CN100467819C

CN100467819C - Construction process for pretension carbon fiber cloth reinforced concrete beam

Info

Publication number: CN100467819C
Application number: CNB2005101107331A
Authority: CN
Inventors: 顾祥林; 高鹏; 张伟平; 李翔
Original assignee: Tongji University
Current assignee: Tongji University
Priority date: 2005-11-24
Filing date: 2005-11-24
Publication date: 2009-03-11
Anticipated expiration: 2025-11-24
Also published as: CN1970974A

Abstract

The invention relates to a construction technology for strengthening concrete beams with prestretching CFRP, in which fixed angle steel and anchorage device are set on two ends of concrete beams and it is prestretched at one end. There is strengthening ribbed plate in the angle steel and support plate is set at the lower part; one of angle steels is corresponded with another in two angle steels and is fixed with the beam by bolt at two ends of concrete beams. The anchorage device is formed by the bottom plate and two upright plates fixing in vertical direction, between which the interval is set. First of all, base rubber for strengthening is set at the bottom of beam, CFRP fabric is used to wind and paste on base plates of two anchorage devices respectively, concrete beam is set between two upright plates of anchorage devices, each one is fixed with the angle steel. At the end of anchorage device hoisting jack is set on the support plate and the pull-rod, which passes through upright plate of anchorage device, angle steel, hoisting jack, gasket and loading sensor, is fixed with nut. The loading sensor is connected with strain box and the hoisting jack is connected with oil pump and oil pressure sensor. The CFRP fabric is prestretched by oil pressured pump and after that it is fixed. Face glue is used to paint the CFRP fabric again so as to combine the CFRP fabric and concrete beams together.

Description

The job practices of pretension carbon fiber cloth reinforced concrete beam

Technical field

The present invention relates to a kind of job practices of pretension carbon fiber cloth reinforced concrete beam, be specifically related to a kind of anchor device and job practices of pretension carbon fiber cloth reinforced concrete beam.

Background technology

Many old buildings are arranged at present, owing to be subjected to the restriction of economy and technical level at that time, the carrying dynamics is low, durability and poor stability in when design, along with the increase of operating period and the variation of service load, be badly in need of reinforcing,, increase the service life to stop potential safety hazard.Studies have shown that: carbon cloth (CFRP) have the deadweight of intensity height, volume little, need not that pad connects, advantage such as corrosion-resistant.Test shows: when reinforcement yielding, the CFRP sheet material has only been given play to the intensity less than 20%, if the CFRP sheet material is applied pretension, can bring into play high-strength characteristic better; If pretensioned CFRP cloth is pasted on the tension face of concrete beam, can effectively improves the anti-bending bearing capacity and the rigidity of beam, and can control the crack.The method of at present pre-stretch-draw CFRP cloth is a lot, as antiarch method and independent bed method, all needs special equipment, and as full-sized car, operation bed, lifting jack etc., expenses such as the installation cost of using in the construction, labour cost, ground tackle expense are higher; Stretching method is that a fixed end and stretch-draw end ground tackle are installed on beam on the beam, CFRP cloth one end is fixed, the other end carries out stretch-draw, though this method construction only needs manpower seldom, but require ground tackle rigidity big and size is little, supporting tensioning equipment needs light and small and exquisite, does not still have mature technique at present and equipment is used in construction.Abroad, the Raafat of the U.S. has developed a cover hydraulic tensioning equipment and an anchor device in 2003, at home, Hunan University develops a cover construction equipment, but this its hydraulic test of two covering devices is all too huge, can't be in real project using, the stretch-draw end has adopted the method for round steel pipe fixation of C FRP cloth in the device that Southeast China University develops, jack pair pull bar with a compact size carries out stretch-draw, but its stretch-draw end device number of spare parts is too many, is unsuitable for promoting on operation and the engineering.

The emphasis of stretching method exploitation is on the beam: realize to large scale that with try one's best light-duty equipment and few manpower the pre-stretch-draw CFRP sheet material that carries out of multispan degree beam is reinforced; Fixing should have very big strength and stiffness to satisfy the requirement to pre-stretching force and distortion with ground tackle, and ground tackle needs that material is common, processing simply is beneficial to popularization simultaneously; Supporting hydraulic tensioning equipment needs volume little in light weight, so that the construction operation at the bottom of long-distance transport and the beam.

