CN112681162A - Construction method for movable split mounting type light formwork cast-in-situ box culvert - Google Patents
Construction method for movable split mounting type light formwork cast-in-situ box culvert Download PDFInfo
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Abstract
The invention discloses a construction method of a movable assembled light formwork cast-in-place box culvert; the construction process flow is as follows; step one, designing and manufacturing an assembled light formwork structure; step two, the mold frame is checked and assembled in an approach way; step three, excavating box culvert foundation pits and treating foundations; step four, installing the construction bottom plate, the guide wall and the wall body steel bars; fifthly, mounting the core mold and the outer mold; sixthly, mounting top plate steel bars; step seven, installing a plug board; eighthly, pouring side wall and top plate concrete and curing the concrete; step nine, disassembling the external mold; step ten, disassembling the edge moving die frame; step eleven, detaching the middle mould frame; and step twelve, constructing subsequent sections. The invention is suitable for the cast-in-place reinforced concrete box culvert construction in highway, railway, water conservancy and municipal pipe gallery projects.
Description
Technical Field
The invention relates to the field of box culvert construction, in particular to a construction method for a movable assembled light formwork cast-in-place box culvert.
Background
The box culvert is a closed reinforced concrete thin-wall structure, has the advantages of simple structure type, simple and convenient construction, good integrity, large rigidity, good durability, low maintenance cost and the like, is commonly used for railway, highway and municipal road engineering, and is more widely applied to hydraulic engineering and municipal pipe gallery engineering. The traditional box culvert construction method is that full framing vertical formwork cast-in-place concrete is erected, the erection and dismantling period of the frame is long, the construction efficiency is low, the labor cost is high, and the disadvantage is more obvious in the project with large box culvert engineering quantity. Meanwhile, the box culvert constructed by the traditional construction method is easy to have the phenomena of poor concrete surface flatness, wrong joints and the like due to the fact that a template is easy to deform or the technical level of workers, the operation quality and the like, and the appearance quality is not easy to guarantee.
With the progress of engineering science and technology and the requirement of the state on quality engineering construction, the traditional construction method needs to be technically improved, for this reason, in recent years, people apply the hydraulic template trolley technology to box culvert construction, but the hydraulic template trolley also has the defects of self heaviness, inconvenience for transition, difficulty in modification, trouble in repair after damage and the like, the disadvantages are very obvious when the construction amount is small and dispersed or box culverts with various section sizes exist, the cost of template amortization is also very high, and the technical popularization is not easy to realize.
Disclosure of Invention
Therefore, in order to solve the defects, the invention provides a construction method of a movable assembled light formwork cast-in-place box culvert; the invention is suitable for the cast-in-place reinforced concrete box culvert construction in highway, railway, water conservancy and municipal pipe gallery projects.
The invention is realized in this way, construct a movable assembling type light die carrier cast-in-place box culvert construction method, characterized by that; the construction process flow is as follows;
step one, designing and manufacturing an assembled light formwork structure; the method comprises the steps of designing and manufacturing a core mold and designing and manufacturing an outer template;
designing and manufacturing a core mold; the core mould consists of an edge mould frame, a middle mould frame, a steel bar lintel between the mould frames and an upper mould plate thereof, wherein the edge mould frame comprises a left mould frame and a right mould frame; the length of the core mould is set according to half of the length of the box culvert segment, and is generally 3.0-4.5 m; each hole box culvert needs to be provided with 2 left die carrier units and 2 right die carrier units; because the middle formwork of the construction method needs to simultaneously meet the construction requirements of two box culvert sections, 2 groups of middle formworks are configured according to each hole box culvert, and each group is provided with 2 middle formwork units; a steel bar lintel is arranged between the middle die frame and the side die frame, and a backing wood and an I-shaped wood back edge D supporting template D are arranged on the steel bar lintel;
designing and manufacturing an outer template; the outer template has the same length as the core template; each section of box culvert is provided with 4 external template units;
selecting a connecting piece; steel bars with the diameter of 25mm are used as pull rods and M24 taper joints A to prop up steel vertical beams C between the outer templates, and the other sides of the vertical beams C are locked by M24 female connecting pads and pressing beams; the side die frame and the outer template are connected by a phi 20mm water-stopping pull rod and are locked by M20 conical joints B and M20 female connecting pads.
