CN114458018A - Prestress construction method - Google Patents
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- CN114458018A CN114458018A CN202210181175.1A CN202210181175A CN114458018A CN 114458018 A CN114458018 A CN 114458018A CN 202210181175 A CN202210181175 A CN 202210181175A CN 114458018 A CN114458018 A CN 114458018A
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- 238000010276 construction Methods 0.000 title claims abstract description 41
- 230000002787 reinforcement Effects 0.000 claims abstract description 102
- 239000004567 concrete Substances 0.000 claims abstract description 49
- 238000007789 sealing Methods 0.000 claims abstract description 10
- 238000009434 installation Methods 0.000 claims abstract description 6
- 238000004519 manufacturing process Methods 0.000 claims abstract description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 25
- 239000003822 epoxy resin Substances 0.000 claims description 4
- 239000003973 paint Substances 0.000 claims description 4
- 229920000647 polyepoxide Polymers 0.000 claims description 4
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- 238000009415 formwork Methods 0.000 claims description 3
- 238000009435 building construction Methods 0.000 abstract description 2
- 229910000831 Steel Inorganic materials 0.000 description 17
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- 230000003014 reinforcing effect Effects 0.000 description 5
- 238000005336 cracking Methods 0.000 description 4
- 230000008569 process Effects 0.000 description 4
- 229910001294 Reinforcing steel Inorganic materials 0.000 description 3
- 230000002411 adverse Effects 0.000 description 3
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- 230000009977 dual effect Effects 0.000 description 3
- 230000005489 elastic deformation Effects 0.000 description 3
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- 238000005452 bending Methods 0.000 description 2
- 238000005520 cutting process Methods 0.000 description 2
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- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04G—SCAFFOLDING; FORMS; SHUTTERING; BUILDING IMPLEMENTS OR AIDS, OR THEIR USE; HANDLING BUILDING MATERIALS ON THE SITE; REPAIRING, BREAKING-UP OR OTHER WORK ON EXISTING BUILDINGS
- E04G21/00—Preparing, conveying, or working-up building materials or building elements in situ; Other devices or measures for constructional work
- E04G21/12—Mounting of reinforcing inserts; Prestressing
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Abstract
The invention discloses a prestress construction method, which relates to the technical field of building construction and comprises the following steps: s1: manufacturing and installing prestressed reinforcements, and pouring concrete after the installation is finished; s2: after pouring is finished, calculating and determining the elongation value of the prestressed reinforcement on each beam and the prestress to be applied; s3: when the strength of the cast concrete reaches a threshold value, stretching prestressed reinforcements on each beam or a plurality of beams in batches; s4: grouting the corrugated pipe after tensioning is finished; s5: and after grouting is finished, sealing the anchor by using prestressed reinforcement. By adopting the scheme, the prestress can be controlled in batches and tensioned, and the prestress tensioned every time and the elongation value of the prestressed reinforcement are controlled, so that the structure has good crack resistance and large rigidity, the durability of the structure is improved, and the construction period is shortened.
Description
Technical Field
The invention relates to the technical field of building construction, in particular to a prestress construction method.
Background
The reinforced concrete structure has wide application range in civil engineering, and various engineering structures can be built by reinforced concrete. However, for a common reinforced concrete structure with a long span and an ultra-long structure, the concrete has the characteristics of great inherent weight, low tensile strength and easiness in cracking, and adverse effects of concrete shrinkage and temperature change on a concrete beam plate result in great construction difficulty, waste of a large amount of manpower and material resources and increase of a construction period.
Therefore, a new construction method is needed to solve this problem.
Disclosure of Invention
The invention aims to provide a prestress construction method, by adopting the scheme, the structure has good crack resistance and high rigidity by controlling the stretching prestress and the elongation value of the prestressed reinforcement, the durability of the structure is improved, and the construction period is shortened.
