Patent Application
20250129557
The present invention relates to the technical field of construction methods for prefabricated segmental bridge construction, specifically to a construction method for splicing prefabricated segmental bridges.
The prefabricated segmental bridge assembly method can be categorized into dry joint, wet joint, and adhesive bonding methods. The primary distinction among these assembly techniques lies in the method of joining the faces of the bridge segments. The dry joint method involves no treatment of the joint surfaces, directly adjoining two bridge segments. The wet joint method involves setting a wet joint between two bridge segments and connecting them by casting the wet joint. The adhesive bonding method involves applying epoxy resin glue to the joint surfaces to adhere the two bridge segments. Due to the severe deficiencies in overall structural and seismic performance of bridges constructed using the dry joint method, the AASHTO “Guide Specifications for Design and Construction of Segmental Concrete Bridges” was temporarily amended in 2003 to discontinue the use of dry joints in new prefabricated segmental bridge constructions.
In the 1990s, bridge splicing technology in China was primarily dominated by wet assembly techniques. With recent developments in bridge technology design finite element methods, the emergence of new domestic bridge segment adhesive materials, the prefabrication of high-performance concrete components, as well as advancements in precise experimental testing and high-accuracy measurement and control technologies, the adhesive bonding method for constructing bridges warrants further widespread adoption.
The most notable feature of the adhesive bonding construction method is the use of epoxy resin adhesive instead of concrete for joint treatment, requiring the application of temporary prestress before the epoxy resin adhesive sets. When removing temporary prestress, the principle is to ensure that no tensile stress occurs at the joint throughout the construction phase.
Applying temporary prestress to make the segmental beam adhesive joint withstand a compressive stress of 0.3 Mpa is one of the essential construction steps in the current segmental beam adhesive bonding method.
The basic construction steps of the adhesive bonding method are: {circle around (1)} lifting the segmental beam→{circle around (2)} moving the lifted segmental beam to adjoin the already erected segmental beam→{circle around (3)} applying epoxy resin glue to the joint surface of the segmental beam→{circle around (4)} applying temporary prestress→{circle around (5)} applying permanent prestress to the cantilever assembly of the segmental beam→{circle around (6)} releasing the lifting equipment→{circle around (7)} cycling to the next segmental beam assembly step.
However, the existing adhesive bonding method has several drawbacks:
First, the time gap between construction steps {circle around (4)} and {circle around (5)} significantly affects the progress of subsequent steps. If work in step {circle around (4)} comes to a halt, the lifting equipment continues to hold the beam due to unapplied permanent prestress, preventing progression to the next work phase and increasing equipment investment.
Second, traditional temporary prestress facilities require the use of temporary tensioning bases and rolled threaded steel as temporary prestress devices, necessitating the embedding of fasteners or drilling holes in the beam surface. When removing temporary prestress, it is also necessary to dismantle the temporary tensioning base and rolled threaded steel, resulting in holes in the permanent beam surface structure. Poor sealing of these holes can lead to leakage, which becomes a major defect of prefabricated segmental beams. Although concrete tensioning bases can be used internally to avoid hole formation, this would increase the structure's self-weight.
Third, the entire construction process is complicated due to the lengthy duration of permanent prestress construction, prolonged equipment release time, resulting in cumbersome operations, an abundance of construction materials, extended construction periods, and low construction efficiency.
Therefore, it is necessary to improve the existing technology.
The objective of this invention is to address the deficiencies and shortcomings of the existing technology by providing a construction method for splicing prefabricated segmental bridges that is simple and efficient, ensuring controllable quality of the segment beam adhesive joints, reducing construction periods, minimizing the materials required; allowing for earlier release of the lifting equipment to enhance construction efficiency; and using steel strands instead of rolled threaded steel, which do not need to be removed during the construction process but are instead embedded within the segment beams as a permanent prestress reserve, thereby avoiding hole formation, preventing leakage, and enhancing the overall safety and reliability of the structure.
To achieve the aforementioned objectives, the following technical solution is employed:
A construction method for splicing prefabricated segmental bridges, comprising several prefabricated segments, which are composed of pier-top segments and non-pier-top segments distinct from the pier-top segments. The construction method includes the following steps:
S1, Manufacturing each prefabricated segment with steel strands embedded along their length direction, with the steel strands in any two adjacent prefabricated segments set in a staggered arrangement. Each non-pier-top segment also has reserved holes for the steel strands from the previously erected prefabricated segment to pass through, with the reserved holes penetrating both ends of the corresponding non-pier-top segment;
S2, Erecting the pier-top segment, installing it on the pier;
S3, Using a beam launcher to lift the corresponding non-pier-top segment to the predetermined assembly position, and applying epoxy resin glue to the corresponding adhesive joint surface;
S4, Threading the embedded steel strands from the previously erected prefabricated segment through the reserved holes in the non-pier-top segment about to be erected;
S5, Using the beam launcher to complete the adhesion of the adhesive joint surface;
S6, Applying temporary tension to the steel strands that have passed through the reserved holes using tensioning equipment before the adhesive joint surface epoxy resin glue sets, to achieve the design allowed compressive stress, completing the temporary tensioning procedure;
S7, Releasing the beam launcher and moving it to the next construction point;
S8, Applying permanent prestress;
S9, Injecting high-strength mortar into the corresponding reserved holes, permanently embedding the steel strands within the corresponding prefabricated segments;
S10, Repeating steps S3-S9 until all prefabricated segments are assembled.
Further, in step S1, steel strands are embedded within both the top and bottom plates of each prefabricated segment.
Further, in step S1, corrugated pipes are installed within the reserved holes.
