CN114922099A - Pier column reinforcing method for cladding FRP (fiber reinforced Plastic) -plastic pipe-iron-based SMA (shape memory alloy) and rubber concrete - Google Patents
Pier column reinforcing method for cladding FRP (fiber reinforced Plastic) -plastic pipe-iron-based SMA (shape memory alloy) and rubber concrete Download PDFInfo
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- CN114922099A CN114922099A CN202210696375.0A CN202210696375A CN114922099A CN 114922099 A CN114922099 A CN 114922099A CN 202210696375 A CN202210696375 A CN 202210696375A CN 114922099 A CN114922099 A CN 114922099A
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- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 title claims abstract description 89
- 239000005060 rubber Substances 0.000 title claims abstract description 70
- 229920003023 plastic Polymers 0.000 title claims abstract description 62
- 239000004033 plastic Substances 0.000 title claims abstract description 62
- 229910001285 shape-memory alloy Inorganic materials 0.000 title claims abstract description 57
- 229910052742 iron Inorganic materials 0.000 title claims abstract description 53
- 229920002430 Fibre-reinforced plastic Polymers 0.000 title claims abstract description 51
- 239000011151 fibre-reinforced plastic Substances 0.000 title claims abstract description 51
- 238000000034 method Methods 0.000 title claims abstract description 46
- 230000003014 reinforcing effect Effects 0.000 title claims abstract description 29
- 238000005253 cladding Methods 0.000 title description 3
- 229920001169 thermoplastic Polymers 0.000 claims abstract description 104
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- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical compound [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 description 1
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- E—FIXED CONSTRUCTIONS
- E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
- E01D—CONSTRUCTION OF BRIDGES, ELEVATED ROADWAYS OR VIADUCTS; ASSEMBLY OF BRIDGES
- E01D22/00—Methods or apparatus for repairing or strengthening existing bridges ; Methods or apparatus for dismantling bridges
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- E—FIXED CONSTRUCTIONS
- E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
- E01D—CONSTRUCTION OF BRIDGES, ELEVATED ROADWAYS OR VIADUCTS; ASSEMBLY OF BRIDGES
- E01D19/00—Structural or constructional details of bridges
- E01D19/02—Piers; Abutments ; Protecting same against drifting ice
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A30/00—Adapting or protecting infrastructure or their operation
- Y02A30/30—Adapting or protecting infrastructure or their operation in transportation, e.g. on roads, waterways or railways
Abstract
The method for reinforcing the pier column coated with FRP (fiber reinforced Plastic) -plastic pipe-iron-based SMA (shape memory alloy) and rubber concrete comprises the following steps of 1, selecting a thermoplastic pipe; step 2, roughening; step 3, wrapping the iron-based SMA strip; step 4, electrifying and exciting the iron-based SMA strip; step 5, splitting the thermoplastic pipe; step 6, enclosing, positioning and semi-circular thermoplastic pipe pieces; step 7, welding the thermoplastic pipes; step 8, pouring rubber concrete; and 9, coating the FRP cloth belt. On one hand, the toughness and the durability of the pier stud are improved by adopting the thermoplastic pipe, and the thermoplastic pipe can serve as a pouring mold; on the other hand, rubber concrete with high energy consumption is used as an anti-collision outer coating of the pier stud, and the effect of dual toughness reinforcement of the pier stud is achieved. In addition, the invention also adopts an iron-based SMA strip to form the annular prestress active restraint on the surface of the pier stud, and the FRP cloth belt is wrapped outside the peripheral thermoplastic pipe to form the annular passive restraint, so that the mutual combination of the internal and external active restraints is formed, and the bearing capacity and the toughness of the pier stud are obviously improved.
Description
Technical Field
The invention relates to the technical field of civil engineering structures, in particular to a pier column reinforcing method for coating FRP (fiber reinforced plastic) -plastic pipe-iron-based SMA (shape memory alloy) and rubber concrete.
