Multi-span continuous beam bridge closure construction method

Abstract

The invention discloses a multi-span continuous beam bridge closure construction method which comprises the following steps: a) respectively pouring No.0 blocks of construction box beams on a plurality of piers of a multi-span continuous beam bridge, b) installing hanging baskets on the No.0 blocks and pouring No.1 blocks and the like until cantilevers of the box beams are constructed to a preset length to form box beam sections, and forming closure openings between the adjacent box beam sections; c) firstly closing the closure openings at the side spans at the two ends, and then installing temporary supporting devices at the closure openings of the middle spans; d) removing the prestressed tendons at the No.0 blocks of the piers; and e) the closure openings of the middle spans are poured at the same time to complete closure of the middle spans. According to the method, closure is conducted at the multiple closure positions at the same time, it is avoided that a concrete box girder of a large cantilever is in a free cantilever state for a long time, the safety in engineering is improved, it can be guaranteed that main girders at the two ends of a closure opening are not dislocated and the structural stability is guaranteed through the adopted temporary supporting device, and the temporary supporting device is convenient to mount and demount; and repeated use can be realized.

Description

Technical Field

[0001] The invention relates to the technical field of bridge construction, and in particular to a closure construction method for a multi-span continuous beam bridge. Background Art

[0002] Continuous beam bridge is the main type of beam bridge, which is mainly constructed by hanging basket cantilever casting. Unlike continuous steel structure bridge, when using hanging basket cantilever casting for continuous beam bridge, it is necessary to temporarily consolidate the bridge pier and the No. 0 block of the main beam to prevent the main beam from overturning. The previous construction method of continuous beam bridge is: first close the side span, then release the temporary consolidation, and finally pour the concrete of the joint section. However, when multi-span continuous beams are constructed by hanging basket cantilever casting, if the traditional joint method is used, it will not only delay the construction period, but also increase the risk of the construction process because the main beam with a large cantilever is in a cantilever state for a long time. Therefore, for multi-span continuous beam bridges, it is of great significance to find a safe, applicable, economical, fast and efficient joint section construction method and device to shorten the construction period and reduce construction risks. Summary of the invention

[0003] In view of the above-mentioned deficiencies in the prior art, an object of the present invention is to provide a multi-span continuous beam bridge closure construction method to solve the problems of low detection efficiency and inability to accurately locate the position of rusted steel bars in the prior art.

[0004] In order to solve the above technical problems, the technical solution adopted by the present invention is as follows: a multi-span continuous beam bridge closure construction method, comprising the following steps: a) Cast the No. 0 block of the construction box beam on each pier of the multi-span continuous beam bridge, and anchor it with prestressed tendons after the No. 0 block reaches the preset strength; b) Install a hanging basket on block No. 0 and cast block No. 1. After block No. 1 reaches the preset strength, anchor it by tensioning the prestressed tendons, move the hanging basket, and cast block No. 2. Repeat this step until block No. n is cast, so that the cantilever of the box beam is constructed to the preset length to form a box beam section, and a joint is formed between adjacent box beam sections; c) First, close the joints at the side spans at both ends, and then install temporary support devices at the joints of multiple middle spans to keep the ends of the box girder sections on both sides of the joints at the middle spans facing each other; d) Release the anchorage force of the prestressed tendons at block No. 0 of each pier; e) Simultaneously pour the bottom slab concrete at the joints of each intermediate span. After the bottom slab concrete reaches the preset strength, pour the web slab concrete, tension some prestressed tendons at the joints, and then pour the top slab concrete. After the top slab concrete reaches the preset strength, tension the remaining prestressed tendons to complete the joint of the intermediate span.

[0005] As an optimization, step f is also included, in which the temporary support device is removed after the middle span is completed.

[0006] As an optimization, the temporary support device includes an upper longitudinal beam and a lower longitudinal beam arranged in parallel, and a plurality of shear-resistant diagonal rods are cross-arranged between the upper longitudinal beam and the lower longitudinal beam to connect the upper longitudinal beam and the lower longitudinal beam as a whole; it also includes embedded parts embedded in the inner wall of one end of the box beam section close to the joint. In step c, the two ends of the upper longitudinal beam and the lower longitudinal beam of the temporary support device are respectively connected to the embedded parts in the box beam section on both sides of the joint.

[0007] As an optimization, the upper longitudinal beam, the lower longitudinal beam and the shear-resistant diagonal rod are all double-jointed steel structures, all of which are spliced ​​by two I-beams, wherein the webs of the two I-beams are parallel and the wing plates are butt-jointed to form a II-shaped structure.