Step two, the mold frame is checked and assembled in an approach way;
(1) after the die carrier arrives at the site, whether the material quality, specification, model and quantity of the die carrier meet the design and construction requirements or not is firstly checked, and trial assembly and inspection are carried out;
(2) before the die carrier is assembled, a leveling field is selected to manufacture a working platform, the die carrier structure is strictly checked during assembling, and the size, the joint, the flatness, the strength, the rigidity and the like of the die carrier are ensured to meet the design requirements;
step three, excavating box culvert foundation pits and treating foundations;
(1) the method comprises the steps of lofting and excavating box culvert foundation pits section by section, excavating to a height of 20-30 cm from a base during mechanical excavation, picking up the base by manual cooperation machinery, avoiding overexcavation and filling, detecting foundation bearing capacity after excavation is finished, and processing when the foundation bearing capacity does not meet design requirements;
(2) pouring cushion concrete after the foundation is processed according to the design until the foundation meets the requirements, and controlling the elevation and the flatness of the top surface of the cushion;
step four, installing the construction bottom plate, the guide wall and the wall body steel bars;
(1) installing a bottom plate, a guide wall, wall body steel bars and a water stop copper sheet;
(2) the forming steel die is used as a side wall and chamfering template, and a support pad is well arranged and locked during installation to ensure the stability of the template;
(3) pouring concrete at one time according to the sequence of the bottom plate and the guide wall, and pouring the guide wall concrete to a position 300mm above the chamfer; leveling the bottom plate and the concrete top surface of the guide wall, and covering, moisturizing, preserving health and cleaning concrete working seams on the top surface of the guide wall in time after construction is finished;
fifthly, mounting the core mold and the outer mold;
(1) during first construction, the core molds are sequentially lifted into the box culvert by a truck crane, and lifted by a jack trolley and moved to be in place and then dropped; jacking the core mould by using a jack trolley during the circulating construction period, moving the core mould to the next section to be in place, and then putting down the mould, wherein the side mould frames on two sides of the middle wall of the box culvert are connected by using water-stopping pull rods with the diameter of 20mm and are locked by using M20 conical joints B and M20 female connecting pads;
(2) sequentially mounting a steel bar lintel, a cushion block and an I-shaped wood back ridge D on adjacent jacking supports of the middle die frame and the side die frame, and supporting a template D at a clearance between the middle die frame and the side die frame;
(3) connecting the middle die set and the side die set by using a fastener type scaffold steel pipe and a fastener to enable the middle die set and the side die set to be in a relative locking state;
(4) hoisting the outer template by using a truck crane and connecting and locking the outer template and a side template frame at the side wall of the box culvert by using a phi 20mm water stop pull rod, an M20 conical joint B and an M20 female connecting pad; locking the outer formworks at the top of the box culvert by using a phi 25mm steel bar pull rod, a conical joint, a pressing beam, a female connecting pad and the like;
sixthly, mounting top plate steel bars; manufacturing and installing top plate steel bars according to the designed size, and forming a quincunx support pad below the steel bar framework by using a concrete protective layer cushion block;
step seven, installing a plug board; installing end socket templates at the top plate and the end of the wall body, clamping the water stop copper sheet by using the end socket templates, and locking the end socket templates by matching scaffold steel pipes during installation;
eighthly, pouring side wall and top plate concrete and curing the concrete; the concrete of the side wall and the top plate is poured in layers and formed at one time, and pumping warehousing and inserting type vibration are adopted, so that the vibration is ensured to be compact, and deformation caused by collision with a template and a steel bar is avoided during pouring; after pouring is finished, covering the culvert top and the wall bodies on two sides in time for moisture preservation and health preservation, and covering the two ends of the culvert by using geotextile, so that the loss of heat energy generated by hydration of concrete in the cavity of the box culvert is reduced, and the moisture preservation and health preservation period is not less than 7 d;
step nine, disassembling the external mold; when the strength of the box culvert concrete reaches more than 2.5MPa, the outer template can be loosened to separate from the concrete; and after the next section of side formwork is installed in place, the outer formwork is moved to the next section by using a truck crane for installation.
Step ten, disassembling the edge moving die frame; removing the side formwork after the concrete reaches the specified formwork removal strength, removing the fastener type scaffold steel pipe before removing the side formwork, removing the wood cushion block above the steel bar lintel, taking out the I-shaped wood back ridge D, the formwork D and the steel bar lintel, and loosening the water stop pull rod on the side formwork;
(1) after a jack trolley is installed and the top edge formwork is lifted, the adjustable base A is rotated to be separated from the ground to the height of 80-100 mm, and the jack descends by 50-80 mm to separate the side formwork from the box culvert top plate;
(2) the jack trolley translates the side formwork towards the middle formwork by 100mm, so that the side formwork is separated from the wall body of the box culvert;
(3) and (3) continuously supporting the left middle formwork to wait for the concrete strength to fall off after the concrete strength reaches a specified value, and moving the side formwork to the 2 nd box culvert section (the next section) and another group of middle formwork for combined installation by using a jack trolley.
Step eleven, detaching the middle mould frame; the middle formwork can be removed after the concrete reaches the specified formwork removal strength;
(1) after the jack trolley is installed and the middle formwork is lifted, the adjustable base B is rotated to be separated from the ground to the height of 80-100 mm, and the jack is descended to separate the middle formwork from the box culvert top plate;
(2) the middle formwork is moved to the 3 rd box culvert section and the side formwork for combined installation by a jack trolley;
twelfth, constructing subsequent sections;
and (3) circularly constructing the bottom plate and the guide wall of the subsequent section according to the three-step four operation steps, and circularly constructing the wall body and the top plate according to the five-step eleven operation steps.
The construction method of the movable assembled light formwork cast-in-place box culvert is characterized by comprising the following steps of (1) constructing a box culvert in a cast-in-place manner; in the first step, the side formwork comprises a plywood panel A, an I-shaped wood back ridge A, a single-side connecting claw A, a section steel cross beam A, a jacking support A, a section steel vertical beam A, a coil buckling type steel pipe support, an adjustable base A and the like which are arranged on the periphery towards the inner side, the section steel vertical beam A replaces the support vertical rod on the side of the formwork, and the vertical rod, the cross rod, the longitudinal rod and the inclined rod on the other side of the support are all made of coil buckling type steel pipes. A corner is arranged below the profile steel vertical beam A, an adjustable base A is arranged below the side formwork, and a jacking support A is arranged on the top of the disc buckling type steel pipe vertical rod.
