CN111906905A - Pre-tensioning prestressed hollow slab polystyrene internal mold and construction method thereof - Google Patents
Pre-tensioning prestressed hollow slab polystyrene internal mold and construction method thereof Download PDFInfo
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- CN111906905A CN111906905A CN202010816227.9A CN202010816227A CN111906905A CN 111906905 A CN111906905 A CN 111906905A CN 202010816227 A CN202010816227 A CN 202010816227A CN 111906905 A CN111906905 A CN 111906905A
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- 229920002223 polystyrene Polymers 0.000 title claims abstract description 66
- 238000010276 construction Methods 0.000 title claims abstract description 44
- 239000004567 concrete Substances 0.000 claims abstract description 83
- 238000000034 method Methods 0.000 claims abstract description 29
- 230000008569 process Effects 0.000 claims abstract description 13
- 229910001294 Reinforcing steel Inorganic materials 0.000 claims abstract description 9
- 229910000831 Steel Inorganic materials 0.000 claims description 43
- 239000010959 steel Substances 0.000 claims description 43
- 230000002787 reinforcement Effects 0.000 claims description 15
- NJPPVKZQTLUDBO-UHFFFAOYSA-N novaluron Chemical compound C1=C(Cl)C(OC(F)(F)C(OC(F)(F)F)F)=CC=C1NC(=O)NC(=O)C1=C(F)C=CC=C1F NJPPVKZQTLUDBO-UHFFFAOYSA-N 0.000 claims description 12
- 238000005520 cutting process Methods 0.000 claims description 9
- 239000002023 wood Substances 0.000 claims description 7
- 239000000835 fiber Substances 0.000 claims description 6
- 238000003825 pressing Methods 0.000 claims description 6
- 239000002002 slurry Substances 0.000 claims description 6
- 238000003780 insertion Methods 0.000 claims description 4
- 230000037431 insertion Effects 0.000 claims description 4
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 claims description 4
- 238000004519 manufacturing process Methods 0.000 claims description 4
- 230000009471 action Effects 0.000 claims description 3
- 230000000740 bleeding effect Effects 0.000 claims description 3
- 239000003795 chemical substances by application Substances 0.000 claims description 3
- 238000004140 cleaning Methods 0.000 claims description 3
- 239000011248 coating agent Substances 0.000 claims description 3
- 238000000576 coating method Methods 0.000 claims description 3
- 238000006073 displacement reaction Methods 0.000 claims description 3
- 238000007667 floating Methods 0.000 claims description 3
- 239000000203 mixture Substances 0.000 claims description 3
- 238000005096 rolling process Methods 0.000 claims description 3
- 238000005204 segregation Methods 0.000 claims description 3
- 238000003756 stirring Methods 0.000 claims description 3
- 238000000465 moulding Methods 0.000 claims description 2
- 238000009415 formwork Methods 0.000 claims 7
- 239000011241 protective layer Substances 0.000 abstract description 7
- 238000007789 sealing Methods 0.000 abstract 1
- 239000010410 layer Substances 0.000 description 11
- 239000002775 capsule Substances 0.000 description 3
- 230000001680 brushing effect Effects 0.000 description 2
- 239000004568 cement Substances 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 238000013461 design Methods 0.000 description 2
- 239000003973 paint Substances 0.000 description 2
- 239000011150 reinforced concrete Substances 0.000 description 2
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 238000005452 bending Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 239000004744 fabric Substances 0.000 description 1
- 238000000227 grinding Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229920006327 polystyrene foam Polymers 0.000 description 1
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B28—WORKING CEMENT, CLAY, OR STONE
- B28B—SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
- B28B7/00—Moulds; Cores; Mandrels
- B28B7/28—Cores; Mandrels
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B28—WORKING CEMENT, CLAY, OR STONE
- B28B—SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
- B28B11/00—Apparatus or processes for treating or working the shaped or preshaped articles
- B28B11/24—Apparatus or processes for treating or working the shaped or preshaped articles for curing, setting or hardening
- B28B11/245—Curing concrete articles
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B28—WORKING CEMENT, CLAY, OR STONE
- B28B—SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
- B28B13/00—Feeding the unshaped material to moulds or apparatus for producing shaped articles; Discharging shaped articles from such moulds or apparatus
- B28B13/02—Feeding the unshaped material to moulds or apparatus for producing shaped articles
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B28—WORKING CEMENT, CLAY, OR STONE
- B28B—SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
- B28B7/00—Moulds; Cores; Mandrels
- B28B7/0002—Auxiliary parts or elements of the mould
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B28—WORKING CEMENT, CLAY, OR STONE
- B28B—SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
- B28B7/00—Moulds; Cores; Mandrels
- B28B7/34—Moulds, cores, or mandrels of special material, e.g. destructible materials
- B28B7/348—Moulds, cores, or mandrels of special material, e.g. destructible materials of plastic material or rubber
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Ceramic Engineering (AREA)
- Mechanical Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Structural Engineering (AREA)
- Manufacturing Of Tubular Articles Or Embedded Moulded Articles (AREA)
Abstract
The invention discloses a construction method of a pre-tensioning prestressed hollow slab polystyrene inner mold, which utilizes a polystyrene inner mold plate pre-embedded in a hollow slab to be not taken out any more, reduces the procedures of the traditional construction process such as the procedures of installing and detaching the inner mold and a sealing head on the premise of ensuring the size of the hollow slab, ensures the thickness of a protective layer of a reinforcing steel bar and the quality of concrete, greatly saves labor cost and shortens the construction period.