Summary of the invention

For achieving the above object, the present invention proposes a kind of job practices of pretension carbon fiber cloth reinforced concrete beam.The present invention includes the job practices of the anchor device and the reinforced concrete beam of pretension carbon fiber cloth.

Anchor device comprises: angle steel, ground tackle, screw bolt and nut;

The angle steel middle part is connected with deep floor, and the bottom is connected with supporting plate, and the two sides all has screw, and angle steel is corresponding in twos, connects firmly with bolt and concrete beam according to the two ends of the position that designs at beam;

Ground tackle is had between two risers at interval by base plate and two vertical connecting firmly of riser, and screw is arranged on the riser;

The job practices of pretension carbon fiber cloth reinforced concrete beam: (1) is smeared the concrete beam bottom to reinforce earlier and is used primer, simultaneously CFRP cloth is twined on two base plates respectively and stickup, (2) ground tackle is installed: concrete beam is between two risers of ground tackle, the base plate of soffit and ground tackle is fitted, and each ground tackle riser connects firmly with bolt with angle steel respectively; (3) tensioning equipment is installed: at the stretch-draw end, jack is placed on the supporting plate, pass ground tackle riser, angle steel, jack, pad, load sensor successively by pull bar then, fix with nut, load sensor is connected with the strain case through data wire, and jack is connected with oil pressure gauge with oil pump through oil pipe; (4) pressure oil pump, the jack drive stay drives ground tackle riser and CFRP cloth, makes CFRP cloth be subjected to stretch-draw, stops pressurization when reaching predetermined pull, tight a bolt, the dismounting tensioning equipment, the screw on the ground tackle of dismounting back is used bolt; (5) the CFRP cloth after the stretch-draw is coated with the glue of wiping one's face once more, CFRP cloth and concrete beam are become one, maintenance a couple of days allows glue reach intensity.

Deep floor that designs on the angle steel and supporting plate can play the effect of resistance to deformation and jack supporting plate simultaneously, and angle steel is fixed on the both sides of beam, can play the reaction frame effect, have very big strength and stiffness, to satisfy the requirement to pre-stretching force and distortion.

The stretch-draw and the anchor system of the present invention's design are simple, practical, the ground tackle volume is little, rigidity is big, and tensioning equipment is light small and exquisite, easy to operate, utilizes common hollow hydraulic jack and corresponding ground tackle, can realize stretch-draw and anchoring to CFRP cloth, maximum tension can reach 100kN.

Description of drawings

Below in conjunction with drawings and Examples the present invention is described in detail.

Fig. 1 stretch-draw and anchor system overall schematic;

Fig. 2 CFRP cloth and ground tackle connection diagram;

Fig. 3 angle steel structural representation;

Fig. 4 stretch-draw terminal structure vertical view;

Fig. 5 fixed end vertical view;

Fig. 6 stretch-draw schematic diagram that finishes.

1. concrete beam, 2. support, 3. angle steel, 4. deep floor, 5. supporting plate, 6. bolt, 7. ground tackle base plate, 8. ground tackle riser, 9.CFRP cloth, 10. pull bar, 11. jack, 12. pads, 13. load sensors, 14. nuts, 15. data wires, 16. oil pipes.

