A post-tensioning anchoring method based on UHPC

Abstract

The present invention discloses a post-tensioning prestressed anchoring method based on UHPC, comprising the following steps: step S1, setting prestressed tendons, rubber plugs, temporary steel frames, temporary anchors, jacks, UHPC in the anchoring area, UHPC in the sealing anchoring area and cement slurry; step S2, pre-setting corrugated pipes, conical casings, grouting holes, reserved channels and air outlets when pouring beams; step S3, inserting prestressed tendons into the expected channels, placing rubber plugs at the bottom of the conical casing; step S4, setting the temporary steel frame on the conical casing; step S5, placing the temporary steel frame on the conical casing; step S6, placing the temporary steel frame on the conical casing; step S7, placing the temporary steel frame on the conical casing; step S8, placing the temporary steel frame on the conical casing; step S9, placing the temporary steel frame on the conical casing; step S10, placing the temporary steel frame on the conical casing; step S11, placing the temporary steel frame on the conical casing; step S12, placing the temporary steel frame on the conical casing; step S13, placing the temporary steel frame on the conical casing; step S14, placing the temporary steel frame on the conical casing; step S15, placing the temporary steel frame on the conical casing; step S16, placing the temporary steel frame on the conical casing; step S17, placing the temporary steel frame on the conical casing; step S18, placing the temporary steel frame on the conical casing; step S19, placing the temporary steel frame on the conical casing; step S20, placing the temporary steel frame on the conical casing; step S21, placing the temporary steel frame on the conical casing; step S22, placing the temporary steel frame on the conical casing; step S23, placing the temporary steel frame on the conical casing; step S24, placing the temporary steel frame on the conical casing; step S25, placing the temporary steel frame on the conical casing; step S26, placing the temporary steel frame on the conical casing; step On the casing, temporary anchors and jacks are set on the temporary steel frame. After the tensioning is completed, the jacks are removed, and the temporary anchors on the temporary steel frame are temporarily anchored. Step S5, the UHPC in the anchoring area is cast in the conical casing after the tensioning is completed. Step S6, when the UHPC in the anchoring area reaches the predetermined strength, the tension is loosened and the excess prestressed tendons are cut off, and the UHPC in the anchoring area is cast in the reserved positions at the anchoring ends on both sides for anchoring. Step S7, cement slurry is poured into the corrugated pipe through the grouting holes and the air outlet holes.

Description

Technical Field

[0001] The invention relates to the technical field of bridge prestressed anchoring, and in particular to a UHPC-based post-tensioned prestressed anchoring method. Background Art

[0002] In prestressed structures, partial failure of prestressed anchoring devices is one of the major causes of prestress loss. Currently, the anchors used in prestressed construction are all metal anchors. When they are used for anchoring, there is a certain amount of shrinkage when the tension is loosened. Due to their material properties, rust often occurs when the anchor is not tightly sealed and the grouting is not dense. Rust fracture is a major cause of prestress failure. Since UHPC has the advantages of high strength, good durability and low porosity, it can be effectively anchored by utilizing the bonding force between it and the prestressed tendons without the use of special anchors. Only temporary anchors are needed for temporary anchoring during construction, which can save anchors and solve the rust problem caused by loose anchor sealing. Summary of the invention

[0003] In order to overcome the deficiencies of the prior art solutions, the present invention provides a post-tensioning prestressed anchoring method based on UHPC.

[0004] The technical solution adopted by the present invention to solve the technical problem is: a post-tensioning prestressed anchoring method based on UHPC, comprising the following steps: step S1, setting prestressed tendons, rubber plugs, temporary steel frames, temporary anchors, jacks, anchoring area UHPC, sealing anchor area UHPC and cement slurry;

[0005] Step S2, pre-setting a corrugated pipe, a conical casing, a grouting hole, a reserved channel and an air outlet hole when pouring the beam body;

[0006] Step S3, inserting the prestressed tendons into the expected channel, and placing a rubber plug at the bottom of the conical casing to prevent the UHPC from flowing into the bellows;

[0007] Step S4, erecting the temporary steel frame on the conical casing, and erecting the temporary anchor and the jack on the temporary steel frame, and removing the jack after the tensioning is completed, and temporarily anchoring by the temporary anchor on the temporary steel frame;

[0008] Step S5, the anchoring zone UHPC is poured into the conical casing after tensioning is completed;

[0009] Step S6, when the anchoring area UHPC reaches a predetermined strength, the excess prestressed tendons are loosened and removed, a certain length is reserved for loosening and embossing, and the reserved positions of the anchoring areas at both ends are poured through the reserved channels for anchoring;

[0010] Step S7, pouring the cement slurry into the corrugated pipe through the grouting holes and the air outlet holes.

[0011] Preferably, the conical casing is a corrugated steel casing.

[0012] Preferably, threaded steel bars are added around the conical casing when it is pre-placed.

[0013] Preferably, in step S6, steel bars need to be reserved at the reserved positions of the anchors at both ends to facilitate the erection of temporary steel frames and better combine the UHPC at that location with the beam body.

