CN104452591A - Cast-in-place box beam construction technology applied to bridge constructions - Google Patents

Abstract

The invention relates to a cast-in-place box beam construction technology applied to bridge constructions. The technology sequentially includes the steps of support foundation construction, support installation, bottom formwork installation, support pre-pressing, pre-pressing removal, bottom formwork elevation adjustment, installation of steel ribs of a bottom plate and steel ribs of a web plate and prestress installation, installation of side formworks and an inner formwork, pouring of bottom plate concrete and web plate concrete, removal of the inner formwork, installation of steel ribs of a top plate and prestress installation, pouring of top plate concrete, maintenance for seven days, carrying out tensioning, duct grouting, removal of a support and end sealing. According to the technology, construction steps and construction conditions in the construction process are optimized, therefore, the construction period can be shortened, the construction cost is lowered, the possibility of safety accidents is reduced, and the overall construction quality is improved.

Description

A kind of construction of cast-in-situ box-beam technique being applied to bridge engineering

Technical field

The present invention relates to construction technology, specifically refer to a kind of construction of cast-in-situ box-beam technique being applied to bridge engineering.

Background technology

Cast-in-situ box girder is the one of bridge engineering central sill, and inside is hollow shape, and there is the edge of a wing both sides, top, and similar chest, thus gains the name, point single case, many casees etc.The case beam of reinforced concrete structure is divided into prefabricated case beam and cast-in-situ box girder, and the case beam prefabricated in independent place can set up in conjunction with Bridge Erector after bottom engineering completes, and can accelerate programming, save the duration; Cast-in-situ box girder is used for Large Scale and Continuous bridge.Commonly at present divide with material, mainly contain two kinds, one is prestressed reinforced concrete case beam, and one is steel box-girder, and wherein, prestressed reinforced concrete case beam is site operation, and except having longitudinal prestressing, some also arranges transverse prestress; Steel box-girder is generally be transported to in-site installation again after processing in the factory, has full steel structure, also has part to add steel bar concrete pave-load layer.

Summary of the invention

The object of the present invention is to provide a kind of construction of cast-in-situ box-beam technique being applied to bridge engineering, this construction technology can shorten construction period, reduces construction cost, reduces the probability occurring security incident, improves integral construction quality.

The present invention is achieved through the following technical solutions:

Be applied to a construction of cast-in-situ box-beam technique for bridge engineering, comprise step successively: bracket basis → support installing → soffit formwork installation → pre-pressing bracket → precompressed unloads → adjusts the reinforcing bar of bed die absolute altitude → base plate and web and installed under prestressing → side template and inner formword and installs → build the reinforcing bar of base plate and web concrete → dismounting inner formword → top board and installed under prestressing → build top plate concrete → health 7 days → stretch-draw → mud jacking → support removing → end-blocking.

Further, described bracket basis adopts two kinds of forms: the first is C30 steel bar concrete Extended chemotherapy, key dimension is 2m × 7m, substrate is rock and adopts φ 28 Bar Anchorage, the long 2m of dowel, spacing 1m is quincuncial arrangement 3 diameter 1.2m digging hole pile foundations, and hole pile foundation requires that base bearing capacity is at least 600KPa; The second is Extended chemotherapy, after to basis compacting, adopt light-duty cone penetrometer to carry out just trial and error test, adopt C30 concreting to build after requirement to be achieved, the pre-buried 2cm steel plate in concrete foundation top and bolt, near bracket basis, gutter is set, avoids ponding to cause immerge.

Further, described support installing: first when vertical pier body formwork by bracket be connected shaped steel and imbed template, and to be connected by rod member be an entirety; Hung after removing pier body formwork and be linked together in pier side and built-in fitting, connected horizontal leverage simultaneously, then transverse distribution beam and sand cylinder are installed.

Further, described support removing: top plate concrete makes earth anchor at back pre-buried φ 28 reinforcing bar before building, and arranges 28 tons of hoist engines, reserves φ 100mm hole at the flap position that steel pipe column is corresponding; First the standard sand in 14 sandboxes is released simultaneously, with tower crane, bed die is removed, then utilize Chain block that 2 groups of Bailey beams are moved to flap position, with hoist engine, 2 groups of Bailey beams are transferred to ground, utilize mobile crane to dismantle on ground, utilize hoist engine or tower crane crossbeam, bracket, steel pipe column to be dismantled accordingly.

Further, when described soffit formwork, side template and inner formword are installed: according to precompressed data point reuse soffit formwork absolute altitude, adopt steel plate pad; Before model sheetinstallat, check its physical dimension, planeness, remove the foreign material in template in time, after precompressed unloading, want even brushing release agent; Installed to two ends symmetry by span centre during model sheetinstallat, two side templates are installed simultaneously and are ensured to stablize; Template machines rear elder generation in the examination spelling of template field; By surveying party unwrapping wire before model sheetinstallat, ensure smoothly linear, seam is tight, corner angle are clearly demarcated; Pull bar is firm, does not run mould, do not rise mould, not spillage when ensureing concrete construction; In both sides, beam-ends arranges spilled water hole, and concrete placings is flowed out by spilled water hole during foreign material cleaning in mould; To template brushing release agent before model sheetinstallat.

