CN104675141B - A kind of FRP pipe constraint cement-base composite material reinforces pillarwork - Google Patents

Abstract

The invention discloses a pier column structure reinforced by FRP pipe restrained cement-based composite materials, which is suitable for pier column reinforcement of all structures, including: pier column, a fiber reinforced composite material base arranged at the bottom of the pier column, surrounding the pier The fiber-reinforced composite material pipe arranged on the column, the limiter for fixing the position of the fiber-reinforced composite material pipe, and the engineering cement-based composite material filled between the fiber-reinforced composite material pipe and the pier column. The invention not only integrates the advantages of fiber reinforced composite material base, fiber reinforced composite material pipe, engineering cement-based composite material and fiber grid mesh, so that their respective advantages can be fully exerted, but also the mutual bonding effect between them The excellent performance of a single material has been greatly improved, and the bearing capacity, anti-scourability, seismic performance, ductility, fatigue resistance and durability of the pier column structure have been effectively improved.

Description

A pier-column structure reinforced by FRP tube-confined cement-based composite material

technical field

The invention belongs to the fields of civil engineering, construction engineering, highway engineering and municipal engineering, and relates to an FRP pipe-constrained cement-based composite material-reinforced pier column structure.

Background technique

Reinforced concrete structures have been widely used in engineering fields such as civil engineering and civil construction, and have become the most widely used structures in our lives. As the main force-bearing member of the structure, the pier column's safety performance affects the overall performance of the entire structure. Due to defects in construction level and design standards, various structural diseases are gradually exposed, especially in harsh environments, such as freeze-thaw, acid, alkali and salt environments, as well as under the impact of rivers and sea water, vehicles, etc. The performance is particularly obvious. The common structural defects of pier columns are reflected in the decrease of pier column bearing capacity, spalling of concrete protective layer, corrosion of steel bars after concrete cracking, reduction of stiffness, and insufficient seismic performance.

The commonly used methods of strengthening pier columns in engineering structures mainly include enlarging section method, pasting steel plate method, pasting FRP cloth reinforcement, circumferential prestressed reinforcement, etc. The above reinforcement methods mainly have problems such as steel plates and prestressed tendons are easy to corrode, resin is easy to peel off and age, affect the use space of the structure, and the operation is relatively cumbersome. Especially for the reinforcement of underwater pier structures, the engineering volume is large and the construction cost is high.

In the patent document with the publication number CN201420198404.1, a concrete column reinforcement system is disclosed. The system uses a steel sleeve as a construction formwork, and relies on anchor bolts to fix the rigid formwork on the surface of the structure. Cement mortar is filled between the structures. The disadvantages are that the steel sleeve has a large mass, is easy to corrode, needs to be spliced in pieces, and has poor sealing performance. The anchor bolts must be fixed inside the reinforcement, which will cause great damage to the structure.

In the patent document with the publication number CN201320011706.9, a reinforcement device for underwater pier columns is disclosed. A steel bracket is set on the top of the reinforcement structure to fix the glass fiber sleeve, and then the fiberglass sleeve and the reinforcement structure are placed between the The gap is filled with grouting material. This invention can overcome the defect that cofferdams need to be built for underwater reinforcement of pier columns, but the device has high requirements for steel supports and needs to be fixed on the surface of the reinforced structure with anchor bolts, especially the upper part of the pier column structure. The support cannot be erected within hours, the operation is more complicated and the damage to the structure is greater.

In the patent document with the publication number CN201320011706.9, a method for reinforcing underwater structures with fiber composite grid bars is disclosed. This invention can greatly improve the compressive bearing capacity of reinforced structures without the need to build cofferdams structure, but the isolation body used in the construction is a steel casing or stainless steel casing, which needs to be assembled in multiple sections, and each section of the casing is composed of two parts cut longitudinally, and the two ends of the isolation body need to be sealed with concrete. More cumbersome. After the reinforcement is completed, the casing or steel formwork needs to be cut and recovered. The operation process is complicated and not conducive to underwater construction.

