CN116674079A - Construction method of prefabricated small box girder - Google Patents
Construction method of prefabricated small box girder Download PDFInfo
- Publication number
- CN116674079A CN116674079A CN202310871042.1A CN202310871042A CN116674079A CN 116674079 A CN116674079 A CN 116674079A CN 202310871042 A CN202310871042 A CN 202310871042A CN 116674079 A CN116674079 A CN 116674079A
- Authority
- CN
- China
- Prior art keywords
- box girder
- tensioning
- small box
- grouting
- concrete
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000010276 construction Methods 0.000 title claims abstract description 43
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 62
- 239000010959 steel Substances 0.000 claims abstract description 62
- 238000000034 method Methods 0.000 claims abstract description 36
- 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 abstract description 26
- 238000005266 casting Methods 0.000 claims abstract description 15
- 239000011148 porous material Substances 0.000 claims abstract description 15
- 238000002360 preparation method Methods 0.000 claims abstract description 8
- 238000005520 cutting process Methods 0.000 claims abstract description 7
- 238000004519 manufacturing process Methods 0.000 claims abstract description 7
- 238000009417 prefabrication Methods 0.000 claims abstract description 5
- 238000007789 sealing Methods 0.000 claims abstract description 5
- 238000004873 anchoring Methods 0.000 claims abstract description 4
- 230000035515 penetration Effects 0.000 claims abstract description 4
- 230000008569 process Effects 0.000 claims description 14
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 12
- 239000002002 slurry Substances 0.000 claims description 11
- 238000013461 design Methods 0.000 claims description 10
- 239000004568 cement Substances 0.000 claims description 9
- 210000002435 tendon Anatomy 0.000 claims description 9
- 230000007613 environmental effect Effects 0.000 claims description 6
- 229920001821 foam rubber Polymers 0.000 claims description 6
- 229910052602 gypsum Inorganic materials 0.000 claims description 6
- 239000010440 gypsum Substances 0.000 claims description 6
- 238000009434 installation Methods 0.000 claims description 6
- 238000005507 spraying Methods 0.000 claims description 6
- 238000003860 storage Methods 0.000 claims description 6
- 230000001360 synchronised effect Effects 0.000 claims description 6
- 238000003466 welding Methods 0.000 claims description 6
- 239000003795 chemical substances by application Substances 0.000 claims description 5
- 230000007547 defect Effects 0.000 claims description 4
- 230000004048 modification Effects 0.000 claims description 4
- 238000012986 modification Methods 0.000 claims description 4
- 230000002457 bidirectional effect Effects 0.000 claims description 3
- 238000003490 calendering Methods 0.000 claims description 3
- 238000005336 cracking Methods 0.000 claims description 3
- 238000005034 decoration Methods 0.000 claims description 3
- 229920001971 elastomer Polymers 0.000 claims description 3
- 238000000227 grinding Methods 0.000 claims description 3
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 claims description 3
- 239000007788 liquid Substances 0.000 claims description 3
- 239000000463 material Substances 0.000 claims description 3
- 239000003973 paint Substances 0.000 claims description 3
- 230000001681 protective effect Effects 0.000 claims description 3
- 230000000007 visual effect Effects 0.000 claims description 3
- 230000008901 benefit Effects 0.000 description 3
- 238000009415 formwork Methods 0.000 description 3
- 238000007667 floating Methods 0.000 description 2
- 230000007306 turnover Effects 0.000 description 2
- 239000002390 adhesive tape Substances 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 239000004744 fabric Substances 0.000 description 1
- 238000011049 filling Methods 0.000 description 1
- 238000007689 inspection Methods 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 238000005498 polishing Methods 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 230000002787 reinforcement Effects 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
- 239000002023 wood Substances 0.000 description 1
Classifications
-
- 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
- B28B23/00—Arrangements specially adapted for the production of shaped articles with elements wholly or partly embedded in the moulding material; Production of reinforced objects
- B28B23/02—Arrangements specially adapted for the production of shaped articles with elements wholly or partly embedded in the moulding material; Production of reinforced objects wherein the elements are reinforcing members
- B28B23/04—Arrangements specially adapted for the production of shaped articles with elements wholly or partly embedded in the moulding material; Production of reinforced objects wherein the elements are reinforcing members the elements being stressed