The invention is realized by the following technical scheme:
a prestress construction method comprises the following steps:
s1: manufacturing and installing prestressed reinforcements, and pouring concrete after the installation is finished;
s2: after pouring is finished, calculating and determining the elongation value of the prestressed reinforcement on each beam and the prestress to be applied;
s3: when the strength of the cast concrete reaches a threshold value, stretching prestressed reinforcements on each beam or a plurality of beams in batches;
s4: grouting the corrugated pipe after tensioning is finished;
s5: and after grouting is finished, sealing the anchor by using prestressed reinforcement.
Compared with the prior art, for a common reinforced concrete structure with a large-span and ultra-long structure, the prestressed construction method has the advantages that the prestressed construction method has the characteristics of self-weight, low tensile strength and easiness in cracking, and the adverse influence of concrete shrinkage and temperature change on a concrete beam plate is solved; specifically, firstly, prestressed reinforcements are required to be manufactured and installed, the reinforcements are required to be linearly arranged according to requirements strictly, the height of each control point in the vertical direction is ensured to meet the design requirements, a curve is required to be smooth, the positions of reverse bending points are constructed according to a graph, wherein the prestressed reinforcements of the beams are symmetrically or centrally arranged in the cross section of the beam, after the installation is finished, concrete is poured, before the concrete is poured, a detailed pouring scheme is formulated to ensure that the concrete on the inner side of an anchor backing plate is compact, after the pouring is finished, due to the fact that the construction time of the prestressed reinforcements on each beam is different, the elongation value of the prestressed reinforcements on each beam and the prestress to be applied need to be calculated and determined, the prestressed reinforcements are tensioned in batches, the prestress for tensioning of each bundle of prestressed reinforcements in the first batch is the same, the prestress for tensioning each bundle of prestressed reinforcements in the second batch is the same, and by analogy, the tension force is respectively determined, the influence of elastic deformation of structural members generated by batch tensioning of the prestressed reinforcements on the tensioning of the prestressed reinforcements in the first batch is avoided; when the strength of the cast concrete reaches a threshold value, the prestressed reinforcement begins to be tensioned, wherein the threshold value is that the strength of the concrete reaches more than 80%; grouting the reserved corrugated pipe after tensioning is finished, and sealing the anchor by using prestressed steel bars after grouting is finished; the prestressed reinforcement is tensioned to enable the concrete with the section to obtain the pre-stress, the reinforcement and the concrete are combined into a whole to obtain the bonded prestressed concrete, and the prestressed concrete is tensioned in batches by controlling the prestress, so that the structure has good crack resistance and large rigidity, the durability of the structure is improved, and the construction period is shortened.
Further optimization, the prestress applied to one or more beams of prestressed reinforcement on each beam should be uniform and consistent; the prestress applying device is used for applying the same prestress to one or more bundles of prestress steel bars in the same batch, and the condition that the stress state which is unfavorable for the structure does not occur in each stage is ensured.
Further optimizing, when prestress is applied to the prestressed steel bars, the actual elongation values of the prestressed steel bars do not exceed +/-6% of the calculated elongation values; in the scheme, the prestressed tensioning is carried out by adopting a stress and strain dual control method, the stress control is taken as a main method, the elongation value is used for checking, the elongation value of the prestressed reinforcement is calculated or trial-drawn before tensioning is carried out, if the actual elongation value of the prestressed reinforcement exceeds the range of +/-6% of the calculated elongation value during tensioning, the tensioning is stopped, and the tensioning can be continued after the reason is found.
Further optimizing, when prestress is applied to the prestressed reinforcement, the actual tension prestress of the prestressed reinforcement is not more than +/-5% of the calculated prestress; in this scheme, prestressed beam adopts one end or both ends stretch-draw, and the effective prestressing force of prestressing force reinforcing bar after the design requirement stretch-draw is: when the linear rib beam and the two-span inner curve rib beam are tensioned, the final effective prestress of the structure is not less than 1050 MPa; when the curve reinforcing beam with more than two spans is tensioned, the final effective prestress of the maximum span of prestress loss is larger than or equal to 950 MPa. When the construction needs to be tensioned, the maximum tensioning stress should not be greater than 1.03 times the tensioning control force σ con. The relative deviation between the actually established prestress value after the prestressed reinforcement is tensioned and anchored and the design specified inspection value is not more than +/-5%.
