Composite prestressed reinforcement system for hydraulic concrete structure and its construction method

Abstract

The present invention discloses a composite prestressed reinforcement system for a hydraulic concrete structure and a construction method thereof, which relates to the field of hydraulic concrete structure reinforcement systems. The composite prestressed reinforcement system for a hydraulic concrete structure comprises: a prestressed carbon fiber plate, the two ends of the prestressed carbon fiber plate are respectively fixed to the bottom end of a hydraulic concrete T-beam through a first anchoring mechanism and a first tensioning mechanism; and at least two prestressed steel strands are also included, the prestressed steel strands are symmetrically fixed below the partitions on the two sides of the bottom of the hydraulic concrete T-beam, one end of the prestressed steel strand is connected to the second tensioning mechanism, and the other end is connected to the second anchoring mechanism; the construction method comprises: laying out and positioning, base surface treatment; anchor installation; prestressed carbon fiber plate, prestressed steel strand installation and laying; glue preparation, application of carbon fiber plate adhesive; prestressed tensioning, locking; surface sealing treatment. The composite prestressed reinforcement system for a hydraulic concrete structure and a construction method thereof provided by the present invention can effectively increase the strength and rigidity of the structure, improve the bearing capacity of the structure, and at the same time reduce the deflection and deformation of the structure, and can play a role in reducing and sealing cracks.

Description

Technical Field

[0001] The invention relates to the technical field of hydraulic concrete structure reinforcement systems, and in particular to a hydraulic concrete structure composite prestressed reinforcement system and a construction method thereof. Background Art

[0002] Hydraulic concrete structures (aqueducts, water intake towers, traffic bridges and working bridges, plant buildings, etc.) have insufficient bearing capacity or structural cracks due to overload, insufficient reinforcement area, small structural section, various damages and other reasons (such as reconstruction, expansion, grade improvement, etc.). In order to ensure the safety of the structure and restore its normal use function, reinforcement treatment must be carried out.

[0003] Traditional methods of reinforcing concrete structures include increasing the cross-section, gluing steel, gluing carbon fiber composite materials, implanting steel bars, external prestressing, etc. However, there are problems such as complex construction technology, certain damage to the original structure, changes to the existing structure, and failure to fully utilize the high performance of the reinforcement materials.

[0004] The non-prestressed reinforcement technology of in vitro bonding of high-performance materials has obvious stress lag phenomenon, and cannot fully utilize the high performance of the reinforced materials. The reinforced structure is prone to bonding failure, and the stress structure is complex, the reinforcement effect is not obvious, and its main function is to inhibit the further development of defects and serve as a structural safety reserve.

[0005] External prestressed structural reinforcement technology is to apply prestressing to make the structure generate stress to offset the stress generated by part of the load, thereby achieving the purpose of improving the bearing capacity of the structure. It is an active reinforcement method, with clearer force than other reinforcement types, and more direct and effective reinforcement. Most of the existing external prestressed reinforcements use prestressed steel strands as the prestressing system. The external prestressed reinforcement of steel structures has problems such as small external cable tension force, relatively difficult anti-corrosion and protection. The use of carbon fiber plate prestressed cables has the advantages of light material, high strength, corrosion resistance, and fatigue resistance. Therefore, using carbon fiber materials as external prestressed cables can overcome the above problems. Carbon fiber materials have excellent tensile properties, but their shear resistance is poor. They cannot be arranged on the side of the structure (such as the side of the beam), and cannot improve the lateral stiffness of the structure or close lateral cracks. Therefore, carbon fiber plate prestressed cables are generally arranged on the tensile side of the structure (such as the bottom of the beam).

[0006] The external prestressed reinforcement method has the above advantages and has been widely used in the reinforcement of concrete structures. If the carbon fiber plate can be used for the tensile part of the positive section of the structure and the steel strand can be used for the eccentric tensile side, the high performance of the carbon fiber material can be fully utilized, and the shear resistance of the steel strand can be brought into play. This composite prestressed reinforcement system will be more reliable and the reinforcement effect will be more obvious. Summary of the invention

[0007] The purpose of the present invention is to provide a composite prestressed reinforcement system for hydraulic concrete structures to solve the structural damage and unsatisfactory reinforcement effect existing in the prior art.

[0008] The purpose of the present invention is to provide a method for constructing a composite prestressed reinforcement system for hydraulic concrete structures, in which a prestressed carbon fiber plate system is applied to the tensile portion of the positive section of the structure, and a prestressed steel strand system is applied to the eccentric tensile zone of the structure. The two are organically combined to form a composite prestressed reinforcement system, which can fully utilize the high tensile strength of the carbon fiber material and the ability of the steel strand to adapt to lateral deformation, and further improve the reinforcement effect.

