CN102587296A - Self-balancing external prestressing strengthening method for bridge structure - Google Patents
Self-balancing external prestressing strengthening method for bridge structure Download PDFInfo
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- CN102587296A CN102587296A CN2012100398452A CN201210039845A CN102587296A CN 102587296 A CN102587296 A CN 102587296A CN 2012100398452 A CN2012100398452 A CN 2012100398452A CN 201210039845 A CN201210039845 A CN 201210039845A CN 102587296 A CN102587296 A CN 102587296A
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Abstract
The invention relates to a self-balancing external prestressing strengthening method for a bridge structure. The self-balancing external prestressing strengthening method is characterized by comprising the following steps of: carrying out interface processing at a connecting place (5) of a top flange of a concrete beam; (2) inserting reinforced bars at the connecting place (5) of the top flange of the concrete beam; (3) installing the reinforced bars at the connecting place (5) of the top flange of the concrete beam; (4) installing the reinforced bar of a steering block (6) and a diverter (9) at the bottom of the beam; (5) symmetrically adding diaphragm plates at a place far away from the end of the beam by 2-3m, and installing an anchorage device (10); (6) concreting the connecting place (5) of the top flange of the beam, the steering block (6) and the newly added diaphragm plates (8); and (7) installing and tensioning an anchoring external cable, thus obtaining a self-balancing external prestressing strengthening structure. An external prestressing system can be used for detecting and adjusting the stress of the cable at any time, inspecting the corrosion condition of the cable and can also be used for maintaining and replacing the cable when necessary. The self-compacting concrete solves the problems of dense reinforcement assembly, complex structure, narrow space of formworks and traditional structural members, cavities caused by the blocking of aggregates and the like, effectively ensures the dense degree of placing concrete and increases the strengthening effect. The self-balancing external prestressing strengthening method can be used for strengthening heavy railroad brides, concrete box girders and T beams.
Description
Technical field
The present invention relates to the bridge and the Structural Engineering field of building subject, be specifically related to a kind of reinforcing intensifying method and construction technology of bridge superstructure, especially the quick reinforcement to heavily loaded railroad bridge promotes.
Background technology
Along with at a high speed with the deepening continuously of passenger dedicated railway line Large scale construction, China railways at a high speed and fast passenger transportation network progressively form, " separating lines for passenger and freight ", existing line are the main pattern that master's means of transportation will become China Railway to start goods train.Therefore, the heavy duty of Existing Railway Bridges transformation reinforcing is one of present problem demanding prompt solution of China railways with assessment.
The heavy haul railway conveying capacity is big, and economic and social benefit is remarkable, and the Development of Railway heavy haul transport has become the direction that the countries in the world railway transportation develops, also is the main path that China quickens to improve railway transport capacity.Accelerate coal transport facility construction and existing line capacity expansion revamping dynamics, the formation transport power is powerful, tissue is advanced, Coal Transport system perfect in shape and function is one of important development content of China's Mid-term and Long-term Plan of the Railway Network.Guarantee that heavy haul railway runs efficiently and safely, each key element of forming the heavy haul railway system must keep high standard, the distinctive high rate of traffic flow of China in addition, and this has higher requirement to China's heavy haul railway technology.
The Heavy-Haul Railway transportation is a comprehensive system engineering, involves the overall process of Railway Design, construction, operation and maintenance.Heavy haul railway is that the suffered dynamic load intensity of bridge, roadbed strengthens with the main difference of general railway; The stand under load increase frequency; Cause that load effect strengthens, the material stress width of cloth strengthens; Cause shorten the application life of Existing Railway Bridges and roadbed and track, the safety stock of aspects such as the intensity of structure, rigidity, stability descends, and the probability that various diseases occur strengthens, the harmfulness aggravation.Through in a few years heavy service, the fracture of bridge diaphragm, beam body crackle, pier rhegma, beam-ends dieback, bearing inclinations, culvert rhegma, culvert distortion and bridges and culverts changeover portion subgrade settlement, interval embankment and the sinking of cutting location, shoulder width deficiency have been produced, bedding is risen soil and polytype diseases such as plate knot of ballast bed, impeded drainage like China Qun Dynasty line, north yellow line.Along with improving constantly and the continuous increase of rate of traffic flow of the heavy increasing of China railways heavy haul transport axle, traction quality, the service condition of Existing Railway Bridges and roadbed will worsen more, and the probability of bridge and subgrade defect generation will further strengthen.
Along with the continuous increase of freight volume, the various diseases of bridge become increasingly conspicuous, and functional performance constantly descends, and especially span is that 32.0m prestressed concrete split blade type beam is on the weak side because of transverse splicing, and the diaphragm phenomenon of rupture exacerbates year by year.Train through the time, indivedual bridges even occurred taking off the bow phenomenon because of the contact net that swing causes too greatly.In order to guarantee transportation safety, guarantee the normal operating condition of equipment, satisfy the ever-increasing needs of freight volume, must reinforce bridge.How to take reinforcement measure to promote its rigidity, intensity and fatigue durability effectively to this type beam body and become the problem that railway transport administration department extremely pays close attention to.
Reinforcement means commonly used has enlarging section reinforcing method, reinforcement by sticking of sheets, FRP material strengthening with external bonding method, changes structure force path reinforcing method and encased steel reinforcing method etc. in the bridge engineering at present.Receive the influence of form of structure or material behavior, these traditional reinforcement means all have certain limitation.
When (1) adopting the enlarging section reinforcing method,, only strengthen, can cause other part of overall structure to form weak floor and great destruction is taken place like this for the part if fail to analyze in the design from integrally-built angle; Strengthen member section, its quality and rigidity will change, and the intrinsic frequency of structure also changes thereupon, probably enter into frequency and the generation covibration of earthquake or wind shake.
(2) though the reinforcement by sticking of sheets construction technology is simpler; Can improve the bearing capacity of structure to a certain extent; But beam surface planeness, cleannes are had relatively high expectations, and the validity of reinforcing depends primarily on the intensity and the durability of binding material, anti-fatigue performance is also stable inadequately.
(3) the FRP reinforcing is not obvious to the raising of the rigidity of structure, and shearing resistance and connectivity problem are all more outstanding, and the durability and the fireproof performance of adhesive surface is relatively poor between FRP material and the concrete.
In sum, there are defectives such as new and old two kinds of material connection reliability bearing capacity not enough, that improve is limited, durability is relatively poor in traditional reinforcement means.Need close traffic at affixing steel plate, FRP material and glue setting up period, this exactly heavy haul railway operation department abstain from that because railway interrupted one day, its economic loss will reach more than one hundred million units.The present invention has developed through repetition test and a kind of railway separate type bridge has been carried out the job practices of intensive treatment, and this technology is based on external prestressing strengthening and self-balancing theory, and prestressed cable is drawn; Concrete compression can not increase former bridge burden when promoting former bridge bearing ability; Effectively improve the fatigue durability of bridge; And reduce former bridge under-clearance height hardly, and the construction uninterrupted traffic, speed of application is fast, cost is low, and the later stage can be changed rope.
Summary of the invention
The suffered dynamic load intensity of heavy haul railway bridge strengthens; The stand under load increase frequency; Cause that load effect strengthens, the material stress width of cloth strengthens; Cause shorten the application life of Existing Railway Bridges and roadbed and track, the safety stock of aspects such as the intensity of structure, rigidity, stability descends, and the probability that various diseases occur strengthens, the harmfulness aggravation.
The object of the present invention is to provide a kind of bridge construction self-balancing external prestressing strengthening method, prestressed cable is drawn, and concrete compression can not increase former bridge burden when promoting former bridge bearing ability; Have do not influence vehicle operating, the external prestressing muscle can be changed and advantage such as stretch-draw repeatedly.
