CN110056127B

CN110056127B - Assembled box groove type FRP (fiber reinforced plastic) section light fiber sea sand concrete beam

Info

Publication number: CN110056127B
Application number: CN201910303333.4A
Authority: CN
Inventors: 卢亦焱; 李杉; 刘真真; 梁鸿骏; 郑傲寒; 赵鹏抟; 黄悦
Original assignee: Wuhan University WHU
Current assignee: Wuhan University WHU
Priority date: 2019-04-16
Filing date: 2019-04-16
Publication date: 2020-07-10
Anticipated expiration: 2039-04-16
Also published as: CN110056127A

Abstract

The invention relates to an assembled box groove type FRP (fiber reinforced plastic) section light fiber sea sand concrete beam, wherein a main body of the assembled beam consists of a beam section with a middle FRP hollow box groove section and beam sections with precast concrete filled at two ends. The middle FRP hollow box groove section beam section comprises a lower FRP box chamber and an upper FRP groove, a box groove partition plate between the lower FRP hollow box chamber and the upper groove is made of FRP corrugated plates, and the plates are used as shear-resistant connecting keys between FRP and concrete. The assembled beam main body lightens the self weight of the beam body through two aspects of materials and structures, is convenient to transport, can be quickly and reliably connected with plates and columns, is simple, convenient and quick to construct, has good adaptability to severe corrosive engineering environments such as coastal ports and the like, and has good social and economic benefits and engineering application prospects.

Description

Assembled box groove type FRP (fiber reinforced plastic) section light fiber sea sand concrete beam

Technical Field

The invention relates to the field of engineering construction in general environment and severe corrosive environments such as coast, harbors and the like, in particular to an assembled box groove type FRP (fiber reinforced plastic) section light fiber sea sand concrete beam.

Background

Reinforced concrete is widely applied to various building projects such as houses, bridges, roads, dams and the like as the most widely applied structural form at present. However, in recent years, the problem of structural performance degradation caused by steel bar corrosion is more prominent, which not only causes potential safety hazard, but also consumes a great deal of manpower and financial resources for repairing and reinforcing the corroded reinforced concrete structure. In 2013, the buildings are built by using sea sand in the multi-floor of the Shenzhen with vision exposure in the mother, and a large amount of chloride ions in the sea sand cause serious corrosion to reinforcing steel bars, so that floor slabs and wall bodies are cracked, a large amount of cracks appear, and serious potential safety hazards are generated. In severe engineering environments with alternate dry and wet conditions, salt spray corrosion and large temperature difference change, such as coastal ports and the like, the problem of sea sand needs to be solved, and a large amount of manpower and material resources are consumed to transport building materials such as cement, river sand, coarse aggregate and the like from the continents in an ocean manner, and seawater desalination treatment needs to be carried out at construction sites. In addition, once the engineering construction is damaged, the maintenance and repair materials are not easy to obtain, so that the traditional reinforced concrete structure cannot meet the building requirements in severe engineering environments such as coastal environments, and a new structural system is urgently needed to be developed. Moreover, for engineering buildings on soft foundations, strict requirements are imposed on the self weight of the structure. In the harsh environment of wet and rainy weather, the water seepage problem of the structure needs to be paid particular attention.

In recent years, Fiber Reinforced Plastic (FRP) is more and more widely applied to the field of structural reinforcement due to a series of excellent properties such as light weight, high strength, corrosion resistance, fatigue resistance and the like, but the examples of direct application to novel structural construction are still less. In fact, the above advantages of the FRP structure provide a good idea for solving the problems of reinforcement corrosion, weak foundation, water seepage, etc. in the building under the severe engineering environment. However, the pure FRP structure also has the disadvantages of large initial investment, low rigidity, low strength utilization rate, etc., so a new structure which optimally combines the FRP material and the concrete material and fully utilizes the tensile property of the FRP material and the compressive property of the concrete material is needed to meet the requirements.

The invention applies FRP material to the fabricated beam structure, fully utilizes the respective excellent performances of FRP and concrete, fully considers the fast and stable splicing connection with the plate and the column, and then pours the concrete in the construction site to integrate the beam, the plate and the column into a whole, thereby having good integrity and ensuring the excellent earthquake resistance. Aiming at the problems that the main structure of most of the existing reinforced concrete assembly beams is complex, a template needs to be erected, the prefabrication process is complicated, the weight is large, the transportation is inconvenient and the like, the design of the FRP box groove type structure and the use of the lightweight fiber concrete greatly reduce the weight of the beam body, and the transportation, the construction and the assembly are convenient. The prefabricated process is simple and easy to do, need not the template during post-cast concrete, can draw materials on the spot, to the engineering building under the marine environment, can use sea sand as the aggregate, saves a large amount of manpower and materials, and economic benefits is outstanding, is a novel practical assembled box channel type FRP section bar lightweight fiber concrete roof beam.