Further, described soffit formwork, side template and inner formword are removed: template unloads to two ends from span centre, unloads horizontal while, at longitudinal symmetrical equilibrium; Inner formword is removed reach 2.5MPa after first time, concreting completed after, side template is removed reach 2.5MPa after second time concreting completes after, soffit formwork and support are removed after structure sets up prestressing force, utilize tower crane during form removable, and ensure that beam body corner angle are complete; Top template adopt hoist engine transfer to base plate place mobile trolley used on, then draw to beam-ends with hoist engine, adopt tower crane remove.

Further, described reinforcing bar and installed under prestressing order: base plate bottom layer reinforcing bar → base plate transverse prestress → base plate top layer reinforcing bar → web reinforcement → longitudinal prestressing → vertical prestressing → first time concrete placings → top board bottom layer of the reinforcing steel → top board transverse prestress → top board top layer reinforcing bar → second time concrete placings.

Further, described soffit formwork is assembled by 3.5m and 1.75m punching block of shaping, and smear putty between plate seam, panel made by 6mm steel plate, and ［ perpendicular muscle made by 10cm channel-section steel, spacing 40cm, and 2 ［ back cord made by 18cm channel-section steel, spacing 80cm, side template and inner formword all adopt 6mm steel plate to make panel, ［ horizontal bar made by 10cm channel-section steel, back cord adopts, and ［ truss space 1.5m assembled by 10cm channel-section steel, by 3m, 2.5m sizing punching block is assemblied to form, inner formword pad adopts diameter 10cm height 50cmC50 precast concrete block, between inner formword, ［ 10cm channel-section steel carries out stull in employing, diagonal brace, inside and outside intermode adopts three road φ 20mm round steel pull bars to reinforce, in inner side tie rod end, the long φ 25mmPVC of 15cm is installed to manage, when after form removable, by end pull bar excision 15cm, and adopt microdilatancy waterproofing mortar shutoff tie rod hole and touch smooth guarantee and concrete surface solid colour.

Further, described hole path pressure grouting adopts vacuum aid grouting technology, and mud jacking mouth and steam vent are arranged according to construction actual needs, mud jacking is carried out again after adopting compressed air removal of contamination before mud jacking, after tension of prestressed tendon anchoring, duct should mud jacking as early as possible, and completes in 48 hours.

The present invention compared with prior art, the beneficial effect had is: the present invention by the construction sequence in Optimizing construction process and execution conditions, thus can shorten construction period, reduces construction cost, reduce the probability occurring security incident, improve integral construction quality.

Detailed description of the invention

Below in conjunction with embodiment, the present invention is described in further detail, but embodiments of the present invention are not limited thereto.

Embodiment:

The invention discloses a kind of construction of cast-in-situ box-beam technique being applied to bridge engineering, comprise step successively: bracket basis → support installing → soffit formwork installation → pre-pressing bracket → precompressed unloads → adjusts the reinforcing bar of bed die absolute altitude → base plate and web and installed under prestressing → side template and inner formword and installs → build the reinforcing bar of base plate and web concrete → dismounting inner formword → top board and installed under prestressing → build top plate concrete → health 7 days → stretch-draw → mud jacking → support removing → end-blocking.

Now mark 50m across the construction of freely-supported prestress box beam for key water control project first stage of the project general main canal aqueduct C2 in Guizhou Province, the present invention is further described.

