CN105113712B - The construction method of GFRP steel high-strength concrete combination beams - Google Patents

Abstract

The invention discloses a GFRP-steel-high-strength concrete composite beam and a construction method thereof, wherein the GFRP-steel-high-strength concrete composite beam includes a compression beam body area made of concrete, and the compression beam body area along the A number of welding studs pre-embedded in the concrete beam body in the length direction, steel webs welded and fixed with the welding studs, GFRP hollow tubes arranged in the opening cavity formed by the steel webs, and welded with the steel webs to close The tension steel plate at the opening end of the cavity; the outer wall of the GFRP hollow tube is close to the concrete beam body area, the steel web or the side wall of the tension steel plate; the end of the steel web close to the compression beam body area is provided with a bending part . The composite beam of the present invention is provided with a hollow cavity inside, the structure has light weight, saves materials, and is low in cost; the steel webs on both sides can be welded to other plates, and the connection is convenient and very reliable; the present invention can fully exert the mechanical properties of the material , improve the bearing capacity of the composite beam, construction safety.

Description

Construction method of GFRP-steel-high-strength concrete composite beam

technical field

The invention relates to building components, in particular to a composite beam and a construction method for the composite beam.

Background technique

Composite beams are flexural structural members combined with a variety of different materials. The composite beam members used in existing projects are all steel-concrete composite beam members. Steel-concrete composite beam members can make full use of the good compressive properties of concrete and the good tensile properties of steel to improve the bearing capacity and ductility of the structure. As shown in Figure 1a and Figure 1b, there are two types of steel-concrete composite beams commonly used at present: steel-concrete slab composite beams and steel-concrete filled beams.

Contents of the invention

After research, the applicant finds that:

From the point of view of stress and material use, these two composite beams have the following defects: the steel upper flange of the steel-concrete slab composite beam generally bears compressive stress, and plays the same role as the concrete slab in the compression zone, which means Part of the flange is not necessary, resulting in a waste of steel; the concrete in the lower part of the steel-concrete filled beam bears tensile stress, and because the tensile strength of concrete is very low, this part of the concrete cannot bear the load when it is under load. Instead, it becomes an unnecessary load on the structure, which not only wastes materials, but also affects the overall performance of the structure. From the perspective of construction, traditional steel-concrete composite beams still need to set up formwork during the construction process, which is complicated in process, and the beam-beam and beam-column connections are loaded and unreliable.

Purpose of the invention: one purpose is to provide a GFRP-steel-high-strength concrete composite beam to solve the above-mentioned problems in the prior art. A further object is to provide a construction method for the above-mentioned GFRP-steel-high-strength concrete composite beam.

Technical solution: a GFRP-steel-high-strength concrete composite beam, including a compression beam body area made of concrete, a number of welding studs pre-embedded in the concrete beam body along the length direction of the compression beam body area, and the welded The steel web fixed by nail welding, the GFRP hollow tube arranged in the opening cavity formed by the steel web, and the tension steel plate welded with the steel web to close the opening end of the cavity; the outer wall of the GFRP hollow tube is close to The concrete beam body area, the steel web or the side wall of the tension steel plate; the end of the steel web near the compression beam body area is provided with a bending part.

In a further embodiment, the connection method between the GFRP-steel-high-strength concrete composite beam and the composite slab is that the bending part of the steel web is welded and fixed with the profiled steel plate by welding studs. The connection method between the GFRP-steel-high-strength concrete composite beam and the steel beam is that a stiffener is welded on the steel web, the stiffener and the connecting plate (8) are fixed by bolts, and the other end of the connecting plate is fixed to the steel beam by bolts connect. The connection mode between GFRP-steel-high-strength concrete composite beam and the gusset plate is that the end of the steel web is provided with a fan-shaped cutout, which is welded and fixed with the gusset plate, and the tension steel plate is welded and fixed with the gusset plate by groove welding . The concrete strength of the compression beam body area is not lower than C40, and the tensile steel plate and steel web are Q345.