-
- 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
- B28B23/00—Arrangements specially adapted for the production of shaped articles with elements wholly or partly embedded in the moulding material; Production of reinforced objects
- B28B23/02—Arrangements specially adapted for the production of shaped articles with elements wholly or partly embedded in the moulding material; Production of reinforced objects wherein the elements are reinforcing members
- B28B23/04—Arrangements specially adapted for the production of shaped articles with elements wholly or partly embedded in the moulding material; Production of reinforced objects wherein the elements are reinforcing members the elements being stressed
- B28B23/043—Wire anchoring or tensioning means for the reinforcements
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Ceramic Engineering (AREA)
- Mechanical Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Structural Engineering (AREA)
- Bridges Or Land Bridges (AREA)
Abstract
The invention relates to the field of construction of constructional engineering, and discloses a construction method of a prefabricated small box girder, which comprises the following steps: s1: the method comprises the steps of manufacturing a template, binding steel bars, installing a hoisting hole reserved box on a box girder side mould during prefabrication of a prefabricated small box girder, connecting the reserved box with the steel side mould through bolts, placing an embedded steel plate on the center of a corresponding support on a girder preparation pedestal, and adopting the embedded steel bars to be welded and fixed with the embedded steel plate; s2: pouring and curing concrete, wherein the concrete pouring of the box girder adopts an inclined layer method, and the box girder is cured in a concentrated manner on a construction site after the pouring of the box girder is completed; s3: prestress tensioning, namely firstly carrying out prestress rib beam penetration, then carrying out prestress rib tensioning, then carrying out anchorage sealing and anchoring, and finally carrying out prestress rib cutting; s4: the construction method of the prefabricated small box girder comprises the steps of grouting the pore canal and carrying out small box Liang Fengdu, wherein the construction method is used for continuously casting, the appearance of concrete is attractive, the investment of a pedestal is reduced, the construction cost is reduced, the positioning is accurate, the investment of labor force is reduced, and the construction efficiency is greatly improved.
Description
Technical Field
The invention relates to the field of construction of constructional engineering, in particular to a construction method of a prefabricated small box girder.
Background
The prefabricated small box girder has the advantages of mature process, economic manufacturing cost, convenient construction and the like, and is a prefabricated bridge structural form of conventional construction which is adopted for newly-built overhead girder bridges in cities at present. In urban bridge construction, in order to avoid influencing the normal operation of urban traffic, the conditions of short construction period and short time are faced. When the small box girder is prefabricated, the prestressed reinforcement can be tensioned only after 7 days of concrete curing (the concrete strength reaches more than 90% of the design strength), and the main factor is that the tensioning is performed when the concrete strength is low, so that the concrete at the girder end is easy to crack after the box girder is arched. After tensioning is finished, beam moving operation can be performed, so that the turnover period of the beam making pedestal is prolonged; meanwhile, when the prefabricated small box girder is provided with a longitudinal slope and a transverse slope, the top surface of a support of the prefabricated small box girder is required to be horizontally arranged, and the traditional mode is usually adjusted by arranging a girder bottom concrete wedge block. The top inclined plane of the concrete wedge block is consistent with the longitudinal and transverse slopes of the prefabricated small box girder. If a concrete wedge is used, an opening is needed on the bottom die of the girder preparation pedestal. For the general beam-making pedestal, the opening positions of the box beams with different lengths may be overlapped, and the construction cannot be performed. In addition, the concrete wedge block has smaller size, but has important structure, the quality problems of loose vibration, slurry leakage and the like are easy to occur during prefabrication construction, and the construction efficiency is reduced.
Disclosure of Invention
Aiming at the defects of the prior art, the invention provides a construction method of a prefabricated small box girder, which solves the problems.
