding nails is 150 mm. The upper surfaces of the outer side parts of the first transverse connecting plate 5-1 and the second transverse connecting plate 6-1 are also provided with shear connectors 7, the shear connectors 7 are cylindrical head welding nails which are arranged in a staggered mode, the height of each cylindrical head welding nail is preferably 80mm, and the distance between every two adjacent cylindrical head welding nails is 200 mm.

In this embodiment, the deck slab 4 is disposed above the i-shaped steel beam 3 and connected to the i-shaped steel beam 3 by the shear connector 7, and the thickness of the deck slab 4 is preferably 120 mm. The upper edges of the bridge decks 4 at the two ends of the prefabricated units 1 are provided with upper edge longitudinal embedded steel bars, and the upper edge longitudinal embedded steel bars of the bridge decks 4 of the adjacent prefabricated units 1 are bound and connected into an integral stress structure through connecting steel bars and longitudinal embedded steel bars. On the basis of fully utilizing the excellent tensile property of the ultrahigh-performance concrete, the structure further enhances the bending and tensile properties of the pier top ultrahigh-performance concrete connecting part, facilitates field construction, and can effectively solve the problem that the concrete bridge deck slab in the hogging moment area of the pier top of the composite beam is easy to crack by tension. The bridge deck is also provided with lower edge longitudinal embedded bars partially extending out, and the lower edge longitudinal embedded bars of two adjacent prefabricated units are arranged in a staggered mode, so that longitudinal connection and overall stress of the bridge deck are further enhanced. The embedded steel bars on the upper edge of the bridge deck are connected with longitudinal steel strips 8 in a spot welding mode, the length of each steel strip 8 is 500 mm-2000 m (1750 mm is preferred), the width of each steel strip is 50 mm-100 mm (60 mm is preferred), the thickness of each steel strip is 5 mm-15 mm (10 mm is preferred), the transverse clear distance between the steel strips is 80mm, and the longitudinal clear distance between the embedded steel strips of adjacent prefabricated units is 100 mm. The longitudinal steel plate strips of two adjacent prefabricated units extend out of the position of the first transverse partition plate or the second transverse partition plate, the longitudinal steel plate strips of the two adjacent prefabricated units are connected through the lap-joint steel bars in the middle of the pier top, and the length of the lap-joint steel bars is 160 mm.

According to the embodiment, the longitudinal connection can be enhanced by welding the steel plate strips on the upper-edge longitudinal embedded steel bars, so that the cast-in-place part only needs to pour the middle area of the I-shaped steel beam of the prefabricated unit, T-shaped pouring is not needed, the cast-in-place amount of concrete is greatly reduced, the shrinkage cracking of the concrete is reduced, and the transverse connection performance of the structure is enhanced.

In this embodiment, longitudinal reinforcement 10 has been arranged to first longitudinal connecting plate and second longitudinal connecting plate both sides, and longitudinal reinforcement 10 collimates with shear force connecting piece 7 on the adjacent longitudinal connecting plate, and its arrange centrally in cast-in-place part region, and the length of single longitudinal reinforcement is 250~450mm, and its tip is 15~35mm with the interval of first cross slab and second cross slab, and the upper and lower interval of longitudinal reinforcement is 60~90 mm. Longitudinal steel bars bound with the shear connectors become U-shaped steel bars with one open end, the longitudinal steel bars bound on the shear connectors 7 on the first longitudinal connecting plate facing the I-beam web 3-2 and concrete surrounded by the longitudinal steel bars bound on the shear connectors 7 on the adjacent second longitudinal connecting plate form a core concrete column, the concrete column bears pressure of the U-shaped steel bars with opposite openings acting on two sides of the core concrete column, the tensile force of the lap joint steel bars is balanced through shearing of the core concrete column and the binding action of non-steel bars and concrete, the stress of the longitudinal connecting plates is enhanced, the bearing capacity of wet joints is improved, and meanwhile, the cracking risk of the concrete is reduced.

In the embodiment, adjacent prefabricated units 1 are arranged oppositely, the first connecting portion 5 of one prefabricated unit 1 is matched with the second connecting portion 6 of the other prefabricated unit 1, the first transverse connecting plate 5-1 is in contact with the second transverse connecting plate 6-1, and the first longitudinal connecting plate 5-3 and the second longitudinal connecting plate 6-3 extend out of the center line of the pier relative to the transverse connecting plates. The first connecting part 5 and the second connecting part 6 together form a pier top cast-in-place ultrahigh-performance concrete component area, and the pier top cast-in-place ultrahigh-performance concrete cast-in-place component 2 is formed after the ultrahigh-performance concrete is cast in place, and the width of the pier top cast-in-place ultrahigh-performance concrete cast-in-place component is preferably 400 mm.