Background
In the long-term service process of the common concrete pier stud, the bearing capacity and the durability of the common concrete pier stud are reduced due to the influence of the external severe environment and human factors, and therefore, a large amount of reinforcement and repair requirements are met. The traditional passive reinforcement methods mainly comprise a section-enlarging reinforcement method, an externally-bonded steel reinforcement method, an FRP reinforcement method and the like, but the reinforcement methods have certain disadvantages. The main disadvantages of the cross section enlarging method are as follows: the construction period is long, the working procedures are complicated, and the use space is influenced; the external bonding steel reinforcing method mainly has the defects of higher construction difficulty, larger influence of technicians on the construction effect and non-corrosion resistance; although the FRP reinforcing method has the advantages of convenient construction, good reinforcing effect, almost no increase of dead weight and the like, the transverse deformation of the concrete column under the load action is uneven, so that the stress concentration of the FRP part region is easy to cause brittle failure and the improvement on the toughness of the pier column is smaller. Meanwhile, the passive restraint concrete column can work after the concrete is stressed and expanded, and the defect that the working efficiency of the material is low due to the fact that the passive restraint concrete column cannot work with the concrete in a cooperative mode exists. Compared with passive restraint, the active restraint can apply hoop restraint force in advance, and the early bearing stage can work with the existing pier stud in a cooperative mode, so that the restraint efficiency of the material is greatly improved. The iron-based shape memory alloy (iron-based SMA) has a shape memory effect, corresponding recovery stress can be generated through heating excitation, and if the iron-based SMA is applied to reinforcement of an existing pier stud, compared with a traditional reinforcement mode, the iron-based SMA not only innovatively changes a constraint method from passive to active, but also can effectively improve the toughness of the existing pier stud. On the other hand, the pier column structure of the bridge is also exposed to the risk of lateral impact, such as the impact of vehicles and ships, and the concrete pier column is also necessary for the reinforcement of the structure in terms of collision resistance as the main load-bearing member.
The existing high-ductility plastic pipe confined concrete column has attracted extensive attention of the engineering industry due to the advantages that the existing high-ductility plastic pipe confined concrete column can obviously improve the durability and toughness of the pier column, can be used as a permanent mold for pouring concrete and the like. However, most of researches are mainly directed to newly built columns, and the existing pier column reinforcement is less in design, wherein the important reason is that the split parts cannot be effectively connected after the plastic pipe is vertically split and the properties of the plastic pipe are basically close to those of the base material, so that the advantages of the outer sleeve are difficult to apply to the existing pier column reinforcement.
Therefore, for those skilled in the art, it is a technical problem to be solved urgently in the engineering industry to develop a novel reinforcing and repairing method for actively and passively restraining and combining existing pillars and to provide a novel reinforcing method capable of comprehensively improving mechanical properties such as corrosion resistance, toughness and impact buffering of the pillars.
Disclosure of Invention
The technical problem to be solved by the invention is to provide a reinforcing method for a pier column coated with FRP (fiber reinforced plastic) -plastic pipe-iron-based SMA (shape memory alloy) and rubber concrete, aiming at overcoming the defects of the prior art, on one hand, the reinforcing method adopts a thermoplastic pipe to improve the toughness and durability of the existing pier column and can play a role of a pouring mold; on the other hand, rubber concrete with high energy consumption is used as an anti-collision outer coating of the existing pier, and the effect of dual toughness reinforcement of the existing pier is achieved. In addition, the invention also adopts an iron-based SMA strip to form the annular prestress active restraint on the surface of the existing pier stud, and the FRP cloth belt is wrapped outside the peripheral thermoplastic pipe to form the annular passive restraint, so that the inner and outer active and passive restraints are combined with each other, and the bearing capacity and the toughness of the existing pier stud are obviously improved.
In order to solve the technical problems, the invention adopts the technical scheme that:
a method for reinforcing a pier column coated with FRP-plastic pipes-iron-based SMA and rubber concrete comprises the following steps.
Step 8, pouring rubber concrete: and (7) pouring rubber concrete in the concrete pouring cavity formed in the step (7) and curing.
In the step 1, if the diameter of the existing pier column is d1, the designed coating thickness of the rubber concrete is a, and the inner diameter of the thermoplastic pipe is d2, then:
a is one tenth to one eighth of d 1; d2= d1+ a + b, wherein b is the fusion loss size and is 3-4 cm.
In the step 8, the rubber mixing amount in the rubber concrete is set according to the collision probability of the existing pier stud; when the collision probability of the existing pier stud is not less than a set value, the rubber mixing amount proportion in the rubber concrete is selected to be 60%, and a is one eighth of d 1; when the collision probability of the existing pier stud is smaller than a set value, the proportion of the rubber mixing amount in the rubber concrete is selected to be 20%.
