SEGMENTAL PRECAST COMPOSITE-MATERIAL COMPOSITE-SLAB COMPOSITE BEAM AND CONSTRUCTION METHOD THEREOF

Abstract

A segmental precast composite-material composite-slab composite beam and a construction method thereof are provided, relating to the technical field of bridge design and construction. The segmental precast composite-material composite-slab composite beam mainly includes a segmental precast orthotropic composite top slab, a web, a bottom slab, and a wet joint between segments. The orthotropic composite top slab is composed of an orthotropic slab and an ultra-high-performance concrete layer (UHPC), and the interface connection of the orthotropic slab and the UHPC structural layer is achieved by a shear key. The UHPC structural layer is superposed with the orthotropic slab in segments in a precast plant to form a composite-slab composite beam segment to be entirely transported, hoisted and assembled, and the connection of the UHPC structural layers between the segments is achieved by casting a transverse wet joint in place.

Claims

1. A segmental precast composite-material composite-slab composite beam structure, comprising a segmental precast orthotropic composite top slab, a web, a bottom slab, and a wet joint between segments, wherein an orthotropic composite-material composite top slab is composed of an orthotropic slab and an ultra-high-performance concrete layer (UHPC), and forms a segmental precast composite-material composite-slab composite beam structure with the web and the bottom slab; the composite beam structure sequentially comprises the bottom slab, the web, the orthotropic top slab, a shear key, a reinforced UHPC structural layer from bottom to top; the bottom slab, the web, the orthotropic top slab and subsidiary members thereof are manufactured in elements in a plant and pre-assembled into a main beam segment, then the shear key is installed on and a reinforcing mesh is laid on the orthotropic top slab, and a UHPC layer is cast and cured to form a precast composite-material composite-slab composite beam segment, which is then transported, hoisted and assembled as a whole, and the connection of the UHPC structural layers between the segments is completed by casting a transverse wet joints in place.

2. The segmental precast composite-material composite-slab composite beam structure according to claim 1, wherein a single segment in the main beam segment has a length of 14 m to 20 m, and the composite top slab is a composite structure formed by superposing the orthotropic top slab and the UHPC structural layer.

3. The segmental precast composite-material composite-slab composite beam structure according to claim 2, wherein the orthotropic slab is made of high-strength steel or fiber reinforced polymer (FRP), and the UHPC layer employs a UHPC structure reinforced by high-strength steel bars or the FRP.

4. The segmental precast composite-material composite-slab composite beam structure according to claim 2, wherein the strength grade of the high-strength steel used in the orthotropic slab is not less than 345 MPa, the strength grade of the fiber reinforced polymer (FRP) is not less than 500 MPa, and the strength grade of the UHPC is not less than 120 MPa.

5. The segmental precast composite-material composite-slab composite beam structure according to claim 2, wherein the orthotropic slab is formed by a deck slab, longitudinal stiffeners and diaphragms, and the longitudinal stiffener is closed U-shaped, inverted T-shaped, or inverted L-shape.

6. The segmental precast composite-material composite-slab composite beam structure according to claim 2, wherein the UHPC structural layer has a thickness of 40 mm to 100 mm, comprising in-plant segmental precast parts and an inter-segment post-cast wet joint part in site.

7. The segmental precast composite-material composite-slab composite beam structure according to claim 2, wherein the UHPC structural layer and the orthotropic slab are connected by a shear key group arranged in an array, and the shear key is made of a material homogenous to the orthotropic slab.

8. The segmental precast composite-material composite-slab composite beam structure according to claim 7, wherein the shear key is constructed with ribbed slabs which are longitudinally arranged along a main beam and has steel bars embedded in notches, and is pre-installed on an element of the orthotropic slab; the shear key is also configured to provide a reinforcement positioning function, and the reinforcement of the UHPC structural layer is precast according to a mesh and positioned and installed at one time; and the thickness of a protective layer, embedded in the UHPC structural layer, of the shear key is not less than 10 mm.

9. The segmental precast composite-material composite-slab composite beam structure according to claim 6, wherein a transverse wet joint of the UHPC structure layers between the segments is arranged at a middle region of adjacent diaphragms of the orthotropic slab, and an area ratio of a single inter-segment wet joint to the UHPC structural layer in a single element is not more than 10%, and the casting is conducted after the adjacent segments are assembled.

10. The segmental precast composite-material composite-slab composite beam structure according to claim 7, wherein the ribbed slabs of the shear key are continuous at a transverse wet joint interface of the UHPC structural layers between the segments.