Solution of the present invention is on the basis of existing technology; A kind of novel bridge structure self-balancing external prestressing strengthening technology is provided; The concrete T-shaped beam top board of two concrete T-shaped beams forms the girder top flange; The concrete T-shaped beam base plate of two concrete T-shaped beams forms the bottom flange, it is characterized in that: 1. junction, concrete beam top flange interface processing; 2. junction, concrete beam top flange bar planting; 3. junction, concrete beam top flange reinforcing bar is installed; 4. the steering block reinforcing bar is installed at the bottom of the beam and is turned to pipeline; 5. increase diaphragm apart from beam-ends 2-3m place symmetry, ground tackle is installed; 6. pour into a mould junction, girder top flange, steering block and newly-increased diaphragm concrete; 7. install, the stretch-draw anchor external tendon, obtain the structure of self-balancing external prestressing strengthening.According to a kind of bridge construction self-balancing external prestressing strengthening method provided by the invention, prestressed cable is drawn, and concrete compression forms self equilibrium systems, can when promoting former bridge bearing ability, not increase former bridge burden; Has advantages such as not influencing vehicle operating.Special in the outstanding characteristics of heavy haul railway bridge fatigue problem, the external prestressing system can detection at any time, the stress of adjustment rope, and rope can also be keeped in repair, changed to the corrosion situation of inspection rope where necessary.Self-compacting concrete has solved that arrangement of reinforcement is intensive, complex structure, template and former member space are narrow and small etc. because of aggregate blocks the problems such as cavity that cause, and effectively guarantees the fluid concrete compactness, has improved consolidation effect.Can be widely used in heavy haul railway bridge, concrete box girder, the reinforcing of T beam, overall cost is low, economic, safety, suitable, and workmanship is easy to guarantee that application prospect is extensive.
It is an overall structure that characteristic of the present invention also is to connect separate type girder top flange separately.Behind the concrete of junction, full-bridge continuous pouring separate type girder top flange; Be connected to an overall structure to separate type girder top flange separately; Not only can increase bending resistance and torsional rigidity; Can also directly bear the stretching force of prestressed cable, form subtriangular self equilibrium systems with external prestressing tendon.Both improve girder rigidity and bearing capacity, increased the bridge lateral globality, do not increased the girder burden again.
Characteristic of the present invention also is increasing diaphragm newly near the beam-ends place.Diaphragm is playing crucial effects aspect the globality of the lateral ties of strengthening bridge, assurance bridge.Not only can improve the lateral stiffness of bridge construction, make the load cross direction profiles of bridge construction be tending towards more reasonable, can also prevent some diseases that bridge causes owing to the weakness of lateral ties effectively.The present invention can effectively strengthen lateral stiffness near the newly-increased diaphragm in beam-ends place.
Characteristic of the present invention also is the anchoring crossbeam of newly-increased diaphragm as external prestressing tendon.Girder beam-ends prestress pipe complicated layout does not have the anchoring space of external prestressing tendon; Two bridge end slits are narrow, also do not have the stretch-draw space, even there is construction space, difficulty of construction is also big especially.Adopt newly-increased diaphragm as anchoring crossbeam outer prestressed anchor of fixing body and stretch-draw cable wire easily, also can satisfy the requirement of cable wire in lateral arrangement.Can the bearing object outer huge anchored force of prestressed strand of newly-increased diaphragm can be delivered to the anchored force of external prestressing steel bundle in the roof and floor and web of original separate type girder again.The external prestressing bridge construction has huge dependence to ground tackle; The prestressing force that cable wire applies relies on the anchor point ground tackle to keep fully; External prestressing is asked for to bear than the more disadvantageous dynamic load of prestressing with bond muscle and is also produced fatigue problem thus simultaneously; In case the ground tackle assembly goes wrong, its consequence that causes is catastrophic, so the external prestressing ground tackle must provide reliability and the safety more much higher than general prestressing with bond ground tackle.The present invention takes newly-increased diaphragm can address these problems as the anchoring crossbeam of external prestressing tendon.
Characteristic of the present invention is that also the steering structure of external prestressing steel bundle is arranged on the diaphragm place of original separate type girder, both can adopt reinforced concrete structure, also can adopt steel work.Transfer in the external prestressing concrete structure is a kind of special tectonic; It is except that anchoring structure; External prestressing tendon is the unique and associated member of concrete bodies in striding; And bearing the vital task that the steel bundle turns to, also is one of structure construction of most important in the external prestressing concrete structure, most critical.The present invention combines original diaphragm that steering structure is set, and can steering force be directly passed to the roof and floor and the web of separate type girder, reasonable stress; And can guarantee the position of external tendon, the active force that enough intensity is arranged and can transmit the steel bundle reliably.
Characteristic of the present invention is that also steering block and junction, girder bottom flange fluid concrete together form integral body if adopt the steel concrete steering structure.Like this, be equivalent to T at the diaphragm place and become case, its good use the bending resistance of case beam, torsional rigidity and globality be superior to the characteristics of T beam greatly.Simultaneously, can effectively strengthen the bridge lateral globality.Experimental study and engineering practice show that for railroad bridge, derail is directly relevant with lateral rigidity of bridge, therefore must guarantee Lateral Stiffness of Railway Bridge.
Characteristic of the present invention is that also steel concrete steering structure plain bars is by the ring muscle that turns to pipeline, the stirrup and forming to reinforcing bar in length and breadth near what concrete surface was arranged of remaining silent.Wherein, the ring muscle is to surround the single reinforcing bar that turns to pipeline, suppose that pulling force all bears by encircling muscle, can calculate very easily and surround the single ring concrete steel muscle area that turns to pipeline.Be distributing bar to reinforcing bar in length and breadth, evenly arrange at the steering structure concrete surface by certain reinforcement ratio.The stirrup of remaining silent is to surround the stirrup of remaining silent that all turn to pipeline, also belongs to distributing bar, and generally its area of reinforcement equals to encircle the area of reinforcement of muscle.
Characteristic of the present invention is that also the present invention develops a kind of new steel structure steering block, is made up of i iron, horizontal coupled system, sway bracing, U type hoop if adopt steel work as steering structure.
Characteristic of the present invention is also that in the steel work steering block according to the longitudinal length of steel work steering block, 50cm is provided with an i beam at interval; I beam should adopt the i iron that meets national current standard " hot-rolled steel section " GB/T 706-2008 regulation, and highly is not less than 250mm, and web thickness is not less than 10mm.
Characteristic of the present invention also is in the steel work steering block, along i iron longitudinal separation 1-1.5m the web stiffening rib is set one, and the angle steel intersection is welded on the web stiffening rib and forms sway bracing.Angle steel should adopt the angle steel that meets national current standard " hot-rolled steel section " GB/T 706-2008 regulation, and the limit thickness of angle steel should not be less than 10mm; Angle steel and web stiffening rib are taked three weld all around connected modes; At the i iron roof and floor horizontal coupled system is set along i iron longitudinal separation 1-1.5m.
Characteristic of the present invention also is in the steel work steering block, at the bottom of i beam welding U type hoop.U type hoop is welded by steel plate, turns to pipeline to pass U type hoop and arranges, so just fixing prestressed cable.
Characteristic of the present invention is that also external tendon should adopt plant-manufactured finished product rope, and the finished product rope should adopt the steel strand rope or the non-bending steel cable rope of hot extrude high density polyethylene (HDPE) oversheath, steering gear, ground tackle and should be supporting with it.
Characteristic of the present invention also is the steering gear of steering gear employing cluster type, is made up of interior pipe and outer steel pipe.The cluster type steering gear can realize the replaceable design of whole bundle steel strand.The suffered dynamic load intensity of railroad bridge strengthens; The stand under load increase frequency; Cause that load effect strengthens, the material stress width of cloth strengthens, cause shorten the application life of Existing Railway Bridges and roadbed and track, the safety stock of aspects such as the intensity of structure, rigidity, stability descends; The probability that various diseases occur strengthens, the harmfulness aggravation, and durability and fatigability problem are outstanding.The external prestressing system can detection at any time, the stress of adjustment rope, and the corrosion situation of inspection rope can also be carried out steel strand where necessary and changed, and has effectively solved the durability and the fatigability problem of railroad bridge.
