Patent Application
20240344280
The present disclosure relates to the technical field of bridge design and construction, and in particular to a segmental precast composite-material composite-slab composite beam and a construction method thereof.
With the increase of span, the mechanical property and economic performance of the bridge structure are more and more sensitive to the influence of the section of main girders. Especially for a large-span cable-stayed bridge, the excessive self-weight of the main girder structure may cause a sharp increase of the dead load axial force of the main girder, the cable tower and the decrease of the static buckling stability of the structure, and other problems.
Orthotropic steel bridge deck or FRP (fiber reinforced polymer) bridge deck is light in structure and high in bearing capacity. However, due to its low local stiffness is low, coupled with temperature, heavy load, overload and other factors, the orthotropic steel bridge deck or FRP bridge deck is prone to pavement damage, fatigue cracking of bridge deck structure, and other diseases.
Due to the advantages of large bridge deck stiffness and excellent economic performance, the composite beam is widely used in the bridge engineering in China and at abroad. However, the concrete deck slab structure of conventional composite beams has is prone to cracking and water seepage due to large self-weight, which may lead to the problem of insufficient durability of the beam structure. As the existing composite bridge deck system constructed by superposing ordinary concrete and steel slabs or FRP slabs cannot effectively reduce the self-weight of the structure and the wet joints are poor low in crack resistance, the quality requirements of rapid precast and assembling cannot be satisfied.
It is provided a steel-UHPC (ultra-high-performance concrete) composite-slab composite beam structure for an ultra-large-span bridge and a construction method thereof according to an embodiment of the present disclosure. The problem that the guarantee of the overall stiffness of the composite bridge deck and the low weight increase cannot be achieved at the same time in the related technology is solved.
In a first aspect, a steel-UHPC composite-slab composite beam is provided, including:
multiple PBL (Perfobond rib) shear keys distributed at intervals in a transverse direction of bridge, where each PBL shear key includes multiple steel plates distributed at intervals in a bridge direction, the bottoms of the steel plates are welded to the orthotropic slab, and the tops of the steel plates are provided with multiple groove type openings distributed at intervals in the bridge direction;
The UHPC structural layer has a thickness of 40 mm to 100 mm, including in-plant segmental precast parts and an inter-segment post-cast wet joint part in site. An area ratio of a single inter-segment wet joint to the UHPC structural layer of the single segment is not more than 10%.
In some embodiments, the orthotropic slab is made of high-strength steel or a composite material, where the strength grade of the high-strength steel is not less than 345 MPa, and the strength grade of the fiber reinforced polymer (FRP) is not less than 500 MPa.
In some embodiments, the groove type opening may be one of a circular hole, an elliptical hole, or a trapezoidal hole, and an opening above the through hole. The opening communicates with the through hole, and the diameter of the upper opening is smaller than the size of the bottom opening.
In some embodiments, all shear studs are divided into multiple shear stud groups distributed at intervals in the transverse direction of bridge, and each shear stud group includes multiple shear studs distributed at intervals in the bridge direction. The shear studs are welded to the upper surface of the bridge deck slab.
In some embodiments, the ultra-high-performance concrete layer include steel fibers. The length of the steel fiber is not more than 12 mm, and the strength grade of the UHPC is not less than 120 MPa.
In some embodiments, the orthotropic slab includes a bridge deck slab and multiple longitudinal stiffeners. The longitudinal stiffeners are distributed on the lower surface of the bridge deck slab at intervals in the transverse direction of bridge.
In some embodiments, the longitudinal stiffeners may be U-shaped ribs, I-shaped ribs, or inverted-T-shaped ribs.
In some embodiments, at least one PBL shear key is provided between two adjacent longitudinal stiffeners.
In some embodiments, the transverse wet joint employs a rectangular tongue-and-groove structure or a dovetail joint structure.
In a second aspect, a construction method of the steel-UHPC composite-slab composite beam as above is provided. The construction includes:
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.
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 top slab (i.e., orthotropic slab) of the main beam is completed, a transverse wet joint between the 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.
The technical solution provided by the present disclosure has the beneficial effects that the local mechanical property of the orthotropic slab can be improved, and the overall mechanical property of the orthotropic slab can be guaranteed without significantly increasing the weight of the composite bridge deck structure, and thus the spanning ability of the composite bridge deck structure is improved.
It is provided a segmental precast composite-material composite-slab composite beam and a construction method thereof according to an embodiment of the present disclosure. A connecting assembly is arranged on the orthotropic slab. The connecting assembly includes multiple PBL keys, multiple shear studs and multiple layers of reinforcing mesh. Multiple steel plates are arranged on the orthotropic slab, first transverse steel bars are arranged in the groove type openings on the steel plates so as to connect the multiple steel plates distributed at intervals in a transverse direction of bridge. A PBL shear key structure formed by the steel plates and the first transverse steel bars not only effectively and reliably connects the orthotropic slab to the ultra-high performance concrete layer, but also can bear the shear force generated by the overall stress of the composite bridge deck structure, thus the overall stiffness and the overall stress performance of the composite bridge deck structure are improved. Meanwhile, the multiple shear studs on the orthotropic slab can enhance the local stiffness of the composite bridge deck structure, and then the thinner ultra-high-performance concrete layer can ensure 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.
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.
In the drawings: 11—orthotropic bridge deck slab; 21—longitudinal stiffener; 31—UHPC layer; 40—PBL shear-resistant steel plate; 41—groove type opening; 50—reinforcing mesh; 51—first transverse steel bar; 51—longitudinal steel bar; 53—second transverse steel bar; 61—wet joint.
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.
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.
As shown in
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.
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.
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.
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.
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.
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.
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.
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.
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
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.
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.
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.