The specific embodiment

Will be at the two ends of the concrete beam on the support 21 according to the corresponding in twos angle steel 3 of installing in the position that designs, every pair of angle steel pierces beam section with four bolts 6, there is deep floor 4 at the angle steel middle part, supporting plate 5 is arranged at the bottom, spacing between two ground tackle risers 8 is identical with the concrete beam breadth of section, calculate the use length of CFRP cloth 9, CFRP cloth is twined and stickup to fixed end and stretch-draw end ground tackle base plate 7 respectively, then, at the bottom of the polishing concrete beam, smear primer for the beam primary coat, the ground tackle of having pasted CFRP cloth is installed on the beam, concrete beam 1 is between two ground tackle risers 8, soffit and ground tackle base plate are fitted, each riser of ground tackle connects firmly with angle steel 3 usefulness bolts 6 respectively, at the stretch-draw end, jack is placed on the supporting plate 5, penetrate ground tackle riser 8 successively by pull bar 10 then, angle steel 3, jack 11, pad 12, load sensor 13, fixing with nut 14, load sensor 13 is connected with the strain case through data wire 15, and jack 11 is connected with oil pressure gauge with oil pump through oil pipe 16; Pressure oil pump, jack make the oil cylinder jacking, and pull bar drives ground tackle and CFRP cloth, makes CFRP cloth be subjected to stretch-draw, observe the load counter on the strain case, when reaching predetermined pull, stop pressurization, tight a bolt, dismounting tensioning equipment and pull bar, the screw on the ground tackle of dismounting back is used bolt; CFRP cloth after the stretch-draw is coated with the glue of wiping one's face once more, CFRP cloth and concrete beam are become one, maintenance a couple of days allows glue reach intensity.Break away from if any the position at the bottom of the beam of CFRP cloth after the tension and injustice, the hollowing phenomenon may occur, add the CFRP cloth jack-up of rod chapelet, it can be contacted with the soffit the hollowing place with wooden unit.Keep beam and CFRP cloth in maintenance processes, not to be subjected to external interference.

Its supporting capacity of small-sized hollow jack that the present invention uses is 130kN, and stroke is 76mm, and body height is 184mm, highly is 260mm after the maximum extension, and maximum outside diameter is 69mm, and this kind jack external diameter and body height are all very little, is suitable for operating at the bottom of the beam; Have in light weightly, install easy to carryly, bearing capacity is higher to satisfy characteristics such as stretch-draw needs.

The resistance-strain drawing and pressing type load sensor that adopts, its maximum range is a 50kN power, sensitivity is 0.5%, its data output apparatus adopts the static resistance strain gauge, and on the normal pressure machine, load sensor and data output apparatus are carried out data scaling in advance, when big load, can select the wide range load sensor for use.

The present invention can be used for pretension carbon fiber cloth reinforced concrete beam in the actual engineering.

Claims

1. the job practices of pretension carbon fiber cloth reinforced concrete beam is characterized in that:

(1) earlier the reinforcing primer is smeared in beam body bottom; Carbon cloth is twined on two ground tackle base plates respectively and stickup; Ground tackle is had between two risers at interval by base plate and two vertical connecting firmly of riser, and screw is arranged on the riser;

(2) ground tackle is installed: ground tackle is installed to the concrete beam bottom, and concrete beam is between two risers of ground tackle, and each riser of ground tackle connects firmly with bolt with angle steel respectively, and the angle steel middle part is provided with deep floor, and supporting plate is arranged at the bottom;

(3) tensioning equipment is installed: at the stretch-draw end, jack is placed on the supporting plate, penetrate ground tackle riser, angle steel, jack, pad, load sensor successively by pull bar then, fix with nut, load sensor is connected with the strain case through data wire, and jack is connected with oil pressure gauge with oil pump through oil pipe;

(4) pressure oil pump, the jack drive stay drives ground tackle and carbon cloth, makes carbon cloth be subjected to stretch-draw, stops pressurization when reaching predetermined pull, tightens the bolt on ground tackle top, the dismounting tensioning equipment, the screw of ground tackle top and the bottom, dismounting back is used bolt;

(5) carbon cloth after the stretch-draw is coated with the glue of wiping one's face, carbon cloth and concrete beam are become one, maintenance a couple of days allows glue reach intensity.

2. pretension carbon fiber cloth reinforced concrete beam job practices as claimed in claim 1 is characterized in that, the anchor device of pretension carbon fiber cloth comprises: angle steel, ground tackle, screw bolt and nut; Wherein:

(1) the angle steel middle part is provided with deep floor, and supporting plate is arranged at the bottom, and the two sides of angle steel all has screw, and angle steel is corresponding in twos, connects firmly with bolt and concrete beam according to the two ends of the position that designs at beam;

(2) ground tackle is had between two risers at interval by base plate and two vertical connecting firmly of riser, and screw is arranged on the riser.