CN112681617A

CN112681617A - Fiber reinforced composite material spiral stirrup and method thereof

Info

Publication number: CN112681617A
Application number: CN202011538328.0A
Authority: CN
Inventors: 薛伟辰; 胡翔
Original assignee: Tongji University
Current assignee: Tongji University
Priority date: 2020-12-23
Filing date: 2020-12-23
Publication date: 2021-04-20

Abstract

The application belongs to the technical field of civil engineering, and particularly relates to a fiber reinforced composite material spiral stirrup and a method. The spiral stirrup is made of corrosion-resistant fiber reinforced composite materials, and the cross section of a single limb of the spiral stirrup is circular or rectangular. The FRP spiral stirrup consists of continuous FRP rib rectangular coils. The FRP spiral stirrup is similar to a spring and can be axially stretched and compressed, so that the FRP spiral stirrup is convenient to store, transport and bind on site. By utilizing the longitudinal stretching and compressing characteristics of the FRP spiral stirrup, the angles between the two opposite sides of the rectangular coil and the axis can be adjusted as required so as to adapt to the shearing states of different members and fully exert the material strength of the FRP stirrup. The application has the characteristics of convenience in production and forming, accurate size, material saving, convenience in construction and the like. The durability of the concrete structure can be effectively improved, and the concrete structure is suitable for coastal areas and areas using a large amount of snow melting salt in the north, and has wide application prospect.

Description

Fiber reinforced composite material spiral stirrup and method thereof

Technical Field

The application belongs to the technical field of civil engineering.

Background

The durability problem of the concrete structure caused by the corrosion of the steel bars is becoming more and more serious, and the corrosion of the steel bars becomes the primary reason for influencing the durability of the concrete structure. Because the steel stirrup is located the outermost side of the steel reinforcement cage, the steel stirrup is more easily influenced by the environment. More than forty years of scientific research and engineering practice at home and abroad shows that the adoption of the fiber reinforced composite material rib (FRP rib for short) stirrup to replace the common steel stirrup is an effective method for thoroughly solving the problems. The FRP rib is a novel high-performance material formed by bonding a plurality of strands of continuous fibers (such as glass fibers, carbon fibers, aramid fibers and basalt fibers) by using a base material (such as epoxy resin, polyethylene resin, polyamide resin and the like) and extruding and drawing the base material by a special die.

At present, FRP (fiber reinforced Plastic) reinforcements suitable for civil engineering are usually formed by pultrusion, and in order to meet the anchoring requirement, common FRP stirrups usually adopt a lap joint mode, as shown in figure 1. These forms of FRP stirrups require very long lap lengths, often requiring a large number of ties to form a stable framework of tendons, which is inconvenient for construction.

Disclosure of Invention

The application aims to provide a fiber reinforced composite material spiral stirrup capable of replacing a steel stirrup in a concrete structure, the spiral stirrup is made of corrosion-resistant fiber reinforced composite (FRP), the durability of the concrete structure can be effectively improved, the spiral stirrup is suitable for coastal areas and areas using a large amount of snow melting salt in the north, and the spiral stirrup has a wide application prospect. The continuous FRP spiral stirrup fundamentally avoids the problem that the concrete member loses efficacy due to corrosion of the steel bar, saves materials, avoids complex construction procedures and has wide application prospect.

Technical scheme one

A fiber reinforced composite spiral stirrup comprising a continuous rectangular coil of fiber reinforced composite reinforcement.

The projection of the coil on a plane vertical to the longitudinal axis is rectangular, the coil is poured in concrete to form a member, and the coils on two opposite sides are in opposite spiral states. Further, the pitch(s) of the rectangular coils and the angles (α and β) of the two pairs of limbs are adjusted to accommodate the clipped state of the different members.

The fiber in the fiber reinforced composite material is at least one of carbon fiber, glass fiber, basalt fiber, aramid fiber and hybrid fiber. The resin in the fiber reinforced composite material is at least one of unsaturated polyester, o-benzene resin, vinyl resin, epoxy resin, inorganic resin or thermoplastic resin material.

Further limiting the scope, the spiral stirrup is made of FRP; and in the further step, the composite material is made of corrosion-resistant FRP. The FRP helical stirrups are composed of continuous rectangular coils of FRP bars, which are rectangular in plan projection perpendicular to the longitudinal axis. The single-limb cross section of the FRP rib rectangular coil is circular or rectangular.

The method has the characteristics of convenience in production and molding, accurate size, material saving, convenience in storage, transportation and construction and the like.

Technical scheme two

An application method of a fiber reinforced composite material spiral stirrup is characterized in that,

step 1, prefabricating in a factory, and injection-molding the full-length FRP rib into a continuous FRP rib rectangular coil, wherein the planar projection of the continuous FRP rib rectangular coil perpendicular to the longitudinal axis is rectangular.

And 2, the rectangular coil of the FRP spiral stirrup is similar to a spring and can be axially compressed, so that the FRP spiral stirrup is convenient to store and transport.

And 3, the FRP rib rectangular coil can be axially stretched like a spring, so that the binding on site is facilitated. When in field binding, the axial tensile and compression characteristics of the rectangular coil of the FRP reinforcement can be utilized, the distance(s) of the rectangular coil and the angles (alpha and beta) of two pairs of side limbs are adjusted to adapt to the shearing state of different members, and the material strength of the FRP stirrup is fully exerted.