In this embodiment, the bridge deck 4 and the cast-in-place member 2 are both formed by pouring ultrahigh-performance concrete, and the ultrahigh-performance concrete in this embodiment is ultrahigh-performance fiber reinforced concrete.

The construction method of the pier top longitudinal connection structure of the light composite beam comprises the following steps:

s1: the prefabricated unit 1 of the prefabricated steel-ultra-high performance concrete light composite beam is prefabricated in a factory, and the concrete steps are as follows:

s1.1: welding a web plate 3-2, an upper edge wing 3-1 and a lower edge wing 3-3 in a factory to form an I-shaped steel beam 3, or directly adopting a market finished product hot rolling I-shaped processing to form the I-shaped steel beam 3;

s1.2: arranging and temporarily fixing the two I-shaped steel beams 3 in parallel, and connecting and fixing the first connecting part 5 or the second connecting part 6 on the end parts of the two I-shaped steel beams 3;

s1.3: welding a shear connecting piece 7 at the corresponding positions of the upper flange 3-1, the first connecting part 5 and the second connecting part 6 of the I-shaped steel beam 3;

s1.4, binding longitudinal steel bars 10 at corresponding positions of the shear connectors 7 of the first longitudinal connecting plate 5-3 and the second longitudinal connecting plate 6-3;

s1.5: erecting a formwork above the I-shaped steel beam 3, firstly binding a steel mesh at the lower edge of a bridge deck, then placing a steel plate strip 8 welded with a shear connector on the steel mesh, then binding the steel mesh at the upper edge of the bridge deck, connecting the upper surface of the steel plate strip with the steel bar in a spot welding manner, then pouring ultrahigh-performance concrete, and carrying out maintenance in time;

s1.6: and when the poured ultrahigh-performance concrete meets the design requirement, removing the template, and storing to a specified position to form the prefabricated assembly type steel-ultrahigh-performance concrete light composite beam prefabricated unit 1.

S2: erecting prefabricated units 1 which are oppositely arranged and are prefabricated by the S1 on a construction site, and oppositely arranging two prefabricated units 1 which are connected with a first connecting part 5 and a second connecting part 6, so that the first connecting part 5 and the second connecting part 6 are matched to form a pier top cast-in-place component area;

s3: connecting the longitudinally pre-embedded steel plate strips 8 at the upper edges of two adjacent prefabricated units 1 in a lap-joint steel bar 8-1 spot welding mode, and pouring ultrahigh-performance concrete in the area of the cast-in-place part 2 in a site manner by paying attention to the staggered arrangement of the longitudinally pre-embedded steel bars at the lower edges;

s4: and maintaining the cast-in-place component 2 to achieve the design strength, namely completing the construction of the pier top longitudinal connection of the light composite beam.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (10)

1. A pier top longitudinal connection structure of a light combined beam comprises prefabricated units which are oppositely arranged and cast-in-place components which are arranged between the prefabricated units and the cast-in-place components; the prefabricated units comprise a plurality of I-shaped steel beams, bridge decks arranged on the I-shaped steel beams and connecting parts arranged at the end parts of the I-shaped steel beams; the connecting part comprises a first connecting part arranged at the end part of one prefabricated unit and a second connecting part arranged on the other prefabricated unit; the first connecting part comprises first transverse connecting plates and first transverse partition plates, the first transverse connecting plates are connected between the I-shaped steel beams and on two sides of the I-shaped steel beams, and even number of first longitudinal connecting plates are symmetrically arranged on the first connecting part along the center of each I-shaped steel beam; the second connecting part comprises second transverse connecting plates and second transverse partition plates, the second transverse connecting plates are connected between the I-shaped steel beams and on two sides of the I-shaped steel beams, and odd second longitudinal connecting plates are symmetrically arranged on the second connecting part along the center of each I-shaped steel beam; the first transverse connecting plate is characterized in that the first longitudinal connecting plate does not extend to the bottoms of the first transverse connecting plate and the first transverse partition plate, namely, a reserved space is formed between the first longitudinal connecting plate and the bottoms of the first transverse connecting plate and the first transverse partition plate; the first transverse connecting plate is in contact with the second transverse connecting plate, and the first longitudinal connecting plate and the second longitudinal connecting plate extend out to the center line of the pier relative to the transverse connecting plates.

2. The pier top longitudinal connecting structure of the light-weight composite beam as claimed in claim 1, wherein a reserved space with a height of 80-120 mm is arranged between the first longitudinal connecting plate and the bottom of the first transverse partition plate.