Further preferably, the step S3 further includes the following sub-steps: when each beam is tensioned with prestressed reinforcement, the prestressed beam slab template arches according to 1 per mill of span, and the prestressed beam cantilever section arches according to 2 per mill of the length; preferably, when the net span of the prestressed beam is more than 12m, the template arches by 1 per mill of the span, and the overhanging section of the prestressed beam arches by 2 per mill of the length of the overhanging section, so that the stress requirement is met.
Further optimization, the side mold of the prestressed beam needs to be disassembled before tensioning, and the bottom mold of the prestressed beam needs to be disassembled after grouting is finished.
Further optimizing, reserving a corrugated pipe in the poured concrete, reserving a tensioning end grouting hole, a water intake pipe and a midspan grouting hole on the corrugated pipe, wherein the grouting hole is positioned at the end part of the prestressed reinforcement, the water intake pipe is positioned at the position close to the top of the corrugated pipe in each span, and the midspan grouting hole is positioned at the position of the bottom of the corrugated pipe in each span; in the scheme, a tensioning end grouting hole, a water seepage pipe and a midspan grouting hole are reserved on a reserved corrugated pipeline, and the tensioning end grouting hole is arranged at the end part of the prestressed reinforcement and reserved for an anchor backing plate; the corrugated pipe is also provided with a water seepage pipe, the water seepage pipe is arranged at the position close to the top of the corrugated pipe at each span, the water seepage pipe of the support in the curved pipe with more than two spans can be used as a grouting hole, and the middle-span grouting hole is positioned at the bottom of the corrugated pipe at each span.
Further preferably, the step S1 further includes the following sub-steps: before the prestressed reinforcement is installed, the bottom surface soil needs to be solidified so as to ensure that the prestressed girder does not generate support sinking before tensioning.
Further preferably, the step S5 further includes the following sub-steps: when the prestressed reinforcement is used for sealing the anchor, the prestressed reinforcement is coated with an anticorrosive paint before the post-cast strip is sealed and then is cast together with the concrete of the beam post-cast strip, the rest tensioning ends are embedded, and the anchor is embedded into the concrete structure.
Further optimized, the anchorage device is coated with anticorrosive epoxy resin.
Compared with the prior art, the invention has the following advantages and beneficial effects:
the invention provides a prestress construction method, which can control prestress in batches and stretch, control the prestress of each stretching and the elongation value of a prestressed reinforcement, ensure that the structure has good crack resistance and large rigidity, increase the durability of the structure and shorten the construction period;
drawings
In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the drawings that are required to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and that for those skilled in the art, other related drawings can be obtained from these drawings without inventive effort. In the drawings:
FIG. 1 is a schematic step diagram of a prestressed construction method according to the present invention;
fig. 2 is a schematic view of a prestressed reinforcement tensioning batch according to an embodiment of the present invention;
figure 3 is a schematic view of the linear positioning of the prestressed reinforcement in the beam according to an embodiment of the present invention;
FIG. 4 is a diagram of the placement of bellows in a beam according to one embodiment of the present invention.
Reference numbers and corresponding part names in the drawings:
1-corrugated pipe, 2-stretching end grouting hole, 3-water draining pipe and 4-midspan grouting hole.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to examples and accompanying drawings, and the exemplary embodiments and descriptions thereof are only used for explaining the present invention and are not meant to limit the present invention.
Example 1
The embodiment 1 provides a prestressed construction method, as shown in fig. 1, including the following steps:
s1: manufacturing and installing prestressed reinforcements, and pouring concrete after the installation is finished;
s2: after pouring is finished, calculating and determining the elongation value of the prestressed reinforcement on each beam and the prestress to be applied;
s3: when the strength of the cast concrete reaches a threshold value, stretching prestressed reinforcements on each beam or a plurality of beams in batches;
s4: after tensioning is finished, grouting the corrugated pipe 1;
s5: and after grouting is finished, sealing the anchor by using prestressed reinforcement.