In the patent document with the publication number CN201010193601.0, a reinforcement method for wrapping piles in water with reinforced fiber composite material cloth is disclosed. Before use, it is necessary to repair the damaged part with repair mortar, and use a scraper to repair it to the original The size of the structure, and then apply the resin glue on the surface of the fiber cloth for reinforcement. When this method is used in underwater construction, the requirements for divers are high, and the operation is relatively complicated. When the fiber cloth is wound to strengthen the pier column structure, part of the water will inevitably be wrapped in it, which will affect the bonding effect of the resin glue and the resin glue is easy to Ageing.

The emergence of fiber-reinforced composites and engineering cement-based composites (ECC) can well make up for these shortcomings. Under shear and axial loads, ECC exhibits high ductility and ultra-high toughness, much higher than ordinary concrete and steel fiber reinforced concrete. While enhancing the axial compression bearing capacity of the reinforced pier column, the aseismic performance of the pier column structure is improved. The fiber composite material has high tensile strength, good corrosion resistance and durability. It can not only be used as a construction formwork, but also can be used as a reinforcement material to enhance the axial pressure bearing capacity of the pier column. It does not need to be disassembled after the construction is completed, and the operation is simple .

Contents of the invention

Technical problem: The present invention provides a method that takes full advantage of the respective advantages of fiber reinforced composite material base, fiber reinforced composite material pipe, engineering cement-based composite material (ECC) and fiber grid mesh, and the mutual constraints between them make The excellent properties of a single material have been greatly improved, and the fiber-reinforced composite material tube-confined cement-based composite material has effectively improved the bearing capacity, anti-scourability, seismic performance, ductility, fatigue resistance and durability of the pier column structure. Reinforced pier structure. The invention has remarkable reinforcing effect, simple operation method, low later maintenance and repair costs, and obviously prolongs the service life cycle.

Technical solution: The FRP pipe-constrained cement-based composite material-reinforced pier column structure of the present invention includes a pier column, a fiber-reinforced composite material base arranged at the bottom of the pier column, a fiber-reinforced composite material tube arranged around the pier column, and a set The limiter at the upper end of the fiber-reinforced composite material pipe, the engineering cement-based composite material filled between the fiber-reinforced composite material pipe and the pier, the lower end of the fiber-reinforced composite material pipe is fixedly connected with the fiber-reinforced composite material base, and the upper end The stopper is fixedly connected with the pier column. The limiter includes a screw rod, a ferrule fixed at one end of the screw rod, a top plate fixed at the other end of the screw rod, a rigid spring sleeved on the screw rod, a Y-shaped block and a limit nut, and one end of the screw rod passes through the sleeve The hoop is fixedly connected with the surface of the pier, and the Y-shaped block is pressed against the inner wall of the fiber-reinforced composite material tube, and is compressed under the elastic force of the rigid spring. The limit nut is set along the screw rod to adjust the Y-shaped block horizontal position.

In a preferred solution of the present invention, the base material of the fiber-reinforced composite material is carbon fiber, alkali-resistant glass fiber, aramid fiber or basalt fiber, or a hybrid fiber-reinforced composite material composed of two or more of the above-mentioned fibers. The fiber-reinforced composite material base is assembled and spliced by a plurality of segmented components, and a groove is provided on the upper side, and the lower end of the fiber-reinforced composite material pipe is directly inserted into the groove.

In a preferred solution of the present invention, the material of the fiber-reinforced composite pipe is carbon fiber, aramid fiber, basalt fiber or alkali-resistant glass fiber, or a hybrid fiber composite material composed of two or more of the above-mentioned fibers, and the fiber-reinforced composite material The tube is a ring-shaped structure formed by processing and assembling a plurality of FRP material sheets.

In the preferred solution of the present invention, the components of the engineering cement-based composite material are: cement, fly ash, quartz sand, fiber, silica fume, thickener and quick-setting agent.

In the preferred solution of the present invention, the outer surface of the pier column is wound with a fiber grid mesh, and the fiber grid mesh can be a carbon fiber grid mesh, an aramid fiber grid mesh, a basalt grid mesh, an alkali-resistant glass fiber Grid mesh or hybrid fiber grid mesh, the hybrid fiber grid mesh refers to the grid mesh with the above two or more than two kinds of fibers, and the fiber grid mesh can be fixed on the pier by anchor pins superior.