Description
Technical Field
The invention relates to the technical field of roads and bridges, in particular to a pre-tensioning prestressed hollow slab polystyrene internal mold and a construction method thereof.
Background
Along with the continuous development of highway construction, the requirements on engineering quality are continuously improved, and especially the requirements on the quality of prefabricated parts by standardized construction are increasingly strict. The construction method of the pre-tensioning prestressed hollow slab polystyrene inner mold is well suitable for the large environment. The inner mold habit in the construction of the pre-tensioned prestressed hollow slab beam is that firstly, an inflatable capsule is used (but more and more designs are clearly forbidden to use the capsule at present in order to avoid various defects caused by the use of the inflatable capsule), and secondly, a wood mold or a steel mold is used.
The two methods have the defects of out-of-control thickness control of the steel bar protective layer, high cost, multiple working procedures and long construction period. Therefore, a construction process with better performance needs to be invented to thoroughly overcome the above disadvantages.
Disclosure of Invention
The invention aims to: aiming at the problems, the construction method of the pre-tensioning prestressed hollow slab polystyrene inner mold is provided, and the problems that the thickness of a steel bar protective layer is out of control, the cost is high, the processes are multiple, and the construction period is long in the prior art are solved.
The invention is realized by the following scheme:
a pretensioning method prestressed hollow slab polystyrene internal mold construction method comprises an internal mold upper end face, an internal mold lower end face, an internal mold side end face, an internal mold bottom face and an internal mold top face; the inner die is in an octagonal prism shape on the whole, the bottom surface of the inner die and the top surface of the inner die are arranged on the top surface and the bottom surface of the octagonal prism inner die respectively, the bottom surface of the inner die and the top surface of the inner die are in an octagonal structure, and the upper end surface of the inner die, the lower end surface of the inner die and the side end surface of the inner die are arranged on the inner die surface in the octagonal shape respectively.
Preferably, the upper end face of the inner die, the lower end face of the inner die, the side end face of the inner die, the bottom face of the inner die and the top face of the inner die are all provided with fiber yarns.
The invention provides a construction method of a pre-tensioning prestressed hollow slab polystyrene internal mold, which comprises the following steps: the method comprises the following steps:
the first step is as follows: cleaning a pedestal, coating a release agent on the pedestal, manufacturing a steel reinforcement framework on a jig frame, hoisting the steel reinforcement framework to the pedestal, and paving a steel strand at the bottom of the steel reinforcement framework;
step two: preparing an anchor clamp, arranging the anchor clamp at the two ends of the tensioning pedestal, and binding stirrups and constructing reinforcing steel bars; tensioning the steel strand through a jack:
step three: side molds are arranged on the left side and the right side of the steel reinforcement framework; after bottom plate concrete is poured, the polystyrene inner mold is placed into the steel bar framework to be used as the inner mold, the polystyrene inner mold is not taken out any more, and the inner mold is ensured not to float upwards in the process of pouring web plate and top plate concrete;
step four: and curing the pre-tensioned beam concrete, dismantling the side mold after the concrete reaches the strength required by the specification, releasing the tension force of the jack, releasing the prestress, gradually cutting the beam on the same line from the releasing end to the other end, and then moving and storing the beam.