First, according to geological condition, determine that bracket basis adopts two kinds of forms, one is C30 steel bar concrete Extended chemotherapy, and key dimension is 2m × 7m, requires that substrate is rock, and substrate adopts φ 28 Bar Anchorage, the long 2m of dowel, spacing 1m quincuncial arrangement; The first is 3 diameter 1.2m digging hole pile foundations, and hole pile foundation requires that substrate is basic unit, and bearing capacity is not less than 600KPa.The second is Extended chemotherapy, for soil property basis, requires to adopt light-duty cone penetrometer to carry out just trial and error test after to basis compacting, adopts C30 concreting to build, the pre-buried 2cm steel plate in concrete foundation top and bolt after requirement to be achieved.Near bracket basis, gutter is set, avoids ponding to cause immerge.Support adopts three across unequal span Bailey beam structure, is 18m+7.41m+18m across spacing.Longeron laterally adopts 15 Bailey beam horizontal arrangement, and spacing is the wide 7.2m of 0.9m+12 × 0.45m+0.9m(), laterally adopt 45cm, 90cm two kinds of bracing frames to connect between beam, 6 roads established altogether by bracing frame; Longitudinal Bailey beam establishes 15, long 45m, with groove pier joint specialized designs rod member, for preventing longeron slippage, with the groove pier joint pad lumps of wood.Transverse distribution beam adopts 4 long I32b i iron of 9m, adopts steel to sew steel and connect between i iron.Distribution beam divides into 25cm height steel sand cylinder, and sand cylinder adopts δ 20 steel plate, φ 350mm(wall thickness 1cm) steel pipe, φ 310mm(wall thickness 1cm) steel pipe manufacturing, build C30 concrete in upper sand cylinder, quicksand hole is established in lower sand cylinder weldering, and in-built standard sand is for adjusting height and unloading.After sand cylinder installs, adopt double-layer plastic cloth to be wrapped up airtight, make moist with sand control cylinder internal standard sand, when unloading, standard sand cannot flow out automatically.［ on 40b channel-section steel shelf bracket, ［ 40b, ［ 28b channel-section steel is welded bracket horizon bar, and ［ 40b channel-section steel is welded diagonal brace by 2 by 2 at 4 Pin 2 to distribute beam seat across end.Horizon bar is connected with the upper anchoring part pin being embedded in pier shaft by bearing pin.Anchoring part adopts 20mm steel plate to process, plate size 1100*400*20mm, and anchoring part two pieces, anchor hole reserved by steel plate, adopts 20mm round steel through anchor hole and, is embedded in pier shaft concrete when building pier shaft concrete in pier shaft reinforcement welding together.Diagonal brace one end adopts φ 80mm steel pin to be connected with the seat pin that casts anchor being embedded in pier shaft, one end and horizon bar pin joint.For ensureing the monolithic stability of bracket, arranging horizontal-associate connected by 4 Pin brackets at bracket diagonal brace, horizontal-associate adopts 2 ［ 32b, 2 [28b channel-section steel and steel plate butt welding making.Span centre adopt double 6 Φ 820(wall thickness 10mm) steel pipe do buttress, arrange to layout 2 along bridge, lateral arrangement 3,6 steel pipe columns form lattice by bridging, strengthen stability, on steel pipe lower end supporting pile basis or Extended chemotherapy, all adopt Flange joint between steel pipe and basis, up and down between steel pipe, flange adopts 16 φ 30mm(70mm long) high-strength bolt connects.Steel tube standard saves high 6m, and adjustment joint is highly respectively 4m, 3m, 2m, 1.5m, 1m, and steel pipe buttress height deducts case beam base plate thickness, bed die height, Bailey beam height, distribution beam height, sand cylinder height and ground level by flowing water absolute altitude and considers and determine.Steel pipe transverse connects employing 2, and ［ butt welding of 28b channel-section steel, with φ 50mm steel pin bolt, diagonal brace adopts, and ［ 12.6 channel-section steels form bridging, and connect with φ 30mm high-strength bolt, and spacing is 6m one.For ensureing the resistance to overturning of support and anti-overturning, establishing 4 gravity anchor ingots in support both sides, to connect with steel pipe column top with 4 road φ 26mm wire rope and making guy.

Then carry out support installing: first when vertical pier body formwork by bracket be connected shaped steel and imbed template, and to be connected with the rod member identical with design size be an entirety; Hung after removing pier body formwork and be linked together in pier side and built-in fitting, connected horizontal leverage simultaneously, then transverse distribution beam and sand cylinder are installed.Steel pipe adopts tower crane segmental hoisting, Flange joint, after often joint lifting puts in place, is connected firmly immediately with bolt, and the vertical bury pipe of adjustment steel pipe, vertical bury pipe must be less than 0.1%, and deviation is not more than 5mm.Plumb aligner is adopted to carry out monitoring measurement during installation.Erection sequence first installs one successively across interior 6 steel pipes, and after reaching first horizontal crossbar position, incite somebody to action horizontal bars and brace pin joint in length and breadth, merogenesis is reinforced.And then carry out the installation of next stage, set up interim cable wind rope if desired, guarantee that steel pipe is stablized.Forbid during erection of steel pipe column to apply pulling force in advance, when connecting diagonal brace or cross bar, if rod member length being discontented with sufficient actual requirement, forbidding to adopt the equipment such as bottle gouard moved by hands to carry out stretch-draw to rod member, now needing to guarantee to meet construction requirement to rod member again processing and fabricating.First Bailey truss is assembled by span burst on ground, is lifted on crossbeam, crossbeam first marks the position of every sheet longeron, accurately lifted by truss and put in place, make lateral connection with bracing frame.The K Nodes contacted with pier stud and steel pipe column in Bailey beam adds 2, and [126 channel-section steels, as vertical supporting, often need 120 across 50m beam altogether.During installation, employing spirit level, level gauge control sandbox height simultaneously, and sandbox will apply pressure before laying, and the Bailey beam after installation is kept in one plane.