The invention uses fiber reinforced composite material base, fiber reinforced composite material pipe, cement-based composite material and grid mesh to strengthen and reinforce the pier column and pile foundation structure of the building locally or as a whole, and is especially suitable for the reinforcement of underwater structural foundations Reinforced, the reinforced pier column structure has high bearing capacity, anti-scouring capacity, seismic performance, ductility, fatigue resistance and durability. The invention has obvious reinforcement effect, simple operation method, low maintenance and repair costs in the later period, and obviously prolongs the service life cycle.

Beneficial effect: compared with the prior art, the present invention has the following advantages:

1. The limiter is positioned accurately and can be recycled

Most of the pier reinforcement devices disclosed in existing patent documents and related documents use square, convex or anchor bolts as stopper devices, which are installed on the inner wall of the formwork, and the length of the stopper is fixed. In the process of installing the limiter, it is often necessary to cut through the outer construction formwork to destroy the integrity of the formwork. Although these limiting devices can play the role of limiting, they are greatly affected by the construction environment during the construction process, and the limiting devices are easy to slide down to the bottom of the sleeve with the pouring material, losing the role of limiting. Secondly, if the symmetrical construction on both sides cannot be guaranteed during the construction process, it is easy to cause the formwork to shift laterally and cannot be adjusted.

The positioning of the limiter designed by the present invention is more accurate. The upper end of the Y-shaped baffle is sleeved on the screw rod, and the lower end is connected with the inner wall of the fiber reinforced composite material tube. The screw rod is fixed on the surface of the structure through a circular hoop, so that no slipping occurs. During the construction process, according to the requirements of the reinforcement scheme, the length of the stopper can be adjusted at any time by adjusting the position of the stop nut to ensure that the position of the formwork is accurate and no deviation occurs. After the construction is completed, the limit device can be removed for recycling to save materials.

2. Convenient construction, save construction cost

In the patent document with the publication number CN201320011706.9, a reinforcement device for an underwater pier is disclosed, in which a steel bracket is arranged on the top of the reinforcement structure to fix the glass fiber casing. Although it overcomes the defect of building a cofferdam for underwater reinforcement of pier columns, the device has high requirements for steel supports and needs to be fixed on the surface of the reinforced structure with anchor bolts. Especially when the upper clearance of the pier column structure is small, the support cannot be erected, and the operation is relatively difficult. Complexity, high construction cost, and great damage to structures. And when pouring the grout, it needs to be cured for at least 8 hours for every 15cm of pouring, until the gap in the sleeve is filled.

In the present invention, the fiber-reinforced composite material base is used as the construction support, and the fiber-reinforced composite material tube is directly inserted into the groove on the base, and at the same time plays the role of a limiter and a hoop constraint, and the inside of the groove is provided with a compressible The sealing strip does not need to build construction supports or build construction cofferdams during reinforcement, and is easy to operate, especially suitable for strengthening underwater concrete piers. The grouting material adopts engineering cement-based composite material (ECC material), which does not require segmented and graded construction, and can be poured and formed at one time, which significantly shortens the construction period. Fiber-reinforced composite material base is assembled from two or more parts, with various structural forms, and can be prefabricated according to the needs of reinforcement projects. Compared with stainless steel, the construction cost can be greatly reduced.

3. The fiber-reinforced composite material tube is green and environmentally friendly, with high strength and remarkable reinforcement effect

In the patent documents with publication numbers CN200810035614.8, CN200920264541.X, CN201220475538.4 and CN201420198404.1, ordinary steel or stainless steel pipes are used as the construction formwork. The tensile strength is inferior to that of FRP materials, and iron and steel enterprises not only need to invest a lot of material resources and energy resources in the production process, but also discharge a lot of waste: waste water, waste gas and solid waste. These wastes are harmful to the environment and pose a threat to human health.

The invention provides a fiber-reinforced composite material pipe as a construction template. The elastic modulus of the FRP material is small, about 25%-75% of ordinary steel bars, and the tensile strength provided is about 10 times that of ordinary steel bars. The hoop restraint strength is higher and the reinforcement effect is more significant. FRP material is a kind of high-performance green environmental protection material. It has the characteristics of light weight, high strength, corrosion resistance, good durability and convenient construction. The production of FRP material does not need to consume a lot of material resources and energy materials, and will not cause harm to the environment.