Compared with the prior art, for a common reinforced concrete structure with a large-span and ultra-long structure, the prestressed construction method has the advantages that the prestressed construction method has the characteristics of self-weight, low tensile strength and easiness in cracking, and the adverse influence of concrete shrinkage and temperature change on a concrete beam plate is solved; specifically, firstly, prestressed reinforcements are required to be manufactured and installed, the reinforcements are required to be linearly arranged according to requirements strictly, the height of each control point in the vertical direction is ensured to meet the design requirements, a curve is required to be smooth, the positions of reverse bending points are constructed according to a graph, wherein the prestressed reinforcements of the beams are symmetrically or centrally arranged in the cross section of the beam, after the installation is finished, concrete is poured, before the concrete is poured, a detailed pouring scheme is formulated to ensure that the concrete on the inner side of an anchor backing plate is compact, after the pouring is finished, due to the fact that the construction time of the prestressed reinforcements on each beam is different, the elongation value of the prestressed reinforcements on each beam and the prestress to be applied need to be calculated and determined, the prestressed reinforcements are tensioned in batches, the prestress for tensioning of each bundle of prestressed reinforcements in the first batch is the same, the prestress for tensioning each bundle of prestressed reinforcements in the second batch is the same, and by analogy, the tension force is respectively determined, the influence of elastic deformation of structural members generated by batch tensioning of the prestressed reinforcements on the tensioning of the prestressed reinforcements in the first batch is avoided; when the strength of the cast concrete reaches a threshold value, the prestressed reinforcement begins to be tensioned, wherein the threshold value is that the strength of the concrete reaches more than 80%; grouting the reserved corrugated pipe 1 after tensioning is finished, and sealing the anchor by using prestressed steel bars after grouting is finished; the prestressed reinforcement is tensioned to enable the concrete with the section to obtain the pre-stress, the reinforcement and the concrete are combined into a whole to obtain the bonded prestressed concrete, and the prestressed concrete is tensioned in batches by controlling the prestress, so that the structure has good crack resistance and large rigidity, the durability of the structure is improved, and the construction period is shortened.
In this embodiment, the prestressing force applied to one or more bundles of prestressed reinforcements on each beam should be uniform and consistent; the prestress applying device is used for applying the same prestress to one or more bundles of prestress steel bars in the same batch, and the condition that the stress state which is unfavorable for the structure does not occur in each stage is ensured.
In the embodiment, when prestress is applied to the prestressed reinforcement, the actual elongation value of the prestressed reinforcement is not more than +/-6% of the calculated elongation value; in the scheme, the prestressed tensioning is carried out by adopting a stress and strain dual control method, the stress control is taken as a main method, the elongation value is used for checking, the elongation value of the prestressed reinforcement is calculated or trial-drawn before tensioning is carried out, if the actual elongation value of the prestressed reinforcement exceeds the range of +/-6% of the calculated elongation value during tensioning, the tensioning is stopped, and the tensioning can be continued after the reason is found.
In the embodiment, when prestress is applied to the prestressed reinforcement, the actual tension prestress of the prestressed reinforcement is not more than +/-5% of the calculated prestress; in this scheme, prestressed beam adopts one end or both ends stretch-draw, and the effective prestressing force of prestressing force reinforcing bar after the design requirement stretch-draw is: when the linear rib beam and the two-span inner curve rib beam are tensioned, the final effective prestress of the structure is not less than 1050 MPa; when the curve reinforcing beam with more than two spans is tensioned, the final effective prestress of the maximum span of prestress loss is larger than or equal to 950 MPa. When the construction needs to be tensioned, the maximum tensioning stress should not be greater than 1.03 times the tensioning control force σ con. The relative deviation between the actually established prestress value after the prestressed reinforcement is tensioned and anchored and the design specified inspection value is not more than +/-5%.