In order to achieve the above purpose, the present invention provides the following technical solutions: the construction method of the prefabricated small box girder comprises the following steps:
s1: the method comprises the steps of manufacturing a template, binding steel bars, installing a hoisting hole reserved box on a box girder side mould during prefabrication of a prefabricated small box girder, connecting the reserved box with the steel side mould through bolts, placing an embedded steel plate on the center of a corresponding support on a girder preparation pedestal, and adopting the embedded steel bars to be welded and fixed with the embedded steel plate;
s2: casting and curing concrete, namely casting the box girder by adopting an inclined layer method, wherein the casting is firstly started by a bottom plate at one end, the bottom plate of the box girder is pushed to the other end, the inclined layering casting of a web plate is started by one end which is firstly cast after the bottom plate is cast to 5-8 meters, then casting of a top plate of the box girder is carried out, casting of the bottom plate, the web plate and the top plate are pushed in a step shape, and after casting of the box girder is completed, concentrated curing is carried out on a construction site;
s3: prestress tensioning, namely firstly carrying out prestress rib beam penetration, then carrying out prestress rib tensioning, then carrying out anchorage sealing and anchoring, and finally carrying out prestress rib cutting;
s4: grouting the pore canal and plugging the small box girder.
Preferably, in the S1, in the process of manufacturing the mould and binding the steel bars, the matched steel wedge blocks are selected according to the gradients of the longitudinal and transverse slopes of the prefabricated small box girders, the steel wedge blocks are welded and fixed with the embedded steel plates, the top surfaces of the steel wedge blocks are inclined surfaces, the bottom surfaces of the steel wedge blocks are planes, and the steel wedge blocks are prefabricated according to the gradients of the longitudinal and transverse slopes of the prefabricated small box girders and are assembled and used on site.
Preferably, in the step S1, trial splicing and rust removal are performed at first in the process of template installation, then the template is subjected to formal splicing, and the templates are numbered, so that the sequence is correct in the later splicing process;
after the formal splicing is finished, the staggered platform at the joints of the templates is polished and leveled, so that the joints of the templates are smoothly transited, the template paint is painted before all templates of the box girder are installed to facilitate the formwork removal, the box girder templates are lifted and installed by adopting a gantry crane, a base is cleaned up, a bottom plate, web steel bars and a fixed prestressed pipeline are bound, then an outer mold is installed, the outer mold is firstly erected, a template foot support and a template bottom opening pull rod are utilized to temporarily and stably install rubber foam between the joints of the outer mold so as to prevent slurry leakage, rubber foam strips are adhered to the templates before the installation of the templates, rubber pads consistent with the toothed plates are required to be filled in the toothed plates, and slurry leakage of the toothed joints is prevented.
Preferably, the S2 concrete pouring and curing specifically further comprises that when the surface finish of the concrete is different according to different parts and the exposed surface is not provided with decoration design, the exposed surface without the template is calendered or napped during pouring, the exposed surface with the template is provided with the same type of template and coated with the same type of template remover, the template is smooth, deformation and slurry leakage are avoided, and when the defect of the surface quality is found, the modification is carried out after the approval of the related department door.
Preferably, in the curing of the concrete in S2, if the environmental temperature is above 10 ℃ or the concrete strength is greater than 60% of the design strength in 3 days, a water spraying curing mode is adopted, and if the environmental temperature is below 10 or the concrete strength is less than 60% of the design value in 3 days, a steam curing mode is adopted;
after the beam is moved, concrete is continuously cured, if a water spraying curing mode is adopted before, the beam is continuously sprayed and cured after being moved to the beam storage pedestal, and if a steam curing mode is adopted before, the beam is continuously steam cured or wrapped and cured on the beam storage pedestal after being moved.
Preferably, the materials for tensioning and grouting the prestressed tendons in the step S3 mainly comprise steel strands, anchor clamps, cement and grouting agents;
and the prestress rib is threaded, namely, whether the position of an anchor backing plate is accurate or not is checked before the prestress rib is threaded, whether the inside of a pore canal is smooth or not, no water or other sundries exist, all prestress ribs in one steel beam are threaded into the pore canal integrally after being threaded, and a threading net sleeve or a special traction head is arranged at the front end of the prestress rib during integral threading, so that the prestress rib is kept straight and is dragged only forwards and backwards and cannot be twisted.
Preferably, the prestress tensioning is required to meet the following requirements:
(1) The concrete should reach the strength and elastic modulus (or age) of the concrete during stretching, and the prestressed tendon stretching should adopt a stretching force and elongation double control method;
(2) The tensioning equipment adopts an intelligent synchronous prestress tensioning system, and the grouting equipment adopts a vacuum grouting method so as to ensure the tensioning precision and grouting fullness;
(3) Grouting in time after tensioning is completed, grouting is full, and the quality of the grouting liquid meets the standard requirement;
(4) The steel strand is cut by adopting a grinding wheel saw, and gas welding cutting is strictly forbidden;
(5) In the tensioning process, necessary protective measures are needed to ensure the safety of operators and equipment.