The construction method of the movable assembled light formwork cast-in-place box culvert is characterized by comprising the following steps of (1) constructing a box culvert in a cast-in-place manner; in the first step, the middle formwork is provided with a plywood panel B, an I-shaped wood back ridge B, a single-side connecting claw B, a section steel beam B, a top support B, a disc buckle type steel pipe bracket, an adjustable base B and the like from top to bottom.
The construction method of the movable assembled light formwork cast-in-place box culvert is characterized by comprising the following steps of (1) constructing a box culvert in a cast-in-place manner; in the first step, the outer template is composed of a plywood panel C, an I-shaped wood back ridge C, a single-side connecting claw C, a profile steel vertical beam C and the like from outside to inside; i-shaped wood back ridges C and single-side connecting claws C are distributed between the plywood panel C and the profile steel vertical beam C.
The invention has the following advantages: the invention provides a construction method of a movable split mounting type light formwork cast-in-place box culvert through improvement; the invention is suitable for the cast-in-place reinforced concrete box culvert construction in road, railway, water conservancy and municipal pipe gallery projects; the invention has the following characteristics;
(1) the movable assembled light formwork mainly comprises a disc buckle type steel pipe, a jacking support, an adjustable base, profile steel and the like, and forms a formwork structure by using a plywood panel, an I-shaped wood back ridge, a profile steel vertical (transverse) beam and the like. The formwork takes a plywood formwork with a smooth surface as a panel, and the poured concrete has the advantages of few joints, few bubbles, good glossiness, flatness and attractiveness.
(2) The movable assembled light formwork in the construction method adopts a core formwork structure of a middle formwork and an edge formwork, the reserved interval between the formwork enables the side formwork to be conveniently detached, the edge formwork is detached firstly after cast-in-place concrete reaches certain strength, the middle formwork is kept to be continuously supported, the structural span of the box culvert during the equal strength of the concrete is greatly reduced, and according to the formwork detaching rule of GB50666 concrete structure engineering construction Specification and SL677 hydraulic concrete construction Specification, when the span of a concrete top plate is reduced to corresponding conditions after the technology is applied, the allowable formwork detaching strength of the concrete can be greatly reduced, so that the quick turnover of the box culvert formwork can be realized, and the construction speed is accelerated.
(3) Compared with the traditional construction method for erecting the full framing formwork and casting the box culvert in situ, the movable assembled light formwork is equivalent to 60% of the weight of the former (adopting a steel formwork panel), has light self-weight of the structure, is quick and simple to mount and dismount, can realize quick turnover, greatly improves the working efficiency, reduces the labor cost, and has the advantages of good strength, rigidity and stability, good concrete forming quality, safer operation, less occupied construction site, environmental protection and the like.
(4) Compared with a hydraulic template trolley, the movable assembled light formwork has the advantages of small steel consumption, light dead weight, convenience in moving and transition, easiness in modification, good adaptability to structural sections, capability of greatly reducing the cost of template amortization and the like.
Drawings
FIG. 1 is a flow chart of a construction process of a movable assembled light formwork cast-in-place box culvert;
FIG. 2 is a structural design drawing of an assembled light formwork;
FIG. 3 is a side form structural layout;
FIGS. 4 to 5 are structural design diagrams of the outer mold frame and the middle mold frame;
FIG. 6 is a view of a in FIG. 2;
FIG. 7 is a view showing a large scale of B in FIG. 2;
FIG. 8 is a view of the larger scale of C in FIG. 2;
figure 9 is a cross-sectional view of a box culvert floor and guide walls;
FIG. 10 is a schematic view of the installation of the core and outer molds;
FIG. 11 is a schematic side form falling view;
FIG. 12 is a schematic side view of the side form;
FIG. 13 is a schematic side formwork advancing view;
figure 14 is a schematic view of the middle formwork supporting box culvert (middle formwork continues to support);
figure 15 is a box culvert plan view.
Wherein: the concrete structure comprises a core die 1, a side die frame 101, a left die frame 1011, a right die frame 1012, an intermediate die frame 102, an outer die plate 2, a plywood panel A301, a plywood panel B302, a plywood panel C303, a die plate D304, an I-beam back ridge A401, an I-beam back ridge B402, an I-beam back ridge C403, an I-beam back ridge D404, a single-side connecting claw A501, a single-side connecting claw B502, a single-side connecting claw C503, a profile steel beam A601, a profile steel beam B602, a profile steel vertical beam A701, a corner 7011, a profile steel vertical beam C703, an adjustable base A801, an adjustable base B802, a top support A901, a top support B902, a steel bar lintel 10, a skid 11, a phi 25mm steel bar pull rod 12, a taper joint 13, a female connecting cushion 14, a press beam 15, a phi 20mm water stop pull rod 16, an M20 female connecting cushion 17, a fastener type scaffold steel pipe 18, an M20 taper joint B19 and.
Detailed Description
The present invention will be described in detail with reference to fig. 1 to 15, and the technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The invention provides a construction method of a movable split mounting type light formwork cast-in-place box culvert through improvement; the construction method is suitable for cast-in-place reinforced concrete box culvert construction in highway, railway, water conservancy and municipal pipe gallery projects.