Disclosure of Invention

The invention mainly aims to provide an assembled box groove type FRP (fiber reinforced plastic) section light fiber sea sand concrete beam, which aims to realize the quick splicing and integral pouring of plates and columns, improve the construction efficiency and simultaneously have good adaptability to corrosive ions, soft foundations and the like in engineering environments such as coastal ports and the like.

In order to achieve the purpose, the assembled box groove type FRP profile light fiber sea sand concrete beam comprises an assembled beam main body and is characterized in that: the FRP beam body of the assembly beam main body is of an integrated prefabricated structure, and the FRP beam body is formed by enclosing an FRP bottom plate and two FRP side plates;

the FRP partition plate is characterized by also comprising two middle beam sections and end beam sections which are arranged perpendicular to the axis of the main beam of the assembly beam; the assembly beam main body is divided into three beam sections by the two middle beam sections and the end beam section FRP partition plates along the axis direction of the FRP beam body, wherein the three beam sections are respectively a middle beam section and two end beam sections; the two end beam sections are precast concrete solid filling beam sections, and the lengths of the two end beam sections respectively account for 1/5-1/3 of the total length of the FRP beam body;

the upper part of the assembly beam main body is horizontally provided with two through long FRP ribs which are arranged in parallel along the axis direction of the FRP beam body; positioning holes are formed in the FRP partition plates of the two middle beam sections and the end beam section, and the full-length FRP ribs are fixedly connected with the FRP partition plates of the two middle beam sections and the end beam section through the positioning holes;

the two end beam sections are precast with end precast concrete; the double-limb channel steel is characterized by also comprising two groups of double-limb channel steel which are arranged back to back, wherein one end of the double-limb channel steel is embedded in the end precast concrete, the other end of the double-limb channel steel extends out of the end section of the end beam section, and the length of the extending part of the double-limb channel steel is not less than 1/4 of the length of the embedded part of the double-limb channel steel;

the flange width M of the single double-limb channel steel is not less than 1/5 of the beam width M; the web height H of the double-limb groove steel is not lower than 1/3 of the beam height H; meanwhile, the height H of the web is not more than 4/5 of the height H of the beam;

the middle beam section is internally provided with a groove type hollow box, and the groove type hollow box comprises an upper FRP groove and a lower FRP box chamber; a middle beam section FRP box groove partition plate is horizontally arranged between the upper FRP groove and the lower FRP box chamber; fiber sea sand concrete is cast in the upper FRP groove in situ; the middle beam section FRP box groove partition plate is a corrugated plate, and the corrugated surface of the corrugated plate is the contact surface of the middle beam section FRP box groove partition plate and the fiber sea sand concrete.

Preferably, the soil layer thickness of the precast concrete at the end parts of the upper side of the upper flange of the double-limb channel steel and the lower side of the lower flange of the double-limb channel steel is not less than 10 mm; the thickness of each FRP side plate and each FRP bottom plate is not less than 10 mm; the thicknesses of the flanges and the webs of the double-limb groove steel are not less than 6 mm;

the diameter of the full-length FRP rib is not less than 8mm and not more than 50 mm; the net distance between the outer surfaces of the two through-length FRP ribs is not less than 2 times of the diameter of the through-length FRP ribs, and the minimum distance from the outermost edges of the through-length FRP ribs to the upper surface of the fiber sea sand concrete is not less than 10 mm.

Furthermore, the FRP beam body and the full-length FRP rib of the assembly beam main body are made of any one of CFRP, GFRP or AFRP;

the fiber sea sand concrete is light high-ductility fiber sea sand concrete, and the fiber is any one of steel fiber, alkali-resistant glass fiber, carbon fiber, aramid fiber, polypropylene fiber or nylon synthetic fiber; the end precast concrete is any one of ordinary concrete, self-compacting concrete, recycled concrete or fiber concrete;

the double-limb channel steel is made of marine-grade stainless steel, and the type of the double-limb channel steel is any one of UNS 30400, UNSS31600, UNSS32304, UNS 31803 and UNS 32750.