The rubber mixed in the rubber concrete is waste rubber particles with the particle size of 1-3 cm.
In the step 1, the lowest thickness of the thermoplastic pipe is not less than 3mm, and the tensile strength is not less than 22 MPa.
In step 3, the wrapped iron-based SMA strip is anchored at the end by using a rivet.
In the step 3, the pretensioning strain of the iron-based SMA strip is 4%; in step 4, the energizing temperature of the iron-based SMA strip is 200 ℃.
In step 7, the method for welding the two semicircular thermoplastic pipe pieces comprises the following steps:
step 7A, installing a welding device: the welding device comprises a heating sheet, a plastic pipe clamping part and a plastic pipe butt joint driving mechanism; two groups of heating sheets are respectively arranged at two enclosed gaps of the two semicircular thermoplastic pipe sheets; the plastic pipe clamping parts are at least eight groups; the top and the bottom of each semicircular thermoplastic pipe piece are respectively provided with at least two groups of plastic pipe clamping parts; each group of pipe clamping parts are clamped on the inner wall surface and the outer wall surface of the corresponding semicircular thermoplastic pipe piece; the tail part of each group of pipe clamping parts is respectively provided with one plastic pipe butt joint driving mechanism, and the plastic pipe butt joint driving mechanisms are all distributed along the radial direction of the existing pier column.
Step 7B, heating by a heating plate: the heating plate is electrified and heated to a set temperature.
And 7C, welding: all the plastic pipe butt joint driving mechanisms synchronously and radially move towards the direction of the circle center of the existing pier stud, so that the enclosing parts of the two semicircular thermoplastic pipe pieces form a molten state under the heating action of the heating sheets; and then, withdrawing the heating plate, and enabling all the plastic pipe butting driving mechanisms to continuously move synchronously and radially towards the direction of the circle center of the existing pier stud, so that the two semicircular thermoplastic pipe pieces are welded to form the cylindrical welded thermoplastic pipe.
And 7D, after the welding parts of the two semicircular thermoplastic pipe pieces are cooled, withdrawing the plastic pipe clamping part and the plastic pipe butt joint driving mechanism.
And 7D, before the welding parts of the two semicircular thermoplastic pipe pieces are cooled, utilizing an iron sheet to remove the molten part extruded and overflowed from the welding parts, and further ensuring the smoothness of the welding parts.
Has the beneficial effects that:
1. the method is quick, efficient, green and economical when the existing pier stud is reinforced, can improve the bearing capacity of the existing pier stud and effectively improve the corrosion resistance and the impact resistance of the existing pier stud, and is suitable for the field of reinforcing and repairing the pier stud of the urban bridge and the bridge under the corrosive environment.
2. According to the invention, through the vertical welding mode of the thermoplastic pipes, experimental research proves that the welding mode can ensure that the welding thermoplastic pipes are close to the mechanical property of the parent metal, so that the advantages of high durability, high ductility and low cost of the plastic pipes in the building structure can be effectively applied; meanwhile, mechanical construction can be realized under the actual condition, and the construction efficiency is greatly improved. In addition, in the welding process, all plastic pipe butt joint driving mechanisms synchronously and radially move towards the direction of the circle center of the existing pier stud, so that the radial thickness between the welded thermoplastic pipes and the existing pier stud is kept consistent, the subsequently filled rubber concrete is radially kept uniform, the problem of non-uniform transverse deformation of the concrete column under the load action is avoided, meanwhile, the problem of brittle failure of the FRP partial region due to stress concentration can be avoided, and the toughness of the existing pier stud can be greatly improved.
3. The invention utilizes the characteristics of the rubber concrete of both strength and energy consumption, and brings the rubber concrete as the outer coating into the pier column structure, thereby improving the bearing capacity of the pier column and obviously improving the impact resistance of the pier column; meanwhile, the rubber concrete is used as green concrete, and waste rubber tires can be effectively recycled, so that the strategic target of national low-carbon development is met.
4. The FRP-plastic pipe reinforcing system adopted in the invention not only realizes high durability and high bearing capacity of the reinforced pier stud structure, but also can be used as a rubber concrete pouring template for the plastic pipe with low cost, thereby realizing the construction targets of high efficiency and low cost.