The method is characterized in that:
(1) the movable assembled light formwork mainly comprises a disc buckle type steel pipe, a jacking support, an adjustable base, profile steel and the like, and forms a formwork structure by using a plywood panel, an I-shaped wood back ridge, a profile steel vertical (transverse) beam and the like. The formwork takes a plywood formwork with a smooth surface as a panel, and the poured concrete has the advantages of few joints, few bubbles, good glossiness, flatness and attractiveness.
(2) The movable assembled light formwork in the construction method adopts a core formwork structure of a middle formwork and an edge formwork, the reserved interval between the formwork enables the side formwork to be conveniently detached, the edge formwork is detached firstly after cast-in-place concrete reaches certain strength, the middle formwork is kept to be continuously supported, the structural span of the box culvert during the equal strength of the concrete is greatly reduced, and according to the formwork detaching rule of GB50666 concrete structure engineering construction Specification and SL677 hydraulic concrete construction Specification, when the span of a concrete top plate is reduced to corresponding conditions after the technology is applied, the allowable formwork detaching strength of the concrete can be greatly reduced, so that the quick turnover of the box culvert formwork can be realized, and the construction speed is accelerated.
(3) Compared with the traditional construction method for erecting the full framing formwork and casting the box culvert in situ, the movable assembled light formwork is equivalent to 60% of the weight of the former (adopting a steel formwork panel), has light self-weight of the structure, is quick and simple to mount and dismount, can realize quick turnover, greatly improves the working efficiency, reduces the labor cost, and has the advantages of good strength, rigidity and stability, good concrete forming quality, safer operation, less occupied construction site, environmental protection and the like.
(4) Compared with a hydraulic template trolley, the movable assembled light formwork has the advantages of small steel consumption, light dead weight, convenience in moving and transition, easiness in modification, good adaptability to structural sections, capability of greatly reducing the cost of template amortization and the like.
The process principle is as follows: the plywood panel, the I-shaped wood back ridge and the profile steel vertical (transverse) beam are used as main bodies to assemble an outer mold (core mold) template, the disc buckling type steel pipe and a jacking support, an adjustable base, the profile steel and the like of the disc buckling type steel pipe are used as main structures to build a support, the core mold template and the support are locked through the unilateral connecting claws to form an assembled light mold frame, the light mold frame can be recycled after being assembled and formed for the first time, and a re-assembled frame body is not required to be disassembled in the process. The lifting, moving and frame falling in-place of the die carrier are realized by the aid of the jack trolley, so that the movable assembled light die carrier is formed. The formworks on two sides of the concrete wall body are locked by a split screw.
After the bottom plate and the guide wall are concrete-constructed, the movable assembled light formwork constructed by the device and the method is used for carrying out box culvert side wall and top plate concrete construction, so that the construction speed can be accelerated, the construction quality and safety are improved, and the movable assembled light formwork is more green and environment-friendly.
As shown in fig. 1, the movable split-mounting type light formwork cast-in-place box culvert construction process flow is as follows:
firstly, construction preparation;
the design and manufacture of the assembled light formwork structure comprise core mold design and manufacture and outer formwork design and manufacture;
(1) designing and manufacturing a core mold; as shown in fig. 2, the core mold 1 is composed of a side mold frame 101, a middle mold frame 102, a steel bar lintel 10 between the mold frames and an upper mold plate thereof, wherein the side mold frame 101 comprises a left mold frame 1011 and a right mold frame 1012; the length of the core mould 1 is set according to half of the length of the culvert section, and is generally 3.0-4.5 m; each box culvert is required to be provided with 2 left die carrier 1011 units and 2 right die carrier 1012 units; because the middle formwork 102 in the method needs to meet the requirement of two box culvert sections, 2 groups of middle formworks 102 are configured according to each hole box culvert, and each group is provided with 2 middle formwork 102 units.
As shown in fig. 6, a steel bar lintel 10 is arranged between the middle formwork 102 and the side formwork 101, and a skid 11 and an i-beam back ridge D404 support a cushion formwork D304 are arranged thereon.
As shown in fig. 3, the side formwork 101 is composed of a plywood panel a301, an i-shaped wood back ridge a401, a single-side connecting claw a501, a profile steel beam a601, a top support a901, a profile steel vertical beam a701, a disc-buckled steel pipe support, an adjustable base a801 and the like arranged on the periphery towards the inner side, the profile steel vertical beam a701 replaces a support vertical rod on the side of the formwork, and vertical rods, transverse rods, longitudinal rods and inclined rods on the other side of the support all adopt disc-buckled steel pipes. A corner 7011 is arranged below the profile steel vertical beam A701, an adjustable base A801 is arranged below the side formwork, and a jacking A901 is arranged on the top of the disc buckle type steel pipe vertical rod.
As shown in fig. 5, the middle mold frame 102 is composed of, from top to bottom, a plywood panel B302, an i-beam back edge B402, a single-side connecting claw B502, a profile steel beam B602, a top bracket B902, a coil-fastened steel tube bracket, an adjustable base B802, and the like.