Further, in step S2, after installing the pier-top segment on the pier, it is temporarily or permanently fixed.
Further, the beam launcher is either a bridge girder erection machine or a bridge building machine.
Further, the temporary prestress applied in step S6 is designed and implemented according to the permanent prestress applied in step S8, serving as the permanent prestress reserve for the prefabricated segmental bridge.
Compared to the existing technology that uses temporary tensioning bases and rolled threaded steel as temporary prestress devices to provide compressive stress on the segmental beam adhesive joint surface, in existing technology, after temporary tensioning is performed, it is necessary to dismantle the temporary tensioning bases and rolled threaded steel. However, the present invention applies embedded steel strands and tensioning of these strands to supply compressive force on the adhesive joint surface of the segmental beams, achieving the following technical effects:
First, it eliminates the need to dismantle corresponding equipment/materials after completion of the operation. Instead, the steel strands are directly integrated into the bridge's structural stress system, reducing on-site construction steps and materials, thus enhancing construction efficiency.
Second, the prestressing effect of steel strands surpasses that of rolled threaded steel and can serve as a safety reserve for permanent prestress, thereby increasing the structural safety reserve of the bridge.
Third, the construction process allows for earlier release of the beam launcher, improving construction efficiency.
Fourth, there is no need to create holes in the top plate beam top of the prefabricated segment, avoiding the issue of water leakage due to difficulties in sealing holes. This effectively simplifies the construction process, improves construction efficiency, and also benefits construction quality.
In summary, the construction method for splicing prefabricated segmental bridges provided by this invention is simple, efficient, and widely adaptable. It not only ensures controllable quality of the segmental beam adhesive joint surface but also facilitates shortening the construction period and enhancing construction efficiency.
In
The invention is further described below in connection with the accompanying drawings.
A construction method for splicing prefabricated segmental bridges, as shown in
S1, Manufacturing each prefabricated segment with steel strands 4 embedded along their length direction. Specifically, the embedded length of the steel strands 4 should ensure they can pass through another prefabricated segment adjacent to their corresponding segment, meeting the tensioning length requirements of the steel strands 4 without conflicting with the permanent prestress. In this embodiment, steel strands 4 are embedded within the top and bottom plates of each prefabricated segment, with steel strands 4 in any two adjacent prefabricated segments set in a staggered arrangement, meaning that the steel strands 4 within any two adjacent prefabricated segments do not overlap in both the horizontal and vertical planes, and it is ensured that the steel strands 4 are spaced apart at a distance allowed by standards. Reserved holes 5 for the steel strands 4 from the previously erected prefabricated segment are also provided within each non-pier-top segment 3, with these reserved holes 5 traversing the ends of the corresponding non-pier-top segment 3. In this embodiment, to facilitate the formation of the reserved holes 5, the corrugated pipes 6 are also installed within the reserved holes 5 to facilitate the passage of steel strands 4.
S2, Erecting the pier-top segment 2, as shown in
S3, Using beam launching machinery, such as a girder launcher or bridge building machine, to lift the corresponding non-pier-top segment 3 to the predetermined assembly position and applying epoxy resin glue on the corresponding adhesive joint surface.
S4, Threading the embedded steel strands 4 from the previously erected prefabricated segment through the corresponding reserved holes 5 in the non-pier-top segment 3 about to be erected.
S5, Completing the adhesion of the adhesive joint surface using the beam launching machinery.
S6, Tensioning the steel strands 4 that have passed through the reserved holes 5 using tensioning equipment before the adhesive joint surface epoxy resin glue sets, achieving the design-allowed compressive stress (not less than the design-allowed compressive stress of 0.3 Mpa in this embodiment, though other embodiments may vary according to their specific design stress requirements), thus completing the temporary tensioning process, i.e., applying temporary prestress.
S7, Releasing the beam launching machinery and moving it to the next construction point.
S8, Applying permanent prestress.
S9, Injecting high-strength mortar into the corresponding reserved holes 5, permanently embedding the steel strands 4 within the corresponding prefabricated segments.
S10, Repeating steps S3-S9 until all prefabricated segments are assembled.
In this embodiment, the temporary prestress tensioned in step S6 is designed and implemented according to the permanent prestress applied in step S8, serving as the permanent prestress reserve for the prefabricated segmental bridge, thereby further improving the construction quality of the bridge.
For ease of understanding and implementation by those skilled in the art, as shown in
The number of prefabricated segments includes 1 pier-top segment 2 and M non-pier-top segments 3. The n non-pier-top segments 3 on the left side of the pier-top segment 2 are sequentially labeled as non-pier-top segments U1, U2, . . . . Un; the N non-pier-top segments 3 on the right side of the pier-top segment 2 are labeled as non-pier-top segments D1, D2, . . . . DN, where n+N=M, and n, N, and M are positive integers. It's noted that in step S3, two non-pier-top segments 3 are simultaneously lifted to the predetermined assembly position. If M is an odd number, the final non-pier-top segment 3 assembly requires lifting only one non-pier-top segment 3 in step S3.
As shown in
As shown in
Following the adhesive construction of non-pier-top segments Un and DN, the process mirrors that described above and thus is not reiterated here.
It is to be noted that this invention's construction method for splicing prefabricated segmental bridges is versatile, applicable not only to the aforementioned cantilever assembly construction but also to consecutive span assembly construction, as referenced in
The embodiments described herein are merely preferred embodiments of the invention. Therefore, all equivalent changes or modifications made to the construction, features, and principles described within the scope of this invention's patent application are included within the scope of this invention's patent application.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2023113812196 | Oct 2023 | CN | national |