Characteristic of the present invention is that also used reinforced concrete is a self-compacting concrete.The self-compacting concrete system of mixing adopts the commercial concrete agitator to stir.Should detect after the self-compacting concrete system of mixing is accomplished, the slump should be at 240mm～270mm; The slump divergence is at 600mm～700mm; U type appearance test difference in height Δ h is less than 30mm; The V funnel passes through the time at 4s～25s, and coarse aggregate size is 5mm～20mm, and faller gill shape content is less than 10%, and the fineness modulus of fines is greater than 2.3.Self-compacting concrete has been broken through the limitation of traditional vibrated concrete on molding mode; Rely on self gravitation (or only needing the external force slight vibration) just can freely trickle fully; Pass through filling template every nook and cranny, reinforcing bar gap, be met the intensity and the favorable durability ability of requirement after the sclerosis.Self-compacting concrete has not only guaranteed the effect of reinforcing from the performance of material, has also guaranteed consolidation effect from construction technology.
Characteristic of the present invention is that also in the bar planting spacing of step in 2. be that 25cm～40cm is in length and breadth to equidistant layout.
Characteristic of the present invention also is the mounting reinforcing steel bars net at reinforced concrete mid-height place, junction, concrete beam top flange.Diameter should adopt 12mm, arranges that distance is preferably the half the of bar planting distance, promptly according to 12.5cm～20cm in length and breadth to equidistant layout.Junction, concrete beam top flange concrete height is generally 15cm～25cm, if need arrange two-layer steel mesh reinforcement greater than 25cm.
A kind of bridge construction self-balancing external prestressing strengthening method of the present invention is characterized in that according to the method for the invention relative operation comprises following key step:
Steps A: junction, concrete beam top flange interface processing
In said steps A, may further comprise the steps:
(1) rendering layer and the decorative layer of junction, top flange are removed, until exposing concrete surface;
(2), need its rejected region is removed to closely knit place if there are initial imperfections such as cavity in the concrete of junction, top flange;
(3) with the concrete chisel hair, and a cutter hair degree of depth is not less than 6mm, then the scum silica frost, the dust that show of water cleaning concrete;
(4) if when the reinforcing bar at structural strengthening position has corrosion phenomena, need show rust cleaning to reinforcing bar; When the ratio of corrosion of steel bar area and former section area in the structure surpasses 1/12, need recruit reinforcing bar.
Step B: concrete beam top flange junction bar planting
Its key points for operation:
When (1) adopting the bar planting technology, the strength grade of concrete of bridge main member must not be lower than C25, and other concrete members strength grade must not be lower than C20.
(2) the bridge force-bearing bar planting sticks with glue agent and should adopt A level glue; Can adopt B level glue during only by structure requirement bar planting.
(3) bar planting spacing should be according to 25cm～40cm in length and breadth to equidistant layout.
Step C: junction, concrete beam top flange reinforcing bar is installed
The mounting reinforcing steel bars net at concrete mid-height place, junction, concrete beam top flange.Diameter should adopt 12mm, arranges that distance is preferably the half the of bar planting distance, promptly according to 12.5cm～20cm in length and breadth to equidistant layout.Junction, concrete beam top flange concrete height is generally 15cm～25cm, if need arrange two-layer steel mesh reinforcement greater than 25cm.
Step D: the steering block reinforcing bar is installed at the bottom of the beam and is turned to pipeline
In said step D, may further comprise the steps:
(1) the external tendon steering block should be installed in separate type girder diaphragm place, and diaphragm and steering block are stressed jointly, the active force that enough intensity can be arranged and can transmit the steel bundle reliably.Turn to pipeline it to be arranged near web as far as possible, because this layout stressed comparatively favourable to the separate type kingpost baseplate, and help prestressed transmission.
(2) with former concrete beam diaphragm bottom flange bottom concrete chisel hair, and a cutter hair degree of depth is not less than 6mm, then the scum silica frost, the dust that show of water cleaning concrete.
(3) in the bar planting of cutter hair concrete surface, spacing should be according to 25cm～40cm in length and breadth to equidistant layout.
(4) arrange the ring muscle, remain silent stirrup and near concrete surface arrange in length and breadth to reinforcing bar.Wherein, the ring muscle is to surround the single reinforcing bar that turns to pipeline, can try to achieve by simplifying computational methods.Suppose pulling force all by the ring muscle bear, can calculate very easily and surround the single ring concrete steel muscle area that turns to pipeline.Be distributing bar to reinforcing bar in length and breadth, evenly arrange at the steering structure concrete surface by certain reinforcement ratio.The stirrup of remaining silent is to surround the stirrup of remaining silent that all turn to pipeline, also belongs to distributing bar, and generally its area of reinforcement equals to encircle the area of reinforcement of muscle.
(5) steering gear is arranged on former concrete beam bottom, adopts the cluster type steering gear, is made up of interior pipe and outer steel pipe.The cluster type steering gear can realize the replaceable design of whole bundle steel strand.
The external tendon steering block also can not adopt common reinforced concrete structure, and adopts steel work.The present invention develops a kind of new steel structure steering block, is made up of i iron, horizontal coupled system, sway bracing, U type hoop.Its construction key step is:
(1) according to the longitudinal length of steering block, 50cm is provided with an i beam at interval.
(2) i beam should adopt the i iron that meets national current standard " hot-rolled steel section " GB/T 706-2008 regulation, and highly is not less than 250mm, and web thickness is not less than 10mm;
(3) along i iron longitudinal separation 1-1.5m the web stiffening rib is set one, the angle steel intersection is welded on the web stiffening rib and forms sway bracing.Angle steel should adopt the angle steel that meets national current standard " hot-rolled steel section " GB/T706-2008 regulation, and the limit thickness of angle steel should not be less than 10mm; Angle steel and web stiffening rib are taked three weld all around connected modes.
(4) at the i iron roof and floor horizontal coupled system is set along i iron longitudinal separation 1-1.5m.
(5) at the bottom of i beam welding U type hoop.U type hoop is welded by steel plate, turns to pipeline to pass U type hoop and arranges, so just fixing prestressed cable.
Step e: increase diaphragm apart from beam-ends 2-3m place symmetry, ground tackle is installed
In said step e, may further comprise the steps:
(1) will increase the connecting portion concrete chisel hair of diaphragm and former concrete beam newly, and a cutter hair degree of depth is not less than 6mm, then the scum silica frost, the dust that show of water cleaning concrete.
(2) in the bar planting of cutter hair concrete surface, spacing should be according to 25cm～40cm in length and breadth to equidistant layout.
(3) arrange the diaphragm reinforcing bar, notice that the diaphragm reinforcing bar will be connected with bar planting, strengthens overall operation property.
(4) external tendon ground tackle installing and locating.The newly-increased diaphragm of the present invention both can be strengthened integral working, can be used as the anchoring crossbeam again, and easy construction can avoid original girder beam-ends prestress anchoraging complicated, does not have the problem of construction space.The ground tackle material should satisfy the requirement of " prestressed strand is with ground tackle, anchor clamps and connector " (GB/T 14370-2007) standard, and the external pre-stress bundle ground tackle adopts the strand tapered anchorage of corresponding standard, and ground tackle should satisfy the requirement that integral body is changed bundle and adjustment stretching force.The used steel pipe of ground tackle all adopts the seamless steel pipe that meets the GB8163-87 regulation, and other performance of ground tackle should satisfy the requirement of GB/T14370-2000 standard.