5. According to the reinforcing method combining active restraint and passive restraint, the initial lateral confining pressure can be applied to the concrete member by the active restraint of the prestress provided by the iron-based SMA strip, the expansion of the concrete is delayed by the cooperative work of the active restraint and the passive restraint with the existing pier stud, and the overall performance of the member is improved; meanwhile, the external FRP strip is wrapped to form passive restraint, and a three-way passive restraint effect is provided for the existing pier stud, so that the bearing capacity of the existing pier stud can be obviously improved by mutually combining the internal and external active and passive restraints.
5. The reinforcing mode provided by the invention can correspondingly adjust the proportion of the rubber concrete and the selection of the FRP cloth reinforcing mode according to the requirements of actual engineering conditions, is flexible and various, and can effectively meet different reinforcing requirements.
Drawings
FIG. 1 shows a cross-sectional view of a concrete column after reinforcement by the method of the invention.
Fig. 2 shows a front view of the reinforcement method according to the invention.
Fig. 3 shows a schematic view of the two semicircular thermoplastic segments of the present invention surrounding the existing pier stud at the location to be reinforced.
Fig. 4 shows a schematic view of a welding apparatus of the present invention for welding two semicircular thermoplastic tube sheets.
FIG. 5 shows a schematic diagram of the iron-based SMA strip anchoring and energizing in accordance with the present invention; wherein (a) shows a schematic of the anchoring of an iron-based SMA ribbon on a concrete column; (b) the figure shows a schematic diagram of the energization of a single ferrous SMA ribbon.
FIG. 6 shows a schematic of the consolidation process of the present invention; wherein (a) shows a schematic representation of a concrete column after roughening; (b) the figure shows a schematic of wrapping an iron-based SMA ribbon; (c) the figure shows a schematic view of a semi-circular thermoplastic segment after being enclosed; (d) the figure shows a schematic view of rubber concrete casting; (e) the figure shows the covering schematic diagram of FRP cloth belt.
Among them are:
1. a thermoplastic tube; 2, FRP cloth belts; 3. a rubber concrete outer coating; 4. existing pier studs; 5. an iron-based SMA strip; 6. melting the butt joint part; 7. a heating plate; 8. a plastic pipe butt joint driving mechanism; 9. a plastic pipe clamping part; 10. chiseling a hair layer; 11. a power-on excitation device; 12. a rivet anchoring zone; 13. the direction of the current flow.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings and specific preferred embodiments.
In the description of the present invention, it should be understood that the terms "left side", "right side", "upper part", "lower part", etc. indicate orientations or positional relationships based on those shown in the drawings, only for convenience of description and simplification of description, but do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, "first", "second", etc. do not represent an important degree of the component, and thus, are not to be construed as limiting the present invention. The specific dimensions used in the present example are only for illustrating the technical solution and do not limit the protection scope of the present invention.
As shown in fig. 5, a method for reinforcing a pier column coated with FRP-plastic pipe-iron-based SMA and rubber concrete includes the following steps.
The thermoplastic pipe is preferably a plastic pipe with high ductility and thermoplasticity in the market, such as PE pipe, HDPE pipe and the like. After the relevant dimensions are determined, selecting according to national standard specifications and corresponding plastic pipe specifications on the market, wherein the minimum thickness of the plastic pipe is not less than 3mm, and the tensile strength is not less than 22 MPa.
as shown in the figure, the end part of the iron-based SMA strip is anchored by a rivet 12 and is electrified and excited in a parallel mode by an electrifying device 11, and the current schematic diagram is shown in the figure.
As shown in fig. 3, enclosing the two semicircular thermoplastic pipe pieces obtained in the step 5 on the periphery of the part to be reinforced of the existing pier stud to form a thermoplastic pipe to be welded; and then, positioning the thermoplastic pipe to be welded by adopting the temporary support so that the thermoplastic pipe to be welded is concentric with the existing pier stud.
Welding the two semicircular thermoplastic tube sheets positioned in step 6 with a welding device to form a complete welded thermoplastic tube, as shown in figure 6 c; a concrete pour cavity is formed between the fused thermoplastic pipe and the existing pier stud and the temporary support is removed.
The method for welding the two semicircular thermoplastic pipe sheets preferably comprises the following steps.