And in the third step, the smooth surface of the side template is ensured when the side template is placed, rust is avoided, the height difference of the joint of the template and the plate is controlled within 2mm, and the gap of the template is welded and polished to be smooth.
In the second step, tensioning is strictly carried out according to the tensioning force and pressure gauge data provided by technicians, double control is carried out through the elongation, when the deviation between the actual elongation and the theoretical elongation is more than 6 percent, or the conditions of yarn slipping, yarn breaking and the like occur, tensioning is immediately stopped, and tensioning can be carried out again after reason searching treatment; and during tensioning, safety baffles are arranged at two ends, and a tensioning person adopts an intelligent tensioning and pushing jack to tension the steel strand on the side surface of the beam end.
In the third step: when concrete is manufactured, concrete mixture is uniformly mixed, the color is consistent, the slump is controlled to be 100-140 mm, and the concrete cannot be used due to overlarge slump, segregation and bleeding; the stirring time of the concrete should be controlled to be more than 2.5 minutes.
During pouring, layered blanking and horizontal layered continuous pouring are carried out, the thickness of each layer is not more than 30cm, and the upper-layer concrete can be poured after the lower-layer concrete is vibrated to be compact so as to ensure that the concrete has good compactness.
When the polystyrene internal mold is fixed; a 16-diameter steel bar hook with the distance of 1m is arranged for fixing and preventing the polystyrene internal mold from shifting and floating; steel pipe pressing bars with the spacing of 1m are arranged on the outer die, and a wood board with the thickness of 1cm and the thickness of 10 cm-15 cm is arranged under the pressing bar and pressed on the polystyrene inner die.
After the polystyrene internal mold is fixed, concrete on the side surface and the top surface is poured immediately; when pouring, each layer of symmetrical concrete on two sides of the polystyrene internal mold is filled, the thickness of each layer is not more than 30cm, the vibrator is vertically inserted into the concrete and is inserted into the bottom concrete by 50mm, the collision of reinforcing steel bars, the polystyrene internal mold and other embedded parts is avoided, the insertion points are arranged in a staggered mode, the moving distance is 1.5 times of the vibration action radius, the distance between the vibrator and the side mold is kept by 50-100 mm, after each position is vibrated, the vibrating rod is slowly lifted out while vibrating, bubbles are expelled from the bottom and the side, particularly, the vibration is strengthened at the rabbet joints of the beam and the horseshoe part of the side plate, and the honeycomb pitted surface is prevented from being formed after molding; when the concrete stops sinking and no air bubble appears, the surface is flat and slurry is spread, the concrete is smeared, compacted and smoothed by wood, and after slurry is to be settled, the concrete is smeared for the second time and is napped, so that the concrete is combined with a bridge deck pavement layer.
When the strength of the concrete reaches more than 85% of the designed strength, the age of the concrete is not less than 7 days, and the elastic modulus is not less than 80% of the 28d elastic modulus of the concrete, the concrete can be expanded; before the tension is released, the side die and the flange template which limit the displacement are firstly dismantled; when the tension is released, two 250T jacks are adopted for releasing the tension integrally; installing a screw coupler, tensioning and finish rolling twisted steel and a movable cross beam; the jack is fed with oil, the movable cross beam is jacked by the jack, so that the bolt screwed on the fixed cross beam can be loosened, the fixed bolt is unscrewed, and the jack is slowly unloaded, namely the tension releasing work is completed; and (5) dismantling various cross beams, connecting devices and jacks, and moving to another line for construction.
In summary, due to the adoption of the technical scheme, the invention has the beneficial effects that:
1. the construction method of the polystyrene internal mold of the invention utilizes the polystyrene internal mold plate pre-embedded in the hollow slab to be not taken out any more, reduces the procedures (such as the procedures of installing and detaching the internal mold and the end-capping head) of the traditional construction process on the premise of ensuring the size of the hollow slab, ensures the thickness of the protective layer of the reinforcing steel bar and the quality of concrete, greatly saves the labor cost and shortens the construction period
2. The construction method of the polystyrene internal mold can ensure the thickness of the reinforced concrete protective layer and prolong the service life of the beam slab.
3. The construction method of the polystyrene internal mold has the advantages of simplified and clear process, cost saving and construction period shortening.