[0008] Compared with the prior art, the present invention has the following advantages: the closure method for a multi-span continuous beam bridge provided by the present invention is to close multiple closure positions simultaneously, replacing the successive closure in the traditional construction method, which can avoid the concrete box girder with a large cantilever being in a free cantilever state for a long time, thereby improving the safety in the project. The temporary support device used can ensure that the main beams at both ends of the closure mouth do not move when the temporary anchorage on the top of the pier is released, and the stability of the structure when pouring concrete in the closure section, and the temporary support device is easy to install and disassemble and can be used repeatedly. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 This is the construction structure diagram of block 0; Figure 2 This is a schematic diagram of the construction structure of Block 1; Figure 3 It is the structural schematic diagram of the box girder section after forming; Figure 4 is a structural schematic diagram of a temporary support device; Figure 5 It is a schematic diagram of the main structure of the temporary support device installation; Figure 6 A schematic diagram of the top view of the temporary support device installation; Figure 7 A schematic diagram of the cross-sectional structure of the temporary support device installation; In the figure, 1-bridge pier, 2-block No. 0, 3-hanging basket, 4-block No. 1, 5-box girder section, 6-joint mouth, 7-upper longitudinal beam, 8-lower longitudinal beam, 9-shear-resistant diagonal rod, 10-embedded parts. DETAILED DESCRIPTION

[0010] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0011] In order to make the purpose, 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 in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents the selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0012] It should be noted that similar numbers and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings. In the description of the present invention, it should be noted that the orientation or position relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. is based on the orientation or position relationship shown in the drawings, or the orientation or position relationship in which the invention product is usually placed when used, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance. In addition, the terms "horizontal", "vertical", etc. do not mean that the components are absolutely horizontal or suspended, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly tilted. In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0013] Example: See Figure 1-Figure 7 A method for closure construction of a multi-span continuous beam bridge comprises the following steps: a) If Figure 1As shown in the figure, the No. 0 block 2 of the box beam is cast on each pier 1 of the multi-span continuous beam bridge, and the prestressed tendons are used to anchor the No. 0 block 2 after it reaches the preset strength. The No. 0 block 2 is located directly above the pier 1. It is the first block extending from the pier 1 to both sides and is also a very critical part of the entire bridge structure. In cantilever construction, the No. 0 block 2 is the first segment to be cast and constructed by the bracket. It serves as the foundation and operating platform for the subsequent segment construction and is crucial to the stability and safety of the entire bridge.

[0014] b) If Figure 2-Figure 3 As shown, a hanging basket 3 is installed on block 0 2 and block 1 4 is cast. After block 1 4 reaches the preset strength, it is anchored by tensioning prestressed tendons, and the hanging basket 3 is moved. This step is repeated to cast block 2, block 3, etc., until block n is cast, so that the cantilever of the box beam is constructed to a preset length to form a box beam section 5, and a joint 6 is formed between adjacent box beam sections 5. Specifically, when the continuous beam cantilever is constructed in sections, after the construction of block 0 2 is completed, the longitudinal prestressed steel bars of block 1 4 need to be connected with the prestressed steel bars of block 0 2. These prestressed steel bars will not be cut off in the middle of the span, but will pass through the corrugated pipe to ensure the transmission of force and the continuity of the structure. Prestressed tendons are also used between other blocks to anchor, thereby completing the section construction of the entire box beam section 5 (main beam), until the box beam section 5 reaches the maximum cantilever stage, and a joint 6 is formed between adjacent cantilevers. Among them, the hanging basket 3 is a conventional equipment in bridge construction, and its structure and installation method are no longer redundant.

[0015] c) If Figure 4-Figure 7 As shown, the joints 6 at the side spans at both ends are firstly closed by a conventional joint closing method, and then temporary support devices are installed at the joints 6 of multiple middle spans, so that the ends of the box beam sections 5 on both sides of the joints 6 at the middle spans are kept facing each other. Specifically, in this embodiment, the temporary support device includes an upper longitudinal beam 7 and a lower longitudinal beam 8 arranged in parallel, and a plurality of shear-resistant diagonal rods 9 are cross-arranged between the upper longitudinal beam 7 and the lower longitudinal beam 8 to connect the upper longitudinal beam 7 and the lower longitudinal beam 8 as a whole; and also includes an embedded part 10 embedded in the inner wall of one end of the box beam section 5 near the joint 6. The ends of the upper longitudinal beam 7 and the lower longitudinal beam 8 of the temporary support device are respectively connected to the embedded parts 10 in the box beam sections 5 on both sides of the joint 6 to resist the shear force in the vertical plane, prevent the box beam sections 5 on both sides of the joint 6 from slipping, and ensure the stability of the structure during the subsequent construction process. The upper longitudinal beam 7, the lower longitudinal beam 8 and the shear-resistant diagonal rod 9 are all double-jointed steel structures, and are all joined by two I-beams, wherein the webs of the two I-beams are parallel and the wing plates are butted to form a II-shaped structure.