Step 7A, installing a welding device: as shown in fig. 4, the welding device comprises a heating plate 7, a plastic pipe butt-joint driving machine 8 and a plastic pipe clamping part 9; two groups of heating sheets are respectively arranged at two enclosed gaps of the two semicircular thermoplastic pipe sheets; the plastic pipe clamping parts are at least eight groups; the top and the bottom of each semicircular thermoplastic pipe piece are respectively provided with at least two groups of plastic pipe clamping parts; each group of pipe clamping parts are clamped on the inner wall surface and the outer wall surface of the corresponding semicircular thermoplastic pipe piece; the tail part of each group of pipe clamping parts is respectively provided with a plastic pipe butt joint driving mechanism which is arranged along the radial direction of the existing pier column. The plastic pipe butt joint driving mechanism is in the prior art, and is preferably a full-automatic hydraulic oil cylinder.
Step 7B, heating by a heating sheet: the heating plate is energized and heated to a set temperature, such as 160 ℃.
And 7C, welding: all the plastic pipe butt joint driving mechanisms synchronously and radially move towards the direction of the circle center of the existing pier stud, so that the enclosed parts of the two semicircular thermoplastic pipe pieces form a molten state under the heating action of the heating sheet (preferably heating for 10-15 min); and then, withdrawing the heating plate, and enabling all the plastic pipe butting driving mechanisms to continuously move synchronously and radially towards the direction of the circle center of the existing pier stud, so that the two semicircular thermoplastic pipe pieces are welded to form the cylindrical welded thermoplastic pipe.
And 7D, after the welding parts of the two semicircular thermoplastic pipe pieces are cooled (preferably, the melting parts are cooled for 3-5 min), withdrawing the plastic pipe clamping part and the plastic pipe butt joint driving mechanism.
And 7D, before the welding parts of the two semicircular thermoplastic pipe pieces are cooled, utilizing an iron sheet to remove the molten part extruded and overflowed from the welding parts, and further ensuring the smoothness of the welding parts.
Step 8, pouring rubber concrete: as shown in d of fig. 6, in the concrete placing cavity formed in step 7, rubber concrete is placed and cured.
The rubber concrete is preferably blended with waste rubber particles having a particle size of 1 to 3 cm. The preparation method of the rubber concrete is preferably as follows: the waste rubber particles are subjected to soaking pretreatment for 24 hours, the soaked waste rubber particles are doped into cement in advance, and then the cement is fully stirred with other aggregates, so that the adverse effect of floating of the waste rubber particles is reduced.
The rubber mixing amount in the rubber concrete is preferably set according to the collision probability of the existing pier column.
When the collision probability of the existing pier stud is not less than the set value, the rubber mixing amount proportion in the rubber concrete is selected to be 60%, and a is one eighth of d 1.
When the collision probability of the existing pier stud is smaller than a set value, the rubber mixing amount in the rubber concrete is selected to be 20%.
In the rubber concrete pouring process, the concrete vibrating rod is preferably adopted for vibrating, and the compactness of the outer coating of the rubber concrete is ensured.
The curing method of the rubber concrete preferentially comprises the following steps: and after the rubber concrete is poured for 3 to 7 days and reaches 75 percent of the required strength, slightly polishing the outer surface of the fusion-welding thermoplastic pipe to ensure the adhesion of the FRP cloth belt and the fusion-welding plastic pipe.
Before the FRP cloth belt, the surface of the welding thermoplastic pipe contacted with the FRP cloth belt needs to be roughened firstly so as to promote the adhesive force between the FRP cloth belt and the thermoplastic pipe.
The covering method of the FRP cloth belt on the periphery of the fused thermoplastic pipe comprises full covering and interval covering. The specific coating mode can be correspondingly adjusted according to the actual engineering requirement.
When the interval wrapping is adopted and the original bearing capacity of the existing pier stud needs to be improved by 50% or more, the wrapping interval of the FRP cloth belt on the periphery of the fusion thermoplastic pipe is not less than 40mm (the preferred interval is 40 mm), and the number of the wrapping layers of the FRP cloth belt is not less than three layers (the preferred three layers).
Furthermore, before the FRP cloth belt is wrapped, the FRP cloth belt is preferably completely soaked by epoxy resin, and is continuously extruded without bubbles in the wrapping process so as to ensure the integrity of the FRP cloth belt-thermoplastic pipe system. After the epoxy resin is cured, an FRP-plastic pipe-rubber concrete outer coating system which is shown in figure 1 is formed and used for improving the performance of the existing pier column.
