Construction method of super-long bridge abutment

Abstract

The invention discloses a super-long bridge abutment construction method which comprises the steps that for a super-long bridge abutment supported on three bridge piers, the super-long bridge abutment is divided into prefabricated bridge abutment sections on the two sides and a cast-in-place section in the middle, and tensioning holes and butt joint steel bars are arranged on the prefabricated bridge abutment sections; during construction, a jig frame is arranged around a middle pier, a bottom formwork is laid on the jig frame, and a middle through hole of the bottom formwork is tightly attached to and surrounds the middle pier; one ends of the prefabricated bridge abutment sections are supported on the end bridge piers, the other ends of the prefabricated bridge abutment sections are all supported on the bottom formwork, a cast-in-place groove is formed between the two prefabricated bridge abutment sections, and the two sides of the cast-in-place groove exceed the middle bridge piers; the corresponding butt-joint steel bars on the two sides are connected, prestressed steel strands penetrate through the tensioning holes in the two sides at the same time, and side formworks at the two ends of the cast-in-place groove are installed; a cast-in-place groove is poured, and the prestressed steel strand is tensioned and locked; the tensioning holes are filled; and the side formworks, the bottom formwork and the jig frame are dismantled. According to the method, transportation and hoisting inconvenience caused by the overlength prefabricated abutment section is avoided, jig frame waste is avoided, fall is avoided, and slurry leakage is avoided during pouring.

Description

Technical Field

[0001] The invention relates to an assembled abutment, and in particular to a method for constructing an ultra-long abutment. Background Art

[0002] Prefabricated abutments are prefabricated in factories and installed on-site, significantly reducing construction time compared to cast-in-place abutments. Prefabricated abutments are generally shorter and can be installed directly on piers without requiring further splicing. However, for a few extra-long abutments, transportation and lifting limitations require segmentation and on-site splicing. At present, for extra-long abutments (generally installed on three piers), the abutment section is first supported and placed on the piers, so that the two abutment sections are separated on the piers to form a cast-in-place trough. After pouring, the adjacent abutment sections are spliced. There are two major difficulties in this construction method: 1) The length of the abutment section must be longer than the distance between adjacent piers. When the distance between adjacent piers is large, the abutment section will be too long, which brings inconvenience to transportation and lifting; 2) The width of the abutment section is larger than the piers. Before pouring the cast-in-place trough, bottom formwork and side formwork need to be set up. In order to install the bottom formwork and side formwork, a tire frame is also required. The tire frame is only used to support the bottom formwork and side formwork, which is relatively wasteful; 3) When the abutment section is hoisted, at the splicing end of the abutment section, the abutment section is partially supported on the pier and partially supported on the bottom formwork. If the installation accuracy of the tire frame is not high and the elevation of the bottom formwork is not properly controlled, there will be a drop between the pier and the bottom formwork, resulting in leakage during pouring. Summary of the Invention

[0003] The purpose of the present invention is to provide a method for constructing an extra-long abutment, which avoids the inconvenience of transportation and lifting caused by the extra-long prefabricated abutment section, does not waste the frame, does not have a drop, and does not leak slurry during pouring.

[0004] The technical solution adopted in the present invention is: A method for constructing an extra-long abutment, wherein the extra-long abutment supported on three piers is divided into precast abutment sections on both sides and a cast-in-place section in the middle, the precast abutment sections being provided with through tensioning holes and butt-jointed steel bars extending outwards. During construction, a cradle is first arranged around the middle pier, and a bottom formwork is laid on the cradle, with the middle through-hole of the bottom formwork closely surrounding the middle pier. Two precast abutment sections are then hoisted, with one end of the precast abutment section supported on the end pier and the other end entirely supported on the bottom formwork, forming a cast-in-place trough between the two precast abutment sections, with both sides of the cast-in-place trough extending beyond the middle pier. Rebar connectors are then used to connect the corresponding butt-jointed steel bars on both sides, prestressed steel strands are simultaneously passed through the tensioning holes on both sides, and side formwork at both ends of the cast-in-place trough is installed on the bottom formwork. The cast-in-place trough is then cast, and after the concrete reaches a certain strength, the prestressed steel strands are tensioned and locked. The tensioning holes are then filled, and finally the side formwork, bottom formwork, and cradle are removed.

[0005] Preferably, before hoisting the prefabricated abutment section, a position control line is marked on the bottom template; when hoisting the prefabricated abutment section, ensure that its two sides and ends are aligned with the position control line.