3. The pier top longitudinal connection structure of the light-weight composite beam as claimed in claim 1 or 2, wherein the cast-in-place ultrahigh-performance concrete between the first connection part and the second connection part forms a longitudinal integral structure.

4. The lightweight composite girder pier top longitudinal connection structure of claim 1 or 2, wherein the cast-in-place part extends 50-120 mm along the bottom of the I-shaped steel girder.

5. The lightweight composite beam pier top longitudinal connection structure as claimed in claim 1 or 2, wherein upper edge longitudinal embedded steel bars are arranged on the upper edge of the bridge deck; and a steel plate strip is welded on the upper edge of the longitudinal embedded steel bar.

6. The lightweight composite beam pier top longitudinal connection structure of claim 5, wherein the steel plate strip protrudes with respect to the first diaphragm plate or the second diaphragm plate; the transverse clear distance between the steel plates is 50-90 mm, the longitudinal clear distance between the steel plates of the adjacent prefabricated units is 90-120 mm, and the steel plates are connected with the steel plates below the longitudinal embedded steel bars on the upper edge of the bridge deck of the other prefabricated unit through the lapping steel bars to form an integral stress structure; the length of the lap joint steel bar is 120-180 mm; and the steel plate strips are welded with shear connectors.

7. The pier top longitudinal connecting structure of the light-weight composite beam as claimed in claim 3, wherein shear connectors are arranged on the first longitudinal connecting plate and the second longitudinal connecting plate, and longitudinal steel bars are tied on the shear connectors.

8. The pier top longitudinal connection structure of the light-weight combination beam as claimed in claim 7, wherein the length of the longitudinal steel bar is 250-450 mm, the distance between the end part of the longitudinal steel bar and the first diaphragm plate or the second diaphragm plate is 15-35 mm, and the vertical distance between the longitudinal steel bar is 60-90 mm; the longitudinal steel bars bound with the shear connectors become U-shaped steel bars with one open end, and the concrete surrounded by the longitudinal steel bars bound on the shear connectors on the first longitudinal connecting plate facing the web plate of the I-shaped steel beam and the longitudinal steel bars bound on the shear connectors on the adjacent second longitudinal connecting plate form a core concrete column.

9. A construction method of the pier top longitudinal connection structure of the light composite beam according to any one of claims 1 to 8, characterized by comprising the following steps:

s1: prefabricating a steel-ultrahigh performance concrete light composite beam prefabricating unit in a factory;

s2: erecting prefabricated units obtained by prefabricating the S1 and arranged oppositely on a construction site, and arranging two prefabricated units for connecting the first connecting part and the second connecting part oppositely;

s3: connecting the steel plate strips below the longitudinal embedded steel bars at the upper edges of the two adjacent prefabricated units in a lap steel bar spot welding mode, keeping the longitudinal embedded steel bars at the lower edges of the two prefabricated units in a staggered arrangement, and pouring ultrahigh-performance concrete in situ between the first connecting part and the second connecting part to form a longitudinal integral structure;

s4: and maintaining the cast-in-place ultrahigh-performance concrete part to reach the design strength, and finishing the construction of the longitudinal connection of the pier tops of the light composite beam.

10. The construction method of the pier top longitudinal connection structure of the light-weight composite girder according to claim 9, wherein the prefabrication method of the prefabricated unit comprises the steps of:

s11: welding a web plate, an upper edge wing and a lower edge wing in a factory to form an I-shaped steel beam, or directly processing the I-shaped steel by adopting a market finished product hot rolled I-shaped steel to form the I-shaped steel beam;

s12: arranging and temporarily fixing the two I-shaped steel beams in parallel, and connecting and fixing the first connecting part or the second connecting part at the end parts of the two I-shaped steel beams;

s13: welding shear connectors at corresponding positions of the upper edge wing, the first connecting part and the second connecting part of the I-shaped steel beam;

s14: binding longitudinal steel bars at corresponding positions of the shear connectors of the first longitudinal connecting plate and the second longitudinal connecting plate;

s15: erecting a formwork above the I-shaped steel beam, firstly binding a steel mesh at the lower edge of the bridge deck, then placing a steel plate strip welded with the shear connector on the steel mesh, then binding the steel mesh at the upper edge of the bridge deck, connecting the upper surface of the steel plate strip with the steel bar in a spot welding manner, then pouring ultrahigh-performance concrete, and timely maintaining;

s16: and when the poured ultrahigh-performance concrete meets the design requirement, removing the template, and storing to a specified position to form the prefabricated assembly type steel-ultrahigh-performance concrete light composite beam prefabricated unit.

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