(2) Designing and manufacturing an outer template; the outer template 2 has the same length as the core template 1; each section of box culvert is provided with 4 external template 2 units;
as shown in fig. 4, the external form comprises a plywood panel C303, an i-shaped wood back edge C403, a single-side connecting claw C503, a profile steel vertical beam C703 and the like from outside to inside; i-shaped wood back ridges C403 and single-side connecting claws C503 are distributed between the plywood panel C303 and the section steel vertical beams C703.
(3) Selecting a connecting piece; as shown in figure 7, a steel bar with the diameter of 25mm is adopted between the outer formworks 2 and is threaded to be used as a pull rod 12 and an M24 taper joint A13 to support a steel vertical beam C703, and the other side of the vertical beam C703 is locked by an M24 female connecting pad 14 and a pressing beam 15.
As shown in fig. 8, the side formwork 101 and the outer formwork 2 are connected by a water stop pull rod 16 with the diameter of 20mm and are locked by female connecting pads 17 of M20 taper joints B19 and M20.
Step two, the mold frame is checked and assembled in an approach way;
(1) after the die carrier arrives at the site, whether the material quality, specification, model and quantity of the die carrier meet the design and construction requirements or not is firstly checked, and trial assembly and inspection are carried out;
(2) before the die carrier is assembled, a leveling field is selected to manufacture a working platform, the die carrier structure is strictly checked during assembling, and the size, the joint, the flatness, the strength, the rigidity and the like of the die carrier are ensured to meet the design requirements;
step three, excavating box culvert foundation pits and treating foundations;
(1) the method comprises the steps of lofting and excavating box culvert foundation pits section by section, excavating to a height of 20-30 cm from a base during mechanical excavation, picking up the base by manual cooperation machinery, avoiding overexcavation and filling, detecting foundation bearing capacity after excavation is finished, and processing when the foundation bearing capacity does not meet design requirements;
(2) pouring cushion concrete after the foundation is processed according to the design until the foundation meets the requirements, and controlling the elevation and the flatness of the top surface of the cushion;
step four, as shown in fig. 9, the construction bottom plate, the guide wall and the wall body steel bars are installed
(1) Installing a bottom plate, a guide wall, wall body steel bars and a water stop copper sheet;
(2) the forming steel die is used as a side wall and chamfering template, and a support pad is well arranged and locked during installation to ensure the stability of the template;
(3) pouring concrete at one time according to the sequence of the bottom plate and the guide wall, and pouring the guide wall concrete to a position 300mm above the chamfer; leveling the bottom plate and the concrete top surface of the guide wall, and covering, moisturizing, preserving health and cleaning concrete working seams on the top surface of the guide wall in time after construction is finished;
step five, as shown in fig. 10, the core mold and the outer mold are installed;
(1) during first construction, the core mould 1 is sequentially lifted into the box culvert by a truck crane, and lifted by a jack trolley 20 and moved to be in place and then dropped; during the circulating construction period, a jack trolley 20 is used for jacking the core mould 1, the core mould is moved to the next section to be in place and then is placed on a frame, side mould frames 101 on two sides of the middle wall of the box culvert are connected by a water stop pull rod 16 with the diameter of 20mm and are locked by female connecting pads 17 of M20 taper joints B19 and M20;
(2) the method comprises the following steps that a steel bar lintel 10, a cushion block 11, an I-shaped wood back ridge D404 and a template D304 supporting a gap between a middle die frame 102 and a side die frame 101 are sequentially arranged on adjacent jacking supports of the middle die frame 102 and the side die frame 101;
(3) connecting the middle formwork 102 and the side formwork 101 by using the fastener type scaffold steel pipe 18 and a fastener to enable the middle formwork and the side formwork to be in a relative locking state;
(4) hoisting the outer template 2 by using a truck crane and connecting and locking the outer template with a side template 101 at the side wall of the box culvert by using a phi 20mm water stop pull rod 16, an M20 taper joint B19 and an M20 female connecting pad 17; the outer formworks at the top of the box culvert are locked by a phi 25mm steel bar pull rod 12, a conical joint 13, a pressing beam 15, a female connecting pad 14 and the like;
sixthly, mounting top plate steel bars; manufacturing and installing top plate steel bars according to the designed size, and forming a quincunx support pad below the steel bar framework by using a concrete protective layer cushion block;
step seven, installing a plug board; installing end socket templates at the top plate and the end of the wall body, clamping the water stop copper sheet by using the end socket templates, and locking the end socket templates by matching scaffold steel pipes during installation;
eighthly, pouring side wall and top plate concrete and curing the concrete; the concrete of the side wall and the top plate is poured in layers and formed at one time, and pumping warehousing and inserting type vibration are adopted, so that the vibration is ensured to be compact, and deformation caused by collision with a template and a steel bar is avoided during pouring; after pouring is finished, covering the culvert top and the wall bodies on two sides in time for moisture preservation and health preservation, and covering the two ends of the culvert by using geotextile, so that the loss of heat energy generated by hydration of concrete in the cavity of the box culvert is reduced, and the moisture preservation and health preservation period is not less than 7 d;
step nine, disassembling the external mold; when the strength of the box culvert concrete reaches more than 2.5MPa, the outer template 2 can be loosened to separate from the concrete; and after the next section of side formwork 101 is installed in place, the outer formwork 2 is moved to the next section by using a truck crane for installation.