In this embodiment, the step S3 further includes the following sub-steps: when each beam is tensioned with prestressed reinforcement, the prestressed beam slab template arches according to 1 per mill of span, and the prestressed beam cantilever section arches according to 2 per mill of the length; preferably, when the net span of the prestressed beam is more than 12m, the template arches by 1 per mill of the span, and the overhanging section of the prestressed beam arches by 2 per mill of the length of the overhanging section, so that the stress requirement is met.
In this embodiment, the side form of the prestressed beam needs to be removed before tensioning, and the bottom form of the prestressed beam needs to be removed after grouting.
In the embodiment, a corrugated pipe 1 is reserved in poured concrete, a tensioning end grouting hole 2, a water draining pipe 3 and a midspan grouting hole 4 are reserved on the corrugated pipe 1, the grouting holes are located at the ends of prestressed reinforcements, the water draining pipe 3 is located at the position close to the top of the corrugated pipe 1 in each span, and the midspan grouting hole 4 is located at the position of the bottom of the corrugated pipe 1 in each span; in the scheme, a tensioning end grouting hole 2, a water seepage pipe 3 and a midspan grouting hole 4 are reserved on a reserved corrugated pipe 1, and the tensioning end grouting hole 2 is arranged at the end part of a prestressed reinforcement and reserved for an anchor backing plate; the corrugated pipe 1 is also provided with a water intake pipe 3, the water intake pipe 3 is arranged at the position close to the top of the corrugated pipe 1 at each span, the water intake pipe 3 of the support in the curved pipe with more than two spans can be used as a grouting hole, and the span center grouting hole 4 is arranged at the bottom of the corrugated pipe 1 at each span.
In this embodiment, the step S1 further includes the following sub-steps: before the prestressed reinforcement is installed, the bottom surface soil needs to be solidified so as to ensure that the prestressed girder does not generate support sinking before tensioning.
In this embodiment, the step S5 further includes the following sub-steps: when the prestressed reinforcement is used for sealing the anchor, the prestressed reinforcement is coated with an anticorrosive paint before the post-cast strip is sealed and then is cast together with the concrete of the beam post-cast strip, the rest tensioning ends are embedded, and the anchor is embedded into the concrete structure.
In this embodiment, the anchor is coated with an anti-corrosive epoxy resin.
Example 2
The embodiment 2 is further optimized based on the embodiment 1, and as shown in fig. 2 to fig. 4, a specific implementation is provided, which includes the following specific steps:
(1) and manufacturing and installing prestressed reinforcements.
Firstly, when the reinforcing steel bars are prestressed, construction is strictly carried out according to a drawing, and the quantity, the quality and the types of the reinforcing steel bars must meet the requirements of the drawing and relevant national standards.
And secondly, linearly arranging ribs strictly according to design requirements, ensuring that the height of each control point in the vertical direction meets the design requirements, smoothing a curve, and constructing the position of a reverse bend point according to a graph. The prestressed reinforcement positioning structure is shown in detail in fig. 3.
Thirdly, when the reinforcement is laid, the reinforcement must be closely matched with the specialties of water, electricity, warm water and the like, and the vertical position of the prestressed reinforcement is prevented from being influenced by an electric pipeline, an upper water pipeline and a lower water pipeline as much as possible.
And fourthly, the anchorage devices and the bearing plates at the tensioning end and the fixed end are reliably fixed, and the tensioning line is kept to be vertical to the surface of the bearing plate.
Fifthly, carefully checking the corrugated pipe 1 after the steel bars are bound, and timely repairing the corrugated pipe if the corrugated pipe is damaged; if welding work is carried out during the lengthening of the common steel bars, the prestressed steel bars and the corrugated pipe 1 are strictly forbidden to be burnt.