Step F: cast junction, girder top flange, steering block and newly-increased diaphragm concrete concrete adopt self-compacting concrete, comprise that self-compacting concrete mixes system, cast, maintenance.
Self-compacting concrete is mixed system:
Adopt the commercial concrete agitator to stir.Its raw material are:
(1) cement: adopt common 42.5 portland cements;
(2) flyash: I level flyash;
(3) sand: river sand, medium sand, fineness modulus 2.58, II district grating is qualified, bulk density 1576kg/m
3, apparent density 2610kg/m
3
(4) stone: rubble, the 5-20mm continuous grading is qualified, and faller gill shape content is 9.2%, crush index 3.4, bulk density 1470kg/m
3, apparent density 2700kg/m
3
(5) water reducing agent: high efficiency water reducing agent, water-reducing rate is greater than 25%.
After concrete mixing is accomplished, should carry out slump consistancy test, the mobile appearance test of L type, the test of U type appearance, the test of V funnel, its testing result should satisfy following standard: the slump should be controlled at 240mm～270mm; The slump divergence should be controlled at 600mm～700mm; U type appearance test difference in height Δ h should be less than 30mm; The V funnel should be controlled at 4s～25s through the time.
The self-compacting concrete cast:
(1) half an hour before the cast,, water is moistening former concrete beam and template fully;
(2) the self-compacting concrete cast can be adopted mechanical continuous pouring and artificial continuous pouring, recommends to use mechanical continuous pouring.Guarantee that as far as possible continuous several plug hole pours into a mould simultaneously, can carry out suitably inserting smashing with long pricker in case of necessity with wooden mallet to steel plate percussion vibration a little during cast, guarantee the closely knit of fluid concrete;
Answer each position distortion of attention structure when (3) pouring into a mould, answer strenthening member of continuous pouring to finish, and the middle ware break time can not surpass the concrete initial set time;
The self-compacting concrete maintenance:
After concrete pouring is accomplished, should in time execute water curing, guarantees 7～14 day curing time: should execute the water curing least four times preceding 7 day every day: the working in morning, and before having a meal noon, before have supper the dusk, between evening 11～12.Every day is executed water curing early, middle and late three times in back 7 days.
Step G: installation, stretch-draw anchor external tendon
The material of external tendon should satisfy the requirement of " steel strand for prestressed concrete " (GB/T 5224), " un-bonded prestressed steel strand " (JG 161), " the building cable is used high-density polyethylene plastics " (CJ/T 3078), " structure is used the seamless steel pipe standard " (GB/T 8162), " cable stayed bridge hot extruded polyethylene high strength steel cable technical condition " (GB/T 18365), " unbonded prestressing tendon special anti-corrosion lubricating grease " (JG 3007-93) and " semi-refined paraffin wax " standards such as (GB 254).External tendon should adopt plant-manufactured finished product rope, and the finished product rope should adopt the steel strand rope or the non-bending steel cable rope of hot extrude high density polyethylene (HDPE) (be called for short HDPE) oversheath, and should be supporting with steering gear, ground tackle.
Technique scheme of the present invention is compared traditional reinforcement means and is had the following advantages:
(1) a kind of bridge construction self-balancing external prestressing strengthening method provided by the invention; External tendon is arranged in former girder bottom through steering block, pours into a mould self-compacting concrete in junction, former girder top flange, both can give full play to the reinforcement effect of external tendon; Can let junction, top flange concrete directly bear pre-applied force again; Thereby when promoting former bridge bearing ability, do not increase former bridge burden, i.e. self equilibrium systems.
(2) the present invention is increasing diaphragm newly near the beam-ends place.Not only can improve the lateral stiffness of bridge construction, can also be with increasing the anchoring crossbeam of diaphragm newly as external prestressing tendon.Girder beam-ends prestress pipe complicated layout does not have the anchoring space of external prestressing tendon; Two bridge end slits are narrow, also do not have the stretch-draw space, even there is construction space, difficulty of construction is also big especially.Adopt newly-increased diaphragm as anchoring crossbeam outer prestressed anchor of fixing body and stretch-draw cable wire easily, also can satisfy the requirement of cable wire in lateral arrangement.
(3) the present invention is arranged on the diaphragm place of original separate type girder with the steering structure of external prestressing steel bundle, both can adopt reinforced concrete structure, also can adopt steel work.Transfer not only can be installed at the bottom of the beam, and for the girder of separate type, also can be installed in the middle interconnecting piece position of two separate type girders.The linear layout of external tendon facade can be provided with the straight horizontal line segment, also can be provided with, and like this, just can satisfy different linear arrangement requirement, and is applied widely.
(4) the present invention is if adopt the steering structure of steel concrete, and steering block and junction, girder bottom flange fluid concrete together form integral body.Like this, be equivalent to T at the diaphragm place and become case, can effectively strengthen the bridge lateral globality.
(5) the present invention, is made up of i iron, horizontal coupled system, sway bracing, U type hoop according to a kind of new steel structure steering block of invention exploitation if adopt the steering structure of steel work, and easy construction is quick, and is economic and practical.
(6) to the outstanding characteristics of railroad bridge fatigue problem, prestressing with bond can't detect and change rope after grouting finishes, and the external prestressing system can detection at any time, the stress of adjustment rope, and rope can also be keeped in repair, changed to the corrosion situation of inspection rope where necessary.
(7) adopt self-balancing external prestressing strengthening technology of the present invention, little to the influence of structure headway, do not influence vehicle pass-through.So technical method of the present invention is particularly suitable for railroad bridge, overpass bridge and bridge crossing, and the structure strict to headway.
(8) because the present invention has utilized self-compacting concrete in casting process, to need not the moulding of vibrating; Therefore the invention solves that arrangement of reinforcement is intensive, complex structure, template and former member space are narrow and small etc. blocks the problems such as cavity that cause because of aggregate; And reduced the conventional concrete construction and shaken, crossed the pitted skin of hierarchical cellular up and down that shakes and cause because of leakage; Improved concrete quality and endurance quality, thereby simplified reinforcing construction process greatly, the position that ordinary concrete can't be constructed possibly become; Be specially adapted to the ruggedized construction member of some complicacies, the opposite sex, expanded the scope of application greatly.
(9) because the present invention has utilized the self-compacting concrete technology, significantly reduced the noise pollution in traditional vibrated concrete construction, alleviated working strength of workers significantly.Because the preparation self-compacting concrete need utilize industrial solid castoffs such as flyash, granulated blast-furnace slag, silicon ash in a large number, help the comprehensive utilization of resource and the protection of ecological environment simultaneously.
In sum; Compared with prior art; Self-balancing external prestressing strengthening technology of the present invention combines the self-balancing principle, utilizes self-compacting concrete, external prestressing advantage separately, can effectively improve existing bridge rigidity and bearing capacity, does not increase former axle load simultaneously and carries.To the outstanding characteristics of heavy haul railway bridge fatigue problem, the external prestressing system can detection at any time, the stress of adjustment rope, and rope can also be keeped in repair, changed to the corrosion situation of inspection rope where necessary.Self-compacting concrete has solved that arrangement of reinforcement is intensive, complex structure, template and former member space are narrow and small etc. because of aggregate blocks the problems such as cavity that cause, and effectively guarantees the fluid concrete compactness, has improved consolidation effect.Can be widely used in heavy haul railway bridge, concrete box girder, the reinforcing of T beam, overall cost is low, economic, safety, suitable, and workmanship is easy to guarantee that application prospect is extensive.