Step ten, disassembling the side moving mold frame 101; after the concrete reaches the specified form removal strength, the side formwork 101 can be removed, the fastener type scaffold steel pipe 18 is removed before the side formwork 101 is removed, then the wood cushion block 11 above the steel bar lintel 10 is removed, the I-shaped wood back ridge D404, the formwork D304 and the steel bar lintel 10 are taken out, and then the water-stopping pull rod 16 on the side formwork 101 is released.
(1) After the jack trolley 20 is installed and the top edge formwork 101 is lifted, the adjustable base A801 is rotated to be separated from the ground to the height of 80-100 mm, and the jack descends by 50-80 mm to separate the side formwork 101 from the box culvert top plate (see figure 11);
(2) the jack trolley 20 translates the side formwork 101 by 100mm towards the middle formwork 102, so that the side formwork 101 is separated from the box culvert wall body (see figure 12);
(3) as shown in fig. 13, the leave mold frame 102 continues to support and wait for the concrete strength to reach a predetermined value and then to be dropped. The edge formwork 101 is moved to the next section of the 2 nd culvert section by a jack trolley 20 and is assembled with another group of formwork 102 (see fig. 13).
Step eleven, detaching the middle mould frame; the middle formwork 102 can be removed after the concrete reaches the specified formwork removal strength;
(1) after the jack trolley 20 is installed and the middle formwork 102 is lifted, the adjustable base B802 is rotated to be separated from the ground to the height of 80-100 mm, and the jack is lowered to separate the middle formwork 102 from the box culvert top plate;
(2) the middle formwork 102 is moved to the 3 rd box culvert section and the side formwork 101 to be assembled and installed by a jack trolley 20;
twelfth, constructing subsequent sections;
and (3) circularly constructing the bottom plate and the guide wall of the subsequent section according to the three-step four operation steps, and circularly constructing the wall body and the top plate according to the five-step eleven operation steps.
Analyzing corresponding benefits of the invention;
the economic benefits are as follows: the movable assembled light formwork adopted by the construction method is processed in a factory standard mode, is assembled and formed on site at one time, does not need to be disassembled and assembled again when box culvert sections are constructed in a circulating mode and the construction site is transferred in a short distance, and compared with the traditional full-hall support formwork erecting and cast-in-place box culvert scheme, the construction method can greatly save labor cost and shorten the construction and disassembly periods of the formwork support.
Taking the construction of the box culvert of the 1-section of the Tianfu Dadao of the traffic infrastructure PPP project in the Meishan city as an example, the total time for erecting and dismantling the formwork of the traditional full formwork scheme needs 200 days calculated according to a set of formwork construction 40 box culvert sections (the length of the sections is 9.0 m), while the construction method only needs 60 days, can shorten 140 days compared with the former, and the saving rate of the formwork erecting and dismantling period reaches 70 percent. The comparative analysis of construction costs for the two solutions is shown in table 1.
Comparison of different scheme costs Table 1
As can be seen from table 1, when a box culvert project with 40 sections and a length of 360m is constructed, the total cost is 2506784 yuan when the full framing scheme is adopted, and the total cost is 684684 yuan when the movable split mounting type light formwork cast-in-place box culvert construction scheme is adopted, so that the formwork construction cost is saved by 1822100 yuan compared with the full framing scheme, the cost saving rate is 72.7%, and the economic benefit is remarkable.
(II) social benefits: the movable assembled light formwork has light dead weight, is simple and convenient to mount and dismount and move, can shorten the construction period of the formwork and reduce the labor cost. The mould frame is assembled by adopting parts produced in a standardized way, so that the mould frame is convenient to recycle, and the spreading and selling cost of the mould frame is reduced. The box culvert constructed by the light formwork has the advantages of few concrete joints, few bubbles, good glossiness, flatness and attractiveness and improvement on the concrete forming quality. The construction method innovatively adopts the technology of detaching the middle formwork from the middle formwork, and when the span of the concrete top plate is reduced to the corresponding condition after the technology is applied, the allowable formwork detaching strength of the concrete can be greatly reduced, so that the rapid turnover of the box culvert formwork can be realized, and the construction progress is accelerated. The whole trolley for the die carrier unit is translated, so that the disassembling, assembling and hoisting work is reduced, and the construction safety risk is reduced. The die carrier is disassembled and assembled, so that the noise pollution and the field occupation of the traditional construction are reduced, the green and environment-friendly effect is realized, and the construction method has good social benefits and higher popularization and application values.