Then soffit formwork installation is carried out, pre-pressing bracket is carried out after installation, pre-pressing bracket supports an important step of checking and accepting, and it is that the work progress of simulating superstructure is tested to support, is the necessary condition whether whether checking supported design is reasonable and can be delivered for use.Support is set up complete, in order to eliminate between support and the nonelastic deformation of ground, and measure the elastic deformation value of support, the line style of guard box beam and absolute altitude, carry out pre-pressing bracket according to designing requirement.12 all carry out ballast test across simply supported beam support.According to designing requirement, prefabricating load is not less than 1.1 times of the deadweight of case beam, is often 435.8m across case beam concrete ³, unit weight gets 26KN/m ³, heap carrying capacity is 1246 tons.Precompressed adopts 1 ton of special sand pocket to carry out piling prepressing, construction period, should carry out preparation and the sluicing measure of rainy day sand pocket covering.Precompressed divides 40%, 80%, 110% 3 grade of precompressed, and its load weight is respectively 498.6 tons, 997 tons, 1246 tons, and need 1246 bags of sand, every bag of area is about 0.64m ², every layer of preloading 360 tons, preloading four layers can meet the demands completely, highly about 2.5m.Case beam cross section at the bottom of web, 3, base plate center observes, longitudinally observation point is established to observe at distribution beam place and support single span span centre, before precompressed to the observation of bed die absolute altitude once, first, second and third grade of loading is observed for latter 2 hours, observes to settlement stability; Settlement observation is carried out to pile foundation or Extended chemotherapy, totally six points; After being unloaded by prefabricating load again to the observation of bed die absolute altitude once, from above observational data, the elastic deformation of support and the settling amount of ground is calculated.

Each measuring point elevation of top surface H1 value and basic elevation J1 value is first measured with level gauge before loading, each measuring point elevation of top surface H2 value is measured when loading 40%, each measuring point elevation of top surface H3 value is measured when loading 80%, each measuring point elevation of top surface H4 value and basic elevation J2 value is measured when loading 110%, each measuring point elevation of top surface H5 value is measured after unloading, carry out data to arrange analysis according to Measurement results, determine the camber of case beam, adjustment bed die absolute altitude.Will check before precompressed that situation set up by support, guarantee that the material of all uses all will meet the requirements, all solder joints, connection are wanted firmly, check one by one.Want symmetrical during precompressed and place sand pocket, in case bias voltage is unbalance.Load and will stress raisers be prevented in uninstall process, causing template to produce inhomogeneous deformation.

Then, carry out reinforcing bar and the installed under prestressing of base plate and web, side template and inner formword are installed, and carry out building base plate and web concrete after installation, then inner formword is removed, carry out reinforcing bar and the installed under prestressing of top board, after then building top plate concrete, health 7 days, and carry out stretch-draw and mud jacking, last striking, end-blocking, whole construction technology terminates.

The dismounting of the support in said process and all templates first to be torn open after should following, first prop up the principle order of tearing open afterwards carries out.Top plate concrete makes earth anchor at back pre-buried φ 28 reinforcing bar before building, and arranges 28 tons of hoist engines, reserves φ 100mm hole at the flap position that steel pipe column is corresponding.First the standard sand in 14 sandboxes is released simultaneously, with tower crane, bed die is removed, then utilize Chain block that 2 groups of Bailey beams are moved to flap position, with hoist engine, 2 groups of Bailey beams are transferred to ground, utilize mobile crane to dismantle on ground.Hoist engine or tower crane is utilized crossbeam, bracket, steel pipe column to be dismantled accordingly.

According to precompressed data point reuse bed die absolute altitude when above-mentioned soffit formwork, side template and inner formword are installed, adopt steel plate pad; Before model sheetinstallat, check its physical dimension, planeness, remove the foreign material in template in time, after precompressed unloading, want even brushing release agent; Installed to two ends symmetry by span centre during model sheetinstallat, two side templates are installed simultaneously and are ensured to stablize; Template machines rear elder generation in the examination spelling of template field; By surveying party unwrapping wire before model sheetinstallat, ensure smoothly linear, seam is tight, corner angle are clearly demarcated; Pull bar is firm, does not run mould, do not rise mould, not spillage when ensureing concrete construction; In both sides, beam-ends arranges spilled water hole, and concrete placings is flowed out by spilled water hole during foreign material cleaning in mould; To template brushing release agent before model sheetinstallat.For the first time before concrete placings, reserve internal diameter 5cmPVC pipe in top board chamfering position as internal mold top plate tie rod hole.Remove web internal mold after concrete placings for the first time, top board internal mold is fixed by installation φ 20mm round steel pull bar.