Description of drawings
Accompanying drawing is used to provide further understanding of the present invention, and constitutes the part of manual, is used to explain the present invention with embodiments of the invention.Wherein
Fig. 1 is a heavy haul railway prestressed concrete freely-supported T beam bridge elevation;
Fig. 2 is heavy haul railway prestressed concrete freely-supported T beam bridge standard section figure;
Fig. 3 is a heavy haul railway prestressed concrete freely-supported T beam bridge diaphragm profile;
Fig. 4 is the junction bar planting of girder top board, fluid concrete sketch map;
Fig. 5 a is that external tendon steel concrete transfer is installed cast sketch map one;
Fig. 5 b is that external tendon steel concrete transfer is installed cast sketch map two;
Fig. 6 a is an external tendon steel work transfer scheme of installation one;
Fig. 6 b is an external tendon steel work transfer scheme of installation two;
Fig. 7 is a steel work transfer constructional drawing;
Fig. 8 a reinforces back structure facade to arrange sketch map one;
Fig. 8 b reinforces back structure facade to arrange sketch map two;
Fig. 9 is intrafascicular steering gear scheme of installation of steel;
Figure 10 is a steering gear structure drawing;
Reference numeral is expressed as among the figure: 1-concrete T-shaped beam top board; 2-concrete T-shaped beam web; 3-concrete T-shaped beam base plate; The 4-diaphragm; 5-top board junction; The 6-steering block; The 7-external tendon; 8-increases diaphragm newly; The steering gear of 9-external tendon; 10-external tendon ground tackle; Pipe in the 11-HDPE; The outer steel pipe of 12-; 13-top flange reinforced concrete; 14-i beam, 15-horizontal coupled system, 16-sway bracing, 17-U type hoop; 18-web stiffening rib; Three weld all arounds of 19-.
The specific embodiment
Below in conjunction with accompanying drawing the preferred embodiments of the present invention are described, wherein Reference numeral is expressed as among the figure: 1-concrete T-shaped beam top board; 2-concrete T-shaped beam web; 3-concrete T-shaped beam base plate; The 4-diaphragm; Junction, 5-top flange; The 6-steering block; The 7-external tendon; 8-increases diaphragm newly; The steering gear of 9-external tendon; 10-external tendon ground tackle; Pipe in the 11-HDPE; The outer steel pipe of 12-; 13-top flange reinforced concrete; 14-i beam, 15-horizontal coupled system, 16-sway bracing, 17-U type hoop; 18-web stiffening rib; Three weld all arounds of 19-.
Solution of the present invention is on the basis of existing technology; A kind of bridge construction self-balancing external prestressing strengthening method is provided; The concrete T-shaped beam top board of two concrete T-shaped beams forms the girder top flange; The concrete T-shaped beam base plate of two concrete T-shaped beams forms the bottom flange, it is characterized in that may further comprise the steps: A, junction, girder top flange interface processing; B, the junction bar planting of girder top flange; C, installation junction, girder top flange reinforcing bar; Steering block is installed at the bottom of D, the beam and is turned to pipeline; E, increase diaphragm, ground tackle is installed near beam-ends symmetry; F, cast junction, girder top flange, newly-increased diaphragm concrete; G, installation, stretch-draw anchor external tendon obtain the structure of self-balancing external prestressing strengthening.
Characteristic of the present invention also is through the bottom bar planting in the girder top flange; Junction, two girder top flanges cast self-compacting concrete; External tendon is arranged in the girder bottom; Junction, top flange concrete and external prestressing tendon form subtriangular self equilibrium systems, and said girder comprises T beam, concrete box girder, hollow slab beam, normal reinforced concrete beam or the prestressed concrete beam that has existed.
Characteristic of the present invention also is the newly-increased diaphragm near beam-ends 2-3m place.
Characteristic of the present invention also is the anchoring crossbeam of newly-increased diaphragm as external prestressing tendon, and the ground tackle of external prestressing tendon is arranged in the newly-increased diaphragm.
Characteristic of the present invention is that also the steering structure of external prestressing steel bundle is arranged on the diaphragm place of original separate type girder.
Characteristic of the present invention is that also the transfer of external prestressing steel bundle adopts reinforced concrete structure or adopts steel work not have; Transfer is installed at the bottom of the beam; Perhaps be installed in the middle interconnecting piece position of two separate type girders for the girder of separate type, perhaps the linear layout of external tendon facade is provided with the straight horizontal line segment.
Characteristic of the present invention also is external prestressing steel bundle transfer if adopt reinforced concrete structure, in step D, comprises the construction sequence that the steering block plain bars is installed, and in step F, comprises cast steering block Concrete Construction step.
Characteristic of the present invention also be steering block and junction, girder diaphragm bottom flange together fluid concrete form integral body.
Characteristic of the present invention is that also steel concrete steering structure plain bars is by the ring muscle that turns to pipeline, the stirrup and forming to reinforcing bar in length and breadth near what concrete surface was arranged of remaining silent; The ring muscle is to surround the single reinforcing bar that turns to pipeline; Be distributing bar to reinforcing bar in length and breadth, evenly arrange at the steering structure concrete surface that the stirrup of remaining silent is to surround the stirrup of remaining silent that all turn to pipeline by certain reinforcement ratio; Belong to distributing bar, its area of reinforcement equals to encircle the area of reinforcement of muscle.
Characteristic of the present invention also is external prestressing steel bundle transfer if adopt steel work, and the steel work transfer is made up of i beam, horizontal coupled system, sway bracing and U type hoop.
Characteristic of the present invention also is the longitudinal length according to the steel work transfer; 50cm is provided with an i beam at interval, and i beam adopts the i iron that meets national current standard " hot-rolled steel section " GB/T 706-2008 regulation; And highly be not less than 250mm, web thickness is not less than 10mm.
Characteristic of the present invention also is along i beam longitudinal separation 1-1.5m the web stiffening rib to be set one; The angle steel intersection is welded on the web stiffening rib and forms sway bracing; Angle steel should adopt the angle steel that meets national current standard " hot-rolled steel section " GB/T 706-2008 regulation; And the limit thickness of angle steel should not be less than 10mm, and angle steel and web stiffening rib are taked three weld all around connected modes, at the i beam roof and floor horizontal coupled system is set along i beam longitudinal separation 1-1.5m.
Characteristic of the present invention is that also U type hoop is welded by steel plate at the bottom of i beam welding U type hoop, turns to pipeline to pass U type hoop and arranges, thus the outer prestressed strand of fixed body.
Characteristic of the present invention is that also external prestressing tendon adopts plant-manufactured finished product rope; The finished product rope adopts the steel strand rope or the non-bending steel cable rope of hot extrude high density polyethylene (HDPE) oversheath; Steering gear and ground tackle are supporting with it, and the cluster type steering gear is adopted in steering gear, are made up of interior pipe and outer steel pipe.
Characteristic of the present invention is that also said concrete is a self-compacting concrete, and the self-compacting concrete system of mixing adopts the commercial concrete agitator to stir, and its raw material are: cement: adopt common 42.5 portland cements; Flyash: I level flyash; Sand: river sand, medium sand, fineness modulus 2.58, II district grating is qualified, bulk density 1576kg/m
3, apparent density 2610kg/m
3Stone: rubble, the 5-20mm continuous grading is qualified, and faller gill shape content is 9.2%, crush index 3.4, bulk density 1470kg/m
3, apparent density 2700kg/m
3Water reducing agent: high efficiency water reducing agent, water-reducing rate is greater than 25%.
Characteristic of the present invention also is to detect after the self-compacting concrete system of mixing is accomplished, and the slump should be at 240mm～270mm; The slump divergence is at 600mm～700mm; U type appearance test difference in height Δ h is less than 30mm; The V funnel passes through the time at 4s～25s, and coarse aggregate size is 5mm～20mm, and faller gill shape content is less than 10%, and the fineness modulus of fines is greater than 2.3.
Characteristic of the present invention is that also the bar planting spacing in step B is that 25cm～40cm is in length and breadth to equidistant layout.