Further, the present invention also provides a method for manufacturing the above-mentioned GFRP-steel-high-strength concrete composite beam, comprising the following steps:

Step 1. Steel plate cutting, blanking and welding, control the thickness deviation of the steel plate within ±0.07mm, the vertical deviation of the top of the steel web is less than 0.3mm, and a fan-shaped cut is opened at the end of the steel web; weld by groove welding Tensile steel plates and steel webs, welding studs and steel webs are welded by fusion welding;

Step 2. Coating a layer of epoxy resin on the top surface of the tension steel plate, inserting the GFRP hollow tube into the top surface of the tension steel plate;

Step 3. After hoisting in place, weld the steel web and the gusset plate through butt welds, and connect the tension steel plate and the gusset plate through groove welding;

Step 4. Concrete is poured on the upper surface of the GFRP hollow pipe and cured until it is completely hardened.

In the above manufacturing method, if it is necessary to connect and fix the composite beam with other beams, the method further includes the following steps:

Step 31. Connect and fix the composite beam with other beams: directly weld other beams to the steel web of the composite beam, or weld stiffeners on the steel web, and hinge with other beams through the stiffeners.

In the above manufacturing method, if the floor panel adopts a composite panel, the method also includes the following steps:

Step 32. After the joint installation is completed, the profiled steel plate is laid on the uncast GFRP-steel-high-strength concrete composite beam, the profiled steel plate and the composite beam are connected by welding studs, and the composite beam and composite slab are integrally poured.

Beneficial effects: the composite beam of the present invention is provided with a hollow cavity inside, the structure has light weight, saves materials, and is low in cost; the steel webs on both sides can be welded to other plates, and the connection is convenient and very reliable; the present invention can make the mechanical properties of materials The performance is fully exerted, the bearing capacity of the composite beam is improved, and the construction is safe.

Description of drawings

Figure 1a and Figure 1b are structural schematic diagrams of the prior art.

Fig. 2 is a schematic cross-sectional view of a GFRP-steel-high-strength concrete composite beam.

Figures 3a and 3b are strain diagrams of the cross-section of the GFRP-steel-high-strength concrete composite beam.

Figure 4 is a schematic diagram of the connection between the GFRP-steel-high-strength concrete composite beam and the node area.

Fig. 5 is a schematic diagram of the connection between the GFRP-steel-high-strength concrete composite beam and the composite slab.

Figure 6 is a schematic diagram of the connection between the GFRP-steel-high-strength concrete composite beam and the steel beam.

detailed description

As shown in Figure 2, the GFRP-steel-high-strength concrete composite beam of the present invention mainly includes a concrete area, and the concrete forms a compression beam body area 1, along the direction of the length of the compression beam body area, a Row of welding studs 5. Two sets of steel webs 4 are located on the side walls of the concrete area, one end of which is provided with a bent portion 41, and the other end extends outward, the steel webs and the concrete area form a cavity with a longitudinal opening, and the GFRP hollow pipe 3 (in this implementation A thin-walled hollow tube in the example) is located in the cavity, and the open end is closed by the tension steel plate 2. The connection method of each component can be that welding studs are welded to the steel web, and the steel web and the tensile steel plate are welded and fixed by groove welding. The upper surface of the tensile steel plate is coated with adhesive such as epoxy resin, and connected with the GFRP thin-walled hollow tube. The size of the GFRP thin-walled hollow tube matches the size of the hollow cavity. During prefabrication, the welding studs are welded to the steel web, the upper surface of the tensile steel plate is coated with adhesive, the GFRP thin-walled hollow tube is placed on the surface coated with adhesive, and the tensile steel plate and the steel web are The plate is welded and fixed to form the frame of the beam body, and concrete is poured in the relevant area.

In this embodiment, the hollow tube is not only high in strength but also light in weight, which is a new technical idea completely different from the prior art.

Turning to FIG. 5 , in a further embodiment, the GFRP-steel-high-strength concrete composite beam is connected to the composite slab in such a way that the bending part of the steel web is fixed by welding the profiled steel plate 6 with the welding stud 7 . After welding into a whole, the concrete is poured.