[0009] A composite prestressed reinforcement system for hydraulic concrete structures of the present invention comprises:

[0010] A prestressed carbon fiber plate, wherein both ends of the prestressed carbon fiber plate are respectively fixed to the bottom end of the hydraulic concrete T-beam through a first anchoring mechanism and a first tensioning mechanism; and further comprising,

[0011] At least two prestressed steel strands are symmetrically fixed below the partitions on both sides of the bottom of the hydraulic concrete T-beam. One end of the prestressed steel strand is connected to the second tensioning mechanism, which is arranged close to the first tensioning mechanism. The other end of the prestressed steel strand is connected to the second anchoring mechanism, which is arranged close to the first fixing mechanism.

[0012] Furthermore, the first anchoring mechanism includes a fixed end support, a fixed end anchor is arranged on one side of the fixed end support, the prestressed carbon fiber plate passes through the fixed end support and is connected to the fixed end anchor, and the fixed end support is fixed to the bottom end of the hydraulic concrete T-beam by six symmetrically arranged chemical anchors.

[0013] Furthermore, the first tensioning mechanism includes a tensioning end support, a tensioning end anchor is provided on one side of the tensioning end support, and a tensioning tool is provided on the other side, the tensioning end anchor is connected to the tensioning tool by a tensioning screw passing through the tensioning end support, nuts are provided on the ends of both ends of the tensioning screw, the prestressed carbon fiber plate is fixedly connected to the tensioning end anchor, and the tensioning end support is fixed to the bottom end of the hydraulic concrete T-beam by six symmetrically arranged chemical anchors.

[0014] Furthermore, the prestressed carbon fiber plate is fixed to the bottom end of the hydraulic concrete T-beam through a plurality of pressure strips.

[0015] Furthermore, the second anchoring mechanism includes a first C-shaped channel steel, an extruded anchor head is arranged on one side of the first C-shaped channel steel, first stiffening plates are arranged at both ends and the C-shaped opening of the first C-shaped channel steel, the prestressed steel strand passes through the cavity surrounded by the first stiffening plate and the first C-shaped channel steel and is connected to the extruded anchor head, and the first C-shaped channel steel is fixed to the side of the hydraulic concrete T-beam by four symmetrically arranged chemical anchors.

[0016] Furthermore, the second tensioning mechanism includes a second C-shaped channel steel, a clip anchor is arranged on one side of the second C-shaped channel steel, second stiffening plates are arranged at both ends and the C-shaped opening of the second C-shaped channel steel, the prestressed steel strand passes through the cavity surrounded by the second stiffening plate and the second C-shaped channel steel and is connected to the clip anchor, and the second C-shaped channel steel is fixed to the side of the hydraulic concrete T-beam by four symmetrically arranged chemical anchors.

[0017] A construction method of a composite prestressed reinforcement system for a hydraulic concrete structure of the present invention comprises the following steps:

[0018] 1) Wire positioning and base surface treatment:

[0019] The installation positions of the prestressed carbon fiber plates and prestressed steel strands are determined by measuring and laying out. The groove depth of the first anchoring mechanism, the first tensioning mechanism, the second anchoring mechanism, and the second tensioning mechanism installation parts is 2 to 3 cm. The loose layer of concrete on the bonding surface of the prestressed carbon fiber plates on the hydraulic concrete T-beam is polished until the fresh concrete is completely exposed. The concave surface of the polished concrete is repaired with epoxy repair glue, and the high convex surface of the concrete should be polished flat. Finally, the base surface is rinsed and dried. The design gap between the prestressed carbon fiber plate and the concrete is 3 mm to 5 mm.

[0020] 2) Anchor installation;

[0021] The first anchoring mechanism and the first tensioning mechanism as well as the second tensioning mechanism and the second anchoring mechanism are fixed to the two ends of the hydraulic concrete T-beam by chemical anchor bolts, and the steel bar detector is used to avoid the steel bars on the hydraulic concrete T-beam (4) and mark the bolt drilling position, the drilling hole is perpendicular to the concrete surface, and the deviation of the drilling center position does not exceed 3 mm;

[0022] When using chemical hoses or anchor glue to implant bolts, the glue in the hole should be full and the bolts should be perpendicular to the structural surface; the tensioning anchor end of the prestressed steel strand needs to be bonded to the concrete surface;

[0023] The center line of the fixed end support and the tension end support should be parallel or overlapped with the center line of the prestressed carbon fiber plate or the prestressed steel strand. The deviation of the center extension line of the fixed end support and the tension end support calculated according to the full length of the prestressed carbon fiber plate or prestressed steel strand shall not exceed ±5mm;

[0024] The gaps between the mounting holes on the fixed-end support and the bolts after trimming due to drilling deviation should be filled with epoxy repair glue during installation. The gaps between the fixed-end support and the tension-end support and the concrete after leveling should also be filled or leveled with epoxy repair glue.