The invention has the following advantages and beneficial effects:

and the FRP partition plates are adopted along the axis direction of the beam to divide the assembly beam main body into an end beam section and a middle beam section. In the process of prefabricating the assembly beam main body, light fiber concrete is poured on the end beam section, back-to-back double-limb groove-shaped steel is embedded in the end beam section, the groove-shaped steel is made of special ocean-grade stainless steel and can be suitable for severe ocean engineering environment, the cross section of the end part of the assembly beam main body extends outwards, the web can be quickly spliced with a beam column joint, and the flange can bear partial negative bending moment. Meanwhile, the materials used for the main body of the prefabricated assembly beam are all light materials, so that the prefabricated assembly beam is convenient to transport from a prefabricated site to a construction site.

The middle beam section adopts a box-groove type section, the upper groove is poured with light high-ductility fiber sea sand concrete, a template is not needed, the corrosion resistance of the FRP is utilized, local materials can be used for construction under the marine environments such as coastal environments, islands and the like, and the quick, safe, economical and light construction is realized. Meanwhile, the tensile property of the FRP and the compressive property of the concrete are fully exerted structurally, the self weight of the beam body is reduced, and the method has good adaptability to the engineering environment under a soft foundation. These properties bring great convenience to actual engineering construction and application.

In the stress process, although the bottom layer FRP of the middle beam section can be suddenly broken and failed, the function of the bottom layer FRP is equivalent to providing early warning, the residual section can still bear higher load, the fiber concrete with high ductility can generate larger deformation until the concrete layer is crushed and finally damaged, the characteristic is considered to have the characteristic of quasi-ductility, and the safety of the structure is improved.

The upper part of the main body of the assembly beam is provided with an FRP rib bearing negative bending moment. When the FRP ribs are positioned, positioning holes can be formed in the FRP partition plates at the two ends of the assembly beam main body in advance according to the calculated number and diameter of the FRP ribs, then the FRP ribs are inserted in the axis direction according to the holes to realize the positioning of the FRP ribs, binding is not needed, and construction is convenient and reliable.

Drawings

Fig. 1 is a schematic perspective view of the present invention.

FIG. 2 is a longitudinal sectional view of the FRP beam body of the present invention along the axis thereof.

FIG. 3 is a schematic cross-sectional view of the end beam section double-limb channel steel of the present invention.

Fig. 4 is a schematic cross-sectional view of a section of a spar of the present invention.

In the figure: FRP curb plate 1, FRP bottom plate 2, middle part roof beam section FRP case groove division board 3, middle part roof beam section and tip beam section FRP division board 4 lead to long FRP muscle 5, tip precast concrete 6, two limb channel steel 7, fibre sea sand concrete 8.

Detailed Description

The present invention will be described in further detail with reference to the following examples and accompanying drawings;

assembled box channel type FRP section light fibre sea sand concrete beam as shown in the figure, including the assembly beam main part, its characterized in that: the FRP beam body of the assembly beam main body is of an integrated prefabricated structure and is formed by enclosing an FRP bottom plate 2 and two FRP side plates 1; the FRP partition plate is characterized by also comprising two middle beam sections and end beam sections which are arranged perpendicular to the axis of the main beam of the assembly beam, wherein the FRP partition plate is an FRP partition plate 4; the assembly beam main body is divided into three beam sections by two middle beam sections and an end beam section FRP partition plate 4 along the axis direction of the FRP beam body, wherein the three beam sections are respectively a middle beam section and two end beam sections; the two end beam sections are precast concrete solid filling beam sections, and the length of the two end beam sections respectively accounts for 1/5-1/3 of the total length of the FRP beam body;

the upper part of the assembly beam main body is horizontally provided with two through long FRP ribs 5 which are arranged in parallel along the axis direction of the FRP beam body; positioning holes are formed in the FRP partition plates 4 of the two middle beam sections and the end beam sections, and the full-length FRP ribs 5 are fixedly connected with the FRP partition plates 4 of the two middle beam sections and the end beam sections through the positioning holes; end precast concrete 6 is precast at the two end beam sections; two groups of double-limb channel steel 7 which are arranged back to back are also arranged, one end of the double-limb channel steel 7 is embedded in the end precast concrete 6, the other end of the double-limb channel steel 7 extends out of the end section of the end beam section, and the length of the extending part of the double-limb channel steel 7 is not less than 1/4 of the length of the embedded part of the double-limb channel steel 7;

the flange width M of the single channel steel of the double-limb channel steel 7 is not less than 1/5 of the beam width M; the web height H of the double-limb groove steel 7 is not lower than 1/3 of the beam height H; meanwhile, the height H of the web is not more than 4/5 of the height H of the beam; the middle beam section is internally provided with a groove type hollow box which comprises an upper FRP groove and a lower FRP box chamber; a middle beam section FRP box groove partition plate 3 is horizontally arranged between the upper FRP groove and the lower FRP box chamber; fiber sea sand concrete 8 is cast in situ in the upper FRP groove; middle part roof beam section FRP case groove division board 3 adopts the buckled plate, and the corrugated surface of buckled plate is middle part roof beam section FRP case

groove division board

3 and 8 fibrous sea sand concrete's contact surface.

