CN111749114A - Structure and Construction Method of Negative Moment Zone of Steel Truss-UHPC Composite Girder Bridge - Google Patents

Abstract

The invention discloses a hogging moment area structure of a steel truss-UHPC (ultra high performance concrete) composite beam bridge and a construction method, which relate to the technical field of bridge structures and comprise the following steps: steel trusses and UHPC decking; the steel truss girder comprises two main trusses which are transversely arranged at intervals and connected, each main truss comprises a lower chord and an upper chord, and UHPC is filled in the lower chord; the UHPC bridge deck is connected with the upper surfaces of the two upper chords; the upper chord member and the lower chord member are provided with vertical web members, the two sides of each vertical web member are sequentially symmetrically provided with a compression web member and a tension web member in an alternating mode, and the lower chord member and the upper chord member are connected with an integral gusset plate at the joints. The invention can solve the technical problems that the lower chord of the existing steel truss girder is easy to be stressed and unstable, the bridge deck is easy to be pulled and cracked, and the node is easy to be damaged by fatigue.

Description

Structure and Construction Method of Negative Moment Zone of Steel Truss-UHPC Composite Girder Bridge

technical field

The invention relates to the technical field of bridge structures, in particular to a negative bending moment area structure and a construction method of a steel truss-UHPC composite girder bridge.

Background technique

At present, steel-concrete composite bridges have been favored and paid attention by scholars and engineers. Compared with concrete bridges, they have the advantages of high strength, light weight, short construction period, and good seismic performance.

In the related art, the steel truss-concrete composite girder bridge is an important branch of the steel-concrete composite structure bridge, and it is a new bridge type based on the optimization of the concrete box girder web and floor. After the webs and bottom plates of the concrete box girder are replaced by the webs and chords of the truss system, the material utilization rate is improved and the structural weight is greatly reduced, so this bridge type has great competitive advantages. The main advantages of steel truss-concrete composite girder bridges are reflected in the following two aspects: 1. The truss members are mainly subjected to axial force, and the material utilization rate is high, and greater flexural rigidity can be obtained under the same material consumption; 2. The construction period is short and the construction method is flexible.

However, due to the structural and material properties, the common steel truss-concrete composite girder bridge structure has the following problems:

1. The lower chord of the steel truss girder is prone to compression and instability;

2. The bridge deck is susceptible to tension cracking;

3. The nodes are prone to fatigue damage.

SUMMARY OF THE INVENTION

The embodiments of the present invention provide a structure and construction method for the negative bending moment area of a steel truss-UHPC composite girder bridge, so as to solve the problem that the lower chord of the steel truss girder is susceptible to compression and instability, the bridge deck is susceptible to tension cracking, and the joints are easily fatigued in the related art. Destruction of technical issues.

In a first aspect, a negative bending moment zone structure of a steel truss-UHPC composite girder bridge is provided, including:

A steel truss girder includes two main trusses arranged and connected laterally at intervals, each of the main trusses includes a lower chord and an upper chord, the lower chord is filled with UHPC; the upper chord and the lower chord are filled with UHPC; A vertical web rod is arranged at the fulcrum of each main truss, and a compression web rod and a tension web rod are arranged symmetrically and alternately on both sides of the vertical web rod. An integral gusset plate is connected at the node where the compression web rod and the tension web rod are connected, and each of the integral gusset plate is extended with two obliquely convex side plates, and the two obliquely convex side plates are respectively connected with one of the compression webs and tension webs;

UHPC bridge deck, which is connected with the upper surfaces of the two upper chords.

In some embodiments, the compression web is a box-shaped section, and the tension web is an I-shaped section.

In some embodiments, the centerline of the compression and tension webs intersects the centerline of the lower or upper chord at a point.

In some embodiments, the UHPC bridge deck includes a plurality of UHPC bridge deck segments connected in sequence, and two adjacent UHPC bridge deck segments are connected by wet joints, and the wet joints are provided with lap joints. rebar.