[0025] 3) Installation and laying of prestressed steel strands;

[0026] The prestressed steel strands are arranged symmetrically on both sides of the hydraulic concrete T-beam. The prestressed steel strands pass through the reserved holes on the C-shaped channel steel. The second anchoring mechanism is fixed to the hydraulic concrete T-beam by squeezing the anchor head. The chemical anchor bolts that pass through the C-shaped channel steel and are fixed to the hydraulic concrete T-beam should avoid the prestressed steel strands; the deviation of the drilling center position should not exceed 5mm. When using chemical hoses or rebar glue to implant bolts, ensure that the glue in the hole is full and the bolts are perpendicular to the concrete surface;

[0027] The second tensioning mechanism and the second anchoring mechanism at both ends of the prestressed steel strands are sealed around the joints with the hydraulic concrete T-beam, and glue injection holes and exhaust holes are reserved. After the sealing inspection and pressure test, glue injection is carried out. After the glue liquid is solidified, it is inspected and additional glue injection is carried out in a timely manner;

[0028] The center line of the second tensioning mechanism and the second anchoring mechanism should be parallel to or overlap with the center line of the prestressed steel strand.

[0029] 4) Prepare glue and apply carbon fiber board adhesive;

[0030] During the installation and laying of prestressed carbon fiber panels, the straightness of the carbon fiber panels should be checked, and the straightness deviation of the entire length should not exceed 20mm;

[0031] After the prestressed carbon fiber plate is in place, the first tensioning mechanism (pressurized and tensioned to 15% of the designed tensioning stress value) is used to check whether there is a gap between the prestressed carbon fiber plate and the surface of the hydraulic concrete T-beam between the tensioning end anchor and the fixed end anchor. If there is a high convex contact point or surface, the pressure should be relieved, disassembled and polished before tensioning and inspection.

[0032] 5) Prestressing and locking;

[0033] The prestressed carbon fiber plate 1 is tensioned in stages, and both sides of the prestressed steel strands 5 are tensioned simultaneously, using symmetrical, staged, cyclic tensioning.

[0034] First, the prestressed steel strands are tensioned. Two hydraulic jacks are used to tension the strands at symmetrical positions on both sides at the same time. The tensioning control stress is 0.6f ptk (Strength standard value).

[0035] The tensioning is carried out in stages to 30%, 50%, 80% and 100% of the designed tensioning stress value. During the tensioning process, the stress is controlled by an oil pressure gauge and the actual elongation of the stranded wire is measured to verify the prestressing value.

[0036] Secondly, prestressed carbon fiber plates are tensioned, pressurized and tensioned to 30% of the designed tension stress value, and check whether there is any glue squeezed out between the edge of the carbon fiber plate and the concrete surface. If there is no glue squeezed out locally, the pressure should be released and the glue should be replenished before tensioning; check whether the anchor stroke displacement corresponds to the burnt line during pre-tensioning.

[0037] Gradually pressurize and tension to 50%, 70%, 90%, and 100% of the designed tension stress value, and check whether the travel displacement of the tension end anchor meets the requirements of the theoretical elongation. According to the specification requirements, the error between the travel displacement of the tension end anchor and the theoretical elongation should not be greater than ±6%;

[0038] When the tension stress value and the travel displacement of the tensioning end anchor meet the theoretical elongation requirements, tighten the locking bolts on the tensioning screw into place. After pausing for 5 minutes without other abnormal conditions, remove the jack and anchor tensioning bracket; at the same time, tighten the bolts on the clamping strip to ensure that there is no gap between the prestressed carbon fiber plate and the clamping strip.

[0039] When pressurizing or depressurizing, the jack stroke speed should be controlled within 20mm / min, and it is strictly forbidden to quickly punch or release the jack stroke. All tensioning should be completed within the applicable period of the carbon plate glue (60min).

[0040] After the tensioning is completed and the compression strip is installed, the glue filling work of the prestressed carbon fiber board can begin. It is required that the gap between the prestressed carbon fiber board and the hydraulic concrete T-beam is filled with adhesive, and the adhesive on the edge of the prestressed carbon fiber board is full and at a 45-degree angle to the concrete base.

[0041] 6) Surface sealing treatment.

[0042] After the prestressing is locked, the prestressed steel strands and their tensioning mechanisms and anchoring mechanisms are protected with epoxy mortar, and then polyurea material is applied on the surface of the prestressed carbon fiber plate and epoxy mortar for sealing treatment to ensure the durability of the prestressed carbon fiber plate and prestressed steel strands.

[0043] In the above technical scheme, the beneficial effect of the composite prestressed reinforcement system for hydraulic concrete structure provided by the present invention is: the prestressed carbon fiber plate and the prestressed steel strand reinforcement system are cleverly combined to form a set of composite prestressed reinforcement system, which can give full play to the characteristics of carbon fiber material, such as light weight, high tensile strength and aging resistance, and can also utilize the characteristics of steel strands to adapt to the side deformation of the structure. The composite prestressed reinforcement system for hydraulic concrete structure can effectively increase the strength and rigidity of the structure, improve the bearing capacity of the structure, and at the same time reduce the deflection deformation of the structure, and can play a role in reducing and closing cracks. The composite prestressed reinforcement system for hydraulic concrete structure is arranged on the surface of the reinforced structure, causes little damage to the structure, does not destroy the integrity of the original structure, is easy to lay, anchor and tension, and is quick to construct.