11. A construction method of the segmental precast composite-material composite-slab composite beam structure according to claim 1, wherein the premanufacturing is as follows: a web, a bottom slab, and an orthotropic slab of a top slab, comprising a shear key on the top thereof, of a main beam, are manufactured in a precast site according to the elements and are transported to an assembly site to be assembled into a segment, and then a UHPC structural layer is casted on the orthotropic slab and then is cured to form a segmental precast composite-material composite-slab composite beam segment; site installation is as follows: the segment is transported to a bridge site to be hoisted and assembled, and after the connection of the members such as the web, the bottom slab and the orthotropic slab of the top slab of the main beam is completed, a transverse wet joint between segments is cast in place; construction steps are as follows: manufacturing of a main beam element, assembling of a beam segment, installation of a reinforcement mesh and an end formwork, in-plant pouring and curing of a UHPC layer, transportation and hoisting of a composite-slab composite beam segment, assembling of a beam, cast-in-place and curing of a transverse wet joint between the segments.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] To describe the technical solutions in the embodiments of the present disclosure or in the prior art more clearly, the following briefly introduces the accompanying drawings required for describing the embodiments. Apparently, the accompanying drawings in the following description show merely some embodiments of the present disclosure, and those of ordinary skill in the art may still derive other drawings from these accompanying drawings without creative efforts.

[0028] FIG. 1 shows a schematic diagram of a first steel-UHPC composite-slab composite beam in accordance with an embodiment of the present disclosure;

[0029] FIG. 2 shows a wet joint structure in accordance with an embodiment of the present disclosure;

[0030] FIG. 3 shows a positional relationship between a PBL key and steel bars in accordance with an embodiment of the present disclosure;

[0031] FIG. 4 shows a shear-resistant steel plate groove type 1 in accordance with an embodiment of the present disclosure;

[0032] FIG. 5 shows a shear-resistant steel plate groove type 2 in accordance with an embodiment of the present disclosure; and

[0033] FIG. 6 shows a shear-resistant steel plate groove type 3 in accordance with an embodiment of the present disclosure.

[0034] In the drawings: 11orthotropic bridge deck slab; 21longitudinal stiffener; 31UHPC layer; 40PBL shear-resistant steel plate; 41groove type opening; 50reinforcing mesh; 51first transverse steel bar; 51longitudinal steel bar; 53second transverse steel bar; 61wet joint.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0035] The following clearly and completely describes the technical solutions in the embodiments of the present disclosure with reference to the accompanying drawings in the embodiments of the present disclosure. Apparently, the described embodiments are merely a part rather than all of the embodiments of the present disclosure. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present disclosure without creative efforts shall fall within the protection scope of the present disclosure.

[0036] It is provided a segmental precast composite-material composite-slab composite beam structure according to an embodiment of the present disclosure, which not only can improve the local mechanical property of the orthotropic slab, but also can guarantee the overall mechanical property of the orthotropic slab without significantly increasing the weight of the composite bridge deck structure, and thus the spanning ability of the composite bridge deck structure is improved.

[0037] As shown in FIG. 1, a segmental precast composite-material composite-slab composite beam structure is provided by an embodiment of the present disclosure, including: an orthotropic bridge deck slab 11; [0038] a UHPC structural layer 31 laid on the orthotropic bridge deck slab 11; and [0039] a PBL shear-resistant steel plate 40 embedded in the ultra-high-performance concrete layer 31, which includes: [0040] multiple PBL shear-resistant steel plates distributed at intervals along a transverse direction of bridge, where the bottoms of the PBL shear-resistant steel plates 40 are welded to the orthotropic bridge deck slab 11, and the tops of the PBL shear-resistant steel plates 40 are provided with multiple groove type openings 41 distributed at intervals in a bridge direction; [0041] multiple layers of reinforcing mesh 50, including multiple first transverse steel bars 51, multiple longitudinal steel bars 52, and second transverse steel bars 53, where the first transverse steel bars 51 and the longitudinal steel bars 52 are arranged in a crisscross staggered manner, the first transverse steel bars 51 are placed in the groove type openings 41, and the second transverse steel bars are placed on the PBL shear-resistant steel plates.

[0042] It is provided a segmental precast composite-material composite-slab composite beam according to an embodiment of the present disclosure. The segmental precast composite-material composite-slab composite beam includes an orthotropic bridge deck slab 11, a UHPC layer 31, and a PBL shear key embedded in the UHPC layer 31. The UHPC layer 31 is laid on the orthotropic bridge deck slab 11 and is connected to the orthotropic bridge deck slab 11 through the PBL shear-resistant steel plate 40. A reinforcing mesh 50 includes first transverse steel bars 51 and longitudinal steel bars 52 which are arranged in a crisscross manner, and the first transverse steel bars 51 penetrate into groove type openings 41 in the PBL shear-resistant steel plates 40 to form a PBL shear key structure, which not only can effectively and reliably connect the orthotropic bridge deck slab 11 to the UHPC layer 31, but also can bear the shear force generated by the overall stress of the composite bridge deck structure, thus improving the overall stiffness and the overall stress performance of the composite bridge deck structure. Moreover, by using the UHPC as a pavement part on the orthotropic bridge deck slab 11, multiple layers of reinforcing mesh 50 can be arranged, which not only can make the thickness of the UHPC layer thinner, but also can guarantee that the stress performance of the composite bridge deck structure satisfies the requirements, so the composite bridge deck structure is lighter in self weight, and is more suitable for application in the bridge with a larger span.