4. The construction method of the polystyrene internal mold greatly promotes the field civilized construction and standardized construction, and the whole construction process is standard, orderly and controllable.
5. The construction method of the polystyrene internal mold can reduce the labor intensity of workers, greatly save the labor and has low technical requirement on the workers.
Drawings
FIG. 1 is a flow chart of the construction process of the polystyrene internal mold of the pretensioned prestressing hollow slab according to the invention;
FIG. 2 is a schematic view of the inner mold structure of the present invention;
FIG. 3 is a schematic side view of the inner mold of the present invention;
FIG. 4 is a schematic top view of the upper end surface of the inner mold of the present invention;
FIG. 5 is a schematic structural view of a stopper bar according to the present invention;
description of the drawings: 1. the upper end surface of the inner die; 2. the lower end surface of the inner die; 3. an inner mold side end face; 4. the bottom surface of the inner mold; 5. a top surface of the inner mold; 6. fiber yarn; 7. and (5) a limiting strip.
Detailed Description
All of the features disclosed in this specification, or all of the steps in any method or process so disclosed, may be combined in any combination, except combinations of features and/or steps that are mutually exclusive.
Any feature disclosed in this specification (including any accompanying claims, abstract) may be replaced by alternative features serving equivalent or similar purposes, unless expressly stated otherwise. That is, unless expressly stated otherwise, each feature is only an example of a generic series of equivalent or similar features.
In the description of the present invention, it is to be understood that the terms "upper", "lower", "left", "right", and the like, indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience in describing the present invention and simplifying the description, but do not indicate or imply that the referred devices or elements must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present invention.
Furthermore, the terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first," "second," etc. may explicitly or implicitly include one or more of that feature.
Example 1
As shown in fig. 2 to 5, a pre-tensioning prestressed hollow slab polystyrene internal mold comprises an internal mold upper end surface 1, an internal mold lower end surface 2, an internal mold side end surface 3, an internal mold bottom surface 4 and an internal mold top surface 5; the inner die is in an octagonal prism shape as a whole, the inner die bottom surface 4 and the inner die top surface 5 are respectively arranged on the top surface and the bottom surface of the octagonal prism inner die, the inner die bottom surface 4 and the inner die top surface 5 are in an octagonal structure, and the inner die upper end surface 1, the inner die lower end surface 2 and the inner die side end surface 3 are respectively arranged on the octagonal inner die surface;
the internal mold is integrally formed by pouring polystyrene, so that the cost can be effectively reduced, and the internal mold has certain strength.
The inner die comprises an inner die and is characterized in that the upper end face 1 of the inner die, the lower end face 2 of the inner die, the side end face 3 of the inner die, the bottom face 4 of the inner die and the top face 5 of the inner die are respectively provided with a fiber yarn 6, the fiber yarns 6 are embedded into the inner surface of each end face, and the strength of each end face is increased through the fiber yarns 6, so that the structural integrity of each end face can be ensured when each end face is impacted;
all be provided with the spacing groove under centre form up end 1, the centre form on terminal surface 2, the centre form side end face 3, because when using the polystyrene centre form, need pour the polystyrene centre form, because the pouring of cement produces the slip when pouring in order to prevent the polystyrene centre form, and required needs are fixed the polystyrene centre form, in this application, will all be provided with the spacing groove on each terminal surface of polystyrene centre form and die cavity contact, can be very convenient fix the polystyrene centre form through the spacing groove.
The spacing groove includes a plurality of spacing 7, a plurality of spacing 7 set up side by side, spacing 7 indent setting down, and the junction smooth transition on spacing groove and centre form up end 1, centre form lower extreme face 2, centre form side end face 3.
When using, place the polystyrene centre form and pour the die cavity, then sink into spacing 7 through buckling the reinforcing bar in, fix the polystyrene centre form, prevent the removal of polystyrene centre form.