Above-mentioned soffit formwork, side template and inner formword are removed: template unloads to two ends from span centre, unloads horizontal while, at longitudinal symmetrical equilibrium; Inner formword is removed reach 2.5MPa after first time, concreting completed after, side template is removed reach 2.5MPa after second time concreting completes after, soffit formwork and support are removed after structure sets up prestressing force, utilize tower crane during form removable, and ensure that beam body corner angle are complete; Top template adopt hoist engine transfer to base plate place mobile trolley used on, then draw to beam-ends with hoist engine, adopt tower crane remove.Unsuitable form removal when temperature sharply changes, removes end mould, inner membrance, side form sprinkles water covering curing later.

Above-mentioned reinforcing bar and installed under prestressing order: base plate bottom layer reinforcing bar → base plate transverse prestress → base plate top layer reinforcing bar → web reinforcement → longitudinal prestressing → vertical prestressing → first time concrete placings → top board bottom layer of the reinforcing steel → top board transverse prestress → top board top layer reinforcing bar → second time concrete placings.Reinforcing bar adopts HRB400, is divided into 10mm, 12mm, 16mm, 20mm tetra-kinds of specifications.Bar splice adopts welding, and joint location staggers mutually, and the quantity of arbitrary section bar splice must be less than 50% of reinforcing bar radical.The length of double welded joint is not less than 5d, and single fillet welded length is not less than 10d.Beam body reinforcing bar Minimal Protective layer is 35mm, adopts plastic cushion to guarantee headroom.Lower bellows need be covered during reinforcement welding, in order to avoid its scaling loss is destroyed by welding slag.

Above-mentioned concrete adopts automatic gauge mixing, and concrete tank car is transported to job site, and pumping is put in storage.First check raw material reserve status and inspection situation before concrete placings, the water content of sand material is detected, determines coordination in works, issue charger sheet to blending station by test room.Mix will stir, solid colour, must not have segregation and excreting water phenomenon, detects the slump of concrete, air content, out-of-machine temperature, placement temperature, and makes real curing raw test specimen, stretch-draw test specimen on request.Concreting principle: first build base plate and build web again; Left and right web symmetry is built; Concrete is built to two ends in the middle of the beam body, and the while of adopting 2 concrete pumps, symmetry is carried out.Concrete delamination thickness 30 ㎝, the front and back of upper strata and lower floor are built distance and are decided to be 10m.Concrete placings and second time are built the length of time more than 7 days, should not set up reinforced mesh at connecting portion simultaneously for the first time.Before carrying out second time concreting, need the concrete to first time builds to carry out dabbing process, and adopt high pressure geomantic omen to rinse well, ensure in face, storehouse without any foreign material.Must carry out continuously in box beam concrete casting process, must not interrupt, concrete the building in upper strata must complete before the initial set of lower-layer concrete.Continuous concreting, one-shot forming.Strengthen the concrete casting building technology located below bearing, anchor plate, bellows, guarantee vibration compacting.Special messenger is arranged to check support and template deformation situation in concrete placings process.Concrete adopts poker vibrator to vibrate, layout evenly, vibrating spear is forbidden to touch bellows during concrete vibrating, in order to avoid there is displacement, hole seam spillage in bellows, affect stretch-draw, concrete tamping degree has stopped discharge with its blibbing of field observation, concrete no longer sinks and occurs that cement paste is as the criterion on surface, slowly should propose vibrating spear after everywhere has shaken.Moving interval should not exceed 1.5 times of vibrating spear operating radius, and keeps the distance of 5 ~ 10cm with side form, inserts lower-layer concrete 5 ~ 10cm when vibrating.The personnel of building are divided into Liang Ge teams and groups, and each teams and groups establish 1 commander, 3 works of vibrating, and four general works are responsible for dismantling pump line.Subregion vibrates, and carries out the system of listing, clearly defining responsibilities.Adopt secondary to receive sizing process after concreting, namely carry out after first time wipes one's face and receive slurry routinely, then carry out second time and wipe one's face to receive and starch, for the second time the time of wiping one's face is selected in build and carries out for rear 6-8 hour.Start after concrete final set to cover geotextiles watering maintenance, prevent moisture from evaporating too fast, special messenger is responsible for, and the frequency of watering must ensure that concrete surface is moistening.The temperature difference between the water temperature of maintenance and concrete surface should control, within 15 DEG C, to prevent due to excessive temperature differentials, causes concrete to crack.After case beam side is removed, due to cannot covering be wrapped up, concrete wet curing outside case beam.

Above-mentioned concrete proportioning design and control with raw material are:

A. design by impervious concrete during design of concrete, adopt normal silicate P.O52.5 class g cement, aluminic acid acid calcium content is 6-8%.

B. maximum size of coarse aggregate is 25mm, adopts washing measure, and strict control coarse aggregate mud content, clod content are less than 0.2%; Fine aggregate adopts water washed rubble to process, and mud content, clod content all can be effectively controlled; Fine aggregate fineness modulus controls at 2.4-2.8, and content of stone powder controls within 7%.