The thickness of soil layers of the precast concrete 6 at the upper side of the upper flange of the double-limb groove steel 7 and the lower side of the lower flange of the double-limb groove steel 7 is not less than 10 mm; the thickness of the FRP side plate 1 and the thickness of the FRP bottom plate 2 are not less than 10 mm; the thickness of the steel plate of the flange and the web of the double-limb groove steel 7 is not less than 6 mm;

the diameter of the full-length FRP rib 5 is not less than 8mm and not more than 50 mm; the net distance between the outer surfaces of the two through-length FRP ribs 5 is not less than 2 times of the diameter of the through-length FRP ribs 5, and the minimum distance from the outermost edge of the through-length FRP ribs 5 to the upper surface of the fiber sea sand concrete 8 is not less than 10 mm.

The fabricated box-channel FRP section light fiber sea sand concrete beam as claimed in

claim

1 or 2, wherein: the FRP beam body of the assembly beam main body and the full-length FRP rib 5 are made of any one of CFRP, GFRP or AFRP; the fiber sea sand concrete 8 is light high-ductility fiber sea sand concrete, and the fiber is any one of steel fiber, alkali-resistant glass fiber, carbon fiber, aramid fiber, polypropylene fiber or nylon synthetic fiber; the end precast concrete 6 is any one of ordinary concrete, self-compacting concrete, recycled concrete or fiber concrete; the double-limb channel steel 7 is made of ocean-grade stainless steel and is one of UNSS30400, UNS 31600, UNSS32304, UNS 31803 and UNS 32750.

Firstly, producing the FRP beam body, and performing one-step prefabrication molding by adopting a pultrusion process. The FRP beam body comprises an FRP side plate 1, an FRP bottom plate 2, a middle beam section FRP box groove partition plate 3, a middle beam section and an end beam section FRP partition plate 4.

And then, the FRP ribs are arranged according to the stress condition, and parameters such as the diameter, the number, the net spacing and the like of the FRP ribs are determined. Positioning holes are formed in the FRP partition plates 4 of the middle beam section and the end beam section according to a reinforcement arrangement scheme, and the positioning holes in the two FRP partition plates, perpendicular to the beam axis, of the assembled beam main body are ensured to be consistent in position during hole forming, so that the same FRP reinforcement can penetrate through the positioning holes in the two plates to realize positioning. And after the hole is opened, the FRP rib penetrates through the positioning holes of the two FRP plates from one end of the assembly beam main body to complete positioning. In this example, two FRP ribs having a diameter of 12mm are arranged on the upper part of the assembly beam main body, and the thickness of the outer protective layer of each FRP rib is 25 mm.

Concrete is then poured at the ends of the assembled beam body, and the type of filled concrete includes but is not limited to: common concrete, self-compacting concrete, recycled concrete, fiber concrete, and high-performance concrete. In this embodiment, the precast concrete 6 at the end portion is made of lightweight fiber concrete in order to reduce the dead weight of the beam body. The fiber added in the fiber concrete is polyvinyl alcohol (PVA) fiber, and the aggregate is uniformly fine aggregate quartz sand. In the pouring process, double-limb channel steel 7 arranged back to back is embedded in fiber concrete, the channel steel 7 is made of special marine grade stainless steel UNS 31803, and extends out of a beam end so as to be spliced and connected with beam column joints in site construction, and the length of the extending part is 1/2 of the length of the embedded part. The width of the flange of the channel steel is 1/3 beam width, and the thickness of the concrete on the upper side of the upper flange and the lower side of the lower flange is 1/5 beam height. The web height is 3/5 of the beam height, and the web spacing of the back-to-back double-limb channel steel is 1/3 of the beam width. The thickness of the steel plates of the web plate and the flange of the channel steel is 14 mm.