Characteristic of the present invention also is the mounting reinforcing steel bars net at reinforced concrete mid-height place, junction, concrete beam top flange; Diameter adopts 12mm; Arrange that distance is preferably the half the of bar planting distance; In length and breadth to equidistant layout, junction, concrete beam top flange concrete height is generally 15cm～25cm according to 12.5cm～20cm, if need arrange two-layer steel mesh reinforcement greater than 25cm.
The specific embodiment is a heavy haul railway prestressing force freely-supported T beam bridge, and self-balance prestress reinforcing technique according to the present invention may further comprise the steps:
Steps A: junction, concrete T-shaped beam top flange 5 interface processing
Fig. 1 is a heavy haul railway prestressed concrete freely-supported T beam bridge elevation; Have five diaphragms 4 between the concrete T-shaped beam top board 1 of prestressed concrete freely-supported T beam bridge as shown in Figure 1 and the concrete T-shaped beam base plate 3; Diaphragm 4 is provided with perpendicular to concrete T-shaped beam web 2, and prestressed concrete freely-supported T beam bridge as shown in Figure 1 includes common section and contains two kinds of different sections of diaphragm section.
Fig. 2 is heavy haul railway prestressed concrete freely-supported T beam bridge standard section figure; As shown in Figure 2, the standard section of present embodiment comprises concrete T-shaped beam top board 1, concrete T-shaped beam web 2 and concrete T-shaped beam base plate 3.
Fig. 3 is a heavy haul railway prestressed concrete freely-supported T beam bridge diaphragm profile; As shown in Figure 3; Through perpendicular to two concrete T-shaped beams willfully the annular diaphragm 4 on the face be coupled to integral body to two concrete T-shaped beams, annular diaphragm 4 is simultaneously perpendicular to concrete T-shaped beam top board 1, concrete T-shaped beam web 2 and the concrete T-shaped beam base plate 3 of two concrete T-shaped beams.
In said steps A, may further comprise the steps:
Fig. 4 is the junction bar planting of girder top board, fluid concrete sketch map; It is as shown in Figure 4,
Concrete T-shaped beam top board 1 bottom of section is junction, T beam top flange 5 between the two concrete T-shaped beam webs 2 of (1) two concrete T-shaped beam, the rendering layer and the decorative layer of junction, top flange 5 is removed, until exposing concrete surface;
(2), need its rejected region is removed to closely knit place if there are initial imperfections such as cavity in the concrete of junction, top flange 5;
(3) with 5 bottom surfaces, junction, top flange cutter hair, and a cutter hair degree of depth is not less than 6mm, then scum silica frost, the dust on water cleaning concrete surface;
(4) if when the reinforcing bar at structural strengthening position has corrosion phenomena, need show rust cleaning to reinforcing bar; When the ratio of corrosion of steel bar area and former section area in the structure surpasses 1/12, need recruit reinforcing bar.
Step B: junction, concrete T-shaped beam top flange 5 concrete surface bar plantings
Its key points for operation:
When (1) adopting the bar planting technology, the strength grade of concrete of bridge main member must not be lower than C25, and other concrete members strength grade must not be lower than C20.
(2) the bridge force-bearing bar planting sticks with glue agent and should adopt A level glue; Can adopt B level glue during only by structure requirement bar planting.
(3) bar planting spacing should be according to 25cm～40cm in length and breadth to equidistant layout.
Step C: the plain bars that junction, concrete T-shaped beam top flange 5 is installed
Fig. 4 is the junction bar planting of girder top board, fluid concrete sketch map; As shown in Figure 4, the reinforced concrete 13 mid-height place mounting reinforcing steel bars nets in the concrete T-shaped beam top flange.Diameter should adopt 12mm, arranges that distance is preferably the half the of bar planting distance, promptly according to 12.5cm～20cm in length and breadth to equidistant layout.The height of T beam top flange reinforced concrete 13 is generally 15cm～25cm, if need arrange two-layer steel mesh reinforcement greater than 25cm.
The reinforcing bar and the external tendon steering gear 9 of steering block 6 are installed at the bottom of the step D:T beam beam
According to the present invention, steering block 6 both can adopt reinforced concrete structure, can adopt steel work again.Fig. 5 a is that external tendon steel concrete transfer is installed cast sketch map one; Fig. 5 b is that external tendon steel concrete transfer is installed cast sketch map two; Shown in Fig. 5 a and Fig. 5 b,
In said step D, may further comprise the steps:
(1) external tendon steering block 6 is installed in separate type girder diaphragm 4 places, and diaphragm 4 is stressed jointly with steering block 6, the active force that enough intensity can be arranged and can transmit the steel bundle reliably.
(2) with former concrete beam diaphragm 4 bottom flanges bottoms concrete chisel hair, and a cutter hair degree of depth is not less than 6mm, then the scum silica frost, the dust that show of water cleaning concrete.
(3) in the bar planting of cutter hair concrete surface, spacing should be according to 25cm～40cm in length and breadth to equidistant layout.
(4) arrange the ring muscle, remain silent stirrup and near concrete surface arrange in length and breadth to reinforcing bar.
(5) external tendon steering gear 9 is arranged on former concrete beam bottom, adopts the cluster type steering gear.Fig. 7 is intrafascicular steering gear scheme of installation of steel; As shown in Figure 7, according to the linear layout of external tendon 7, pre-buried external tendon steering gear 9 in steering block 6.Fig. 9 is intrafascicular steering gear scheme of installation of steel; Figure 10 is a steering gear structure drawing; Shown in figure 10, external tendon steering gear 9 is made up of with outer steel pipe 12 pipe 11 in the HDPE.
(6) Fig. 5 b is that external tendon steel concrete transfer is installed cast sketch map one; Shown in Fig. 5 b, according to the method for the invention, external tendon steering block 6 also can be arranged on the middle interconnecting piece position of two separate type girders, can satisfy the various linear arrangement requirement of external tendon 7 like this.
External tendon steering block 6 is developed a kind of new steel structure steering block if adopt steel work according to the present invention, by i beam 14, horizontal coupled be 15, sway bracing 16, U type hoop 17 form.Fig. 6 a is an external tendon steel work transfer scheme of installation one; Fig. 6 b is an external tendon steel work transfer scheme of installation two; Fig. 7 is a steel work transfer constructional drawing; Like Fig. 6 a, Fig. 6 b, shown in Figure 7,
Its construction key step is:
(1) according to the longitudinal length of steering block 6,50cm is provided with an i beam 14 at interval.The steering block 6 of present embodiment is made up of two i beams 14.
(2) i beam 14 should adopt the i iron that meets national current standard " hot-rolled steel section " GB/T 706-2008 regulation, and highly is not less than 250mm, and web thickness is not less than 10mm.The i beam 14 that present embodiment is selected for use highly is 300mm, and web thickness is 13mm.
(3) Fig. 7 is a steel work transfer constructional drawing; As shown in Figure 7,14 longitudinal separation 1-1.5m are provided with web stiffening rib 18 one along i beam, and the angle steel intersection is welded on and forms sway bracing 16 on the web stiffening rib 18.Angle steel should adopt the angle steel that meets national current standard " hot-rolled steel section " GB/T 706-2008 regulation, and the limit thickness of angle steel should not be less than 10mm; Angle steel and web stiffening rib 18 are taked three weld all around connected modes.The transverse width of the steering block 6 of present embodiment is 2880mm; 14 longitudinal separation 1m are provided with web stiffening rib 18 along i beam, and the thickness of web stiffening rib 18 is 10mm, and the limit thickness of angle steel is 10mm; As shown in Figure 7, the welding manner of angle steel and web stiffening rib 18 is three weld all arounds 19.
(4) Fig. 7 is a steel work transfer constructional drawing; As shown in Figure 7, at i beam 14 roof and floors horizontal coupled being set along i beam 14 longitudinal separation 1-1.5m is 15.It is 15 that present embodiment forms horizontal coupled according to the thick steel plate of longitudinal separation 1m welding 10mm.