In some embodiments, shear grooves are cast on the upper surface of the main truss at intervals, and shear nails are arranged in the shear grooves.

In some embodiments, the shear grooves are elliptical.

In some embodiments, epoxy mortar is also poured on the upper surface of the main truss.

In some embodiments, the two main trusses are connected to form an integral body by a parallel connection assembly, and the parallel connection assembly includes a plurality of upper parallel links, a plurality of lower parallel links and a plurality of diagonal struts, each of the The two ends of the upper flat link are respectively connected to the upper chords of the two main trusses, the two ends of each of the lower flat links are respectively connected to the lower chords of the two main trusses, and the two ends of each diagonal strut are respectively connected The upper chord of one of the main trusses and the lower chord of the other of the main trusses.

A second aspect provides a construction method for the above-mentioned steel truss-UHPC composite girder bridge structure in the negative bending moment area, comprising the following steps:

Two main trusses and UHPC decks of prefabricated steel trusses;

Fill UHPC inside the bottom chords of the two main trusses;

Connect and erect two main trusses to form steel trusses;

Surface mount connecting UHPC bridge decks on both main trusses.

The embodiments of the present invention provide a structure and construction method for the negative bending moment area of a steel truss-UHPC composite girder bridge. The steel truss girder is combined with the UHPC bridge deck, the material properties of steel and UHPC are fully utilized, and the common steel truss composite girder is effectively solved. The bridge deck in the negative bending moment area is prone to cracking in tension; only filling the lower chord with UHPC can effectively avoid the lower chord from being unstable under compression and improve the bearing capacity of the lower chord. At the same time, the integral gusset plate can increase the stiffness of the joint, and the fatigue resistance of the joint is significantly improved.

Description of drawings

In order to illustrate the technical solutions in the embodiments of the present invention more clearly, the following briefly introduces the accompanying drawings used in the description of the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained from these drawings without creative effort.

Fig. 1 is the sectional view of the negative bending moment zone structure of the steel truss-UHPC composite girder bridge provided by the embodiment of the present invention;

Fig. 2 is the elevation view of the negative bending moment zone structure of the steel truss-UHPC composite girder bridge provided by the embodiment of the present invention;

Fig. 3 is the enlarged schematic diagram at node A in Fig. 2;

Fig. 4 is the three-dimensional schematic diagram of Fig. 3;

Fig. 5 is the top view of Fig. 2;

6 is a schematic diagram of block connection of two UHPC bridge decks provided by an embodiment of the present invention;

FIG. 7 is a layout diagram of a parallel coupling assembly provided by an embodiment of the present invention;

Fig. 8 is another arrangement diagram of the parallel coupling assembly provided by the embodiment of the present invention;

9 is a flowchart of a construction method of a steel truss-UHPC composite girder bridge structure in a negative bending moment area provided by an embodiment of the present invention;

In the figure: 1. Steel truss; 11. Main truss; 111. Lower chord; 112. Upper chord; 1121, Shear groove; 1122, Shear nail; 113, Vertical web; 114, Compression web; , tensioned web; 116, integral gusset plate; 1161, oblique raised side plate; 12, flat joint assembly; 121, upper flat link; 122, lower flat link; 123, diagonal strut; 2, UHPC bridge Panel; 21, UHPC bridge deck block; 211, longitudinal reinforcement; 212, transverse reinforcement; 22, wet joint; 23, lap reinforcement.

Detailed ways

In order to make the purposes, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments These are some embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present invention.

The embodiment of the present invention provides a negative bending moment zone structure of a steel truss-UHPC composite girder bridge, which can solve the technical problems that the lower chord of the existing steel truss girder is susceptible to compression and instability, and the bridge deck is susceptible to tension cracking.

Referring to FIG. 1 , a negative bending moment area structure of a steel truss-UHPC composite girder bridge includes: a steel truss girder 1 and a UHPC bridge deck 2 . Among them, UHPC (Ultra-High Performance Concrete) is ultra-high performance concrete, which is a special engineering material with ultra-high strength, toughness and high durability.