[0044] In the above technical scheme, the beneficial effect of the construction method of a composite prestressed reinforcement system for a hydraulic concrete structure provided by the present invention is: the prestressed steel strand system and the prestressed carbon plate system are reasonably arranged, tensioned and locked in sequence, so that the two prestressed systems are organically combined into a complete reinforcement system. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0046] Figure 1 It is a structural schematic diagram of a composite prestressed reinforcement system for a hydraulic concrete structure provided by an embodiment of the present invention;

[0047] Figure 2 yes Figure 1 AA side section view;

[0048] Figure 3 yes Figure 1 A schematic structural diagram of the first anchoring mechanism;

[0049] Figure 4 yes Figure 3 Bottom view of

[0050] Figure 5 yes Figure 1 The structural diagram of the first tensioning mechanism;

[0051] Figure 6 yes Figure 5 Bottom view of

[0052] Figure 7 yes Figure 1 A cross-sectional view of the second anchoring mechanism;

[0053] Figure 8 yes Figure 7 A top view of

[0054] Fig. 9 yes Figure 1 The structural diagram of the second tensioning mechanism;

[0055] Fig.10 yes Fig. 9 Top view of the .

[0056] Description of reference numerals:

[0057] 1. Prestressed carbon fiber plate; 2. First anchoring mechanism; 3. First tensioning mechanism; 4. Hydraulic concrete T-beam; 5. Prestressed steel strand; 6. Partition; 7. Second tensioning mechanism; 8. Second anchoring mechanism; 9. Fixed end support; 10. Anchor end anchor; 11. Tensioning end support; 12. Tensioning end anchor; 13. Tensioning tool; 14. Tensioning screw; 15. Pressure strip; 16. First C-shaped channel steel; 17. Extruded anchor head; 18. First stiffening plate; 19 Clip anchor; 20. Second C-shaped channel steel; 21. Second stiffening plate. DETAILED DESCRIPTION

[0058] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0059] See also Figure 1-10 As shown;

[0060] A composite prestressed reinforcement system for a hydraulic concrete structure of the present invention comprises:

[0061] A prestressed carbon fiber plate 1, both ends of which are fixed to the bottom end of a hydraulic concrete T-beam 4 through a first anchoring mechanism 2 and a first tensioning mechanism 3 respectively; and further comprising:

[0062] At least two prestressed steel strands 5 are symmetrically fixed below the partitions 6 on both sides of the bottom of the hydraulic concrete T-beam 4. One end of the prestressed steel strand 5 is connected to the second tensioning mechanism 6, and the second tensioning mechanism 7 is arranged close to the first tensioning mechanism 3. The other end of the prestressed steel strand 5 is connected to the second anchoring mechanism 8, and the second anchoring mechanism 8 is arranged close to the first fixing mechanism 2.

[0063] The first anchoring mechanism 2 includes a fixed end support 9, a fixed end anchor 10 is arranged on one side of the fixed end support 9, the prestressed carbon fiber plate 1 passes through the fixed end support 9 and is connected to the fixed end anchor 10, and the fixed end support 9 is fixed to the bottom end of the hydraulic concrete T-beam 4 by six symmetrically arranged chemical anchors.

[0064] The first tensioning mechanism 3 includes a tensioning end support 11, a tensioning end anchor 12 is provided on one side of the tensioning end support 11, and a tensioning tool 13 is provided on the other side. The tensioning end anchor 12 and the tensioning tool 13 are connected through a tensioning screw 14 passing through the tensioning end support 11, and nuts are provided on the ends of both ends of the tensioning screw 14. The prestressed carbon fiber plate 1 is fixedly connected to the tensioning end anchor 12, and the tensioning end support 11 is fixed to the bottom end of the hydraulic concrete T-beam 4 through six symmetrically arranged chemical anchor bolts. During prestressing, the jack acts on the tensioning end support 11 and the tensioning tool 13, and the prestressed carbon fiber plate 1 is tensioned by moving the tensioning screw 14. After the tensioning stress value and the travel displacement of the tensioning end anchor meet the theoretical elongation requirements, the nut on the tensioning screw 14 is rotated to lock, and the prestressing is completed.

[0065] The prestressed carbon fiber plate 1 is fixed to the bottom end of the hydraulic concrete T-beam 4 through a plurality of pressure strips 15. The pressure strips 15 are fixed to the bottom end of the hydraulic concrete T-beam 4 through bolts.

[0066] The second anchoring mechanism 8 includes a first C-shaped channel steel 16, an extruded anchor head 17 is arranged on one side of the first C-shaped channel steel 16, first stiffening plates 18 are arranged at both ends and the C-shaped opening of the first C-shaped channel steel 16, the prestressed steel strand 5 passes through the cavity surrounded by the first stiffening plate 18 and the first C-shaped channel steel 16 and is connected to the extruded anchor head 17, and the first C-shaped channel steel 16 is fixed to the side of the hydraulic concrete T-beam 4 by four symmetrically arranged chemical anchor bolts.