3. High sealing performance, no damage to structures

In the patent document with the publication number CN201420198404.1, a concrete column reinforcement system is disclosed. The system uses a steel sleeve as a construction formwork, and the rigid formwork is fixed on the surface of the structure by means of anchor bolts. In the patent document with the publication number CN200910080051.9, a method for reinforcing underwater structures with fiber composite grid bars is disclosed. The isolation body used in the construction is a multi-section assembled steel sleeve or stainless steel sleeve, and A section of casing consists of two parts cut longitudinally, and the two ends of the isolation body need to be sealed with concrete. Due to the high quality of the steel sleeve, it is easy to corrode, and needs to be spliced in pieces, the construction of the above two methods is relatively cumbersome, the sealing performance is poor, and the damage to the structure is also large.

The fiber-reinforced composite material pipe of the present invention is a ring-shaped structure formed by processing and assembling fiber-reinforced composite material sheets. Excellent sealing performance, better waterproof effect. At the same time, the fiber-reinforced composite material tube does not need to be fixed by anchor bolts, it only needs to be inserted into the fiber-reinforced composite material base, and the fiber-reinforced composite material base is fixed on the pier structure through fastening bolts on both sides, without damage to the structure .

5. Good integrity

The publication number is CN201010193601.0, which discloses a reinforcement method of wrapping piles in water with reinforced fiber composite cloth. Before use, repair the damaged part with repair mortar, and repair it to the original structure size with a scraper. Then the fiber cloth is wound on the surface of the reinforced pier structure. Therefore, it is inevitable that part of the moisture will be wrapped in, which will affect the bonding effect of the resin glue and the resin glue will easily age.

In the present invention, the coarse and fine aggregates of concrete, the cement-based composite material for engineering and the grid mesh are embedded together, and no epoxy resin glue is needed for bonding, which improves the bonding strength of the interface and avoids the aging of the resin glue Damage occurs, and at the same time, the restraint effect of the fiber-reinforced composite material pipe greatly improves the overall performance of the structure.

6. Higher durability and corrosion resistance

FRP material is composed of fiber material and matrix material according to a certain ratio. It has high corrosion resistance and fatigue resistance, and can be used for a long time in acid, alkali, chloride salt and humid environment. Compared with the traditional reinforcement method, the present invention can effectively avoid defects such as prestressed tendons, common steel bars and steel plates being easily corroded, epoxy resin being easily peeled off and aging, affecting the usable space of the structure, and cumbersome to operate. Both the construction base and the construction template are made of fiber-reinforced composite materials, avoiding the use of steel, which can effectively improve the durability and corrosion resistance of the reinforced structure while enhancing the reinforcement effect of the structure.

7. Beautiful appearance and wide application range

The invention does not require special equipment, takes up less space, does not affect the normal use of buildings and vehicles, and is especially suitable for strengthening underwater pier structures, without the need to build cofferdam structures, reducing engineering quantities and saving construction costs. The surface of the reinforced structure is smooth and flat, without potholes, and has a beautiful appearance. The invention has a wide range of applications and can be used in various reinforced concrete piers, concrete pile structures, steel pipe piles and H-shaped steel foundations, etc., and its cross-sectional form can be circular, rectangular, elliptical and H-shaped.

Description of drawings

Fig. 1 is the schematic diagram of the pier column structure reinforced by the fiber-reinforced composite material tube restrained cement-based composite material of the present invention (Scheme 1)

Fig. 2 is a schematic diagram of the structure of a pier column reinforced by a fiber-reinforced composite material tube constrained by a cement-based composite material of the present invention (Scheme 2) Fig. 3 is a schematic cross-sectional view of a stopper of the present invention

Fig. 4 is A-A sectional schematic diagram of the present invention

Fig. 5 is a side view of the base of the fiber reinforced composite material of the present invention

Fig. 6 is a schematic diagram of fiber-reinforced composite pipe lap joint of the present invention

In the figure: 1 is a limiter; 2 is a fiber reinforced composite material pipe (FRP pipe); 3 is an engineering cement-based composite material (ECC); 4 is a fiber reinforced composite material base; 5 is a compressible annular sealing strip; 6 7 is the fiber grid mesh; 8 is the top piece; 9 is the rigid spring; 10 is the Y-shaped block; 11 is the limit nut; 12 is the screw; 13 is the ring collar; 14 is Stainless steel fastening bolts; 15 are stainless steel self-tapping screws; 16 are compressible elongated sealing strips.