Sixthly, the beam prestressed steel bars are symmetrically or centrally arranged in the beam section, and when the positioning of the common steel bars and the prestressed steel bars is contradictory, the position of the common steel bars is adjusted by negotiation with the design so as to ensure the position and the shape of the prestressed steel bars.
And seventhly, when the row spacing of the prestressed steel strand bundles is small or the beam column stirrups are dense, welding reinforcing steel bar meshes to the spiral reinforcements under the anchorage device, and checking and calculating the local bearing capacity.
When tension grooves need to be reserved on the beam surface and the beam side, a prestress construction unit needs to provide a tension groove arrangement scheme according to a tension process, variable angle tension machine conditions and the like, and construction can be carried out after the design unit approves.
(2) And the pouring of the prestressed concrete.
Firstly, a detailed pouring scheme should be formulated before concrete pouring, and particularly effective measures should be taken to ensure that the concrete inside the anchor backing plate is dense aiming at the concrete at the tensioning end or the fixed end of the edge of the post-pouring belt, so that the phenomena of cavities, honeycombs, pitted surfaces, bubbles and the like are avoided.
Secondly, when concrete is poured, vibration is carefully vibrated, leakage vibration is strictly prohibited, and the vibrator is prevented from directly colliding the prestressed corrugated pipe 1 and the anchorage device.
And thirdly, after the concrete pouring is finished, besides the concrete test blocks are reserved according to the construction specification requirements, two groups of test blocks are additionally reserved for carrying out maintenance under the same condition so as to determine the tensioning date.
(2) And tensioning the prestressed reinforcement:
first, the prestressed reinforcement tensioning control stress σ con is 1395MPa (0.75fptk), the prestressed tensioning is performed by a dual control method of stress and strain, and the stress control is mainly used and the strain (elongation value) is used for checking. And calculating or trying to pull to determine the elongation value of the prestressed reinforcement before tensioning. If the actual elongation value of the prestressed reinforcement exceeds the calculated elongation value +/-during tensioning
And in the range of 6%, the tensioning is stopped, and the tensioning can be continued after the reason is found.
Secondly, the prestressed beam is stretched at one end or two ends, and the effective prestress of the prestressed reinforcement after the stretching is required to be: when the linear rib beam and the two-span inner curve rib beam are tensioned, the final effective prestress of the structure is not less than 1050 MPa; when the curve reinforcing beam with more than two spans is tensioned, the final effective prestress of the maximum span of prestress loss is larger than or equal to 950 MPa. When the construction needs to be tensioned, the maximum tensioning stress should not be greater than 1.03 times the tensioning control force σ con. The relative deviation between the actually established prestress value after the prestressed reinforcement is tensioned and anchored and the design specified inspection value is not more than +/-5%.
Thirdly, tensioning construction follows the symmetry principle; the longitudinal and transverse beams are correspondingly tensioned simultaneously, and a plurality of beams of prestressed reinforcements on the same beam are suitable for being tensioned synchronously. The tensioning process should ensure that the stress of each prestressed reinforcement in the same beam or multiple beams in the same beam is uniform and consistent.
And fourthly, when the tensioning is carried out bundle by bundle, the condition that the stress state which is unfavorable for the structure does not appear in each stage is ensured, meanwhile, the influence of the elastic deformation of the structural member generated by the tensioning of the prestressed steel bars in the later batch on the tensioning of the prestressed steel bars in the earlier batch is considered, and the tensioning force is respectively determined.
And fifthly, observing deformation and cracks of the beam during tensioning, stopping tensioning immediately and informing a design unit if abnormal conditions such as the degree of disturbance or excessive cracking occur, and continuing to tension after analysis and treatment.
Sixthly, strictly making recording work in the process of prestress tensioning.
(4) And the requirements of the prestressed beam and the slab template are as follows:
firstly, when the net span of the prestressed beam is more than 12m, the template arches according to 1 per mill of the span; 2 per mill of the cantilever section of the prestressed beam according to the length of the cantilever section
And (4) arching.
Secondly, the formwork system of the prestressed beam slab needs to perform solidification treatment on bottom surface soil and then can support the formwork so as to ensure that the prestressed girder does not generate support sinking before tensioning.
And thirdly, the side mold of the prestressed beam is dismantled before tensioning, and the bottom mold can be dismantled after tensioning and grouting are finished and the grouting strength reaches 30 MPa.
(5) And the prestressed reinforcement pore and grouting requirements are as follows:
firstly, when a corrugated pipe 1 is reserved, a grouting hole and a water draining pipe 3 (also serving as an exhaust pipe) are reserved, as shown in fig. 4. Grouting holes should be formed in the end portions of the prestressed reinforcements (reserved anchor backing plates), and when the distance between grouting holes is larger than 12m, grouting hole guide pipes should be additionally arranged in the span. The water pipes 3 are preferably arranged in the area which is 500-1000 mm away from the column side and is close to the top of the pipeline in each span, and the water pipes 3 of the curved pipeline inner support with more than two spans can be used as grouting holes.
Secondly, the grouting hole and the water intake pipe 3 (also used as an exhaust pipe) are tightly connected with the corrugated pipe 1, and slurry leakage is strictly prohibited. When pure cement slurry overflows from each water intake pipe 3 in the grouting process, the water intake pipes 3 are blocked one by one, and then the whole corrugated pipe 1 is subjected to one-time grouting repair, which can be regarded as the completion of the grouting. After grouting, the pore canal should be closed, and the area of the beam end is preferably cast by fine stone concrete.
Thirdly, the grouting of the pore canal of the prestressed concrete is carried out at normal temperature, and the grouting strength of the prestressed concrete can not be frozen until reaching 25 MPa.
(6) And the requirement of sealing the anchor by the prestressed reinforcement:
firstly, the anchor head at the inner tensioning end of the side beam of the post-cast strip does not need to be specially sealed, and the post-cast strip is coated with an anticorrosive paint before being sealed and then is poured together with the concrete of the post-cast strip of the beam; the other tension ends are embedded, and the anchorage device is embedded in the concrete structure.
And secondly, cutting an exposed part after the prestressed reinforcement is anchored by adopting a mechanical method, and strictly prohibiting adopting electric arc cutting. The exposed length of the prestressed reinforcement is not less than 1.5 times of the diameter, and not less than 30 mm.
Thirdly, before the anchor is sealed, the tensioning end and the periphery thereof are washed clean and roughened, and special anticorrosive epoxy resin is coated on the anchor.
Fourthly, adopting C40 micro-expansion fine stone concrete to seal the anchor, and adopting a certain measure to ensure the compactness of the concrete.
The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are merely exemplary embodiments of the present invention, and are not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.
Claims (10)
1. A prestress construction method is characterized by comprising the following steps:
s1: manufacturing and installing prestressed reinforcements, and pouring concrete after the installation is finished;
s2: after pouring is finished, calculating and determining the elongation value of the prestressed reinforcement on each beam and the prestress to be applied;
s3: when the strength of the cast concrete reaches a threshold value, stretching prestressed reinforcements on each beam or a plurality of beams in batches;
s4: after tensioning is finished, grouting the corrugated pipe (1);
s5: and after grouting is finished, sealing the anchor by using prestressed reinforcement.
2. A prestressed construction method according to claim 1, characterized in that the prestress applied to the one or more prestressed reinforcement strands of each girder is uniform.
3. The prestressed construction method as claimed in claim 1, wherein the actual elongation of the prestressed reinforcement is not more than ± 6% of the calculated elongation when the prestressed reinforcement is prestressed.
4. The prestressed construction method as claimed in claim 1, wherein the actual tension prestress of the prestressed reinforcement is not more than ± 5% of the calculated prestress when the prestress is applied to the prestressed reinforcement.
5. The prestressed construction method according to claim 1, wherein said step S3 further comprises the substeps of: when each beam is tensioned with prestressed reinforcement, the prestressed beam slab formwork arches according to 1 per mill of span, and the prestressed beam cantilever section arches according to 2 per mill of the length.