Preferably, the prestressed tendon tensioning specifically comprises the following steps:
firstly, arranging a tensioning instrument host and a special jack at a tensioning end, and enabling the tensioning instrument host and the special jack to be in a linear visual state with a control station;
after the limiting plate is installed, a special jack is lifted, and a data line of the tensioning instrument and the jack is connected;
starting a tensioning intelligent system, controlling a jack through the intelligent system, and carrying out bidirectional synchronous symmetrical tensioning according to a tensioning program;
when the anchor is sealed, the anchor is sealed by quick setting cement or gypsum before grouting, and grouting can be performed after the quick setting cement or gypsum reaches the strength.
Preferably, in the grouting and small box girder plugging process of the S4 pore canal, the continuous end of the small box girder is required to be plugged into a regular shape, and the non-continuous end is required to be plugged to ensure that the continuous end is consistent with the original section, smooth, free of dislocation and cracking, and sundries in the box body are cleaned before plugging.
Compared with the prior art, the invention provides a construction method of the prefabricated small box girder, which has the following beneficial effects:
1. the construction method of the prefabricated small box girder adopts an inclined layer method for pouring, when the pouring is started from a bottom plate at one end, the bottom plate of the pouring box girder is pushed to the other end, after the bottom plate is poured to 5-8 meters, the inclined layering pouring of a web plate is started from the first poured end, then the pouring of a top plate of the box girder is performed, the pouring of the bottom plate, the web plate and the top plate is pushed in a ladder shape, and after the pouring of the box girder is completed, the concentrated maintenance is performed on a construction site.
2. Compared with the traditional concrete wedge block mode, the construction method of the prefabricated small box girder adopts a separated scheme that steel plates are pre-embedded in advance and steel wedge blocks are connected through welding, and has the following advantages: the steel wedge block is prefabricated by a manufacturer and assembled on site, so that the dimensional accuracy is higher than that of the concrete wedge block, the construction quality is ensured, and the requirements of support fitting can be met; the bottom die of the girder preparation pedestal is not required to be opened, and for the prefabricated small box girders with a plurality of specification lengths, a special pedestal is not required to be arranged, so that a universal pedestal can be considered, the investment of the pedestal is reduced, and the construction cost is reduced; the steel wedge-shaped block is convenient to install, accurate in positioning, reduces labor investment, greatly improves construction efficiency,
3. according to the construction method of the prefabricated small box girder, a tension force and elongation double control method is adopted, the small box Liang Chu can be lifted away from the prefabricated pedestal after being tensioned, so that the time of concrete on the prefabricated pedestal is only half of the time required by traditional one-time tensioning, the turnover efficiency of the prefabricated box girder manufacturing pedestal is greatly improved, and the number of prefabricated box girders manufactured in unit time is greatly improved.
Drawings
FIG. 1 is a schematic flow chart of a construction method of the prefabricated small box girder.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Referring to fig. 1, a construction method of a prefabricated small box girder includes the following steps:
s1: the method comprises the steps of manufacturing a template, binding steel bars, installing a hoisting hole reserved box on a box girder side mould during prefabrication of a prefabricated small box girder, connecting the reserved box with the steel side mould through bolts, placing an embedded steel plate on the center of a corresponding support on a girder preparation pedestal, and adopting the embedded steel bars to be welded and fixed with the embedded steel plate;
s2: the concrete pouring and curing are performed by adopting an inclined layer method, when the concrete is poured, the bottom plate at one end is firstly pushed to the other end to pour the bottom plate of the box girder, after the bottom plate is poured to 5-8 meters, the inclined layering pouring of the web plate is firstly performed at one end of the box girder, then the pouring of the top plate of the box girder is performed, the pouring of the bottom plate, the web plate and the top plate is pushed in a ladder shape, and after the box girder is poured, the concentrated curing is performed on a construction site.
S3: prestress tensioning, namely firstly carrying out prestress rib beam penetration, then carrying out prestress rib tensioning, then carrying out anchorage sealing and anchoring, and finally carrying out prestress rib cutting;
s4: grouting the pore canal and plugging the small box girder.