Then describe Fig. 6, the connection mode of GFRP-steel-high-strength concrete composite beam and steel beam is that the steel web is welded with stiffeners, the stiffeners 9 and the connecting plate 8 are fixed by bolts, and the other end of the connecting plate is passed by bolts 11 is fixedly connected with steel beam 10. In other embodiments, the steel web can be directly welded to the beam or fixedly connected in other ways.

Turning to Figure 4, the connection mode between the GFRP-steel-high-strength concrete composite beam and the gusset plate is that the end of the steel web is provided with a fan-shaped cutout 42, which is welded and fixed with the gusset plate, and a joint is formed between the steel web and the gusset plate. Butt weld 43, the tension steel plate is welded and fixed to the gusset plate by groove welding 2a.

It can be seen from the above several embodiments that the present invention provides a new technical concept. This structure is not only light in weight and high in strength, but also very convenient to connect with other structures, and the construction speed is fast. The structure itself is light in weight, can save materials, and has the advantages of low manufacturing cost.

In a further embodiment, the concrete strength of the compression beam body area is not lower than C40, and the tensile steel plate and steel web are Q345.

The method for manufacturing the above-mentioned GFRP-steel-high-strength concrete composite beam comprises the following steps:

Step 1. Steel plate cutting, blanking and welding, control the thickness deviation of the steel plate within ±0.07mm, the vertical deviation of the top of the steel web is less than 0.3mm, and a fan-shaped cut is opened at the end of the steel web; weld by groove welding Tensile steel plates and steel webs, welding studs and steel webs are welded by fusion welding;

Step 2. Coating a layer of epoxy resin on the top surface of the tension steel plate, inserting the GFRP hollow tube into the top surface of the tension steel plate;

Step 3. After hoisting in place, weld the steel web and the gusset plate through butt welds, and connect the tension steel plate and the gusset plate through groove welding;

Step 4. Concrete is poured on the upper surface of the GFRP hollow pipe and cured until it is completely hardened.

In a further embodiment, if it is necessary to connect and fix the composite beam with other beams, the method further includes the following steps: Step 31. Connect and fix the composite beam with other beams: directly weld other beams to the steel web of the composite beam, or Stiffeners are welded on steel webs and hinged to other beams through stiffeners.

In the above manufacturing method, if the floor panel adopts a composite panel, the method also includes the following steps:

Step 32. After the joint installation is completed, the profiled steel plate is laid on the uncast GFRP-steel-high-strength concrete composite beam, the profiled steel plate and the composite beam are connected by welding studs, and the composite beam and composite slab are integrally poured.

It should be noted that the order of the steps in the above embodiment can be adjusted according to the actual situation, and the sequence numbers are for the convenience of description, rather than limiting the order.

Construction case one

The GFRP-steel-high-strength concrete composite beam is characterized in that it consists of concrete in the compression zone (that is, the compression beam body area composed of concrete, the same below), tensile steel plates, GFRP hollow tubes, steel webs and welding studs. The ratio of width b to height h of the composite beam is b/h=3/5; the concrete in the compression zone is subjected to compressive stress when it bears positive bending moment, and the tensile steel plate is subjected to tensile stress when it bears positive bending moment. The concrete in the compression area adopts high-strength concrete above C40, and the tensile steel plate and steel web adopt Q345 steel.

The thickness of the GFRP hollow tube is 2mm, and the length of the outer dimension is 1mm less than the width of the tensile steel plate minus twice the thickness of the steel web, that is, b-2t-1mm, where t is the thickness of the steel web; the length is 100mm shorter than the span of the beam, Both ends are indented by 50mm.

Welding studs are made of Q345 low-carbon steel, welded on the steel web, and the position is 50mm above the top of the GFRP hollow tube. The spacing is designed according to the "Technical Regulations for Steel Concrete Composite Structures" (JGJ138-2001).