C. Admixture adopts Shanxi Huang to rise the efficient retardation water reducing agent of high-performance poly carboxylic acid; Cement consumption is 425Kg/m ³, be greater than the 320Kg/m of code requirement ³; Sand coarse aggregate ratio is 37.5%, and water/binder ratio is 0.32; Examination timing adopts the maximum cooperation of water/binder ratio to be compared to impermeability test.

D. mix 50Kg flyash in order to reduce cement consumption, thus reduce the total water heat-transmission of cement, improve concrete workability, thus avoid concrete crack.

Above-mentioned concrete construction controls:

a.strict control thickness of protection tier, clean protective layer thickness is greater than 19mm, takes C55 high-grade concrete cushion block.

b.during hot weather construction, temperature is higher, takes to water cooling measure to aggregate, reduces concrete and goes out machine and molding temperature, control concrete molding temperature and be less than 32oC.Bath cooling is carried out to concrete transport vehicle vehicle body, site inspection outlet temperature.During concrete placings, strictly will control concrete slump is 160-200mm.Pump line in use can radiation-absorbing warm, and pipeline and concrete material rub also can produce heat, and conveyance conduit wraps up gunnysack, and cooling of throwing cold water on pipeline, irregularly watering above, ensureing that building heat insulating material in concrete process be moisture state.

c.ensure the continuity of concrete placings, do not occur constuction joint or cold seam.Construction machinery not only will be made adequate preparation, and will consider repairing time when breaking down, agitator two concrete tank cars for subsequent use, and an on-the-spot delivery pump for subsequent use, wants a 300KW generator for subsequent use in addition, a set of 750 agitators of blending station configuration.

Before building concrete, construction machinery should be transported to scene.Agitator get ready enough cement, sand, stone and ensure water and electricity supply, machinery allocation must accomplish sequential production, constructor's configuration is worked in three shifts operating personnel.

d.according to concrete conveying capacity, bottom slab concreting area, concrete placings amount, subregion, layering is carried out to building concrete, make concrete with same gradient thin concrete lift, advance in proper order, once arrive top, each lift height is built by 300mm layering substep, and will ensure that concrete covers the time of having built concrete and must not exceed the concrete initial setting time.

e.according to the actual conditions of the gradient of self-assembling formation during concrete pumping, each build band before, during and after arrange that three roads vibrate.First is arranged in pouring out concrete point, and mainly solve the concrete tamping in top, because baseplate reinforcing bar spacing is closeer, second is arranged in concrete toe place, guarantees that bottom is concrete closely knit, and the 3rd road ensures the gradient and the density of concrete at the middle part of the gradient.Along with pushing ahead of concreting work, vibrating spear is also corresponding catches up with, to guarantee the concrete quality of whole height.After chamfer length increases, vibrating head also wants corresponding increase number.

Construction manager supervises the conscientious tamped concrete of workman at the scene, improves concrete compactness, reduces the space between concrete aggregate.

f.the concrete indices of mixing is strictly monitored in job site, and the person in charge at any time to site operation circulates a notice of, and processes the concrete quality problem that scene occurs in time.Testing crew spot-check the slump of concrete at any time, the workability of range estimation concrete, as find concrete have segregation or just coagulation phenomena concrete is cleared up and discharged appearance.

g.adopt secondary to receive sizing process after concreting, namely carry out after first time wipes one's face and receive slurry routinely, then carry out second time and wipe one's face to receive and starch, for the second time the time of wiping one's face is selected in build and carries out for rear 6-8 hour.

h.start after concrete final set to cover geotextiles watering maintenance, prevent moisture from evaporating too fast, special messenger is responsible for, and the frequency of watering must ensure that concrete surface is moistening.The time of concrete watering maintenance is 14 days.The temperature difference between the water temperature of maintenance and concrete surface should control, within 15 DEG C, to prevent due to excessive temperature differentials, causes concrete to crack.After case beam side is removed, due to cannot covering be wrapped up, concrete wet curing outside case beam.Concrete pours in rear cabinet and covers gunnysack or straw screen or mat (bag) in time and often sprinkle water, and establishes powerful fan, accelerating chamber inner air flow, reduce air themperature in case, utilize the cooling measures such as vertical finish rolling corrugated steel pipe water flowing in top board stretch-draw hand-hole place and case.

i.before second time concreting reply first time the cement paste of concrete surface of building and soft layer cut, adopt high pressure geomantic omen to be incorporated into row and rinse, the foreign material in face, storehouse are cleaned out, and abundant face, moistening storehouse but must not ponding; Dabbing should make to expose fresh concrete area and be not less than 75%; During artificial chiseling, concrete strength should reach 2.5MPa, and during air operated machine dabbing, concrete strength should reach 10Mpa.Set up steel bar welding net and mesh resin fiber at connecting portion simultaneously.