Example 2
A construction method of a pre-tensioning prestressed hollow slab polystyrene internal mold comprises the following steps: the method specifically comprises the following steps:
the first step is as follows: cleaning a pedestal, coating a release agent on the pedestal, manufacturing a steel reinforcement framework on a jig frame, hoisting the steel reinforcement framework to the pedestal, and paving a steel strand at the bottom of the steel reinforcement framework;
step two: preparing an anchor clamp, arranging the anchor clamp at the two ends of the tensioning pedestal, and binding stirrups and constructing reinforcing steel bars; tensioning the steel strand through a jack:
step three: side molds are arranged on the left side and the right side of the steel reinforcement framework; after bottom plate concrete is poured, the polystyrene inner mold is placed into the steel bar framework to be used as the inner mold, the polystyrene inner mold is not taken out any more, and the inner mold is ensured not to float upwards in the process of pouring web plate and top plate concrete;
step four: maintaining the pre-tensioned beam concrete, dismantling the side mold after the concrete reaches the strength required by the specification, releasing the tension force of the jack, releasing the prestress, gradually cutting the beam on the same line from the releasing end to the other end, and then moving and storing the beam
The method utilizes the polystyrene inner template pre-embedded in the hollow slab without taking out, reduces the procedures (such as the procedures of installing and detaching the inner mold and the end-capping head) of the traditional construction process on the premise of ensuring the size of the hollow slab, ensures the thickness of the protective layer of the reinforcing steel bar and the quality of concrete, greatly saves labor cost and shortens the construction period.
And in the third step, the smooth surface of the side template is ensured when the side template is placed, rust is avoided, the height difference of the joint of the template and the plate is controlled within 2mm, and the gap of the template is welded and polished to be smooth. In order to ensure that the thickness of the reinforced concrete protective layer meets the design requirement, high-grade cushion blocks penetrate through the longitudinal steel bars, and the cushion blocks of the bottom plate are arranged at intervals;
tensioning is strictly carried out according to tensioning force provided by technicians and pressure gauge data during tensioning, double control is carried out through elongation, when the deviation between the actual elongation and the theoretical elongation is more than 6%, or the conditions of wire slipping, wire breaking and the like occur, tensioning is immediately stopped, and tensioning can be carried out again after reason searching treatment; safety baffles are placed at two ends during tensioning, tensioning personnel are arranged on the side face of the beam end, and standing personnel are forbidden at the front face of the beam end; adopting an intelligent tensioning and pushing jack to tension the steel strand;
in the first step, when the prestressed reinforcement framework is manufactured, the reinforcement is processed in a reinforcement processing workshop and then is transported to a site to be bound and formed according to the requirements of a drawing; manufacturing a steel bar by adopting a numerical control bending machine;
in the third step: when concrete is manufactured, concrete mixture is uniformly mixed, the color is consistent, the slump is controlled to be 100-140 mm, and the concrete cannot be used due to overlarge slump, segregation and bleeding; the stirring time of the concrete should be controlled to be more than 2.5 minutes.
During pouring, layered blanking and horizontal layered continuous pouring are carried out, the thickness of each layer is not more than 30cm, the upper-layer concrete can be poured after the lower-layer concrete is vibrated to be compact, and the good compactness of the concrete is ensured;
when the polystyrene internal mold is fixed; before the polystyrene internal mold is put into the mold each time, whether the polystyrene internal mold is deformed or damaged is checked before the polystyrene internal mold is put into the mold each time; meanwhile, 16-diameter steel bar hooks with the interval of 1m are arranged for fixing and preventing the polystyrene internal mold from shifting and floating; steel pipe pressing bars with the spacing of 1m are arranged on the outer die, and a wood board with the thickness of 1cm and the thickness of 10 cm-15 cm is arranged under the pressing bar and pressed on the polystyrene inner die.
After the shaped polystyrene foam model is fixed, pouring concrete on the side surface and the top surface immediately; when pouring, each layer of symmetrical lower concrete on both sides of the polystyrene internal mold is not more than 30cm thick, the vibrator is vertically inserted into the concrete and is inserted to the bottom concrete by 50mm, but the vibrator is prevented from colliding with reinforcing steel bars and other embedded parts, and particularly the polystyrene internal mold cannot be touched so as to avoid damaging the polystyrene internal mold; the insertion points are arranged in a staggered mode, the moving distance is 1.5 times of the radius of the vibration action, the distance between the insertion points and the side die is kept between 50mm and 100mm, after each position is vibrated, the vibrating rod is lifted out slowly while vibrating, bubbles are expelled from the bottom and the side face, particularly the groove joint of the beam and the horseshoe part of the side plate are strengthened and vibrated, and the honeycomb pitted surface is prevented from being formed after forming; when the concrete stops sinking and no air bubble appears, the surface is flat and slurry is spread, the concrete is smeared, compacted and smoothed by wood, and after slurry is to be settled, the concrete is smeared for the second time and is napped, so that the concrete is combined with a bridge deck pavement layer. The whole pouring process should be continuously carried out, for example, when the concrete pouring is interrupted, the interruption time should be controlled within the initial setting time of the poured concrete;
after the concrete is initially set, covering the concrete with a wet gunny bag and felt cloth as soon as possible, and frequently watering and maintaining the concrete for more than 7 days by using an automatic spraying system so as to keep the surface of the concrete in a wet state as a standard; pouring concrete in hot summer, wherein drying cracks are easy to occur, concrete curing is enhanced according to the temperature and humidity of air, the variety of cement, the mixed additive and the like, and water is poured once every half hour; during winter construction, automatic steam curing equipment is adopted for steam curing after covering, and temperature control is carried out according to related requirements of winter construction;
by maintaining the concrete, the surface of the concrete is maintained at proper temperature and humidity, the interior is fully hydrated, and the strength of the concrete is continuously increased.
When the strength of the concrete reaches more than 85% of the designed strength, the age of the concrete is not less than 7 days, and the elastic modulus is not less than 80% of the 28d elastic modulus of the concrete, the concrete can be expanded; before the tension is released, the side die and the flange template which limit the displacement are firstly dismantled; when the tension is released, two 250T jacks are adopted for releasing the tension integrally; installing a screw coupler, tensioning and finish rolling twisted steel and a movable cross beam; the jack is fed with oil, the movable cross beam is jacked by the jack, so that the bolt screwed on the fixed cross beam can be loosened, the fixed bolt is unscrewed, and the jack is slowly unloaded, namely the tension releasing work is completed; and (5) dismantling various cross beams, connecting devices and jacks, and moving to another line for construction.
When cutting the steel strand, the cut is close to the component. Cutting off the steel wire from the middle by using a grinding wheel cutting machine after the steel wire is released, and ensuring the distance of more than 10cm from the member during cutting. Before hoisting, cutting by using a grinder, and brushing the exposed steel strand at the cutting position with antirust paint. The beams on the same line are cut from the end of the flare to the other end one by one. And (4) brushing antirust paint at two ends of the steel strand to prevent rust.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.
Claims (10)
1. The utility model provides a pretensioning prestressing force cored slab polystyrene centre form which characterized in that: comprises an inner mold upper end surface, an inner mold lower end surface, an inner mold side end surface, an inner mold bottom surface and an inner mold top surface; the inner die is in an octagonal prism shape on the whole, the bottom surface of the inner die and the top surface of the inner die are arranged on the top surface and the bottom surface of the octagonal prism inner die respectively, the bottom surface of the inner die and the top surface of the inner die are in an octagonal structure, and the upper end surface of the inner die, the lower end surface of the inner die and the side end surface of the inner die are arranged on the inner die surface in the octagonal shape respectively.
2. The internal mold of pretensioned prestressing hollow slab polystyrene as claimed in claim 1, wherein: and the upper end face of the inner die, the lower end face of the inner die, the side end face of the inner die, the bottom face of the inner die and the top face of the inner die are all provided with fiber yarns.
3. A construction method of a pre-tensioning prestressed hollow slab polystyrene internal mold comprises the following steps: the method is characterized in that: the method comprises the following steps:
the method comprises the following steps: cleaning a pedestal, coating a release agent on the pedestal, manufacturing a steel reinforcement framework on a jig frame, hoisting the steel reinforcement framework to the pedestal, and paving a steel strand at the bottom of the steel reinforcement framework;
step two: preparing an anchor clamp, arranging the anchor clamp at the two ends of the tensioning pedestal, and binding stirrups and constructing reinforcing steel bars; tensioning the steel strand through a jack:
step three: side molds are arranged on the left side and the right side of the steel reinforcement framework; after bottom plate concrete is poured, the polystyrene inner mold is placed into the steel bar framework to be used as the inner mold, the polystyrene inner mold is not taken out any more, and the inner mold is ensured not to float upwards in the process of pouring web plate and top plate concrete;
step four: and curing the pre-tensioned beam concrete, dismantling the side mold after the concrete reaches the strength required by the specification, releasing the tension force of the jack, releasing the prestress, gradually cutting the beam on the same line from the releasing end to the other end, and then moving and storing the beam.