Although the preferred embodiments of the present invention have been described in detail, the present invention is not limited to the details of the embodiments, and various equivalent modifications can be made within the technical spirit of the present invention, and the scope of the present invention is also within the scope of the present invention.
Claims (10)
1. A method for reinforcing a pier column coated with FRP (fiber reinforced Plastic) -plastic pipe-iron-based SMA (shape memory alloy) and rubber concrete is characterized by comprising the following steps of: the method comprises the following steps:
step 1, selecting a thermoplastic pipe: selecting the inner diameter of the thermoplastic pipe according to the diameter of the existing pier stud and the thickness of the designed coating of the rubber concrete;
step 2, scabbling: performing chiseling treatment on the part to be reinforced of the existing pier stud;
step 3, wrapping and anchoring the iron-based SMA strip: wrapping the existing pier stud by using a pre-stretched iron-based SMA strip;
step 4, electrifying and exciting the iron-based SMA strip: electrifying and exciting the iron-based SMA strip;
step 5, splitting the thermoplastic pipe: vertically splitting the thermoplastic pipe into two uniform semicircular thermoplastic pipe pieces along the diameter direction by using a cutting tool;
step 6, enclosing, positioning and semi-circular thermoplastic pipe pieces: enclosing the two semicircular thermoplastic pipe pieces obtained in the step (1) on the periphery of the part to be reinforced of the existing pier stud to form a thermoplastic pipe to be welded; secondly, positioning the thermoplastic pipe to be welded by adopting a temporary support so that the thermoplastic pipe to be welded is concentric with the existing pier stud;
step 7, welding the thermoplastic pipe: welding the two semicircular thermoplastic pipe pieces positioned in the step (5) by using a welding device to form a complete welded thermoplastic pipe; after the temporary support is removed, a concrete pouring cavity is formed between the welded thermoplastic pipe and the existing pier stud;
step 8, pouring rubber concrete: pouring rubber concrete in the concrete pouring cavity formed in the step 7 and maintaining;
step 9, coating the FRP cloth belt: and after the maintenance of the rubber concrete is finished, wrapping an FRP cloth belt on the periphery of the fusion thermoplastic pipe.
2. The method for reinforcing pier column coated with FRP-plastic pipe-iron-based SMA and rubber concrete as claimed in claim 1, wherein: in the step 1, if the diameter of the existing pier column is d1, the designed coating thickness of the rubber concrete is a, and the inner diameter of the thermoplastic pipe is d2, then:
a is one tenth to one eighth of d 1; d2= d1+ a + b, wherein b is the fusion loss size and is 3-4 cm.
3. The method for reinforcing pier column coated with FRP-plastic pipe-iron-based SMA and rubber concrete as claimed in claim 2, wherein: in the step 8, the rubber mixing amount in the rubber concrete is set according to the collision probability of the existing pier stud; when the collision probability of the existing pier stud is not less than a set value, the rubber mixing amount proportion in the rubber concrete is selected to be 60%, and a is one eighth of d 1; when the collision probability of the existing pier stud is smaller than a set value, the rubber mixing amount in the rubber concrete is selected to be 20%.
4. The method for reinforcing pier column coated with FRP-plastic pipe-iron based SMA and rubber concrete as claimed in claim 1 or 3, wherein: the rubber mixed in the rubber concrete is waste rubber particles with the particle size of 1-3 cm.
5. The method for reinforcing pier column coated with FRP-plastic pipe-iron-based SMA and rubber concrete as claimed in claim 1, wherein: in the step 1, the lowest thickness of the thermoplastic pipe is not less than 3mm, and the tensile strength is not less than 22 MPa.
6. The method for reinforcing pier column coated with FRP-plastic pipe-iron-based SMA and rubber concrete as claimed in claim 1, wherein: in step 3, the wrapped iron-based SMA strip is end anchored using rivets.
7. The method for reinforcing pier column coated with FRP (fiber reinforced Plastic) -plastic pipe-iron-based SMA and rubber concrete as claimed in claim 1, wherein the method comprises the following steps: in the step 3, the pretensioning strain of the iron-based SMA strip is 4%; in step 4, the energizing temperature of the iron-based SMA strip is 200 ℃.