j.according to flat perpendicular curved geometric element calculate bellows from center every 50cm vertical lateral coordinates, 80cm one U-shaped φ 14 reinforcing bar is adopted to position, the every 50cm of curved section is location together, require that pipeline location is accurate, firm, pipeline is straight, and the radius of curvature of any one must not be less than 95% of design load.Pipe installing deviation: pipeline coordinate beam length direction is less than 30mm, and deck-molding direction is less than 10mm; Spacing between pipes is less than 10mm with row, and levels is less than 10mm.Anchor plate will be installed firmly accurately, and the necessary centering of anchor plate, pipeline is straight, keeps on the same axis, guarantees vertical with corrugated tube end.Check anchor plate and pipeline before concrete placings, the position of anchor plate should be accurate, unimpeded anhydrous and other foreign material in duct.

Above-mentioned hole path pressure grouting adopts vacuum aid grouting technology.Adopt Special grouting material to carry out mud jacking, burnt family aqueduct needs 37m3, and stream head aqueduct needs 74m3.Mud jacking mouth and steam vent can be arranged according to construction actual needs, can mud jacking after application of compressed air removal of contamination before mud jacking.After tension of prestressed tendon anchoring, duct should mud jacking as early as possible, and should complete in 48 hours.

Preparation before hole path pressure grouting:

Use emery wheel cuts, and the remaining length after presstressed reinforcing steel cuts off must not be less than 30mm.Presstressed reinforcing steel gap cement paste outside ground tackle is clogged, in order to avoid grout and lose grouting pressure.Steam vent is reserved during sealing off and covering anchorage.Duct with pressure flush of water, with foreign material such as granulated slags in evacuation aperture, ensures that duct is unimpeded before mud jacking.Blow away hole internal water accumulation with air compressor machine after flushing, compressed air will without oil content.But keep duct to soak, make cement paste and hole wall in conjunction with good.

Pipeline pneumatic mortar requires closely knit, and hole path pressure grouting adopts neat slurry, and mud jacking match ratio will carefully than choosing, and adopt optimum mix proportion, must not mix all kinds of villaumite, within 28 days, requirement of strength reaches 50MPa.Cement adopts P.O52.5 low alkali Portland cement, and Admixture adopts Shanxi Huang to rise high-performance high-efficiency water-reducing agent of poly-carboxylic acid, and water-cement ratio adopts 0.26-0.28, is maximumly no more than 3%.Mix and stir rear 3h bleeding rate should to control after 2%, 24h bleeding and should all be absorbed by slurry.Desired consistency controls at 14 ~ 22s.In cement paste, (by testing) mixes suitable expansion agent.Free wxpansion after cement paste mixes expansion agent is greater than 3%.

First discharge water the mud that discharges water again, and the mixing time is no less than l min, deposits in slurry storing tank after mortar sieves.Now in bucket, mortar still wants stirring at low speed, and the quantity that often maintenance is enough is to ensure that the mud jacking energy one-time continuous of every root pipeline completes.Cement paste automodulation must not more than 4Omin to the interval time of pressure people pipeline.

In summary: construction method disclosed by the invention by the construction sequence in optimization construction of cast-in-situ box-beam process and execution conditions, thus can shorten construction period, reduces construction cost, reduces the probability occurring security incident, improve integral construction quality.

The above is only preferred embodiment of the present invention, and not do any pro forma restriction to the present invention, every any simple modification, equivalent variations done above embodiment according to technical spirit of the present invention, all falls within protection scope of the present invention.

Claims (9)

1. one kind is applied to the construction of cast-in-situ box-beam technique of bridge engineering, it is characterized in that, comprise step successively: bracket basis → support installing → soffit formwork installation → pre-pressing bracket → precompressed unloads → adjusts the reinforcing bar of bed die absolute altitude → base plate and web and installed under prestressing → side template and inner formword and installs → build the reinforcing bar of base plate and web concrete → dismounting inner formword → top board and installed under prestressing → build top plate concrete → health 7 days → stretch-draw → hole path pressure grouting → support removing → end-blocking.

2. a kind of construction of cast-in-situ box-beam technique being applied to bridge engineering according to claim 1, it is characterized in that, described bracket basis adopts two kinds of forms: the first is C30 steel bar concrete Extended chemotherapy, key dimension is 2m × 7m, substrate is rock and adopts φ 28 Bar Anchorage, the long 2m of dowel, spacing 1m are quincuncial arrangement 3 diameter 1.2m digging hole pile foundations, and hole pile foundation requires that base bearing capacity is at least 600KPa; The second is Extended chemotherapy, after to basis compacting, adopt light-duty cone penetrometer to carry out just trial and error test, adopt C30 concreting to build after requirement to be achieved, the pre-buried 2cm steel plate in concrete foundation top and bolt, near bracket basis, gutter is set, avoids ponding to cause immerge.