In S1 the template preparation with the steel ligature in-process, select the steel wedge of matching according to the slope of prefabricated little case roof beam longitudinal and transverse slope to with steel wedge and pre-buried steel sheet welded fastening, steel wedge top surface is the inclined plane, and the bottom surface is the plane, steel wedge is prefabricated processing according to the slope of prefabricated little case roof beam longitudinal and transverse slope, and on-the-spot assembly uses, compares traditional concrete wedge mode, adopts pre-buried steel sheet in advance, and the disconnect-type scheme of rethread welded connection steel wedge has following advantage: the steel wedge block is prefabricated by a manufacturer and assembled on site, so that the dimensional accuracy is higher than that of the concrete wedge block, the construction quality is ensured, and the requirements of support fitting can be met; the bottom die of the girder preparation pedestal is not required to be opened, and for the prefabricated small box girders with a plurality of specification lengths, a special pedestal is not required to be arranged, so that a universal pedestal can be considered, the investment of the pedestal is reduced, and the construction cost is reduced; the steel wedge block is convenient to install, accurate in positioning, capable of reducing labor investment and greatly improving construction efficiency.
In the step S1, trial splicing and rust removal are firstly carried out on the templates, then formal splicing of the templates is carried out, and the templates are numbered, so that the sequence is correct in the later splicing process;
polishing and leveling staggered tables at joints of the templates after the formal splicing is finished, enabling the joints of the templates to smoothly transition, coating template paint before all templates of the box girder are installed so as to facilitate the mold release, lifting and installing the box girder templates by adopting a gantry crane, binding a bottom plate, web steel bars and fixing prestressed pipelines after a pedestal is cleaned, installing an outer mold, firstly erecting an outer side mold, installing a temporary stable outer mold between the joint by using a template foot support and a template bottom mouth pull rod so as to clamp rubber foam between the joint for slurry leakage prevention, pasting rubber foam strips on the templates before the template installation, and filling rubber pads consistent with the toothed plates in the toothed plates to prevent slurry leakage of the joint; the appearance of the precast beam slab is an important part of the appearance quality of the bridge, the outer formwork is manufactured by adopting steel plates, enough strength and rigidity are considered when the formwork is designed, the deformation can be avoided under the conditions of installation, concrete construction and the like, the flatness of the dimension is ensured, the smoothness is ensured, the welding seams of the plate surface are reduced as much as possible, and the welding seams are polished; the templates are all designed and processed into large blocks of dies so as to reduce the number of joints during assembly;
after the template is installed, the plane position, the top elevation, the node connection and the longitudinal and transverse stability are checked, so that the template is ensured not to deform, shift and leak slurry in the concrete pouring process. And when the allowable deviation is exceeded, timely adjustment is performed. The joints of the prefabricated box girder and the hollow slab core mould are sealed by back-pasting a back-pasting adhesive tape. Measures are taken to effectively prevent the core mold from floating up. The pressing bar for preventing the core die from floating up needs to be tensioned by a ground anchor and is not directly fixed on the die plate. Before the anchor backing plate is installed, whether the size of the anchor backing plate is correct or not is checked, the anchor backing plate is installed on an end die in a middle mode, bolts of positioning holes are screwed, and the anchor backing plate is strictly centered with the pore canal and is perpendicular to the end portion of the pore canal. The grouting holes of the anchor backing plates are plugged by round wood plugs by adopting plugging measures. Sealing treatment is carried out on the anchor backing plate at the exposed part of the beam body so as to prevent water inflow, slurry inflow and other sundries from corroding the corrugated pipe.
The S2 concrete pouring and curing specifically further comprises that the smooth degree of the concrete surface is different according to different parts, when the exposed surface is not provided with decoration design, the exposed surface without the template is calendered or napped during pouring, the exposed surface with the template is required to be provided with the template of the same type and coated with the template release agent of the same type, the template is required to be smooth, deformation and slurry leakage are avoided, and when the defect of the surface quality is found, the modification is required to be carried out after the approval of the related department door.