Groove welding is used between the tensioned steel plate and the steel web to form a U-shaped structure, and welding studs are welded to the steel web. The GFRP hollow tube penetrates inside the U-shaped structure, rests on the tension steel plate, and uses epoxy resin to fix the position of the tension steel plate. The concrete in the compression zone is poured on the upper surface of the GFRP hollow tube, the GFRP tube is used as the bottom formwork, and the steel web is used as the side formwork.

During the construction stage, the concrete is fluid and has no bearing capacity. The construction load is jointly borne by the U-shaped structure composed of tensile steel plates and rigid webs and GFRP hollow pipes. Both the U-shaped structure and the GFRP hollow tube are in an elastic state during the construction load stage, and the deflection of the beam is controlled to l/250 and not more than 25mm according to the "Steel and Concrete Composite Building (Roof) Cover Structure Structure" (05SG522), and l is Beam span. In the calculation of bearing capacity and deformation, the U-shaped structure and GFRP hollow tube are calculated according to the basic principles of material mechanics and deformation coordination conditions.

During the use phase, the concrete is fully hardened. The designed concrete is all under compressive stress. According to the assumption of plane section, the top of the concrete in the compression zone reaches the ultimate strain ε _c , and the steel plate under tension reaches the yield strain ε _y . The strain diagram of the beam section is shown in Figure 3. According to the deformation coordination condition, the rotation angle of the GFRP hollow tube section is the same as θ, as shown in Figure 3. Therefore, the strain on the upper and lower edges of the GFRP hollow tube is 0.5ε _y . Therefore, the flexural bearing capacity of the steel-concrete composite part is f _y ×b×t ₀ ×(h-0.5h _c ), and the flexural bearing capacity of the GFRP hollow tube is _{0.5ε y} ×E frp ×2mm×b _frp × h _frp .

Among them, E _frp is the elastic modulus of GFRP, b _frp and h _frp are the height and width of GFRP hollow tube, respectively. GFRP-steel-high-strength concrete composite beam is f _y ×b×t ₀ ×(h-0.5h _c )+ _{0.5ε y} ×E frp ×2mm×b _frp ×h _frp . t ₀ is the thickness of the steel plate under tension, and t is the thickness of the steel web. f _y is the design value of compressive strength, h _c is the thickness of the compressed concrete area.

Due to the effect of GFRP hollow tube, the self-weight of GFRP-steel-high-strength concrete composite beam is reduced by γ _c ×b _frp ×h _frp compared with ordinary steel-concrete composite beam, where γ _c is the weight of concrete; the bearing capacity is increased by 0.5ε _y ×E _frp × 2mm × b _frp × h _frp .

The manufacturing process of GFRP-steel-high-strength concrete composite beams is as follows: steel plate blanking and welding, GFRP hollow tube placement, construction and installation positioning, and concrete pouring.

In this embodiment, when the steel plate is cut and blanked, the thickness deviation of the steel plate should be controlled within ±0.07mm, and the vertical deviation of the top end of the steel web should be less than 0.3mm. A sector cut with a radius of 40mm is made at the end of the steel web.

The tension steel plate and the steel web are connected by butt groove welding, the weld size is designed according to the "Code for Design of Steel Structures" (GB50017), and the welding rod is E50 type welding rod. The welding studs and the steel web are connected by welding, and the welding is welded by a BS308 stud welding machine.

After the welding studs are positioned and welded, a layer of epoxy resin is coated on the top surface of the tension steel plate, and the GFRP hollow tube is inserted into the top surface of the tension steel plate.

Before the construction and hoisting, the deflection and bearing capacity of the beam during the hoisting process should be calculated, and the bearing capacity of the GFRP hollow tube should be ignored to choose a reasonable hoisting scheme.

After hoisting in place, the steel web and the gusset plate are welded by butt welds, the weld seam is at a distance from the steel web, and the tension steel plate and the gusset plate are connected by groove welding.

After the connection is completed, set the temporary support according to the construction calculation. If the construction calculation does not require temporary support, do not set it. Then pour concrete on the upper surface of the GFRP hollow pipe and perform curing until it is completely hardened.

