CN101974959A

CN101974959A - Concrete structure FRP end anchor device

Info

Publication number: CN101974959A
Application number: CN 201010502064
Authority: CN
Inventors: 吴智敏; 石昌文; 董海
Original assignee: Dalian University of Technology
Current assignee: Dalian University of Technology
Priority date: 2010-09-30
Filing date: 2010-09-30
Publication date: 2011-02-16

Abstract

The invention relates to a concrete structure FRP end anchor device, belonging to the technical field of civil engineering structural strengthening. The invention is characterized in that: the two ends of a fiber cloth are wound on a steel strap, and then a bolt is used for fixing the steel strap on a concrete beam. The invention solves the technical problems that utilization factor of fiber material is reduced and multiple construction technologies are restricted as a strengthening member in externally bonding FRP strengthening method is peeled and strengthening becomes invalid. Construction is complex and cost is high when special strengthening way is adopted, thus being not applicable to practical project. The invention has the benefits and effects that peeling-off of fiber cloth can be delayed, the fiber cloth can bear force with a beam until the fiber cloth is broken even midspan is in peeling-off failure, so that FRP material can be fully utilized, bearing capacity of beam is effectively improved, and time delay of beam damage is obviously improved.

Description

Concrete structure FRP end anchorage device

Technical field

The invention belongs to civil engineering structure reinforcing technique field, relate to a kind of concrete structure FRP end anchorage device.

Background technology

Fibre reinforced composites (FRP) have been widely used in structural strengthening and the reinforcing in the civil engineering.This material has the tensile strength height, and light weight is corrosion-resistant, and it is little to creep, and is convenient to advantages such as construction.Numerous discovering pastes the concrete beam surface with epoxy resin with FRP, can effectively improve the anti-bending bearing capacity and the rigidity of concrete component.Loading early stage, the collaborative work well of FRP and concrete beam, but along with the increase of load, peeling off appears in the FRP sheet material, thereby loses consolidation effect.FRP stripping damage pattern can be summed up as three kinds: promptly concrete cover stripping damage, FRP cloth end interface peel destroy and the middle stripping damage of FRP.Because the stripping damage of FRP, the intensity of FRP usually can't be fully used, and the degree that causes bearing capacity to improve reduces greatly, has reduced the whole member consolidation effect.This shows that FRP and concrete bonding are the major reasons that influences its consolidation effect.

For improving the bond effect between FRP and the concrete beam, can adopt the embedding of a kind of top layer to paste (NSM-FRP) method, promptly behind concrete surface fluting embedded resin, sticking obedient FRP sheet material is reinforced.Have the scholar to carry out the FRP reinforcement experiment with surperficial embedding subsides method, confirmed that this method compares with outer reinforcing method, anchoring ability is better.But the NSM-FRP method needs complex surfaces to handle, for placing and pasting FRP and need prepare suitable groove.In work progress, the saw blade fluting cuts off the member reinforcing bar probably, therefore can not get under the improved situation in the fluting technology, and surperficial embedding is pasted method and can't be used widely.

The anti-bend reinforced method of another kind of concrete is mechanical fasteners (MF-FRP) method, and this method adopts the mechanical connection reinforcing mode, with a kind of special " rifle " nail is passed FRP and squeezes into concrete, makes the better collaborative work of FRP sheet material and concrete.Compare with outer reinforcing method, this method does not need surfacing, adhesive or experienced operator.Result of the test shows that the MF-FRP method is reinforced can significantly improve the supporting capacity of beam, and has kept the ductility of concrete beam preferably.Yet this method just is used for the very strong special FRP sheet material of shear resistance, and general FRP material is easy to take place shear failure, even the strong FRP material of shear resistance still exists splitting and application life is shorter.The expert who has adopts FRP to make U type hoop and arranges along beam length, can effectively delay peeling off of cloth, but still exist cloth to peel off problem.The expert who has proposes a kind of compoiste adhering technology, and this technology is utilized a kind of novel anchoring piece (anchoring piece is made up of an iron plate and two holdfasts) externally to paste cloth to carry out anchoring.The result shows, pastes the CFRP cloth of 2 layers and 4 layers and the anchoring of employing new technology and all broken, and adopt identical anchorage style and paste the beam generation stripping damage of 6 layers of CFRP.Broken although adopt this technology can satisfy 2 layers and 4 layers of CFRP cloth, a large amount of holdfasts that use have certain damage to concrete beam, and construction is complicated.

Because FRP and concrete stripping damage have limited making full use of of fibrous material, thereby, still need a large amount of research work improving the adhesive property between FRP and the concrete and improving on the FRP utilization rate.

Summary of the invention

The purpose of this invention is to provide a kind of concrete structure FRP end anchorage device, for solving the deficiency that loses consolidation effect after cloth is peeled off easily and peeled off in the direct mounting method.This invention not only can delay individual layer FRP peels off, even peel off the anchoring that still can rely on the cloth two ends FRP is finally broken, thereby improves the utilization rate of cloth, and the ductility can improve beam and destroy the time.