8. The method for reinforcing pier column coated with FRP (fiber reinforced Plastic) -plastic pipe-iron-based SMA and rubber concrete as claimed in claim 1, wherein the method comprises the following steps: in step 7, the method for welding the two semicircular thermoplastic pipe pieces comprises the following steps:
step 7A, installing a welding device: the welding device comprises a heating sheet, a plastic pipe clamping part and a plastic pipe butt joint driving mechanism; two groups of heating sheets are respectively arranged at two enclosed gaps of the two semicircular thermoplastic pipe sheets; the plastic pipe clamping parts are at least eight groups; the top and the bottom of each semicircular thermoplastic pipe piece are respectively provided with at least two groups of plastic pipe clamping parts; each group of pipe clamping parts are clamped on the inner wall surface and the outer wall surface of the corresponding semicircular thermoplastic pipe piece; the tail part of each group of pipe clamping parts is respectively provided with one plastic pipe butt joint driving mechanism, and the plastic pipe butt joint driving mechanisms are all distributed along the radial direction of the existing pier column;
step 7B, heating by a heating plate: electrifying the heating sheet and heating to a set temperature;
and 7C, welding: all the plastic pipe butt joint driving mechanisms synchronously and radially move towards the direction of the circle center of the existing pier stud, so that the enclosing parts of the two semicircular thermoplastic pipe pieces form a molten state under the heating action of the heating sheets; then, the heating sheet is withdrawn, all the plastic pipe butt joint driving mechanisms continue to synchronously and radially move towards the direction of the circle center of the existing pier stud, and the two semicircular thermoplastic pipe pieces are welded to form a cylindrical welded thermoplastic pipe;
and 7D, after the welding parts of the two semicircular thermoplastic pipe pieces are cooled, withdrawing the plastic pipe clamping part and the plastic pipe butt joint driving mechanism.
9. The method for reinforcing pier column coated with FRP-plastic pipe-iron-based SMA and rubber concrete as claimed in claim 8, wherein: and 7D, before the welding parts of the two semicircular thermoplastic pipe pieces are cooled, utilizing an iron sheet to remove the molten part extruded and overflowed from the welding parts, and further ensuring the smoothness of the welding parts.
10. The method for reinforcing pier column coated with FRP (fiber reinforced Plastic) -plastic pipe-iron-based SMA and rubber concrete as claimed in claim 1, wherein the method comprises the following steps: step 9, coating the FRP cloth belt on the periphery of the fused thermoplastic pipe by a full coating method and an interval coating method; when the interval wrapping is adopted and the original bearing capacity of the existing pier stud is required to be improved by 50% or more, the wrapping distance of the FRP cloth belt on the periphery of the fusion thermoplastic pipe is not less than 40mm, and the number of the wrapping layers of the FRP cloth belt is not less than three.
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| US6219991B1 (en) * | 1990-08-06 | 2001-04-24 | Hexcel Corporation | Method of externally strengthening concrete columns with flexible strap of reinforcing material |
| KR100665563B1 (en) * | 2006-09-20 | 2007-01-09 | 채상훈 | Apparatus of mending for pier |
| CN104005567A (en) * | 2014-05-07 | 2014-08-27 | 北京工业大学 | Ultra-high-performance concrete reinforced concrete column with fiber reinforced polymers wound around steel pipe |
| US20160145882A1 (en) * | 2009-11-13 | 2016-05-26 | Mohammad Reza Ehsani | Reinforcement and repair of structural columns |
| CN107059665A (en) * | 2017-06-19 | 2017-08-18 | 桂林理工大学 | A kind of method of utilization pre-stress FRP cloth reinforced steel concrete pier stud |
| CN111236096A (en) * | 2020-03-30 | 2020-06-05 | 福州大学 | Pier column vertical prestressed tendon reinforcing structure and construction method |
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2022
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| US6219991B1 (en) * | 1990-08-06 | 2001-04-24 | Hexcel Corporation | Method of externally strengthening concrete columns with flexible strap of reinforcing material |
| KR100665563B1 (en) * | 2006-09-20 | 2007-01-09 | 채상훈 | Apparatus of mending for pier |
| US20160145882A1 (en) * | 2009-11-13 | 2016-05-26 | Mohammad Reza Ehsani | Reinforcement and repair of structural columns |
| CN104005567A (en) * | 2014-05-07 | 2014-08-27 | 北京工业大学 | Ultra-high-performance concrete reinforced concrete column with fiber reinforced polymers wound around steel pipe |
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