detailed description

The present invention will be further described below in conjunction with embodiment and accompanying drawing. The present invention is a fiber-reinforced composite material tube-constrained cement-based composite material-reinforced pier column structure, as shown in Figure 1, mainly comprising a pier column, a fiber-reinforced composite material base 4 arranged at the bottom of the pier column, surrounding the pier The fiber-reinforced composite material pipe 2 arranged on the column, the engineering cement-based composite material 3 filled between the fiber-reinforced composite material pipe 2 and the pier column, the lower end of the fiber-reinforced composite material base 4 is connected by a compressible sealing strip 5 and The piers are fixedly connected together, and the upper end is fixedly connected with the piers through the limiter 1 . The limiter 1 includes a screw rod 12, a ferrule 13 fixed on one end of the screw rod 12, a top sheet 8 fixed on the other end of the screw rod 12, a rigid spring 9 sleeved on the screw rod 12, a Y-shaped block 10 and a limit screw. Cap 11. One end of the screw 12 passes through the hoop 13 and is fixedly connected to the surface of the pier column. The Y-shaped block 10 presses against the inner wall of the fiber reinforced composite tube 2 and is compressed under the elastic force of the rigid spring 9. The limit nut 11 moves along the screw. It is used to adjust the horizontal position of the Y-shaped block 10. The Y-shaped baffle 10 is welded by two long strips of stainless steel sheets, one of which is "I" shaped and arranged along the inner wall of the fiber-reinforced composite material tube 2, and the other is "V" shaped and is set on the screw rod 12. The shape after the two are connected is similar to a "Y" shape.

Pier column structures mainly include concrete piers, concrete piles, I-shaped steel piles and wooden piles, etc., and their cross-sectional forms mainly include circular, rectangular, oval, H-shaped, etc. Now take fiber-reinforced composite material tube-confined cement-based composite material to reinforce underwater concrete cylindrical piers as an example:

Option 1: Reinforcement construction plan for structures with less damage

① First determine the number, type, section form and reinforcement length of the pier column structure that needs to be repaired, and send professional divers underwater to determine the damage degree of the pier column structure that needs to be repaired and measure the actual size of the concrete column to formulate a repair and reinforcement plan.

② Prefabricate and process fiber reinforced composite material pipe 2, limiter 1 and circular fiber reinforced composite material base fiber reinforced composite material base 4 in the factory, remove scum and marine organisms on the surface of concrete piers, and remove loose concrete on the surface of pier columns , clear the mud at the bottom of the pier column, etc.

③Put the compressible sealing strip 5 into the slot inside the circular fiber-reinforced composite material base 4, and fix it with the bottom of the concrete pier through fastening bolts 14. Put the fiber-reinforced composite tube 2 on the surface of the cylindrical pier, and assemble it into an annular sleeve with stainless steel self-tapping screws 15, as shown in Figure 6, and then fix the assembled fiber-reinforced composite tube 2 on the concrete pier On the circular fiber-reinforced composite base 4 at the bottom.

④In the upper part of the concrete pier column, at a position about 5-10cm away from the top of the fiber reinforced composite material pipe 2, install the stopper 1, insert the Y-shaped block 10 into the inner wall of the fiber reinforced composite material pipe 2, and adjust the stop nut 11 position, so that the length of the limiter 1 meets the requirements of the reinforcement scheme.

⑤ According to the ratio of cement: fly ash: quartz sand: fiber: silica fume: thickener: accelerator = 1:4:0.15:0.002:0.05:0.005:0.005 to prepare engineering cement-based composite materials (ECC materials) 3. Pour the well-mixed engineering cement-based composite material 3 into the fiber-reinforced composite material pipe 2 through the conveying conduit. until the matrix composite material 3 evenly overflows from the upper end of the fiber reinforced composite material pipe 2 .

⑥ Remove the limiter 1 on the upper part of the pier column, and the construction is completed.

Scheme 2: Reinforcement construction scheme for structures with greater damage

① First determine the number, type, section form and reinforcement length of the pier column structure that needs to be repaired, and send professional divers underwater to determine the damage degree of the pier column structure that needs to be repaired and measure the actual size of the concrete column to formulate a repair and reinforcement plan.