Engineering example: a channel reconstructed by 1 part of Tianfu Dadao of a traffic infrastructure PPP project in Meishan city relates to a New southern main canal and a Meishan Peng main canal, the reconstructed lines have 8 sections in total, wherein a second section of an open canal with gradually changed hidden culverts passes through the lower part of the open canal and contains 2900m box culverts; the seventh transition section 175m penetrates through the box culvert totally 3075m, and the method applies a movable assembled light formwork cast-in-place box culvert construction method in the box culvert construction, shortens the installing and detaching period of the formwork support, accelerates the construction progress, reduces the cost, and has good concrete forming quality, safe construction, green and environmental protection. The successful application of the construction process of the movable light formwork cast-in-place box culvert has great guiding significance for similar engineering construction in the future. FIG. 11 is a box culvert design drawing, the section size of a box chamber is 600 multiplied by 450m, the thickness of a bottom plate is 80cm, the thickness of a top plate is 70cm, and two-hole culverts are constructed simultaneously. Therefore, in section 1 of Tianfu great road of traffic infrastructure PPP project in Meishan city, research is carried out on the realization of high-quality and rapid construction of a long box culvert with length of 3075m and a water passing section of 6.0 multiplied by 4.5m in the reconstruction project of an east wind channel, an assembled integral large light template is adopted as an outer mold of the box culvert, a movable assembled light mold frame is adopted as a core mold, and a core mold structure of the middle mold frame and the side mold frames is innovatively adopted, so that the construction technology of the movable assembled light mold frame cast-in-place box culvert is formed, the work efficiency, the quality and the safety are improved, the engineering cost is reduced, the energy conservation and the environmental protection are promoted, and higher economic and technical benefits are obtained.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (4)
1. A construction method of a movable assembled light formwork cast-in-situ box culvert is characterized in that the construction method comprises the following steps of (1) constructing a box culvert on a movable assembled light formwork cast-in-situ box culvert; the construction process flow is as follows;
step one, designing and manufacturing an assembled light formwork structure; the method comprises the steps of designing and manufacturing a core mold and designing and manufacturing an outer template;
1) designing and manufacturing a core mold; the core mould (1) consists of an edge mould frame (101), a middle mould frame (102), a steel bar lintel (10) between the mould frames and an upper mould plate thereof, wherein the edge mould frame (101) comprises a left mould frame (1011) and a right mould frame (1012); the length of the core mould (1) is set according to half of the length of the culvert section, and is generally 3.0-4.5 m; each hole box culvert needs to be provided with 2 left die carrier (1011) units and 2 right die carrier (1012) units; because the middle formwork (102) of the construction method needs to meet the construction requirements of two box culvert sections at the same time, 2 groups of middle formwork (102) are configured according to each hole box culvert, and each group is provided with 2 middle formwork (102) units; a steel bar lintel (10) is arranged between the middle die frame (102) and the side die frame (101), and a backing wood (11) and an I-shaped wood back edge D (404) are arranged on the lintel to support a backing template D (304);
2) designing and manufacturing an outer template; the outer template (2) has the same length as the core template (1); each section of box culvert is provided with 4 outer template (2) units;
3) selecting a connecting piece; steel bars with the diameter of 25mm are threaded between the outer templates (2) and are used as a pull rod (12) and an M24 taper joint A (13) to prop up a profile steel vertical beam C (703), and the other side of the vertical beam C (703) is locked by an M24 female connecting pad (14) and a pressing beam (15); the side die frame (101) and the outer template (2) are connected by a phi 20mm water-stopping pull rod (16) and locked by an M20 conical joint B (19) and an M20 female connecting pad (17); step two, the mold frame is checked and assembled in an approach way;
(1) after the die carrier arrives at the site, whether the material quality, specification, model and quantity of the die carrier meet the design and construction requirements or not is firstly checked, and trial assembly and inspection are carried out;
(2) before the die carrier is assembled, a leveling field is selected to manufacture a working platform, the die carrier structure is strictly checked during assembling, and the size, the joint, the flatness, the strength, the rigidity and the like of the die carrier are ensured to meet the design requirements;
step three, excavating box culvert foundation pits and treating foundations;
(1) the method comprises the steps of lofting and excavating box culvert foundation pits section by section, excavating to a height of 20-30 cm from a base during mechanical excavation, picking up the base by manual cooperation machinery, avoiding overexcavation and filling, detecting foundation bearing capacity after excavation is finished, and processing when the foundation bearing capacity does not meet design requirements;
(2) pouring cushion concrete after the foundation is processed according to the design until the foundation meets the requirements, and controlling the elevation and the flatness of the top surface of the cushion;
step four, installing the construction bottom plate, the guide wall and the wall body steel bars;
(1) installing a bottom plate, a guide wall, wall body steel bars and a water stop copper sheet;
(2) the forming steel die is used as a side wall and chamfering template, and a support pad is well arranged and locked during installation to ensure the stability of the template;
(3) pouring concrete at one time according to the sequence of the bottom plate and the guide wall, and pouring the guide wall concrete to a position 300mm above the chamfer; leveling the bottom plate and the concrete top surface of the guide wall, and covering, moisturizing, preserving health and cleaning concrete working seams on the top surface of the guide wall in time after construction is finished;
fifthly, mounting the core mold and the outer mold;
(1) during first construction, the core mould (1) is sequentially lifted into the box culvert by a truck crane, and is lifted by a jack trolley (20) and moved to be in place and then is dropped; jacking the core mould (1) by using a jack trolley (20) during the circulating construction period, moving to the next section to be in place, and then dropping, wherein the side mould frames (101) on two sides of the middle wall of the box culvert are connected by adopting a water stop pull rod (16) with the diameter of 20mm and locked by using an M20 conical joint B (19) and an M20 female connecting pad (17);