After the end fiber concrete pouring is completed, maintaining for more than 28d, transporting to a construction site, quickly splicing the extended parts of the embedded back-to-back arranged double-limb channel steel 7 and beam column nodes, and completing the positioning and lapping of the prefabricated plates. And finally, performing on-site construction, and pouring the assembled beam main body, the columns and the plates into a whole by adopting high-ductility light fiber sea sand concrete 8 taking sea sand as aggregate, so that the structure has good integrity, and the seismic performance of the structure is greatly improved.

Claims

1. The utility model provides an assembled box channel type FRP section light fibre sea sand concrete beam, includes the assembly beam main part, its characterized in that: the FRP beam body of the assembly beam main body is of an integrated prefabricated structure and is formed by enclosing an FRP bottom plate (2) and two FRP side plates (1);

the FRP partition plate (4) is arranged perpendicular to the axis of the main beam of the assembly beam and comprises two middle beam sections and end beam sections; the assembly beam main body is divided into three beam sections by the two middle beam sections and the end beam section FRP partition plates (4) along the axis direction of the FRP beam body, wherein the three beam sections are respectively a middle beam section and two end beam sections; the two end beam sections are precast concrete solid filling beam sections, and the lengths of the two end beam sections respectively account for 1/5-1/3 of the total length of the FRP beam body;

the upper part of the assembly beam main body is horizontally provided with two through long FRP ribs (5) which are arranged in parallel along the axis direction of the FRP beam body; positioning holes are formed in the FRP partition plates (4) of the two middle beam sections and the end beam section, and the full-length FRP ribs (5) are fixedly connected with the FRP partition plates (4) of the two middle beam sections and the end beam section through the positioning holes;

end precast concrete (6) is precast in the two end beam sections; each end beam section is provided with a group of double-limb channel steel (7) which are arranged back to back, and one end of each group of double-limb channel steel (7) is embedded in the end precast concrete (6); the other end of the double-limb channel steel (7) extends out of the end section of the end beam section, and the length of the extending part of the double-limb channel steel (7) is not less than 1/4 of the length of the embedded part of the double-limb channel steel (7);

the flange width M of the single channel steel of the double-limb channel steel (7) is not less than 1/5 of the beam width M; the height H of a web plate of the double-limb groove steel (7) is not lower than 1/3 of the height H of the beam; meanwhile, the height H of the web is not more than 4/5 of the height H of the beam;

the middle beam section is internally provided with a groove type hollow box, and the groove type hollow box comprises an upper FRP groove and a lower FRP box chamber; a middle beam section FRP box groove partition plate (3) is horizontally arranged between the upper FRP groove and the lower FRP box chamber; fiber sea sand concrete (8) is cast in the upper FRP groove in situ; the middle beam section FRP box groove partition plate (3) is a corrugated plate, and the corrugated surface of the corrugated plate is the contact surface of the middle beam section FRP box groove partition plate (3) and the fiber sea sand concrete (8).

2. The fabricated tank channel type FRP profile light fiber sea sand concrete beam as claimed in claim 1, wherein: the soil layer thickness of the end part precast concrete (6) at the upper side of the upper flange of the double-limb groove steel (7) and at the lower side of the lower flange of the double-limb groove steel (7) is not less than 10 mm; the thickness of the FRP side plate (1) and the thickness of the FRP bottom plate (2) are not less than 10 mm; the thicknesses of the flanges and the web plates of the double-limb groove steel (7) are not less than 6 mm;

the diameter of the full-length FRP rib (5) is not less than 8mm and not more than 50 mm; the net distance between the outer surfaces of the two through-length FRP ribs (5) is not less than 2 times of the diameter of the through-length FRP ribs (5), and the minimum distance from the outermost edge of the through-length FRP ribs (5) to the upper surface of the fiber sea sand concrete (8) is not less than 10 mm.

3. The fabricated box-channel FRP profile light fiber sea sand concrete beam as claimed in claim 1 or 2, wherein: the FRP beam body of the assembly beam main body and the full-length FRP rib (5) are made of any one of CFRP, GFRP or AFRP;

the fiber sea sand concrete (8) is light high-ductility fiber sea sand concrete, and the fiber is any one of steel fiber, alkali-resistant glass fiber, carbon fiber, aramid fiber, polypropylene fiber or nylon synthetic fiber; the end precast concrete (6) is any one of ordinary concrete, self-compacting concrete, recycled concrete or fiber concrete;

the double-limb channel steel (7) is made of ocean-grade stainless steel and is one of UNS S30400, UNS 31600, UNS 32304, UNS 31803 and UNS 32750.