[0067] The second tensioning mechanism 7 includes a second C-shaped channel steel 20, a clip anchor 19 is arranged on one side of the second C-shaped channel steel 20, second stiffening plates 21 are arranged at both ends and the C-shaped opening of the second C-shaped channel steel 20, the prestressed steel strand 5 passes through the cavity surrounded by the second stiffening plate 21 and the second C-shaped channel steel 20 and is connected to the clip anchor 19, and the second C-shaped channel steel 20 is fixed to the side of the hydraulic concrete T-beam 4 by four symmetrically arranged chemical anchors.

[0068] After the tensioning is completed, the prestressed steel strand 5 is locked by the tensioning end anchor 19.

[0069] The performance index requirements of prestressed carbon fiber panels 1 are as follows:

[0070] project Performance Indicators Tensile strength standard value (MPa) ≥2400 Tensile elastic modulus (MPa) <![CDATA[≥1.6×10 5 ]]> Elongation(%) ≥1.6 Interlaminar shear strength (MPa) ≥50 Carbon fiber volume content (%) ≥65

[0071] A construction method of a composite prestressed reinforcement system for a hydraulic concrete structure of the present invention comprises the following steps:

[0072] 1) Wire positioning and base surface treatment:

[0073] The installation positions of the prestressed carbon fiber plate 1 and the prestressed steel strand 5 are determined by measuring and laying out. The groove depth of the installation parts of the first anchoring mechanism 2, the first tensioning mechanism 3, the second tensioning mechanism 7, and the second anchoring mechanism 8 is 2 to 3 cm. The loose concrete layer on the bonding surface of the prestressed carbon fiber plate 1 on the hydraulic concrete T-beam 4 is polished until the fresh concrete is completely exposed. The concave surface of the polished concrete is repaired with epoxy repair glue, and the high convex surface of the concrete should be polished flat. Finally, the base surface is rinsed and dried. The design gap between the prestressed carbon fiber plate and the concrete is 3 mm to 5 mm.

[0074] 2) Anchor installation;

[0075] The first anchoring mechanism 2 and the first tensioning mechanism 4 as well as the second tensioning mechanism 7 and the second anchoring mechanism 8 are fixed to both ends of the hydraulic concrete T-beam 4 by chemical anchor bolts, and a steel bar detector is used to avoid the steel bars on the hydraulic concrete T-beam 4 and calibrate the bolt drilling position. The drilling hole is perpendicular to the concrete surface, and the deviation of the drilling center position does not exceed 3 mm;

[0076] When using chemical hoses or anchor glue to implant bolts, it should be ensured that the glue in the hole is full and the bolts are perpendicular to the structural surface; the tensioning anchor end of the prestressed steel strand 5 needs to be bonded to the concrete surface.

[0077] The center lines of the fixed end support 9 and the tension end support 11 should be parallel to or overlap with the center line of the prestressed carbon fiber plate. The deviation of the center extension lines of the fixed end support 9 and the tension end support 11 calculated according to the full length of the prestressed carbon fiber plate 1 shall not exceed ±5mm.

[0078] The gaps between the mounting holes of the fixed-end support 9 and the tension-end support 11 and the bolts after the drilling deviation is trimmed should be filled with epoxy repair glue during installation. The gaps between the fixed-end support 9 and the tension-end support 11 and the concrete after leveling should also be filled or leveled with epoxy repair glue.

[0079] 3) Installation and laying of prestressed steel strands;

[0080] The prestressed steel strands 5 are symmetrically arranged on both sides of the hydraulic concrete T-beam 4. The prestressed steel strands 5 pass through the reserved holes on the C-shaped channel steel 16. The second anchoring mechanism 8 is fixed to the hydraulic concrete T-beam 4 by squeezing the anchor heads 17. The chemical anchor bolts that pass through the C-shaped channel steel 16 and are fixed to the hydraulic concrete T-beam 4 should avoid the prestressed steel strands 5. The deviation of the center position of the drilling hole does not exceed 5mm. When using chemical hoses or rebar glue to implant bolts, it should be ensured that the glue in the hole is full and the bolts are perpendicular to the concrete surface.

[0081] The second tensioning mechanism 7 and the second anchoring mechanism 8 at both ends of the prestressed steel strand 5 are sealed around the joint of the hydraulic concrete T-beam 4, and glue injection holes and exhaust holes are reserved. Glue injection is carried out after sealing inspection and pressure test. After the glue liquid is solidified, it is checked and additional glue injection is carried out in time.

[0082] The center lines of the second tensioning mechanism 7 and the second anchoring mechanism 8 should be parallel to or overlap with the center line of the prestressed steel strand 5 .

[0083] 4) Prepare glue and apply carbon fiber board adhesive;

[0084] During the installation and laying process of the prestressed carbon fiber plate 1, the straightness of the prestressed carbon fiber plate 1 is checked in particular, and the straightness deviation of the whole length shall not exceed 20 mm.