The steel truss girder 1 includes two main trusses 11 arranged laterally spaced apart and connected, and each main truss 11 includes a lower chord 111 and an upper chord 112 , and the lower chord 111 is filled with UHPC. At the same time, connect the UHPC bridge deck 2 with the upper surfaces of the two upper chords 112 . Specifically, as shown in FIG. 2 , the lower chord 111 has a box-shaped section, and UHPC is filled in the box. Preferably, the area filled with UHPC is located between the two nodes on the left and right of the negative bending moment area of the steel truss-UHPC composite girder bridge structure at the support point of the pier. Considering the force of the main truss 11 at the node, the length of the UHPC filling can be Extend beyond the node area.

Referring to Fig. 2, between the upper chord 112 and the lower chord 111, a vertical web 113 is provided at the fulcrum of each main truss 11, wherein the fulcrum of the main truss 11 refers to the support point of the bridge pier. Both sides of the vertical web rod 113 are symmetrically and alternately provided with a compression web rod 114 and a tension web rod 115, and the lower chord rod 111 and the upper chord rod 112 are connected with the compression web rod 114 and the tension web rod 115. The integral gusset plate 116, as shown in FIG. 3 and FIG. 4 , each integral gusset plate 116 extends with two obliquely convex side plates 1161, and the two obliquely convex side plates 1161 are respectively connected with a compression web 114 It is connected with the tensioned web rod 115 .

Specifically, the lower chord 111 and the upper chord 112 are both box-shaped sections, the compression webs 114 are box-shaped sections, and the tensioned webs 115 are I-shaped sections. The center line of the compression web 114 and the tension web 115 intersects the center line of the lower chord 111 or the upper chord 112 at a point, which can eliminate the influence of the additional bending moment caused by the eccentricity of the node. For each node structure, the integral gusset plate 116 is welded to the side plate of the lower chord 111 or the upper chord 112, so that the integral gusset plate 116 and the side plates of the lower chord 111 and the upper chord 112 are in the same vertical plane. The gusset plate 116 extends two obliquely convex side plates 1161, and the two obliquely convex side plates 1161 are connected with the side plates of the compression web 114 and the tension web 115, so that the integral gusset plate 116 and the lower chord 111 are integrally formed. Or the side plates of the upper chord 112 and the side plates of the compression web 114 and the tension web 115 are in the same vertical plane, and the force of the compression web 114 and the tension web 115 is no longer determined by the lower chord 111 and the tension web. The top plate of the upper chord 112 bears, but is directly transmitted to the side plates of the lower chord 111 and the upper chord 112, so the bearing capacity of the node is improved. The compression web rod 114 and the tension web rod 115 use different cross-sections, which fully utilizes the advantages of closed cross-section and open cross-section, makes connection more convenient, and is conducive to improving the fatigue resistance of joints.

Compared with the prior art, the negative bending moment area structure of the steel truss-UHPC composite girder bridge in the embodiment of the present invention combines the steel truss girder 1 with the UHPC bridge deck 2 to give full play to the material properties of steel and UHPC, effectively solving the problem of ordinary steel. The bridge deck in the negative bending moment area of the truss composite beam is prone to cracking under tension; only filling the lower chord 111 with UHPC can effectively prevent the lower chord 111 from becoming unstable under compression, and improve the bearing capacity of the lower chord 111 without affecting the structure. beautiful. At the same time, the integral gusset plate can increase the stiffness of the joint, and the fatigue resistance of the joint is significantly improved.

As a preferred embodiment, as shown in FIG. 5 , the UHPC bridge deck 2 includes a plurality of UHPC bridge deck blocks 21 connected in sequence, and two adjacent UHPC bridge deck blocks 21 are connected by a wet joint 22 , and the wet The joint 22 is provided with a lap steel bar 23 .