After the construction of the steel bars and the templates is completed, the box girder templates and the steel bars are required to be checked again in time, and inspection and acceptance are required to be performed by a supervision engineer in time after the requirements are met. Meanwhile, before concrete pouring is carried out, related weather conditions must be known, and rainproof measures (a bracket can be built in advance, and rainy cloth can be adopted for covering if raining) are timely carried out.
In the step S2, when the concrete is cured, if the environmental temperature is above 10 ℃ or the concrete strength is more than 60% of the design strength in 3 days, adopting a water spraying curing mode, and if the environmental temperature is below 10 or the concrete strength is less than 60% of the design value in 3 days, adopting a steam curing mode;
after the beam is moved, concrete is continuously cured, if a water spraying curing mode is adopted before, the beam is continuously sprayed and cured after being moved to the beam storage pedestal, if a steam curing mode is adopted before, the beam is continuously steam cured or wrapped and cured on the beam storage pedestal after being moved, and the water condition for curing the concrete is the same as the water for mixing.
The materials for tensioning and grouting the prestressed tendons in the step S3 mainly comprise steel strands, anchor clamps, cement and grouting agents;
and the prestress rib is threaded, namely, whether the position of an anchor backing plate is accurate or not is checked before the prestress rib is threaded, whether the inside of a pore canal is smooth or not, no water or other sundries exist, all prestress ribs in one steel beam are threaded into the pore canal integrally after being threaded, and a threading net sleeve or a special traction head is arranged at the front end of the prestress rib during integral threading, so that the prestress rib is kept straight and is dragged only forwards and backwards and cannot be twisted.
The prestress tensioning needs to meet the following requirements:
(1) The concrete should reach the strength and elastic modulus (or age) of the concrete during stretching, and the prestressed tendon stretching should adopt a stretching force and elongation double control method;
(2) The tensioning equipment adopts an intelligent synchronous prestress tensioning system, and the grouting equipment adopts a vacuum grouting method so as to ensure the tensioning precision and grouting fullness;
(3) Grouting in time after tensioning is completed, grouting is full, and the quality of the grouting liquid meets the standard requirement;
(4) The steel strand is cut by adopting a grinding wheel saw, and gas welding cutting is strictly forbidden;
(5) In the tensioning process, necessary protective measures are needed to ensure the safety of operators and equipment.
The prestressed tendon tensioning method specifically comprises the following steps of:
firstly, arranging a tensioning instrument host and a special jack at a tensioning end, and enabling the tensioning instrument host and the special jack to be in a linear visual state with a control station;
after the limiting plate is installed, a special jack is lifted, and a data line of the tensioning instrument and the jack is connected;
starting a tensioning intelligent system, controlling a jack through the intelligent system, and carrying out bidirectional synchronous symmetrical tensioning according to a tensioning program;
when the anchor is sealed, the anchor is sealed by quick setting cement or gypsum before grouting, and grouting can be performed after the quick setting cement or gypsum reaches the strength.
In the S4 pore canal grouting and small box girder plugging process, the continuous end of the small box girder is required to be plugged into a regular shape, and the discontinuous end is required to be plugged to ensure that the continuous end is consistent with the original section, smooth, free of dislocation and cracking, and sundries in the box body are cleaned before plugging.
Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made therein without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.
Claims (9)
1. The construction method of the prefabricated small box girder is characterized by comprising the following steps of:
s1: the method comprises the steps of manufacturing a template, binding steel bars, installing a hoisting hole reserved box on a box girder side mould during prefabrication of a prefabricated small box girder, connecting the reserved box with the steel side mould through bolts, placing an embedded steel plate on the center of a corresponding support on a girder preparation pedestal, and adopting the embedded steel bars to be welded and fixed with the embedded steel plate;
s2: casting and curing concrete, namely casting the box girder by adopting an inclined layer method, wherein the casting is firstly started by a bottom plate at one end, the bottom plate of the box girder is pushed to the other end, the inclined layering casting of a web plate is started by one end which is firstly cast after the bottom plate is cast to 5-8 meters, then casting of a top plate of the box girder is carried out, casting of the bottom plate, the web plate and the top plate are pushed in a step shape, and after casting of the box girder is completed, concentrated curing is carried out on a construction site;
s3: prestress tensioning, namely firstly carrying out prestress rib beam penetration, then carrying out prestress rib tensioning, then carrying out anchorage sealing and anchoring, and finally carrying out prestress rib cutting;
s4: grouting the pore canal and plugging the small box girder.