6. The prestressed construction method according to claim 1, wherein the side forms of the prestressed girder are disassembled before tensioning, and the bottom form of the prestressed girder is disassembled after grouting.
7. The prestressed construction method according to claim 1, characterized in that a corrugated pipe (1) is reserved in the poured concrete, a tensioning end grouting hole (2), a water intake pipe (3) and a midspan grouting hole (4) are reserved on the corrugated pipe (1), the grouting hole (2) is located at the end of the prestressed reinforcement, the water intake pipe (3) is located at the position close to the top of the corrugated pipe (1) at each span, and the midspan grouting hole (4) is located at the position at the bottom of the corrugated pipe (1) at each span.
8. The prestressed construction method according to claim 1, wherein said step S1 further comprises the substeps of: before the prestressed reinforcement is installed, the bottom surface soil needs to be solidified.
9. The prestressed construction method according to claim 1, wherein said step S5 further comprises the substeps of: when the prestressed reinforcement is used for sealing the anchor, the prestressed reinforcement is coated with an anticorrosive paint before the post-cast strip is sealed and then is cast together with the concrete of the beam post-cast strip, the rest tensioning ends are embedded, and the anchor is embedded into the concrete structure.
10. The prestressed construction method of claim 9, wherein said anchor is coated with an anti-corrosive epoxy resin.
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115199048A (en) * | 2022-07-21 | 2022-10-18 | 中亿丰建设集团股份有限公司 | Large-span prestressed beam invagination type one-time tensioning process |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6105321A (en) * | 1998-10-19 | 2000-08-22 | Karisallen; Kenneth James | Prestressed wood composite laminate |
| CN101550724A (en) * | 2009-04-29 | 2009-10-07 | 中铁十局集团有限公司 | Construction method of large-span post-tensioned prestressed longitudinal and transverse frame beams |
| CN106607989A (en) * | 2016-12-21 | 2017-05-03 | 济南轨道交通集团有限公司 | Rail transit post-stressed U-shaped beam construction technique |
| CN111797458A (en) * | 2020-07-17 | 2020-10-20 | 浙江瓯越交建科技股份有限公司 | Pre-stress batch tensioning control method for zero inverted arch of early-age precast concrete structure |
| CN112647706A (en) * | 2020-07-28 | 2021-04-13 | 安宜建设集团有限公司 | Construction method for long-span concrete beam slow-bonding prestress |
-
2022
- 2022-02-25 CN CN202210181175.1A patent/CN114458018A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6105321A (en) * | 1998-10-19 | 2000-08-22 | Karisallen; Kenneth James | Prestressed wood composite laminate |
| CN101550724A (en) * | 2009-04-29 | 2009-10-07 | 中铁十局集团有限公司 | Construction method of large-span post-tensioned prestressed longitudinal and transverse frame beams |
| CN106607989A (en) * | 2016-12-21 | 2017-05-03 | 济南轨道交通集团有限公司 | Rail transit post-stressed U-shaped beam construction technique |
| CN111797458A (en) * | 2020-07-17 | 2020-10-20 | 浙江瓯越交建科技股份有限公司 | Pre-stress batch tensioning control method for zero inverted arch of early-age precast concrete structure |
| CN112647706A (en) * | 2020-07-28 | 2021-04-13 | 安宜建设集团有限公司 | Construction method for long-span concrete beam slow-bonding prestress |
Non-Patent Citations (2)
| Title |
|---|
| 姚敏利等: "16.2m跨度有黏结钢丝束预应力梁的施工工艺", 《黑龙江水利科技》, vol. 35, no. 3, pages 167 * |
| 朱浪涛: "《建筑结构》", 重庆大学出版社, pages: 195 - 196 * |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115199048A (en) * | 2022-07-21 | 2022-10-18 | 中亿丰建设集团股份有限公司 | Large-span prestressed beam invagination type one-time tensioning process |
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