[0085] After the prestressed carbon fiber plate 1 is in place, pre-tensioning (pressurizing and tensioning to 15% of the designed tensioning stress value) is used to check whether there is a gap between the surface of the prestressed carbon fiber plate 1 and the hydraulic concrete T-beam 4 between the second tensioning mechanism 7 and the second anchoring mechanism 8 at both ends. If there is a high convex contact point or surface, the pressure should be relieved, disassembled, polished, and then tensioned for inspection.

[0086] The main agent of structural adhesive and curing agent are prepared in a mass ratio of 2:1. Apply evenly on the surface of the structure.

[0087] After the adhesive is prepared, in order to allow the adhesive to fully infiltrate, penetrate, and adhere to the bonding surface of the carbon fiber composite sheet, a small amount of adhesive should be scraped on the bonding surface of the carbon fiber composite sheet with a spatula, and it should be scraped vigorously several times, and then scraped to the required colloid thickness of 4 to 10 mm (the specific thickness of the colloid depends on the flatness of the bonding surface of the original structure) according to the principle of thick middle and thin edges in the width direction of the prestressed carbon fiber board 1.

[0088] The performance indicators of carbon fiber board adhesive are as follows:

[0089] project Performance Indicators Tensile strength(MPa) ≥40 Tensile elastic modulus (MPa) ≥2500 Elongation(%) ≥1.5 Flexural strength(MPa) ≥50, and no brittle failure Compressive strength(MPa) ≥70 Steel-steel tensile strength shear value (MPa) ≥14 Positive bond strength with concrete (MPa) ≥2.5, and concrete cohesive failure

[0090] 5) Prestressing and locking;

[0091] The prestressed carbon fiber plate 1 is tensioned in stages, and both sides of the prestressed steel strands 5 are tensioned simultaneously, using symmetrical, staged, cyclic tensioning.

[0092] First, the prestressed steel strands are tensioned. Two hydraulic jacks are used to tension the strands at symmetrical positions on both sides at the same time. The tensioning control stress is 0.6f ptk (Strength standard value).

[0093] The tensioning is carried out in stages to 30%, 50%, 80% and 100% of the designed tensioning stress value. During the tensioning process, the stress is controlled by an oil pressure gauge and the actual elongation of the stranded wire is measured to verify the prestressing value.

[0094] Secondly, prestressed carbon fiber plates are tensioned, pressurized and tensioned to 30% of the designed tension stress value, and check whether there is any glue squeezed out between the edge of the carbon fiber plate and the concrete surface. If there is no glue squeezed out locally, the pressure should be released and the glue should be replenished before tensioning; check whether the anchor stroke displacement corresponds to the burnt line during pre-tensioning.

[0095] The tensioning is carried out in stages with pressure applied to 50%, 70%, 90% and 100% of the designed tensioning stress value, and the stroke displacement of the tensioning end anchor is tested to see whether it meets the requirement of theoretical elongation. According to the specification, the error between the stroke displacement of the tensioning end anchor 12 and the theoretical elongation should not be greater than ±6%.

[0096] σ=F / A (1)

[0097] Where: σ——tensile stress value, MPa;

[0098] F——tension, N;

[0099] A——Cross-sectional area of ​​steel strand, mm 2 .

[0100] ε=Δl / l (2)

[0101] Where: ε——tension strain;

[0102] Δl——elongation of steel strand, mm;

[0103] l——Length of steel strand, mm.

[0104] σ=Eε (3)

[0105] Where: E——elastic modulus of steel strand, MPa;

[0106] The above formula (3) is Hooke's law, the basic law of elastic mechanics, which states that stress and strain are linearly related within the elastic range. When a tensile force value is given to the steel strand, there is a corresponding tensile stress value. The elastic modulus of the material is a known quantity. According to Hooke's formula, the strain of the steel strand can be deduced, and then the theoretical elongation of the steel strand can be obtained.

[0107] The elongation of the steel strand measured during on-site prestressing is its actual elongation. There is a certain error between the theoretical elongation and the actual elongation, and the error range is controlled within ±6%.

[0108] When the tension stress value and the travel displacement of the tension end anchor 12 meet the requirements, tighten the nut on the tension screw 14 into place. After pausing for 5 minutes without other abnormal conditions, remove the jack; at the same time, tighten the bolts on the clamping strip to ensure that there is no gap between the prestressed carbon fiber plate 1 and the clamping strip 15.

[0109] When pressurizing or depressurizing, the jack stroke speed should be controlled within 20mm / min, and it is strictly forbidden to quickly punch or release the jack stroke; all tensioning should be completed within the applicable period of the carbon plate glue (60min).

[0110] After the tensioning is completed and the compression strip is installed, the glue filling work of the prestressed carbon fiber plate 1 can begin. It is required that the gap between the prestressed carbon fiber plate 1 and the hydraulic concrete T-beam 4 is filled with adhesive, and the adhesive on the edge 1 of the prestressed carbon fiber plate is full and forms a 45-degree angle with the base surface of the hydraulic concrete T-beam 4.