Specifically, as shown in FIG. 5 and FIG. 6 , the UHPC bridge deck block 21 is laid with longitudinal steel bars 211 and transverse steel bars 212, and a higher reinforcement ratio can be used. The reinforcement ratio and reinforcement will not affect the pouring quality of UHPC, simplifying the construction process. The overlapping steel bars 23 overlap the longitudinal steel bars 211 provided on the two UHPC bridge deck blocks 21 .

As a preferred embodiment, as shown in FIG. 1 and FIG. 5 , the upper surface of the upper chord 112 of the main truss 11 is casted with shear grooves 1121 at intervals, and shear nails 1122 are arranged in the shear groove 1121. The shear groove 1121 is elliptical . An elliptical shear groove is used to reduce the stress concentration at the corners of the groove. UHPC bridge decks can be prefabricated full width. Due to the small thickness of the UHPC board, there are no complex structures such as annular steel bars at the wet joint 22, and only the lapped steel bar 23 can be provided after chiseling, and the chiseling depth is not less than 5mm. welding.

As a preferred embodiment, epoxy mortar is also poured on the upper surface of the upper chord 112 of the main truss 11 to adjust the gap to facilitate the installation of the UHPC bridge deck.

As a preferred embodiment, as shown in FIG. 1 , FIG. 7 and FIG. 8 , the two main trusses 11 are connected to form a whole through a parallel connection assembly 12 , and the parallel connection assembly 12 includes a plurality of upper flat connecting rods 121 and a plurality of lower flat connecting rods 121 . The connecting rod 122 and a plurality of diagonal struts 123, the two ends of each upper flat connecting rod 121 are respectively connected to the upper chords 112 of the two main trusses 11, and the two ends of each lower flat connecting rod 122 are respectively connected to the lower chords of the two main trusses 11. 111 , two ends of each diagonal strut 123 are respectively connected to the upper chord 112 of one main truss 11 and the lower chord 111 of the other main truss 11 .

Referring to FIG. 9 , an embodiment of the present invention provides a construction method for a structure in the negative bending moment area of a steel truss-UHPC composite girder bridge, comprising the following steps:

Step S1, the two main trusses 11 of the steel truss girder 1 and the UHPC bridge deck 2 are prefabricated. Specifically, the two main trusses 11 of the steel truss 1 and the UHPC bridge deck 2 are prefabricated in the factory, and the longitudinal ends of the prefabricated UHPC bridge deck 2 are chiseled, and the chiseling depth is not less than 5mm.

In step S2 , UHPC is filled in the lower chords 111 of the two main trusses 11 . The lower chord 111 is a box-shaped section, and UHPC is filled in the box. The length of the UHPC filling can extend beyond the node area. Shear nails 1122 are welded on the upper surface of the upper chord 112 of the main truss 11 .

Step S3 , connecting and erecting two main trusses 11 to form a steel truss beam 1 . Specifically, the steel truss 1 is formed by connecting the two main trusses 11 through the parallel connection assembly 12 .

Step S4 , the UHPC bridge deck 2 is mounted and connected on the upper surfaces of the two main trusses 11 . Specifically, epoxy mortar is evenly arranged on the upper surface of the upper chord 112 of the main truss 11 to fill the gap, the UHPC bridge deck 2 is erected on the steel truss 1, the shear groove 1121 is poured, and the steel bar 23 is lapped at the wet joint 22. , pouring and curing, so that the UHPC bridge deck 2 and the steel truss girder 1 form a steel truss-UHPC composite girder bridge.

In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "upper", "lower", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, It is not intended to indicate or imply that the device or element referred to must have a particular orientation, be constructed and operate in a particular orientation, and therefore should not be construed as limiting the invention. Unless otherwise expressly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection, It can also be an electrical connection; it can be a direct connection, an indirect connection through an intermediate medium, or an internal connection between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

It should be noted that, in the present invention, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and are not necessarily required or implied Any such actual relationship or sequence exists between these entities or operations. Moreover, the terms "comprising", "comprising" or any other variation thereof are intended to encompass a non-exclusive inclusion such that a process, method, article or device that includes a list of elements includes not only those elements, but also includes not explicitly listed or other elements inherent to such a process, method, article or apparatus. Without further limitation, an element qualified by the phrase "comprising a..." does not preclude the presence of additional identical elements in a process, method, article or apparatus that includes the element.