Drawings

Fig. 1 shows a conventional FRP stirrup in the form of FRP.

FIG. 2 is an axonometric view of FRP spiral stirrup according to the embodiment of the present application.

Fig. 3 is a diagram of an FRP framework according to an embodiment of the present application.

Fig. 4 is a compressed state diagram of the FRP helical stirrup according to the embodiment of the present application.

Detailed Description

The technical solutions provided in the present application will be further described with reference to the following specific embodiments and accompanying drawings. The advantages and features of the present application will become more apparent in conjunction with the following description.

It should be noted that the embodiments of the present application have a better implementation and are not intended to limit the present application in any way. The technical features or combinations of technical features described in the embodiments of the present application should not be considered as being isolated, and they may be combined with each other to achieve a better technical effect. The scope of the preferred embodiments of this application may also include additional implementations, and this should be understood by those skilled in the art to which the embodiments of this application pertain.

Techniques, methods, and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail but are intended to be part of the specification where appropriate. In all examples shown and discussed herein, any particular value should be construed as merely illustrative, and not limiting. Thus, other examples of the exemplary embodiments may have different values.

The drawings in the present application are in simplified form and are not to scale, but rather are provided for convenience and clarity in describing the embodiments of the present application and are not intended to limit the scope of the application. Any modification of the structure, change of the ratio or adjustment of the size of the structure should fall within the scope of the technical disclosure of the present application without affecting the effect and the purpose of the present application. And the same reference numbers appearing in the various drawings of the present application designate the same features or components, which may be employed in different embodiments.

Examples

step 1, prefabricating in a factory, and injection-molding the full-length FRP rib into a continuous FRP rib rectangular coil, wherein the planar projection of the continuous FRP rib rectangular coil perpendicular to the longitudinal axis is rectangular. As shown in fig. 2.

And 2, the rectangular coil of the FRP spiral stirrup is similar to a spring and can be axially compressed, so that the FRP spiral stirrup is convenient to store and transport. As shown in fig. 4.

And 3, the FRP rib rectangular coil can be axially stretched like a spring, so that the binding on site is facilitated. When in field binding, the axial tensile and compression characteristics of the rectangular coil of the FRP reinforcement can be utilized, the distance(s) of the rectangular coil and the angles (alpha and beta) of two pairs of side limbs are adjusted to adapt to the shearing states of different members, and the material strength of the FRP stirrup is fully exerted. As shown in fig. 2 and 3.

Further:

the continuous rectangular FRP rib coil of the FRP spiral stirrup can be cut into different lengths according to the requirement, and then the FRP spiral stirrup is stretched to the specified stirrup spacing(s) along the longitudinal axis. As shown in fig. 2.

The FRP spiral stirrup is bound and fixed with the FRP longitudinal reinforcement on site, so that an FRP reinforcement framework is formed.

The FRP spiral stirrup can utilize the characteristic that a rectangular coil of the FRP rib is similar to a spring and is convenient to stretch and compress in the axial direction, the FRP spiral stirrup is tightly compressed during storage and transportation so as to save space, the storage and transportation efficiency is improved, and the FRP spiral stirrup is stretched to a specified stirrup interval and two opposite limb angles according to the design requirement during field binding. As shown in fig. 2 and 3.

The FRP spiral stirrup has the advantages of convenient factory forming, easy storage and transportation, and quick and accurate construction.

The FRP spiral stirrup consists of continuous FRP rib rectangular coils, and the projection of the FRP spiral stirrup on a plane vertical to the longitudinal axis is rectangular.

Claims

1. A fiber reinforced composite spiral stirrup comprising a continuous rectangular coil of fiber reinforced composite reinforcement.

2. The fiber-reinforced composite helical stirrup as set forth in claim 1, wherein the fiber in the fiber-reinforced composite is at least one of carbon fiber, glass fiber, basalt fiber, aramid fiber, and hybrid fiber.

3. The fiber-reinforced composite helical stirrup as set forth in claim 1, wherein the resin in the fiber-reinforced composite is at least one of unsaturated polyester, ortho-benzene resin, vinyl resin, epoxy resin, inorganic resin or thermoplastic resin material.

4. The fiber reinforced composite helical stirrup as set forth in claim 1, wherein the helical stirrup is made of FRP.

5. The fiber reinforced composite helical stirrup as set forth in claim 1, made of corrosion-resistant FRP.

6. The fiber reinforced composite helical stirrup as set forth in claim 1, wherein the FRP helical stirrup consists of a continuous rectangular coil of FRP bars, which has a rectangular projection in a plane perpendicular to the longitudinal axis.

7. The fiber reinforced composite helical stirrup as set forth in claim 1, wherein the rectangular coil of FRP tendon has a circular or rectangular cross-section per limb.

8. An application method of a fiber reinforced composite material spiral stirrup is characterized in that,

step 1, prefabricating in a factory, and carrying out injection molding on a full-length FRP rib to form a continuous FRP rib rectangular coil, wherein the planar projection of the continuous FRP rib rectangular coil perpendicular to a longitudinal axis is rectangular;

step 2, the rectangular coil of the FRP spiral stirrup is similar to a spring and can be axially compressed, so that the FRP spiral stirrup is convenient to store and transport;