2. The construction method of the prefabricated small box girder according to claim 1, wherein in the S1 mode, steel wedge blocks matched with the slope of the longitudinal and transverse slopes of the prefabricated small box girder are selected according to the slope of the longitudinal and transverse slopes of the prefabricated small box girder, the steel wedge blocks are welded and fixed with the embedded steel plates, the top surfaces of the steel wedge blocks are inclined planes, the bottom surfaces of the steel wedge blocks are planes, and the steel wedge blocks are prefabricated according to the slope of the longitudinal and transverse slopes of the prefabricated small box girder and are assembled and used on site.
3. The construction method of the prefabricated small box girder according to claim 1, wherein in the step S1, trial splicing and rust removal are performed firstly in the process of installing the templates, then the templates are spliced formally, and the templates are numbered, so that the sequence is correct in the process of splicing later;
after the formal splicing is finished, the staggered platform at the joints of the templates is polished and leveled, so that the joints of the templates are smoothly transited, the template paint is painted before all templates of the box girder are installed to facilitate the mold release, the box girder templates are lifted and installed by adopting a gantry crane, a base is cleaned up, a bottom plate, web steel bars and a fixed prestressed pipeline are bound, then an outer mold is installed, the outer mold is firstly erected, a rubber foam is clamped between the temporary stable outer mold installation joints by utilizing a template foot support and a template bottom opening pull rod to prevent slurry, rubber foam strips are adhered to the templates before the template installation, and rubber pads consistent with the toothed plates are required to be filled in the toothed plates.
4. The method for constructing the prefabricated small box girder according to claim 1, wherein: the S2 concrete pouring and curing specifically further comprises that the smooth degree of the concrete surface is different according to different parts, when the exposed surface is not provided with decoration design, the exposed surface without the template is calendered or napped during pouring, the exposed surface with the template is required to be provided with the template of the same type and coated with the template release agent of the same type, the template is required to be smooth, deformation and slurry leakage are avoided, and when the defect of the surface quality is found, the modification is required to be carried out after the approval of the related department door.
5. The method for constructing a prefabricated small box girder according to claim 1, wherein in the step S2, when the concrete is cured, if the environmental temperature is above 10 ℃ or the concrete strength is greater than 60% of the design strength for 3 days, a water spraying curing mode is adopted, and if the environmental temperature is below 10 or the concrete strength is less than 60% of the design value for 3 days, a steam curing mode is adopted;
after the beam is moved, concrete is continuously cured, if a water spraying curing mode is adopted before, the beam is continuously sprayed and cured after being moved to the beam storage pedestal, and if a steam curing mode is adopted before, the beam is continuously steam cured or wrapped and cured on the beam storage pedestal after being moved.
6. The construction method of the prefabricated small box girder according to claim 1, wherein the materials for tensioning and grouting the prestressed tendons in the step S3 mainly comprise steel strands, anchor clamps, cement and grouting agents;
and the prestress rib is threaded, namely, whether the position of an anchor backing plate is accurate or not is checked before the prestress rib is threaded, whether the inside of a pore canal is smooth or not, no water or other sundries exist, all prestress ribs in one steel beam are threaded into the pore canal integrally after being threaded, and a threading net sleeve or a special traction head is arranged at the front end of the prestress rib during integral threading, so that the prestress rib is kept straight and is dragged only forwards and backwards and cannot be twisted.
7. The method for constructing a prefabricated small box girder according to claim 1, wherein the prestress tensioning is required to meet the following requirements:
(1) The concrete should reach the strength and elastic modulus (or age) of the concrete during stretching, and the prestressed tendon stretching should adopt a stretching force and elongation double control method;
(2) The tensioning equipment adopts an intelligent synchronous prestress tensioning system, and the grouting equipment adopts a vacuum grouting method so as to ensure the tensioning precision and grouting fullness;
(3) Grouting in time after tensioning is completed, grouting is full, and the quality of the grouting liquid meets the standard requirement;
(4) The steel strand is cut by adopting a grinding wheel saw, and gas welding cutting is strictly forbidden;
(5) In the tensioning process, necessary protective measures are needed to ensure the safety of operators and equipment.