[0006] Preferably, when the positions of the corresponding butt-jointed steel bars are staggered within a certain range, the steel bar connector adopts an integral steel bar sleeve; when the positions of the corresponding butt-jointed steel bars are staggered beyond a certain value, the steel bar connector adopts two separate steel bar sleeves, which are connected by a universal joint structure.

[0007] Preferably, protruding steel bars are provided at the top of the pier, and an opening is reserved on the prefabricated abutment section for accommodating the protruding steel bars from the top of the end pier; when the prefabricated abutment section is hoisted, the opening is sleeved on the protruding steel bars from the top of the end pier, and the opening is within the range of the end pier; after the prefabricated abutment section is hoisted, the opening is filled.

[0008] Preferably, the tensioning holes are distributed on both sides of the cross section of the prefabricated abutment section, and the tensioning holes avoid the openings.

[0009] Preferably, one prefabricated abutment section is provided with an anchor groove at one end facing outward, and the anchor groove is at the end of the tensioning hole, and the other prefabricated abutment section is provided with a tensioning groove at one end facing outward, and the tensioning groove is at the end of the tensioning hole; when the prestressed steel strand is tensioned and locked, one end of the prestressed steel strand is anchored in the anchor groove and the other end is tensioned and locked in the tensioning groove; when filling the tensioning hole, the anchor groove and the tensioning groove are filled together.

[0010] Preferably, after casting the cast-in-place trough, epoxy resin is used to fill the surface gaps in the cast-in-place trough area and adjacent areas.

[0011] Preferably, meshes for crack resistance and protection are provided at both ends of the cast-in-place trough.

[0012] Preferably, the concrete used to cast the cast-in-place channel is one grade higher than the concrete used for the precast abutment sections.

[0013] Preferably, before casting the cast-in-place trough, both sides of the cast-in-place trough are roughened.

[0014] The beneficial effects of the present invention are: In this method, both ends of the prefabricated abutment section are supported on the end piers and the bottom formwork laid on the tire frame respectively. The length of the prefabricated abutment section does not need to be longer than the spacing between adjacent piers, avoiding the inconvenience of transportation and lifting caused by the excessive length of the prefabricated abutment section; in this method, the tire frame is used to provide an installation platform for the bottom formwork and the side formwork, and can also be used to support the prefabricated abutment section, so there will be no waste of the tire frame; in this method, the butt ends of the two prefabricated abutment sections are all supported on the bottom formwork, there will be no drop, and there will be no leakage during pouring; in this method, the two prefabricated abutment sections are not only connected by butt steel bars and cast-in-place sections, but also pre-tensioned by prestressed steel strands, so that the formed abutment has better integrity. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0016] Figure 1 It is a schematic diagram of the construction of the super-long abutment in the present invention.

[0017] Figure 2 yes Figure 1 Cross-section view at AA in the middle.

[0018] Figure 3 yes Figure 1 Top view of .

[0019] Figure 4 It is a steel bar connector used when the positions of the corresponding butted steel bars in the present invention are offset by more than a certain value.

[0020] In the figure: 1-anchor groove; 2-prestressed steel strand; 3-protruding steel bar; 4-precast abutment section; 5-butting steel bar; 6-steel bar connector; 7-tensioning groove; 8-pier; 9-cast-in-place section; 10-bottom formwork; 11-cradle; 12-mesh; 13-tensioning hole; 14-opening. DETAILED DESCRIPTION

[0021] To make the objectives, technical solutions, and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Generally, the components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations.

[0022] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for protection, but merely represents selected embodiments of the present application. All other embodiments obtained by persons of ordinary skill in the art based on the embodiments in the present application without creative work are within the scope of protection of the present application.

[0023] The features and performance of the present application are further described in detail below with reference to the embodiments.

[0024] Example 1 This embodiment discloses a method for constructing an ultra-long abutment, for an ultra-long abutment supported on three piers 8, such as Figure 1 and Figure 3 As shown in FIG, the super-long abutment is divided into precast abutment sections 4 on both sides and a cast-in-place section 9 in the middle. Figure 1 and Figure 2 As shown, the prefabricated abutment section 4 is provided with through tensioning holes 13 and outwardly extending butt-jointed steel bars 5; during construction, the following steps are adopted: S1. Figure 1 As shown, a tire frame 11 is arranged around the middle pier 8 , and a bottom template 10 is laid on the tire frame 11 , with the middle through hole of the bottom template 10 tightly surrounding the middle pier 8 .