The above descriptions are only specific embodiments of the present invention, so that those skilled in the art can understand or implement the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (9)

1. The utility model provides a steel purlin-UHPC composite beam bridge hogging moment district structure which characterized in that includes:

the steel truss girder (1) comprises two main trusses (11) which are arranged at intervals in the transverse direction and connected, each main truss (11) comprises a lower chord (111) and an upper chord (112), and UHPC is filled in the lower chord (111); a vertical web member (113) is arranged between the upper chord member (112) and the lower chord member (111) at the pivot of each main truss (11), compression web members (114) and tension web members (115) are sequentially symmetrically and alternately arranged on two sides of the vertical web member (113), integral node plates (116) are respectively connected to the nodes connected with the compression web members (114) and the tension web members (115) of the lower chord member (111) and the upper chord member (112), two inclined convex side plates (1161) extend from each integral node plate (116), and the two inclined convex side plates (1161) are respectively connected with one compression web member (114) and one tension web member (115);

a UHPC bridge deck (2) connected to the upper surfaces of the two upper chords (112).

2. The hogging moment zone structure of steel truss-UHPC composite beam bridge of claim 1, characterized in that:

the compression web members (114) are box-shaped in cross section, and the tension web members (115) are I-shaped in cross section.

3. The hogging moment zone structure of steel truss-UHPC composite beam bridge of claim 1, characterized in that:

the center lines of the compression web members (114) and the tension web members (115) are intersected with the center line of the lower chord member (111) or the upper chord member (112) at one point.

4. The hogging moment zone structure of steel truss-UHPC composite beam bridge of claim 1, characterized in that:

the UHPC bridge deck slab (2) comprises a plurality of UHPC bridge deck slab blocks (21) which are sequentially connected, two adjacent UHPC bridge deck slab blocks (21) are connected through a wet joint (22), and lap-joint steel bars are arranged at the position of the wet joint (22).

5. The hogging moment zone structure of steel truss-UHPC composite beam bridge of claim 1, characterized in that:

shear grooves (1121) are poured on the upper surface of the main truss (11) at intervals, and shear nails (1122) are arranged in the shear grooves (1121).

6. The hogging moment zone structure of steel truss-UHPC composite beam bridge of claim 5, characterized in that: the shear groove (1121) is oval.

7. The hogging moment zone structure of steel truss-UHPC composite beam bridge of claim 1, characterized in that: epoxy mortar is poured on the upper surface of the main truss (11).

8. The hogging moment zone structure of steel truss-UHPC composite beam bridge of claim 1, characterized in that:

the two main trusses (11) are connected through a flat connection assembly (12) to form a whole, the flat connection assembly (12) comprises a plurality of upper flat connecting rods (121), a plurality of lower flat connecting rods (122) and a plurality of inclined supporting rods (123), two ends of each upper flat connecting rod (121) are respectively connected with the upper chords (112) of the two main trusses (11), two ends of each lower flat connecting rod (122) are respectively connected with the lower chords (111) of the two main trusses (11), and two ends of each inclined supporting rod (123) are respectively connected with the upper chord (112) of one main truss (11) and the lower chord (111) of the other main truss (11).

9. A construction method for the hogging moment zone structure of the steel truss-UHPC composite girder bridge according to claim 1, comprising the steps of:

two main trusses (11) of the prefabricated steel truss girder (1) and a UHPC bridge deck (2);

filling UHPC inside the lower chords (111) of the two main trusses (11);

two main trusses (11) are connected and erected to form a steel truss girder (1);

and UHPC bridge decks (2) are installed and connected on the upper surfaces of the two main trusses (11).

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