[0014] Preferably, the UHPC is steam-cured UHPC.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] The present invention provides a post-tensioning prestressed anchoring method based on UHPC, which fully utilizes the advantages of UHPC such as high strength, good durability and low porosity, and can effectively anchor the UHPC without using special anchors by utilizing the bonding force between the UHPC and the prestressed tendons. It can save anchors and solve the corrosion problem caused by loose anchoring. The method has low technical difficulty and great feasibility, and can be used as a high-quality prestressed anchoring method. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is the effect diagram after the implementation of the present invention;

[0018] Figure 2 It is a structural schematic diagram of the present invention;

[0019] Figure 3 Another structural schematic diagram of the present invention;

[0020] Figure 4 This is a schematic diagram of the structure of the UHPC in the anchoring area of ​​the present invention;

[0021] Figure 5 This is a schematic diagram of the structure of the anchoring area UPHC of the present invention;

[0022] Figure 6 It is a structural schematic diagram of the conical casing of the present invention;

[0023] Figure 7 It is a schematic structural diagram of the temporary anchor of the present invention.

[0024] Numbers in the figure:

[0025] Corrugated pipe 1, conical casing 2, grouting hole 3, prestressed tendons 4, rubber plug 5, temporary steel frame 6, temporary anchor 7, jack 8, anchoring area UHPC 9, sealing anchor area UPHC 10, cement slurry 11. DETAILED DESCRIPTION

[0026] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. 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.

[0027] like Figure 1-7 As shown, the present invention provides a post-tensioning prestressed anchoring method based on UHPC, which fully utilizes the advantages of UHPC such as high strength, good durability and low porosity. By utilizing the bonding force between UHPC and prestressed tendons, it can be effectively anchored without using special anchors. It is only temporarily anchored by temporary anchors during construction, which can save anchors and solve the rust problem caused by loose anchor sealing. The specific design scheme includes the following steps:

[0028] Step S1, setting prestressed tendons 4, rubber plugs 5, temporary steel frames 6, temporary anchors 7, jacks 8, anchoring area UHPC 9, sealing anchor area UHPC 10 and cement slurry 11;

[0029] Step S2, pre-setting the corrugated pipe 1, the conical casing 2, the grouting hole 3, the reserved channel and the air outlet hole when pouring the beam body;

[0030] Step S3, inserting the prestressed tendons 4 into the expected channel, and placing the rubber plug 5 at the bottom of the conical casing 2 to prevent the UHPC from flowing into the corrugated pipe 1;

[0031] Step S4, erecting the temporary steel frame 6 on the conical casing 2, and erecting the temporary anchor 7 and the jack 8 on the temporary steel frame 6, and removing the jack 8 after the tensioning is completed, and temporarily anchoring by the temporary anchor 7 on the temporary steel frame 6;

[0032] Step S5, the anchoring zone UHPC 9 is cast in the conical casing 2 after tensioning is completed, the anchoring zone UHPC is provided with grouting holes, and air outlet holes are reserved at the upper part of the template;

[0033] Step S6, when the anchoring area UHPC 9 reaches a predetermined strength, the anchoring area UHPC 10 is tensioned and the redundant prestressed tendons 4 are cut off, a certain length is reserved for loosening and embossing, and the reserved positions of the anchoring areas at both ends are poured through the reserved channels for anchoring;

[0034] Step S7, injecting the cement slurry 11 into the corrugated pipe 1 through the grouting holes 3 and the air outlet holes.

[0035] The conical casing 2 is a corrugated steel casing.

[0036] When the conical casing 2 is pre-installed, threaded steel bars are added around it.

[0037] In step S6, steel bars need to be reserved at the reserved positions of the anchors at both ends to facilitate the erection of temporary steel frames and better combine the UHPC at that location with the beam body.

[0038] The UHPC is steam-curing-free UHPC.

[0039] By using UHPC for post-tensioned prestressed tendon anchoring, the advantages of UHPC such as high strength, good durability and low porosity are fully utilized. By utilizing the bonding force between UHPC and prestressed tendons, it is possible to effectively anchor them without the use of special anchors. Only temporary anchors are used during construction to temporarily anchor them, which can save anchors and solve the rust problem caused by loose anchor sealing.

[0040] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

Claims

1. A post-tensioning anchoring method based on UHPC, characterized in that: The following steps are involved: Step S1, setting prestressed tendons, rubber plugs, temporary steel frames, temporary anchors, jacks, anchoring area UHPC, sealing anchor area UHPC and cement slurry; Step S2, pre-setting a corrugated pipe, a conical casing, a grouting hole, a reserved channel and an air outlet hole when pouring the beam body; Step S3, inserting the prestressed tendons into the expected channel, and placing a rubber plug at the bottom of the conical casing to prevent the UHPC from flowing into the bellows; Step S4, erecting the temporary steel frame on the conical casing, and erecting the temporary anchor and the jack on the temporary steel frame, and removing the jack after the tensioning is completed, and temporarily anchoring by the temporary anchor on the temporary steel frame; Step S5, the anchoring zone UHPC is poured into the conical casing after tensioning is completed; Step S6, when the anchoring area UHPC reaches a predetermined strength, the excess prestressed tendons are loosened and removed, a certain length is reserved for loosening and embossing, and the prestressed tendons are poured through the reserved channels at the reserved positions of the anchoring areas at both ends for anchoring; Step S7, pouring the cement slurry into the corrugated pipe through the grouting holes and the air outlet holes.

2. A post-tensioning anchoring method based on UHPC according to claim 1, characterized in that: The conical casing is a corrugated steel casing.

3. A post-tensioning anchoring method based on UHPC according to claim 1, characterized in that: When the conical casing is pre-placed, threaded steel bars are added around it.

4. A post-tensioning anchoring method based on UHPC according to claim 1, characterized in that: In step S6, steel bars need to be reserved at the reserved positions of the anchors at both ends to facilitate the erection of temporary steel frames and better combine the UHPC at that location with the beam body.

5. A post-tensioning anchoring method based on UHPC according to claim 1, characterized in that: The UHPC is steam-curing-free UHPC.

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