[0025] S2. Figure 1 and Figure 3 As shown, two prefabricated abutment sections 4 are hoisted, one end of the prefabricated abutment section 4 is supported on the end pier 8, and the other end is completely supported on the bottom formwork 10. A cast-in-place trough is formed between the two prefabricated abutment sections 4, and both sides of the cast-in-place trough extend beyond the middle pier 8, that is, the width L of the cast-in-place trough is greater than the diameter of the middle pier 8. In this embodiment, both sides of the cast-in-place trough extend beyond the middle pier 8 by 10 cm.

[0026] S3. Figure 1 As shown, the corresponding butt-jointed steel bars 5 on both sides are connected by using steel bar connectors 6, the prestressed steel strands 2 are passed through the tensioning holes 13 on both sides at the same time, and the side templates at both ends of the cast-in-place trough are installed on the bottom template 10.

[0027] S4. Cast the cast-in-place trough. After the concrete reaches a certain strength, tension the prestressed steel strand 2 and lock it.

[0028] S5. Fill the tensioning hole 13.

[0029] S6. Remove the side formwork, bottom formwork 10 and tire frame 11.

[0030] In order to control the position of the prefabricated abutment section 4 during hoisting, in this embodiment, preferably: before hoisting the prefabricated abutment section 4, a position control line is marked on the bottom template 10; when hoisting the prefabricated abutment section 4, ensure that its two sides and ends are aligned with the position control line.

[0031] In order to strengthen the connection between the prefabricated abutment section 4 and the end pier 8, and strengthen the connection between the cast-in-place section 9 and the middle pier 8, in this embodiment, preferably: Figure 1 and Figure 3 As shown, the top of the pier 8 is provided with a protruding steel bar 3, and the prefabricated abutment section 4 is reserved with an opening 14 for accommodating the protruding steel bar 3 from the top of the end pier 8; when the prefabricated abutment section 4 is hoisted, the opening 14 is sleeved on the protruding steel bar 3 from the top of the end pier 8, and the opening 14 is within the range of the end pier 8; after the prefabricated abutment section 4 is hoisted, the opening 14 is filled. Figure 2As shown, the tensioning holes 13 are distributed on both sides of the cross section of the prefabricated abutment section 4 , and the tensioning holes 13 avoid the openings 14 .

[0032] In order to avoid the anchoring piece and the locking piece of the prestressed steel strand 2 being exposed to the outside, in this embodiment, preferably: Figure 1 As shown, one prefabricated abutment section 4 is provided with an anchor groove 1 at one end facing outward, and the anchor groove 1 is at the end of the tensioning hole 13; the other prefabricated abutment section 4 is provided with a tensioning groove 7 at one end facing outward, and the tensioning groove 7 is at the end of the tensioning hole 13; when the prestressed steel strand 2 is tensioned and locked, one end of the prestressed steel strand 2 is anchored in the anchor groove 1, and the other end is tensioned and locked in the tensioning groove 7; when filling the tensioning hole 13, the anchor groove 1 and the tensioning groove 7 are filled together.

[0033] In order to improve the corrosion resistance, in this embodiment, preferably, after casting the cast-in-place trough, epoxy resin is used to fill the surface gaps in the cast-in-place trough area and adjacent areas (eg, within a range of 50 cm).

[0034] In order to ensure that the outer steel bar has a sufficient protective layer thickness, in this embodiment, preferably: Figure 2 As shown, meshes 12 for crack resistance and protection are provided at both ends of the cast-in-place trough.

[0035] In this embodiment, preferably: the concrete for casting the cast-in-place trough is one grade higher than the concrete for the precast abutment section 4; and before casting the cast-in-place trough, both sides of the cast-in-place trough are roughened.

[0036] In this method, both ends of the prefabricated abutment section 4 are respectively supported on the end piers 8 and the bottom formwork 10 laid on the tire frame 11. The length of the prefabricated abutment section 4 does not need to be longer than the spacing between adjacent piers 8, avoiding the inconvenience of transportation and lifting caused by the excessive length of the prefabricated abutment section 4.

[0037] In this method, the tire frame 11 is used to provide an installation platform for the bottom formwork 10 and the side formwork, and can also be used to support the prefabricated abutment section 4, so that the tire frame 11 will not be wasted.

[0038] In this method, the butt ends of the two prefabricated abutment sections 4 are all supported on the bottom formwork 10, so there is no drop and no mortar leakage during pouring.

[0039] In this method, the two prefabricated abutment sections 4 are not only connected by butting steel bars 4 and cast-in-place sections 9, but are also tensioned and pre-tightened by prestressed steel strands 2, so that the formed abutment has better integrity.