[0016] d) Release the anchoring force of the prestressed steel bars at block 2 of each pier 1. At this time, the support (block 2 of 0) can undergo a slight movement to adapt to the influence of temperature. In other words, after releasing the prestressed steel bars on the top of pier 1, it is equivalent to removing the temporary consolidation of pier 1 to the main beam, and the structural system becomes a continuous beam bridge.

[0017] e) Simultaneously pour the bottom slab concrete at the joint 6 of each intermediate span. After the bottom slab concrete reaches the preset strength, pour the web slab concrete, tension some prestressed tendons at the joint 6, and then pour the top slab concrete. After the top slab concrete reaches the preset strength, tension the remaining prestressed tendons to complete the joint of the intermediate span.

[0018] f) After the middle span is connected, the temporary support device is removed. Specifically, the temporary support device is removed from the inside of the concrete box girder after the connection, and then the concrete box girder is transported out from the inspection port 2 of block 0 for the next bridge construction and can be reused.

[0019] In summary, the closure method for a multi-span continuous beam bridge provided by the present invention is to close multiple closure positions simultaneously, replacing the successive closure in the traditional construction method. This can avoid the concrete box girder with a large cantilever being in a free cantilever state for a long time, thereby improving the safety of the project. The temporary support device used can ensure that the main beams at both ends of the closure mouth do not move when the temporary anchorage on the top of the pier is released, and ensure the stability of the structure when pouring concrete in the closure section. The temporary support device is easy to install and disassemble and can be used repeatedly.

[0020] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the technical solution. Those skilled in the art should understand that those modifications or equivalent substitutions of the technical solution of the present invention that do not depart from the purpose and scope of the technical solution should be included in the scope of the claims of the present invention.

Claims

1. A method for closure construction of a multi-span continuous beam bridge, characterized in that: The following steps are included: a) Cast the No. 0 block of the construction box beam on each pier of the multi-span continuous beam bridge, and anchor it with prestressed tendons after the No. 0 block reaches the preset strength; b) Install a hanging basket on block No. 0 and cast block No.

1. After block No. 1 reaches the preset strength, anchor it by tensioning the prestressed tendons, move the hanging basket, and cast block No.

2. Repeat this step until block No. n is cast, so that the cantilever of the box beam is constructed to the preset length to form a box beam section, and a joint is formed between adjacent box beam sections; c) First, close the joints at the side spans at both ends, and then install temporary support devices at the joints of multiple middle spans to keep the ends of the box girder sections on both sides of the joints at the middle spans facing each other; d) Release the anchorage force of the prestressed tendons at block No. 0 on each pier; e) Simultaneously pour the bottom slab concrete at the joints of each intermediate span. After the bottom slab concrete reaches the preset strength, pour the web slab concrete, tension some prestressed tendons at the joints, and then pour the top slab concrete. After the top slab concrete reaches the preset strength, tension the remaining prestressed tendons to complete the joint of the intermediate span.

2. A multi-span continuous beam bridge closure construction method according to claim 1, characterized in that: The method also includes step f, in which the temporary support device is removed after the middle span is completed.

3. The method for closure construction of a multi-span continuous beam bridge according to claim 1, characterized in that: The temporary support device includes an upper longitudinal beam and a lower longitudinal beam arranged in parallel, and a plurality of shear-resistant diagonal rods are cross-arranged between the upper longitudinal beam and the lower longitudinal beam to connect the upper longitudinal beam and the lower longitudinal beam as a whole; it also includes embedded parts embedded in the inner wall of one end of the box beam section close to the joint mouth. In step c, the two ends of the upper longitudinal beam and the lower longitudinal beam of the temporary support device are respectively connected to the embedded parts in the box beam section on both sides of the joint mouth.

4. A multi-span continuous beam bridge closure construction method according to claim 3, characterized in that: The upper longitudinal beam, the lower longitudinal beam and the shear-resistant diagonal rod are all double-jointed steel structures, and are all joined by two I-beams, wherein the webs of the two I-beams are parallel and the wing plates are butted to form a II-shaped structure.

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