4. The construction method of the pre-tensioned prestressed hollow slab polystyrene inner formwork as claimed in claim 3, characterized in that: and in the third step, the smooth surface of the side template is ensured when the side template is placed, rust is avoided, the height difference of the joint of the template and the plate is controlled within 2mm, and the gap of the template is welded and polished to be smooth.
5. The construction method of the pre-tensioned prestressed hollow slab polystyrene inner formwork as claimed in claim 3, characterized in that: in the second step, tensioning is strictly carried out according to the tensioning force and pressure gauge data provided by technicians, double control is carried out through the elongation, when the deviation between the actual elongation and the theoretical elongation is more than 6 percent, or the conditions of yarn slipping, yarn breaking and the like occur, tensioning is immediately stopped, and tensioning can be carried out again after reason searching treatment; and during tensioning, safety baffles are arranged at two ends, and a tensioning person adopts an intelligent tensioning and pushing jack to tension the steel strand on the side surface of the beam end.
6. The construction method of the pre-tensioned prestressed hollow slab polystyrene inner formwork as claimed in claim 3, characterized in that: in the third step: when concrete is manufactured, concrete mixture is uniformly mixed, the color is consistent, the slump is controlled to be 100-140 mm, and the concrete cannot be used due to overlarge slump, segregation and bleeding; the stirring time of the concrete should be controlled to be more than 2.5 minutes.
7. The construction method of the pre-tensioned prestressed hollow slab polystyrene inner formwork as claimed in claim 6, characterized in that: during pouring, layered blanking and horizontal layered continuous pouring are carried out, the thickness of each layer is not more than 30cm, and the upper-layer concrete can be poured after the lower-layer concrete is vibrated to be compact so as to ensure that the concrete has good compactness.
8. The construction method of the pre-tensioned prestressed hollow slab polystyrene inner formwork as claimed in claim 3, characterized in that: when the polystyrene internal mold is fixed; a 16-diameter steel bar hook with the distance of 1m is arranged for fixing and preventing the polystyrene internal mold from shifting and floating; steel pipe pressing bars with the spacing of 1m are arranged on the outer die, and a wood board with the thickness of 1cm and the thickness of 10 cm-15 cm is arranged under the pressing bar and pressed on the polystyrene inner die.
9. The construction method of the pre-tensioned prestressed hollow slab polystyrene inner formwork as claimed in claim 3, characterized in that: after the polystyrene internal mold is fixed, concrete on the side surface and the top surface is poured immediately; when pouring, each layer of symmetrical concrete on two sides of the polystyrene internal mold is filled, the thickness of each layer is not more than 30cm, the vibrator is vertically inserted into the concrete and is inserted into the bottom concrete by 50mm, the collision of reinforcing steel bars, the polystyrene internal mold and other embedded parts is avoided, the insertion points are arranged in a staggered mode, the moving distance is 1.5 times of the vibration action radius, the distance between the vibrator and the side mold is kept by 50-100 mm, after each position is vibrated, the vibrating rod is slowly lifted out while vibrating, bubbles are expelled from the bottom and the side, particularly, the vibration is strengthened at the rabbet joints of the beam and the horseshoe part of the side plate, and the honeycomb pitted surface is prevented from being formed after molding; when the concrete stops sinking and no air bubble appears, the surface is flat and slurry is spread, the concrete is smeared, compacted and smoothed by wood, and after slurry is to be settled, the concrete is smeared for the second time and is napped, so that the concrete is combined with a bridge deck pavement layer.
10. The construction method of the pre-tensioned prestressed hollow slab polystyrene inner formwork as claimed in claim 3, characterized in that: when the strength of the concrete reaches more than 85% of the designed strength, the age of the concrete is not less than 7 days, and the elastic modulus is not less than 80% of the 28d elastic modulus of the concrete, the concrete can be expanded; before the tension is released, the side die and the flange template which limit the displacement are firstly dismantled; when the tension is released, two 250T jacks are adopted for releasing the tension integrally; installing a screw coupler, tensioning and finish rolling twisted steel and a movable cross beam; the jack is fed with oil, the movable cross beam is jacked by the jack, so that the bolt screwed on the fixed cross beam can be loosened, the fixed bolt is unscrewed, and the jack is slowly unloaded, namely the tension releasing work is completed; and (5) dismantling various cross beams, connecting devices and jacks, and moving to another line for construction.
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Application publication date: 20201110 |