[0040] Example 2 This embodiment specifically discloses two types of steel bar connectors 6 for the method provided in the first embodiment: when the positions of the corresponding butted steel bars 5 are staggered within a certain range, the steel bar connector 6 adopts an integral steel bar sleeve; when the positions of the corresponding butted steel bars 5 are staggered beyond a certain value, such as Figure 4 As shown, the rebar connector 6 comprises two separate rebar sleeves connected by a universal joint structure. The universal joint structure includes a cross-axis, with the two rebar sleeves located on either side of the cross-axis and hinged to a pair of axes of the cross-axis. This embodiment ensures that the corresponding butt-jointed rebars 5 can be connected in place. The embodiments described above are part of the embodiments of the present application, rather than all of the embodiments. The detailed description of the embodiments of the present application is not intended to limit the scope of the present application for protection, but merely represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

Claims

1. A method for constructing an ultra-long abutment, characterized in that: For the extra-long abutments supported on three piers, the extra-long abutments are divided into precast abutment sections on both sides and a cast-in-place section in the middle. The precast abutment sections are provided with through tensioning holes and butt reinforcement extending outwards. During construction: a cradle is first arranged around the middle pier, and a bottom formwork is laid on the cradle. The middle through hole of the bottom formwork is tightly surrounding the middle pier. Then, two precast abutment sections are hoisted, with one end of the precast abutment section supported on the end pier and the other end entirely supported on the bottom formwork. A cast-in-place trough is formed between the two precast abutment sections, and both sides of the cast-in-place trough extend beyond the middle pier. Then, the corresponding butt reinforcements on both sides are connected using steel bar connectors, and the prestressed steel strands are simultaneously passed through the tensioning holes on both sides, and the side formwork at both ends of the cast-in-place trough is installed on the bottom formwork. Then, the cast-in-place trough is cast, and after the concrete reaches a certain strength, the prestressed steel strands are tensioned and locked. Then, the tensioning holes are filled. Finally, the side formwork, bottom formwork and cradle are removed.

2. The super-long abutment construction method according to claim 1, characterized in that: Before hoisting the prefabricated abutment section, mark the position control line on the bottom formwork; when hoisting the prefabricated abutment section, ensure that its two sides and ends are aligned with the position control line.

3. The super-long abutment construction method according to claim 1, characterized in that: When the positions of the corresponding butt joint steel bars are staggered within a certain range, the steel bar connector adopts an integral steel bar sleeve; when the positions of the corresponding butt joint steel bars are staggered beyond a certain value, the steel bar connector adopts two separate steel bar sleeves, which are connected by a universal joint structure.

4. The super-long abutment construction method according to claim 1, characterized in that: There are protruding steel bars at the top of the pier, and an opening is reserved on the prefabricated abutment section for accommodating the protruding steel bars at the top of the end pier; when the prefabricated abutment section is hoisted, the opening is sleeved on the protruding steel bars at the top of the end pier, and the opening is within the range of the end pier; after the prefabricated abutment section is hoisted, the opening is filled.

5. The super-long abutment construction method according to claim 4, characterized in that: The tensioning holes are distributed on both sides of the cross section of the prefabricated abutment section, and the tensioning holes avoid the openings.

6. The super-long abutment construction method according to claim 1, characterized in that: One prefabricated abutment section is provided with an anchor groove at one end facing outward, and the anchor groove is located at the end of the tensioning hole. The other prefabricated abutment section is provided with a tensioning groove at one end facing outward, and the tensioning groove is located at the end of the tensioning hole. When the prestressed steel strand is tensioned and locked, one end of the prestressed steel strand is anchored in the anchor groove and the other end is tensioned and locked in the tensioning groove. When filling the tensioning hole, the anchor groove and the tensioning groove are filled together.

7. The super-long abutment construction method according to claim 1, characterized in that: After pouring the cast-in-place trough, epoxy resin is used to fill the surface gaps in the cast-in-place trough area and adjacent areas.

8. The super-long abutment construction method according to claim 1, characterized in that: Meshes for crack resistance and protection are installed at both ends of the cast-in-place trough.

9. The super-long abutment construction method according to claim 1, characterized in that: The concrete used to pour the cast-in-place trough is one grade higher than the concrete used for the precast abutment sections.

10. The super-long abutment construction method according to claim 1, characterized in that: Before pouring the cast-in-place trough, roughen both sides of the cast-in-place trough.

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