[0111] 6) Surface sealing treatment.

[0112] After the prestressing is locked, the prestressed steel strand 5 and its tensioning mechanism 7 and anchoring mechanism 8 are protected with epoxy mortar, and then polyurea material is applied on the surface of the prestressed carbon fiber plate 1 and the epoxy mortar for sealing treatment to ensure the durability of the prestressed carbon fiber plate 1 and the prestressed steel strand 5. The performance indicators of the single-component polyurea are as follows:

[0113] project Performance Indicators Viscosity (MPa·s) ≥3000 Solid content (%) ≥80 Surface drying time (h) ≤6 Tensile strength(MPa) ≥15 Elongation at break (%) ≥300 Tear strength (N / mm) ≥40 Low temperature flexural properties(℃) ≤-40 Waterproofness (0.4MPa*2h) impermeable Bond strength (MPa) ≥2.0

[0114] The above description is only by way of illustration of certain exemplary embodiments of the present invention. It is undoubted that those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the above drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A composite prestressed reinforcement system for hydraulic concrete structures, characterized in that: include: A prestressed carbon fiber plate (1), wherein two ends of the prestressed carbon fiber plate (1) are respectively fixed to the bottom end of a hydraulic concrete T-beam (4) through a first anchoring mechanism (2) and a first tensioning mechanism (3); include, At least two prestressed steel strands (5), the prestressed steel strands (5) are symmetrically fixed below the partitions (6) on the two side surfaces of the bottom of the hydraulic concrete T-beam (4), one end of the prestressed steel strands (5) is connected to a second tensioning mechanism (7), the second tensioning mechanism (7) is arranged close to the first tensioning mechanism (3), the other end of the prestressed steel strands is connected to a second anchoring mechanism (8), the second anchoring mechanism (8) is arranged close to the first fixing mechanism (2), the first tensioning mechanism (3) includes a tensioning end support (11), one side of the tensioning end support (11) is provided with a tensioning end anchor (12), and the other side is provided with a tensioning tool (13) ), the tensioning end anchor (12) and the tensioning tool (13) are connected via a tensioning screw (14) passing through the tensioning end support (11), nuts are provided at the ends of both ends of the tensioning screw (14), the prestressed carbon fiber plate (1) is fixedly connected to the tensioning end anchor (12), the tensioning end support (11) is fixed to the bottom end of the hydraulic concrete T-beam (4) via six symmetrically arranged chemical anchor bolts, the prestressed carbon fiber plate (1) is fixed to the bottom end of the hydraulic concrete T-beam (4) via a plurality of pressure strips (15), the second tensioning mechanism (7) comprises a second C-shaped channel steel (20), one side of the second C-shaped channel steel (20) A clip anchor (19) is provided, and second stiffening plates (21) are provided at both ends and the C-shaped opening of the second C-shaped channel steel (20). The prestressed steel strand (5) passes through a cavity surrounded by the second stiffening plate (21) and the second C-shaped channel steel (20) and is connected to the clip anchor (19). The second C-shaped channel steel (20) is fixed to the side of the hydraulic concrete T-shaped beam (4) by four symmetrically arranged chemical anchor bolts. The first anchoring mechanism (2) includes a fixed end support (9), and a fixed end anchor (10) is provided on one side of the fixed end support (9). The prestressed carbon fiber plate (1) passes through the fixed end support (9) and is connected to the fixed end anchor (10). The fixed end support (9) is fixed to the bottom end of the hydraulic concrete T-beam (4) by six symmetrically arranged chemical anchor bolts, the second anchoring mechanism (8) comprises a first C-shaped channel steel (16), an extrusion anchor head (17) is arranged on one side of the first C-shaped channel steel (16), first stiffening plates (18) are arranged at both ends and the C-shaped opening of the first C-shaped channel steel (16), the prestressed steel strand (5) passes through the cavity surrounded by the first stiffening plate (18) and the first C-shaped channel steel (16) and is connected to the extrusion anchor head (17), and the first C-shaped channel steel (16) is fixed to the side of the hydraulic concrete T-beam (4) by four symmetrically arranged chemical anchor bolts.