(5) at the bottom of i beam 14 welding U type hoop 17.U type hoop 17 is welded by steel plate, turns to pipeline to pass U type hoop 17 and arranges, so just fixing external tendon 7.
(6) the same with the steel concrete steering structure, Fig. 6 b is an external tendon steel work transfer scheme of installation two; Shown in Fig. 6 b, according to the method for the invention, the external tendon steering block 6 of steel work also can be arranged on the middle interconnecting piece position of two separate type girders, can satisfy the various linear arrangement requirement of external tendon 7 like this.
Step e: apart from the newly-increased diaphragm 8 of beam-ends 2m place cast, the outer cable anchorage 10 of fixing body may further comprise the steps in said step e:
(1) will increase the connecting portion concrete chisel hair of diaphragm 8 and former concrete beam newly, and a cutter hair degree of depth is not less than 6mm, then the scum silica frost, the dust that show of water cleaning concrete.
(2) in the bar planting of cutter hair concrete surface, spacing should be according to 25cm～40cm in length and breadth to equidistant layout.
(3) arrange the reinforcing bar that increases diaphragm 8 newly, notice that the reinforcing bar of newly-increased diaphragm 8 will be connected with bar planting, strengthen overall operation property.
(4) external tendon ground tackle 10 installing and locating.Fig. 8 a reinforces back structure facade to arrange sketch map one; Fig. 8 b reinforces back structure facade to arrange sketch map two; Shown in Fig. 8 a and 8b, external tendon ground tackle 10 is installed in the newly-increased diaphragm 8.Newly-increased diaphragm 8 according to invention is provided with both can be strengthened integral working, can be used as the anchoring crossbeam again, and easy construction can avoid original girder beam-ends prestress anchoraging complicated, does not have the problem of construction space.
Step F: the concrete of cast junction, T beam top flange 5, steering block 6 and newly-increased diaphragm 8
Fig. 8 a reinforces back structure facade to arrange sketch map one; Fig. 8 b reinforces back structure facade to arrange sketch map two; Shown in Fig. 8 a and 8b, newly-increased diaphragm 8 of the present invention will be as the anchoring crossbeam.Concrete adopts self-compacting concrete, comprises that self-compacting concrete mixes system, cast, maintenance.
Self-compacting concrete is mixed system:
Adopt the commercial concrete agitator to stir.Its raw material are:
(1) cement: adopt common 42.5 portland cements;
(2) flyash: I level flyash;
(3) sand: river sand, medium sand, fineness modulus 2.58, II district grating is qualified, bulk density 1576kg/m
3, apparent density 2610kg/m
3
(4) stone: rubble, the 5-20mm continuous grading is qualified, and faller gill shape content is 9.2%, crush index 3.4, bulk density 1470kg/m
3, apparent density 2700kg/m
3
(5) water reducing agent: high efficiency water reducing agent, water-reducing rate is greater than 25%.
After concrete mixing is accomplished, should carry out slump consistancy test, the mobile appearance test of L type, the test of U type appearance, the test of V funnel, its testing result should satisfy following standard: the slump should be controlled at 240mm～270mm; The slump divergence should be controlled at 600mm～700mm; U type appearance test difference in height Δ h should be less than 30mm; The V funnel should be controlled at 4s～25s through the time.
The self-compacting concrete cast:
(1) half an hour before the cast,, water is moistening former concrete beam and template fully;
(2) the self-compacting concrete cast can be adopted mechanical continuous pouring and artificial continuous pouring, recommends to use mechanical continuous pouring.Guarantee that as far as possible continuous several plug hole pours into a mould simultaneously, can carry out suitably inserting smashing with long pricker in case of necessity with wooden mallet to steel plate percussion vibration a little during cast, guarantee the closely knit of fluid concrete;
Answer each position distortion of attention structure when (3) pouring into a mould, answer strenthening member of continuous pouring to finish, and the middle ware break time can not surpass the concrete initial set time;
The self-compacting concrete maintenance:
After concrete pouring is accomplished, should in time execute water curing, guarantees 7～14 day curing time: should execute the water curing least four times preceding 7 day every day: the working in morning, and before having a meal noon, before have supper the dusk, between evening 11～12.Every day is executed water curing early, middle and late three times in back 7 days.
Step G: installation, stretch-draw anchor external tendon 7
Fig. 8 a reinforces back structure facade to arrange sketch map one; Fig. 8 b reinforces back structure facade to arrange sketch map two; Shown in Fig. 8 a and 8b,, the layout of horizontal linear section external tendon 7 is arranged, in the middle of can adopting shown in Fig. 8 a according to stressed needs; Also can adopt triangular arrangement, shown in Fig. 8 b.The steering block of external tendon 7 can be arranged at the bottom of the beam, shown in Fig. 5 a and 6a; Also can be arranged on the middle interconnecting piece position of two separate type girders, shown in Fig. 5 b and 6b.Like this, according to external tendon 7 method for arranging provided by the invention, linear, the lateral attitude of layout external tendon 7 that can be convenient, flexible, steel bundle bundle number.
Stretching force among the present invention is directly born by the concrete of junction, top flange 5, between external tendon 7 and junction, top flange 5 concrete, forms self equilibrium systems, can give full play to the reinforcement effect of external tendon 7, does not increase the burden of existing concrete T-shaped beam again.
The material of external tendon 7 should satisfy " steel strand for prestressed concrete " (GB/T 5224); " un-bonded prestressed steel strand " (JG 161); " the building cable is used high-density polyethylene plastics " (CJ/T 3078); " structure is used the seamless steel pipe standard " (GB/T 8162); " cable stayed bridge hot extruded polyethylene high strength steel cable technical condition " (GB/T 18365); The requirement of " unbonded prestressing tendon special anti-corrosion lubricating grease " (JG 3007-93) and " semi-refined paraffin wax " standards such as (GB 254).The external tendon 7 of present embodiment adopts plant-manufactured finished product rope, and supporting with external tendon steering gear 9, external tendon ground tackle 10.
Understand easily, though above be to combine the T beam bridge to come the explanation that the present invention is carried out, yet the present invention can likewise be applied to other form of structure, like the little case beam in concrete box girder, hollow slab beam, the highway etc.
What should explain at last is: the said the preferred embodiments of the invention that are merely of above concrete real-time mode.Although the present invention has been carried out detailed explanation with reference to previous embodiments, for a person skilled in the art, still can make amendment to the technical scheme that previous embodiment is put down in writing, perhaps part technical characterictic wherein is equal to replacement.All within spirit of the present invention and principle, any modification of being done, be equal to replacement, improvement etc., all should be included within protection scope of the present invention.
Claims (10)
1. bridge construction self-balancing external prestressing strengthening method is characterized in that may further comprise the steps:
A, junction, girder top flange interface processing;
B, the junction bar planting of girder top flange;
C, installation junction, girder top flange reinforcing bar;
Steering block is installed at the bottom of D, the beam and is turned to pipeline;
E, increase diaphragm, ground tackle is installed near beam-ends symmetry;
F, cast junction, girder top flange, newly-increased diaphragm concrete;
G, installation, stretch-draw anchor external tendon obtain the structure of self-balancing external prestressing strengthening.
2. a kind of bridge construction self-balancing external prestressing strengthening method according to claim 1; It is characterized in that through bottom bar planting in the girder top flange; Junction, two girder top flanges cast self-compacting concrete; External tendon is arranged in the girder bottom, and junction, top flange concrete and external prestressing tendon form subtriangular self equilibrium systems, and said girder comprises T beam, concrete box girder, hollow slab beam, normal reinforced concrete beam or the prestressed concrete beam that has existed.
3. a kind of bridge construction self-balancing external prestressing strengthening method according to claim 1 is characterized in that the newly-increased diaphragm near beam-ends 2-3m place.