3. a kind of construction of cast-in-situ box-beam technique being applied to bridge engineering according to claim 1, is characterized in that, described support installing: first when vertical pier body formwork by bracket be connected shaped steel and imbed template, and to be connected by rod member be an entirety; Hung after removing pier body formwork and be linked together in pier side and built-in fitting, connected horizontal leverage simultaneously, then transverse distribution beam and sand cylinder are installed.

4. a kind of construction of cast-in-situ box-beam technique being applied to bridge engineering according to claim 1, it is characterized in that, described support removing: top plate concrete makes earth anchor at back pre-buried φ 28 reinforcing bar before building, and arranges 28 tons of hoist engines, reserves φ 100mm hole at the flap position that steel pipe column is corresponding; First the standard sand in 14 sandboxes is released simultaneously, with tower crane, bed die is removed, then utilize Chain block that 2 groups of Bailey beams are moved to flap position, with hoist engine, 2 groups of Bailey beams are transferred to ground, utilize mobile crane to dismantle on ground, utilize hoist engine or tower crane crossbeam, bracket, steel pipe column to be dismantled accordingly.

5. a kind of construction of cast-in-situ box-beam technique being applied to bridge engineering according to claim 1, is characterized in that, described soffit formwork, side template and inner formword are installed: according to precompressed data point reuse soffit formwork absolute altitude, adopts steel plate pad; Before model sheetinstallat, check its physical dimension, planeness, remove the foreign material in template in time, even brushing release agent after precompressed unloading; Installed to two ends symmetry by span centre during model sheetinstallat, two side templates are installed simultaneously and are ensured to stablize; Template machines rear elder generation in the examination spelling of template field; By surveying party unwrapping wire before model sheetinstallat, ensure smoothly linear, seam is tight, corner angle are clearly demarcated; Pull bar is firm, does not run mould, do not rise mould, not spillage when ensureing concrete construction; In both sides, beam-ends arranges spilled water hole, and concrete placings is flowed out by spilled water hole during foreign material cleaning in mould; To template brushing release agent before model sheetinstallat.

6. a kind of construction of cast-in-situ box-beam technique being applied to bridge engineering according to claim 1, is characterized in that, described soffit formwork, side template and inner formword are removed: template unloads to two ends from span centre, unloads horizontal while, at longitudinal symmetrical equilibrium; Inner formword is removed reach 2.5MPa after first time, concreting completed after, side template is removed reach 2.5MPa after second time concreting completes after, soffit formwork and support are removed after structure sets up prestressing force, utilize tower crane during form removable, and ensure that beam body corner angle are complete; Top template adopt hoist engine transfer to base plate place mobile trolley used on, then draw to beam-ends with hoist engine, adopt tower crane remove.

7. a kind of construction of cast-in-situ box-beam technique being applied to bridge engineering according to claim 1, it is characterized in that, described reinforcing bar and installed under prestressing order: base plate bottom layer reinforcing bar → base plate transverse prestress → base plate top layer reinforcing bar → web reinforcement → longitudinal prestressing → vertical prestressing → first time concrete placings → top board bottom layer of the reinforcing steel → top board transverse prestress → top board top layer reinforcing bar → second time concrete placings.

8. a kind of construction of cast-in-situ box-beam technique being applied to bridge engineering according to claim 1, it is characterized in that, described soffit formwork is assembled by 3.5m and 1.75m sizing punching block, putty is smeared between plate seam, panel made by 6mm steel plate, and ［ perpendicular muscle made by 10cm channel-section steel, spacing 40cm, 2 ［ back cord made by 18cm channel-section steel, spacing 80cm, side template and inner formword all adopt 6mm steel plate to make panel, ［ horizontal bar made by 10cm channel-section steel, back cord adopts, and ［ truss space 1.5m assembled by 10cm channel-section steel, by 3m, 2.5m sizing punching block is assemblied to form, inner formword pad adopts diameter 10cm height 50cmC50 precast concrete block, between inner formword, ［ 10cm channel-section steel carries out stull in employing, diagonal brace, inside and outside intermode adopts three road φ 20mm round steel pull bars to reinforce, in inner side tie rod end, the long φ 25mmPVC of 15cm is installed to manage, when after form removable, by end pull bar excision 15cm, and adopt microdilatancy waterproofing mortar shutoff tie rod hole and touch smooth guarantee and concrete surface solid colour.

9. a kind of construction of cast-in-situ box-beam technique being applied to bridge engineering according to claim 1, it is characterized in that, described hole path pressure grouting adopts vacuum aid grouting technology, mud jacking mouth and steam vent are arranged according to construction actual needs, mud jacking is carried out again after adopting compressed air removal of contamination before mud jacking, after tension of prestressed tendon anchoring, duct should mud jacking as early as possible, and completes in 48 hours.