2. The construction method of the composite prestressed reinforcement system for hydraulic concrete structure according to claim 1 comprises the following steps: 1) Wire positioning and base surface treatment: The installation positions of the prestressed carbon fiber plate (1) and the prestressed steel strand (5) are determined by measuring and laying out, and the installation positions of the first anchoring mechanism (2) and the first tensioning mechanism (3) are 2 to 3 cm deep; the loose concrete layer on the adhesive surface of the prestressed carbon fiber plate (1) on the hydraulic concrete T-beam is polished until fresh concrete is completely exposed, and the polished low concave surface of the concrete is repaired with epoxy repair glue, and the high convex surface of the hydraulic concrete T-beam (4) should be polished flat, and finally the base surface is rinsed and dried; the design gap between the prestressed carbon fiber plate and the concrete is 3 mm to 5 mm; 2) Anchor installation: The first anchoring mechanism (2) and the first tensioning mechanism (3) as well as the second tensioning mechanism (7) and the second anchoring mechanism (8) are fixed to the two ends of the hydraulic concrete T-beam (4) by means of chemical anchor bolts, and a steel bar detector is used to avoid the steel bars on the hydraulic concrete T-beam (4) and to mark the bolt drilling positions, wherein the drilling holes are perpendicular to the surface of the hydraulic concrete T-beam (4), and the deviation of the drilling hole center position does not exceed 3 mm; The center lines of the fixed end support (9) and the tension end support (11) should be parallel to or overlap the center line of the prestressed carbon fiber plate (1). The deviation of the center extension lines of the fixed end support (9) and the tension end support (11) calculated based on the full length of the prestressed carbon fiber plate (1) shall not exceed ±5 mm. 3) Installation and laying of prestressed steel strands: The prestressed steel strands (5) are symmetrically arranged on both sides of the hydraulic concrete T-beam (4); the prestressed steel strands (5) pass through the reserved holes on the C-shaped channel steel (16); the second anchoring mechanism (8) is fixed to the hydraulic concrete T-beam (4) by squeezing the anchor heads (17); the chemical anchor bolts passing through the C-shaped channel steel (16) and fixed to the hydraulic concrete T-beam (4) should avoid the prestressed steel strands (5); the deviation of the center position of the drilling hole does not exceed 5 mm; The second tensioning mechanism (7) and the second anchoring mechanism (8) at both ends of the prestressed steel strand (4) are sealed around the joints with the hydraulic concrete T-beam (4), and glue injection holes and exhaust holes are reserved. After the sealing inspection and pressure test, glue injection is performed, and after the glue liquid is solidified, the inspection is performed and additional glue injection is performed; The center line of the second tensioning mechanism and the second anchoring mechanism should be parallel to or overlap with the center line of the prestressed steel strand; 4) Prepare glue and apply carbon fiber board adhesive: During the installation and laying of the prestressed carbon fiber board (1), check the straightness of the prestressed carbon fiber board 1). The straightness deviation of the whole length shall not exceed 20mm; After the prestressed carbon fiber plate (1) is in place, it is tensioned to 15% of the designed tension stress value by the first tensioning mechanism (3), and it is checked whether there is a gap between the tensioning end anchor (11) and the fixed end anchor (10) and the surface of the hydraulic concrete T-beam (4). If there is a high convex contact point or surface, it should be depressurized, disassembled, polished, and then tensioned for inspection; 5) Prestressing and locking: Prestressing is applied to the prestressed carbon fiber plate (1) and the prestressed steel strands (5) respectively by means of a first tensioning mechanism (3) and a second tensioning mechanism (7); the prestressed carbon fiber plate (1) is tensioned in stages, and the prestressed steel strands (5) on both sides are tensioned in a symmetrical, staged, cyclic manner at the same time; First, the prestressed steel strands are tensioned. Two hydraulic jacks are used to tension the strands at symmetrical positions on both sides at the same time. The tension control stress is 930MPa. The design tension force of each steel strand is 128kN. After considering the 20% prestress loss, the tensile strength of the steel strand is not less than 750MPa. The permanent tension force of each steel strand is 102kN. During the tensioning process, the stress is controlled by an oil pressure gauge, and the actual elongation of the strands is measured to verify the prestressing value; Secondly, prestressed carbon fiber plate is tensioned, pressurized and tensioned to 30% of the designed tension stress value, and check whether there is glue squeezed out between the edge of the carbon fiber plate and the concrete surface. If there is no glue squeezed out locally, the pressure should be released and the glue should be replenished before tensioning; Gradually pressurize and tension to 50%, 70%, 90%, and 100% of the designed tension stress value, and check whether the travel displacement of the tension end anchor meets the requirements of the theoretical elongation. According to the specification requirements, the error between the travel displacement of the tension end anchor and the theoretical elongation should not be greater than ±6%; When pressurizing or depressurizing, the jack stroke speed should be controlled within 20mm / min; After the tensioning is completed and the compression strip is installed, the glue filling work of the prestressed carbon fiber plate (1) can be started. It is required that the gap between the prestressed carbon fiber plate (1) and the hydraulic concrete T-beam (4) is filled with adhesive, and the adhesive on the edge of the prestressed carbon fiber plate (1) is full and forms a 45-degree bevel angle with the base surface of the hydraulic concrete T-beam (4); 6) Surface sealing treatment: After the prestressing force is locked, the prestressed steel strand (5) and its tensioning mechanism (7) and anchoring mechanism (8) are protected with epoxy mortar, and then polyurea material is applied to the surface of the prestressed carbon fiber plate (1) and the epoxy mortar for sealing treatment to ensure the durability of the prestressed carbon fiber plate (1) and the prestressed steel strand (5).

Images