4. a kind of bridge construction self-balancing external prestressing strengthening method according to claim 1 is characterized in that the anchoring crossbeam of newly-increased diaphragm as external prestressing tendon, and the ground tackle of external prestressing tendon is arranged in the newly-increased diaphragm.
5. a kind of bridge construction self-balancing external prestressing strengthening method according to claim 1 is characterized in that the steering structure of external prestressing steel bundle is arranged on the diaphragm place of original separate type girder.
6. a kind of bridge construction self-balancing external prestressing strengthening method according to claim 1; The transfer that it is characterized in that external prestressing steel bundle adopts reinforced concrete structure or adopts steel work not have; Transfer is installed at the bottom of the beam; Perhaps be installed in the middle interconnecting piece position of two separate type girders for the girder of separate type, perhaps the linear layout of external tendon facade is provided with the straight horizontal line segment.
7. a kind of bridge construction self-balancing external prestressing strengthening method according to claim 1; It is characterized in that external prestressing steel bundle transfer if adopt reinforced concrete structure; In step D, comprise the construction sequence that the steering block plain bars is installed, in step F, comprise cast steering block Concrete Construction step.
8. a kind of bridge construction self-balancing external prestressing strengthening method according to claim 7, it is characterized in that steering block and junction, girder diaphragm bottom flange together fluid concrete form integral body.
9. a kind of bridge construction self-balancing external prestressing strengthening method according to claim 8; It is characterized in that steel concrete steering structure plain bars is by the ring muscle that turns to pipeline, the stirrup and forming to reinforcing bar in length and breadth near what concrete surface was arranged of remaining silent; The ring muscle is to surround the single reinforcing bar that turns to pipeline; Be distributing bar to reinforcing bar in length and breadth, evenly arrange at the steering structure concrete surface that the stirrup of remaining silent is to surround the stirrup of remaining silent that all turn to pipeline by certain reinforcement ratio; Belong to distributing bar, its area of reinforcement equals to encircle the area of reinforcement of muscle.
10. according to the described a kind of bridge construction self-balancing external prestressing strengthening method of arbitrary claim in the claim 1 to 5; It is characterized in that external prestressing steel bundle transfer if adopt steel work, the steel work transfer is made up of i beam, horizontal coupled system, sway bracing and U type hoop; Perhaps according to the longitudinal length of steel work transfer, 50cm is provided with an i beam at interval, and i beam adopts the i iron that meets national current standard " hot-rolled steel section " GB/T 706-2008 regulation, and highly is not less than 250mm, and web thickness is not less than 10mm; Perhaps the web stiffening rib is set one along i beam longitudinal separation 1-1.5m; The angle steel intersection is welded on the web stiffening rib and forms sway bracing; Angle steel should adopt the angle steel that meets national current standard " hot-rolled steel section " GB/T 706-2008 regulation; And the limit thickness of angle steel should not be less than 10mm, and angle steel and web stiffening rib are taked three weld all around connected modes, at the i beam roof and floor horizontal coupled system is set along i beam longitudinal separation 1-1.5m; Perhaps at the bottom of i beam welding U type hoop, U type hoop is welded by steel plate, and turn to pipeline to pass U type hoop and arrange, thus the outer prestressed strand of fixed body; Perhaps external prestressing tendon adopts plant-manufactured finished product rope; The finished product rope adopts the steel strand rope or the non-bending steel cable rope of hot extrude high density polyethylene (HDPE) oversheath; Steering gear and ground tackle are supporting with it, and the cluster type steering gear is adopted in steering gear, are made up of interior pipe and outer steel pipe; Perhaps said concrete is a self-compacting concrete, and the self-compacting concrete system of mixing adopts the commercial concrete agitator to stir, and its raw material are: (1) cement: adopt common 42.5 portland cements; (2) flyash: I level flyash; (3) sand: river sand, medium sand, fineness modulus 2.58, II district grating is qualified, bulk density 1576kg/m
3, apparent density 2610kg/m
3(4) stone: rubble, the 5-20mm continuous grading is qualified, and faller gill shape content is 9.2%, crush index 3.4, bulk density 1470kg/m
3, apparent density 2700kg/m
3(5) water reducing agent: high efficiency water reducing agent, water-reducing rate is greater than 25%; Detect after perhaps the self-compacting concrete system of mixing is accomplished, the slump should be at 240mm～270mm; The slump divergence is at 600mm～700mm; U type appearance test difference in height Δ h is less than 30mm; The V funnel passes through the time at 4s～25s, and coarse aggregate size is 5mm～20mm, and faller gill shape content is less than 10%, and the fineness modulus of fines is greater than 2.3; Perhaps the bar planting spacing in step B is that 25cm～40cm is in length and breadth to equidistant layout; Perhaps mounting reinforcing steel bars net at reinforced concrete mid-height place, junction, concrete beam top flange; Diameter adopts 12mm; Arrange that distance is preferably the half the of bar planting distance; In length and breadth to equidistant layout, junction, concrete beam top flange concrete height is generally 15cm～25cm according to 12.5cm～20cm, if need arrange two-layer steel mesh reinforcement greater than 25cm.
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| CN109881574A (en) * | 2019-04-18 | 2019-06-14 | 上海市城市建设设计研究总院（集团）有限公司 | Using the prefabricated bent cap in π type cross section and its method for prefabricating of external prestressing steels |
| CN110042770A (en) * | 2019-04-26 | 2019-07-23 | 南京工大桥隧与轨道交通研究院有限公司 | A method of using the original bridge of external prestressing steel Shu Tuokuan in length and breadth |
| CN110468709A (en) * | 2019-08-16 | 2019-11-19 | 柳州欧维姆机械股份有限公司 | A kind of cable-stayed bridge segmentation guy system and its fabrication and installation method with prestressing force cable saddle structure |
| CN112982187A (en) * | 2021-02-10 | 2021-06-18 | 同济大学 | Method for replacing curve prestressed steel beam in damaged bridge body and reinforcing bridge structure |
| CN113188735A (en) * | 2021-04-30 | 2021-07-30 | 西安公路研究院 | Nondestructive testing method for tension quality of external cable of corrugated steel web continuous rigid frame beam bridge |
| CN113742829A (en) * | 2021-09-03 | 2021-12-03 | 中国铁路设计集团有限公司 | Bridge structure arbitrary section reading processing and section characteristic calculating method |
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| CN109057391A (en) * | 2018-08-24 | 2018-12-21 | 西安建筑科技大学 | It is a kind of for preventing the local stiffening structure of steel-frame structure continuous collapse |
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| CN109881574A (en) * | 2019-04-18 | 2019-06-14 | 上海市城市建设设计研究总院（集团）有限公司 | Using the prefabricated bent cap in π type cross section and its method for prefabricating of external prestressing steels |
| CN109881574B (en) * | 2019-04-18 | 2024-04-09 | 上海市城市建设设计研究总院（集团）有限公司 | Pi-shaped cross section prefabricated bent cap adopting external prestressed tendons and prefabricating method thereof |
| CN110042770A (en) * | 2019-04-26 | 2019-07-23 | 南京工大桥隧与轨道交通研究院有限公司 | A method of using the original bridge of external prestressing steel Shu Tuokuan in length and breadth |
| CN110468709A (en) * | 2019-08-16 | 2019-11-19 | 柳州欧维姆机械股份有限公司 | A kind of cable-stayed bridge segmentation guy system and its fabrication and installation method with prestressing force cable saddle structure |
| CN112982187A (en) * | 2021-02-10 | 2021-06-18 | 同济大学 | Method for replacing curve prestressed steel beam in damaged bridge body and reinforcing bridge structure |
| CN112982187B (en) * | 2021-02-10 | 2022-06-21 | 同济大学 | Method for replacing curve prestressed steel beam in damaged bridge body and reinforcing bridge structure |
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