Technical scheme of the present invention is:

Concrete structure FRP end anchorage device comprises steel disc, screw rod, nut, pad and bonding adhesive.Steel disc be shaped as rectangle, wherein two long limits are polished into ellipse, the stress that reduces the cloth of twining is concentrated, and a hole that is complementary with screw diameter is respectively arranged in the both sides of steel disc long side direction.Paste the both sides of the width of cloth at first outside, close on the position of cloth longitudinal edge, with drill bit get out on the concrete component with steel disc on the hole of hole opposite position, inject bonding adhesive then, standing screw, the buried depth of screw rod are 50mm.The total length of screw rod is determined according to thickness, steel plate thickness and the nut height of buried depth, stickup cloth.Adopt this method to fix one group of screw rod respectively at the cloth two ends.Then the cloth two ends that shear are wrapped on the ready steel disc three layers of cloth below the iron plate, upper two layers respectively.Before twining the free end of cloth one side broad ways is pasted the transparent rubberized fabric of a wide about 10mm, be bonded on the iron plate another side and and steel disc length direction alignment with 502 glue then.Clear up the position of pasting cloth on the concrete at last, the glue bedroom wet fiber cloth with preparing is sleeved on steel disc on the screw rod that fixes then successively, at last nut and pad is sleeved on the screw rod, applies moment of torsion with torque spanner.

Effect of the present invention and benefit are to introduce screw rod as securing member, reliably anchoring outer subsides method cloth, effectively delayed peeling off of cloth, avoided peeling off to make reinforce losing efficacy because of it, still can rely on the anchoring at two ends to continue carrying even peel off cloth until breaking, thereby the utilization rate of cloth is improved, and the ductility of beam also is significantly improved when destroying, overcome that cloth can't be fully used material because of peeling off too early in the general reinforcing method, and this method construction is simple, can be applicable to various FRP materials.

Description of drawings

Accompanying drawing 1 is the steel disc schematic diagram.

Accompanying drawing 2 is screw rod schematic diagrames.

Accompanying drawing 3 is concrete structure FRP end anchorage device schematic diagrames.

Accompanying drawing 4 is concrete structure FRP end anchorage structure drawing of device.

Accompanying drawing 5 is concrete structure FRP end anchorage device plane structure charts.

Accompanying drawing 6 is concrete structure FRP end anchorage device facade structures figure.

Among the figure: 1 steel disc; 2 screw rods; 3 nuts; 4 pads; 5FRP; 6 concrete in tension faces.

The specific embodiment

Be described in detail the specific embodiment of the present invention below in conjunction with technical scheme and accompanying drawing.

According to Fig. 1, part diagram shown in Figure 2, concrete structure cloth anchoring is by steel disc 1, screw rod 2, and nut 3 and pad 4 are formed.Steel disc 1 is a rectangle, and long arris polishes smooth, and is used for twining and compress the cloth that is positioned at below it.At first get out the hole of symmetry with electric drill, be used for fixing screw rod 2 in the precalculated position.Vertical and the position that in boring procedure, will guarantee to hole accurate.After the processing of clear hole, in the hole, inject bonding adhesive, screw rod 2 patchholes, be fixed on the relevant position, to keep the vertical of screw rod 2 during insertion.After the bonding adhesive for the treatment of standing screw 2 then solidifies fully, the cloth that shears is wrapped on the steel disc 1 in advance according to Fig. 3, then with the epoxy resin bedroom wet fiber cloth for preparing, according to Fig. 3 the anchored end at cloth two ends is sleeved on and fixes on the screw rod 2, then pad 4 and nut 3 are sleeved on the screw rod 2, and nut 3 is applied torsion with torque spanner, be used for fastening steel disc 1.

Claims

1. concrete structure FRP end anchorage device, comprise steel disc (1), screw rod (2), nut (3), pad (4) is formed, it is characterized in that: steel disc (1) be shaped as rectangle, wherein two long limits are polished into ellipse, the hole that respectively has one and screw rod (2) diameter be complementary in the both sides of steel disc long side direction, paste the both sides of the width of cloth at first outside, close on the position of cloth longitudinal edge, with drill bit get out on the concrete component and steel disc (1) on the hole of hole opposite position, inject bonding adhesive then, standing screw (2), the buried depth of screw rod (2) is 50mm, the total length of screw rod (2) is according to buried depth, paste the thickness of cloth, steel disc (1) thickness and nut (3) highly come to determine, adopt this method to fix one group of screw rod (2) respectively at the cloth two ends, then the cloth two ends that shear are wrapped in respectively on the ready steel disc (1), the following three layers of cloth of steel disc (1), upper two layers, clear up the position of pasting cloth on the concrete at last, with the epoxy resin bedroom wet fiber cloth for preparing, steel disc (1) is sleeved on successively on the screw rod (2) that fixes then, at last nut (3) and pad (4) are sleeved on the screw rod (2), apply moment of torsion with torque spanner.