② Prefabricate and process fiber reinforced composite material pipe 2, limiter 1 and circular fiber reinforced composite material base 4 in the factory, remove scum and marine organisms on the surface of concrete piers, remove loose concrete on the surface of pier columns, and clean the bottom of pier columns The mud, and the surface treatment of exposed corroded steel bars, etc.

③ The surface of the fiber grid mesh 7 is sandblasted to improve the interface bonding strength between the fiber grid mesh 7 and the engineering cement-based composite material 3 . At the upper, middle and lower parts of the reinforced pier column, four anchor pins 6 with a length of 80 mm are arranged symmetrically at each place (assuming that the thickness of the reinforcement layer is 30 mm), and the fiber grid mesh is fixed on the anchor pins 6 .

④Refer to the steps ③～⑥ in Scheme 1.

The foregoing embodiments are only preferred implementations of the present invention. It should be pointed out that those skilled in the art can make several improvements and equivalent replacements without departing from the principle of the present invention. Technical solutions requiring improvement and equivalent replacement all fall within the protection scope of the present invention.

Claims (7)

1. An FRP pipe-constrained cement-based composite material reinforced pier column structure, characterized in that the structure includes a pier column, a fiber-reinforced composite material base (4) arranged at the bottom of the pier column, and a pier column arranged around the pier column Fiber-reinforced composite material pipe (2), stopper (1) arranged on the upper end of fiber-reinforced composite material pipe (2), engineering cement base filled between said fiber-reinforced composite material pipe (2) and pier column Composite material (3), the lower end of the fiber reinforced composite material pipe (2) is fixedly connected to the fiber reinforced composite material base (4), and the upper end is fixedly connected to the pier through a stopper (1); The limiter (1) includes a screw (12), a ferrule (13) fixed at one end of the screw (12), a top sheet (8) fixed at the other end of the screw (12), ) on the rigid spring (9), Y-shaped block (10) and limit nut (11), one end of the screw (12) passes through the hoop (13) and is fixedly connected to the surface of the pier, and the Y-shaped The baffle (10) presses against the inner wall of the fiber reinforced composite tube (2), and is compressed under the elastic force of the rigid spring (9), and the limit nut (11) is set along the screw rod (12) to adjust the Y The horizontal position of the shaped baffle (10). 2. The pier column structure reinforced by FRP pipe-confined cement-based composite material according to claim 1, characterized in that, the fiber-reinforced composite material base (4) is made of carbon fiber, alkali-resistant glass fiber, aramid fiber, or Basalt fiber, or a hybrid fiber-reinforced composite material composed of two or more of the above-mentioned fibers, the base of the fiber-reinforced composite material (4) is spliced by a combination of multiple segmented components, and grooves are set on the upper side, and the fiber-reinforced composite material The lower end of the composite tube (2) is inserted directly into the groove. 3. The pier column structure reinforced by FRP pipe-confined cement-based composite material according to claim 1, characterized in that, the material of the fiber-reinforced composite material pipe (2) is carbon fiber, aramid fiber, basalt fiber or alkali-resistant glass fiber, or a hybrid fiber composite material composed of two or more of the above-mentioned fibers, and the fiber-reinforced composite material tube (2) is a ring-shaped structure formed by processing and assembling a plurality of FRP material sheets. 4. According to claim 1, 2 or 3, the FRP pipe-constrained cement-based composite material reinforced pier column structure is characterized in that, the components of the engineering cement-based composite material (3) are: cement, pulverized coal Ash, quartz sand, fiber, silica fume, thickener and accelerator. 5. The pier column structure reinforced with FRP pipe-confined cement-based composite material according to claim 1, 2 or 3, characterized in that the outer surface of the pier column is wound with a fiber grid mesh (7). 6. The FRP pipe-confined cement-based composite material reinforced pier column structure according to claim 5, wherein the fiber grid mesh is a carbon fiber grid mesh, an aramid fiber grid mesh, a basalt grid A grid sheet, an alkali-resistant glass fiber grid sheet or a hybrid fiber grid sheet, the hybrid fiber grid sheet refers to a grid sheet with the above-mentioned two or more fibers. 7. The pier column structure reinforced by FRP pipe-confined cement-based composite material according to claim 5, characterized in that, the fiber grid mesh (7) is fixed on the pier column by anchor pins (6).