(2) the method comprises the following steps that a steel bar lintel (10), a cushion block (11), an I-shaped wood back edge D (404) and a template D (304) at a void part between a middle die frame (102) and a side die frame (101) are sequentially arranged on adjacent jacking supports of the middle die frame (102) and the side die frame (101);
(3) connecting a middle formwork (102) and a side formwork (101) by using a fastener type scaffold steel pipe (18) and a fastener to enable the middle formwork and the side formwork to be in a relative locking state;
(4) hoisting the outer template (2) by using a truck crane and connecting and locking the outer template with a side formwork (101) at the side wall of the box culvert by using a phi 20mm water stop pull rod (16), an M20 conical joint B (19) and an M20 female connecting pad (17); the outer formworks at the top of the box culvert are locked by a phi 25mm steel bar pull rod (12), a conical joint (13), a pressing beam (15), a female connecting pad (14) and the like;
sixthly, mounting top plate steel bars; manufacturing and installing top plate steel bars according to the designed size, and forming a quincunx support pad below the steel bar framework by using a concrete protective layer cushion block;
step seven, installing a plug board; installing end socket templates at the top plate and the end of the wall body, clamping the water stop copper sheet by using the end socket templates, and locking the end socket templates by matching scaffold steel pipes during installation;
eighthly, pouring side wall and top plate concrete and curing the concrete; the concrete of the side wall and the top plate is poured in layers and formed at one time, and pumping warehousing and inserting type vibration are adopted, so that the vibration is ensured to be compact, and deformation caused by collision with a template and a steel bar is avoided during pouring; after pouring is finished, covering the culvert top and the wall bodies on two sides in time for moisture preservation and health preservation, and covering the two ends of the culvert by using geotextile, so that the loss of heat energy generated by hydration of concrete in the cavity of the box culvert is reduced, and the moisture preservation and health preservation period is not less than 7 d;
step nine, disassembling the external mold; when the strength of the box culvert concrete reaches more than 2.5MPa, the outer template (2) can be loosened to separate from the concrete; after the next section of side formwork (101) is installed in place, the outer formwork (2) is moved to the next section by a truck crane for installation;
step ten, disassembling the edge moving die carrier (101); after the concrete reaches the specified form removal strength, removing the side formwork (101), removing the fastener type scaffold steel pipe (18) before removing the side formwork (101), then removing the wood cushion block (11) above the steel bar lintel (10), taking out the I-shaped wood back ridge D (404), the formwork D (304) and the steel bar lintel (10), and then loosening the water stop pull rod (16) on the side formwork (101);
(1) after a jack trolley (20) is installed and the top edge formwork (101) is lifted, the adjustable base A (801) is rotated to be separated from the ground to the height of 80-100 mm, and the jack is lowered by 50-80 mm to separate the side formwork (101) from the box culvert top plate;
(2) the jack trolley (20) translates the side formwork (101) by 100mm towards the middle formwork (102) to enable the side formwork (101) to be separated from the box culvert wall body;
(3) the remaining formwork (102) continues to support and wait for the concrete strength to drop after reaching a specified value, and a jack trolley (20) is used for transferring the side formwork (101) to the 2 nd culvert section (the next section) and another group of formwork (102) for combined installation;
step eleven, detaching the middle mould frame; the middle formwork (102) can be removed after the concrete reaches the specified formwork removal strength;
(1) after a jack trolley (20) is installed and the middle formwork (102) is lifted, the adjustable base B (802) is rotated to be separated from the ground to the height of 80-100 mm, and the jack is lowered to separate the middle formwork (102) from the box culvert top plate;
(2) the middle formwork (102) is moved to the 3 rd box culvert section and the side formwork (101) for combined installation by a jack trolley (20);
twelfth, constructing subsequent sections;
and (3) circularly constructing the bottom plate and the guide wall of the subsequent section according to the three-step four operation steps, and circularly constructing the wall body and the top plate according to the five-step eleven operation steps.
2. The construction method of the movable assembled light formwork cast-in-place box culvert according to claim 1, characterized in that; in the first step, the side formwork (101) is composed of a plywood panel A (301), an I-shaped wood back edge A (401), a single-side connecting claw A (501), a section steel beam A (601), a jacking A (901), a section steel vertical beam A (701), a disc buckling type steel pipe support, an adjustable base A (801) and the like which are arranged on the periphery towards the inner side, the section steel vertical beam A (701) is used for replacing a support vertical rod on the side of the formwork, and a vertical rod, a transverse rod, a longitudinal rod and an oblique rod on the other side of the support are all made of disc buckling type steel pipes; a corner (7011) is arranged below a profile steel vertical beam A (701), an adjustable base A (801) is arranged below a side formwork, and a jacking A (901) is arranged on the top of a disc buckle type steel pipe vertical rod.
3. The construction method of the movable assembled light formwork cast-in-place box culvert according to claim 1, characterized in that; in the first step, the middle formwork (102) is provided with a plywood panel B (302), an I-shaped wood back edge B (402), a single-side connecting claw B (502), a section steel beam B (602), a top support B (902), a coil buckle type steel pipe support and an adjustable base B (802) from top to bottom.
4. The construction method of the movable assembled light formwork cast-in-place box culvert according to claim 1, characterized in that; in the first step, the outer template is composed of a plywood panel C (303), an I-shaped wood back edge C (403), a single-side connecting claw C (503), a profile steel vertical beam C (703) and the like from outside to inside; i-shaped wood back edges C (403) and single-side connecting claws C (503) are distributed between the plywood panel C (303) and the section steel vertical beams C (703).
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| NL2036718A (en) | 2023-10-27 | 2024-02-27 | China Harbour Eng Co Ltd | Construction method for foundation pit of cast-in-place box culvert |
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