[0043] In this embodiment, the PBL shear-resistant steel plates 40 are arranged at intervals in a bridge direction and provided with groove type openings 41, thus solving the problem of difficult perforation when laying the reinforcing mesh 51. The circular hole dislocation problem caused by welding and fixing deformation of long steel plates can be avoided by arranging the multiple steel plates 40 at intervals in the bridge direction, and thus the construction is more convenient.

[0044] Specifically, the groove type opening includes a circular through hole and an opening above. In accordance with this embodiment, the groove type opening 41 is convenient for the first transverse steel bars 51 to penetrate into the multiple shear-resistant steel plates 40 arranged along a transverse direction of bridge, and rapid construction can be achieved to make the PBL shear-resistant steel plates 40 and the first transverse steel bars 51 form a PBL shear key, which makes the overall force transmission performance more reliable.

[0045] In this embodiment, the distance between the PBL shear-resistant steel plates 40 in the transverse direction of bridge is 550 mm to 650 mm, and the net distance between the PBL shear-resistant steel plates in the bridge direction is 100 mm to 200 mm. Meanwhile, the shear-resistant steel plate 40 has a thickness of 8 mm to 12 mm, a height of 30 mm to 60 mm, and a length of 400 mm to 600 mm.

[0046] In this embodiment, a rectangular tongue-and-groove joint or a dovetail joint form is employed; the arrangement distance between the joints is 600 mm, which corresponds to the arrangement distance of the longitudinal stiffeners and the shear key shear-resistant steel plates.

[0047] More specifically, the ultra-high-performance concrete layer 2 has a thickness of 40 mm to 100 mm. With this thickness, the composite bridge deck structure may conform to the design requirements, and the quality of the UHPC layer in the composite bridge deck structure can satisfy the stress performance requirements of the structure.

[0048] In this embodiment, the first transverse steel bars 51, the second transverse steel bars 53 and the longitudinal steel bars 52 are arranged in a crisscross staggered manner, with simple structure and high laying efficiency. If ordinary steel fiber reinforced concrete is adopted, due to its low strength, the reinforcement content has to be increased to increase the crack resistance.

[0049] Further, the orthotropic bridge deck slab 11 includes a top slab and multiple longitudinal stiffeners 21. The multiple longitudinal stiffeners 21 are arranged on the lower surface of the top slab at intervals in a transverse direction of bridge. In this embodiment, the orthotropic bridge deck slab 11 further includes transverse stiffeners. The structure and arrangement of the transverse stiffeners may employ any in the conventional art and will not be described in detail here.

[0050] Preferably, the longitudinal stiffener 21 is a U-shaped rib, an I-shaped rib, or an inverted T-shaped rib. In this embodiment, the UHPC layer 31 and the PBL shear-resistant steel plate structure on the orthotropic bridge deck slab 11 have good mechanical properties in both overall strength and local strength, so many different types of longitudinal stiffeners can be used, and the longitudinal stiffeners are preferably U-shaped ribs, I-shaped ribs or inverted T-shaped ribs. As shown in FIG. 1, in this embodiment, the longitudinal stiffener 21 is a U-shaped rib, and other types will not be described in detail again.

[0051] It is provided a construction method of a composite-material composite-slab composite beam as above according to an embodiment of the present disclosure. The construction method includes the following steps.

[0052] In this embodiment, the method is easy to implement. The overall and local mechanical properties of the composite bridge deck structure manufactured by using this construction method can be improved without increasing the weight of the composite bridge deck structure.

[0053] The steel main beam segment and the steel-UHPC composite bridge deck slab are manufactured in the factory. After the assembling of the steel main beam segments is completed on a general assembly jig, the UHPC is cast on the steel bridge deck slab and then is thermally cured to form a steel-UHPC composite bridge deck slab composite beam segment. The segment is transported to a bridge site by a barge, and then is hoisted, welded and assembled, and then a transverse wet joint between the segments is cast in place. Construction steps are as follows: the PBL key and the steel main beam deck slab are welded together, the installation of three layers of dense reinforcing mesh is completed in sequence in the assembly site, the end formworks are installed and cast, and then the UHPC layer is casted; and after the UHPC layer is cured by high-temperature steam to reach the design strength, the segment is transported to a bridge site to be welded and assembled into the steel-UHPC composite beam, and then a transverse wet join between the segments is cast in place to achieve the longitudinal connection of the steep-UHPC composite-slab composite beams.