The connection of other beams to this beam can be realized by direct welding on the steel web or by welding stiffeners on the steel web for hinge joint. If the floor slab adopts composite slabs, after the joint installation is completed, the profiled steel plates are laid on the uncast GFRP-steel-high-strength concrete composite beams, and the profiled steel plates and composite beams are connected by welding nails. The beams and slabs are then integrally poured. The GFRP-steel-high-strength concrete composite beam is connected with the steel beam, and the stiffener is welded on the steel web of the composite beam, and the web of the steel beam is connected to the stiffener by bolts and connecting plates.

In conclusion, in the above embodiments, GFRP (glass fiber composite material) is used to form a hollow section in the composite beam, which can not only save materials without weakening the mechanical performance of the steel-concrete composite, but also effectively improve the structure. carrying capacity. The invention adopts new ideas and new materials to improve the combined bearing capacity and construction safety; and adopts a new structural structure to fully exert the mechanical properties of the materials, and solves the problem of connection between structures well, realizing the reduction of material consumption. Minimization and safety of construction.

The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various equivalent transformations can be carried out to the technical solutions of the present invention. These equivalent transformations All belong to the protection scope of the present invention.

Claims (3)

1. A method for manufacturing GFRP-steel-high-strength concrete composite beams, characterized in that, The GFRP-steel-high-strength concrete composite beam includes a compression beam body area (1) made of concrete, a number of welding studs (5) pre-embedded in the concrete beam body along the length direction of the compression beam body area, and the The steel web (4) welded and fixed by the above welding studs, the GFRP hollow tube (3) arranged in the opening cavity formed by the steel web, and the tension steel plate welded with the steel web to close the opening end of the cavity ( 2); the outer wall of the GFRP hollow tube is close to the concrete beam body area, the steel web and the side wall of the tension steel plate; the end of the steel web close to the compression beam body area is provided with a bending part (41); The connection mode of GFRP-steel-high-strength concrete composite beam and composite slab is that the bent part of the steel web is welded and fixed with the profiled steel plate (6) by welding studs; The connection method between GFRP-steel-high-strength concrete composite beams and steel beams is that the steel webs are welded with stiffeners, the stiffeners and the connecting plate (8) are fixed by bolts, and the other end of the connecting plate is fixed to the steel beam by bolts connect; The connection mode between GFRP-steel-high-strength concrete composite beam and the gusset plate is that the end of the steel web is provided with a fan-shaped cutout, which is welded and fixed with the gusset plate, and the tension steel plate is welded and fixed with the gusset plate by groove welding ; The concrete strength of the compression beam body area is not lower than C40, and the tensile steel plate and steel web are Q345; The method comprises the steps of: Step 1. Steel plate cutting, blanking and welding, control the thickness deviation of the steel plate within ±0.07mm, the vertical deviation of the top of the steel web is less than 0.3mm, and a fan-shaped cut is made at the end of the steel web; welded by groove welding Tensile steel plates and steel webs, welding studs and steel webs are welded by fusion welding; Step 2. Coat a layer of epoxy resin on the top surface of the tension steel plate, and insert the GFRP hollow tube into the top surface of the tension steel plate; Step 3. After hoisting in place, weld the steel web and gusset plate through butt welds, and connect the tension steel plate and gusset plate through groove welding; Step 4. Pour concrete on the upper surface of the GFRP hollow pipe and cure until it is completely hardened. 2. the method for manufacturing GFRP-steel-high-strength concrete composite beam as claimed in claim 1, is characterized in that, also comprises: Step 31. Connect and fix the composite beam with other beams: directly weld other beams to the steel web of the composite beam, or weld stiffeners on the steel web, and hinge with other beams through the stiffeners. 3. the method for manufacturing GFRP-steel-high-strength concrete composite beam as claimed in claim 2, is characterized in that, also comprises: Step 32. After the joint installation is completed, the profiled steel plate is laid on the uncast GFRP-steel-high-strength concrete composite beam, the profiled steel plate and the composite beam are connected by welding nails, and the composite beam and composite slab are integrally poured.