8. The method for constructing a prefabricated small box girder according to claim 6, wherein the prestressed tendon tensioning specifically comprises the following steps:
firstly, arranging a tensioning instrument host and a special jack at a tensioning end, and enabling the tensioning instrument host and the special jack to be in a linear visual state with a control station;
after the limiting plate is installed, a special jack is lifted, and a data line of the tensioning instrument and the jack is connected;
starting a tensioning intelligent system, controlling a jack through the intelligent system, and carrying out bidirectional synchronous symmetrical tensioning according to a tensioning program;
when the anchor is sealed, the anchor is sealed by quick setting cement or gypsum before grouting, and grouting can be performed after the quick setting cement or gypsum reaches the strength.
9. The construction method of the prefabricated small box girder according to claim 1, wherein in the grouting and small box girder plugging process of the S4 pore canal, the continuous end of the small box girder is required to be plugged into a regular shape, the non-continuous end is required to be plugged to ensure the same, smooth and smooth as the original section, no dislocation and no cracking, and sundries in the box body are cleaned before plugging.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310871042.1A CN116674079A (en) | 2023-07-17 | 2023-07-17 | Construction method of prefabricated small box girder |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310871042.1A CN116674079A (en) | 2023-07-17 | 2023-07-17 | Construction method of prefabricated small box girder |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN116674079A true CN116674079A (en) | 2023-09-01 |
Family
ID=87781185
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202310871042.1A Pending CN116674079A (en) | 2023-07-17 | 2023-07-17 | Construction method of prefabricated small box girder |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN116674079A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115026944A (en) * | 2022-06-27 | 2022-09-09 | 中交(南京)建设有限公司 | Method for pre-stressed construction of highway municipal prestressed concrete precast box girder |
-
2023
- 2023-07-17 CN CN202310871042.1A patent/CN116674079A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115026944A (en) * | 2022-06-27 | 2022-09-09 | 中交(南京)建设有限公司 | Method for pre-stressed construction of highway municipal prestressed concrete precast box girder |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN112342934B (en) | Construction method of high-stability curve bridge plate | |
| CN108638324A (en) | A kind of construction method of prefabricated case beam | |
| CN108360721A (en) | Precast concrete ultrathin type bidirectional stress type steel bar truss laminated floor slab | |
| CN105484391A (en) | Construction method for manufacturing heat-preservation waterproof wall through light heat-preservation GRC disassembling-free formworks | |
| CN110184941A (en) | A kind of bridge main tower construction method | |
| CN116674079A (en) | Construction method of prefabricated small box girder | |
| CN111778860A (en) | Process method for assembling sections of high-speed rail bridge | |
| CN110184948A (en) | A kind of Bridge beam construction method | |
| CN113738119A (en) | Large-span prestressed concrete beam roof tooth block tensioning construction method with bonding | |
| CN114892552A (en) | Box girder type bridge reconstruction construction method | |
| CN107288024B (en) | Assembled beam body and construction method thereof | |
| CN104631332A (en) | Prestressed concrete T-shaped beam on-site prefabricating erection construction method | |
| CN113638304B (en) | Concrete beam type bridge hidden cover beam structure system and construction method thereof | |
| CN108316150B (en) | Construction system and construction method for main tower and steel anchor beam of cable-stayed bridge | |
| CN114438896A (en) | Assembling construction method for assembled segmental beam of 100t span-pier gantry crane | |
| CN106607989A (en) | Rail transit post-stressed U-shaped beam construction technique | |
| CN101550724A (en) | Construction method of large-span post-tensioned prestressed longitudinal and transverse frame beams | |
| CN108867392A (en) | Precast beam adjustable type tire construction method | |
| CN108544655A (en) | The curved beam prefabricated construction method of curved bridge | |
| CN103422443B (en) | The multidirectional coupling precasting process of frame culvert segment long line method and frame culvert segment template system | |
| WO2024041054A1 (en) | Prefabricated track structure for built-in pump house section in rail transportation and construction method | |
| CN110904854B (en) | Arch bridge construction method adapting to removal progress | |
| CN115890877A (en) | Adjustable diaphragm plate template and construction method thereof | |
| CN216108007U (en) | Concrete beam type bridge and cast-in-situ hidden cover beam thereof | |
| CN116122169A (en) | Steel plate composite beam and construction method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |