CN104846744A - Construction method for pouring and forming urban viaduct curve type pier stud in one-off mode - Google Patents

Abstract

The invention discloses a construction method for one-time pouring and molding of urban elevated curved pier columns, wherein the construction steps are as follows: first step, pre-embedded main reinforcement positioning of pier columns; The third step is to measure and set out; the fourth step is to set up scaffolding; the fifth step is to process and install steel bars; the sixth step is to process and install formwork; the seventh step is to pour concrete; the eighth step is to remove formwork and maintain health; the ninth step , Scaffold removal; The invention provides a construction method of one-time pouring and forming of urban elevated curved pier columns, which has the characteristics of fast construction, reasonable structure, economic benefits, etc., and is widely applicable to urban high-pier bridges, especially urban high-pier landscape bridges.

Description

A construction method for one-time pouring and forming of urban elevated curved pier columns

technical field

The invention relates to a construction method of a viaduct, in particular to a construction method of one-time casting and forming of curved pier columns of an urban viaduct.

Background technique

With the rapid development of economy and urban traffic, the bridges in viaducts gradually require "landscape", and the shaping of the image of the city or region by the bridge landscape is also more and more concerned by people, and it must match the shaping of the image of the city or region .

Compared with beams, piers are closer to people's point of view. The shape, volume, surface treatment and appendages of pier columns all form landscape elements and are the focus of aesthetic design.

In recent years, bridge piers have also developed from early cylindrical piers to slender and beautiful light-weight piers, especially curved piers are widely used in China.

The curved piers have strong applicability and beautiful appearance, avoid the defects of traditional construction methods, are technologically advanced, reliable, applicable, and economically reasonable, and have achieved significant economic and social benefits.

However, the structure is complex: the steel bars are inclined and dense, the space positioning is difficult, the formwork is outwardly inclined and the operation space in the mold is small, and there are many embedded parts on the top of the pier.

The traditional construction method is that the main reinforcement of the pier body is lengthened one by one on site, the horizontal stirrups are bound layer by layer, the formwork of the standard section and the curved section of the pier body are installed in stages, and the concrete is poured in stages. Appearance and quality defects such as joints and low pass rate of protective layer.

Aiming at these defects, the present invention proposes a construction method for one-time pouring and forming of urban elevated curved pier columns.

Contents of the invention

The technical problem to be solved by the present invention is to provide a construction method for one-time pouring of urban elevated curved pier columns. The pier columns have strong applicability and beautiful appearance, and avoid the defects of traditional construction methods.

The present invention provides a construction method for one-time pouring and forming of urban elevated curved pier columns. The construction steps are as follows: the first step, the pre-embedded main reinforcement of the pier column is positioned: the pre-embedded main reinforcement, the steel reinforcement of the cap is welded firmly, and the hoops are bound to form a rigid skeleton ; The second step is to chisel the joint part of the pier body and the cap: after the concrete strength of the cap reaches 2.5MPa, the concrete on the top surface of the cap inside the pre-embedded steel bar of the pier body is chiseled until stones are exposed on the concrete surface, and then Rinse clean; the third step is to measure and stake out; use a total station to set the vertical and horizontal axes of the pier column and the inner and outer plane contour lines of the column mold on the top surface of the platform, and the ink fountain will pop up the connection line to measure the elevation around the bottom of the pier and use it as a reinforcement binding , installation and formwork reference; the fourth step, scaffold erection; around the pier body, use Φ48mm×3.5mm bowl buckle bracket or fastener type steel pipe to set up double-row scaffolding as a working platform for pier body reinforcement installation, formwork installation and dismantling, and concrete pouring; The surroundings of the scaffolding are closed, and the foundation is placed on the bearing platform and the treated and hardened foundation. Steel pipes and fasteners are used on the inner and outer sides to set inclined bars or scissors braces according to the requirements of the specifications. The distance between the inner side of the scaffolding and the outer formwork is reserved for formwork installation, demolition and distance removal. , the working layer and the scaffolding within the width of the channel are fully paved and stable, and the railings on the peripheral platform are 1.2m higher than the uppermost working layer; Step 5, steel bar processing and installation; 1) Main steel wire head processing: main steel bar of pier body (≥Φ25mm) Connected by rolling straight thread sleeves; 2) Processing of semi-finished products: Semi-finished products are processed by classification, and the main reinforcement and stirrup of the variable section section are processed by numbering and stacked one by one; 3) Reinforcement skeleton processing of pier body: pier column reinforcement skeleton In the steel bar processing workshop, the long-line tire mold of the whole tire mold on the flat ground is used as a whole, and the fixed curve section is set by the section steel + the long-line tire mold of the steel bar skeleton of the standard section pier body with adjustable length. According to the layout of the main reinforcement of the pier body, the tire mold adopts an adjustable supporting steel frame. ;The sixth step is formwork processing and installation; before formwork installation, formwork is configured and numbered according to the height of the pier body, and the whole is pre-assembled to complete the formwork seam, wrong platform, and flatness adjustment; the pre-assembled qualified formwork reaches the local unevenness of the plate surface ≤1.0mm, the height difference between two adjacent boards is ≤1.0mm, the seam is ≤1.0mm, the overall surface flatness of the formwork is ≤3.0mm, and the paint is used as an adjustment mark after the back rib of the formwork that has passed the trial assembly; the pre-assembled acceptance is qualified The formwork is split into pieces, and the polishing machine is repeatedly polished to a bright metal color, and a uniform release agent is used to spread evenly on the surface of the formwork, slightly air-dried, and covered with a plastic film to prevent dust; the seventh step is concrete pouring; curved pier The column pier body and the tie beam concrete are integrally poured into shape, the concrete of the pier body is vibrated and compacted, and the concrete pouring string tube is reserved at the main reinforcement of the upper and lower floors where the tie beam on the top of the pier extends into the pier column, and the upper and lower passages for vibrator personnel are disconnected. The steel bars are connected by rolling straight thread sleeves, and the upper and lower layers and the adjacent steel bar joints are staggered at a distance of not less than 35d; Wooden and steel pipes are supported in a well shape on the upper opening of the formwork, and the bottom opening is no more than 2.0 meters away from the top surface of the concrete. The concrete is hoisted by a truck crane and unloaded in series. Layers are layered according to the horizontal 30cm, and adjacent pier columns are poured in turn. For construction, multiple vibrating rods are pre-installed around and in the middle of a single pier column to vibrate. When pouring the upper layer, the plug-in vibrator extends into the lower layer by 5-10cm. After the concrete strength reaches 2.5MPa, the pier top support is completed. The concrete is manually chiseled; the eighth step is to remove the formwork and maintain its health; the crane cooperates with the manual to complete the dismantling of the formwork. Use plastic film and scotch tape to tightly wrap and cover to keep the film tightly covered so that the surface of the component is always in a wet state; the ninth step is to remove the scaffolding; For the remaining materials, utensils and sundries, draw a safe area and set up warning signs when dismantling.

In the first step, the long-term exposed steel bars are painted with anti-rust cement slurry, and the connecting wire ends of the main bars are screwed into mechanical sleeves or protective caps, and the whole package is protected against rust.

In the sixth step, the formwork is installed piece by piece by means of a crane and manual adjustment. The bottom section formwork is fixed by the pre-embedded reinforcement of the cap. When the formwork is assembled, it is adjusted in place according to the sequence of pre-assembled numbers and marks. Paste and polish flush, the protective layer pads are vertically attached to the formwork, check the center deviation and verticality of the formwork after each section of the formwork is assembled, fasten the connection accessories, the formwork installation is completed, and the verticality and center position after passing the test On the top of the formwork, use cable wind ropes with tensioners to fix the four sides of the steel formwork in a figure-eight shape.

In the seventh step, after the concrete pouring is completed, the grouting is performed on the top of the pier to control the flatness of the surface, and the second grouting is performed when the concrete is about to set and has not yet set. Before the formwork is removed, the concrete on the pier body and the top of the tie beam is collected After light, use geotextiles to cover the top concrete to store water and maintain health.

In the eighth step, in the high temperature season, a drip irrigation bucket is installed on the top of the pier to connect the perforated water pipe to wrap the pier body with film and drip for maintenance. In winter construction, after the plastic film is wrapped, a thick double-layer geotextile is added to wrap it for heat preservation and maintenance. The inner side of the bracket is covered with canvas and heated for curing to ensure that the concrete is not lower than 10°C in the first 7 days after pouring.

Compared with the prior art, the present invention has the following beneficial effects: A construction method for one-time pouring and molding of urban elevated curved pier columns provided by the present invention: 1. The quality is significantly improved, and the pier body steel bar processing and the overall production of flat tire mold long-line method are adopted The standardized operation of the factory is convenient for quality control and acceptance. The site is assembled into a whole in sections to ensure the installation accuracy of the steel bars of the pier body; It is beneficial to formwork seam joints, stagger inspection, and plane position and verticality control, which improves the appearance quality and geometric accuracy of the finished pier column, and realizes that there is no tie rod hole in the finished pier body; the formwork is coated with uniform high-quality release agent, and the pier column Concrete is poured continuously at one time, which ensures that the finished pier has no construction joints after the formwork is removed, and the color of the concrete is consistent.

2. The construction is safe and the risk is small. Compared with conventional on-site processing, the on-site processing and on-site assembly installation of steel bars are less affected by external factors; the secondary installation, support, and dismantling procedures of traditional formwork are cancelled, which improves construction safety.

3. In terms of construction period and progress, the steel skeleton of the pier column is mass-produced on-site by tire mold method, and it works in parallel with the construction of the platform cap. The steel bars are loosely tied on site, the steel bars and formwork are installed in two times, and the concrete is poured in two times. Compared with the construction period of a single pier column, the construction period can be shortened by 4 to 5 days.

4. In terms of cost saving and economic benefits, the present invention improves the utilization rate of templates and steel pipe support turnover materials; reduces the waste of steel bar processing materials, improves work efficiency, and cancels the secondary joint treatment of conventional construction, the erection and removal of scaffolding operation platforms, The investment in formwork installation and dismantling personnel and lifting and hoisting equipment has realized the effective conversion of the process, accelerated the progress, and reduced the project management expenses.

Description of drawings

Fig. 1 is a construction process flow chart of the present invention.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

The construction method provided by the invention has the characteristics of fast construction, reasonable structure, economic benefits, etc., and is widely applicable to urban high-pier bridges, especially urban high-pier landscape bridges.

The technological principle of the construction method provided by the present invention is as follows: steel pipe scaffolding is erected around the pier body as a working platform for installation of the pier body reinforcement skeleton, formwork installation and dismantling, and concrete pouring. Installed as a whole, the formwork of the pier body is assembled in sections using shaped steel formwork in the form of a pier body curve.

The operation plan of the present invention is: 1. The pre-embedded main reinforcement of the pier column is positioned and welded firmly with the reinforcement of the cap, and a sufficient number of stirrups are bound to form a rigid skeleton to prevent the deformation of the pre-embedded reinforcement during concrete pouring and vibration of the cap , shifting, apply rust-proof grout to the long-term exposed steel bars, screw the main bar connecting wire head into the mechanical sleeve or protective cap, and wrap the whole body for anti-rust protection.

2. After the concrete strength of the chiseled cap at the junction of the pier body and the cap reaches 2.5 MPa, the concrete on the top surface of the cap inside the pre-embedded steel bar of the pier body shall be chiseled until more stones are exposed on the concrete surface (fresh concrete), and Rinse well.

3. Measurement and setting out Use the total station to place the vertical and horizontal axes of the pier column and the contour lines of the inner and outer planes of the column formwork on the top of the platform, and the ink fountain will pop up the connection line to measure the elevation around the bottom of the pier, which will be used as the benchmark for steel bar binding, installation and formwork erection .

4. Scaffold erection Around the pier body, use Φ48mm×3.5mm bowl buckle bracket or fastener type steel pipe to set up double-row scaffolding as a working platform for pier body reinforcement installation, formwork installation and dismantling, and concrete pouring.

The surroundings of the scaffolding are closed, and the foundation is placed on the platform cap and the treated hardened foundation. Steel pipes and fasteners are used on the inside and outside to set up inclined rods or scissors braces according to the specifications to ensure the overall stability of the scaffold.

Between the inner side of the scaffold and the outer formwork, formwork installation, demolition distance and distance are reserved, the scaffolding boards are fully paved within the working layer and the width of the channel, and the railings on the peripheral platform are 1.2m higher than the uppermost working layer.

5. Steel bar processing and installation A steel bar processing area is set up on site, which is specially used for steel bar stacking and processing.

1. Thread head processing of main reinforcement: The main reinforcement of the pier body (≥Φ25mm) is connected by a rolling straight thread sleeve, and a wire head processing operation platform is set up on site, realizing the streamlined operation of steel bar blanking, wire head processing, grinding, finished product stacking, and acceptance inspection .

2. Processing of semi-finished products: Semi-finished products are processed by classification. For the main reinforcement and stirrup of the variable cross-section section due to the different sizes of each part, it is processed and stacked by numbering one by one.

3. Processing of pier body steel bar skeleton: In order to ensure the accuracy and installation efficiency of the on-site pier body steel bar installation, and effectively solve the technical problems of different directions and sizes of the main bars and stirrups in the curved section, the pier column steel bar frame is made of flat ground in the steel bar processing workshop. The overall production of the tire mold by the long-line method.

Due to the fixed size of the curve section of the pier body, the section steel is used to set the fixed curve section + the long-line tire mold of the standard pier body reinforcement skeleton with adjustable length. It is suitable for the production of steel skeletons with different cross-sections and is convenient for lifting and shifting.

Taking the rectangular bergamot-style pier of the viaduct approach bridge in Nantong City as an example, the height direction of the pier column is changed from a straight line section to a 4m curved section. The cross-sectional size of the top of the section is 2.3×2.0m, and the cross-sectional size of the top of the curved section of the side pier is 2.3×2.5m. The center line of the staked tire mold coincides with the axis of the straight and curved section of the pier body on the flat ground, and [12.6 channel steel is used to press the pier Membrane pedestals are set at intervals of 1.5m between straight sections and 1m between curved sections (adjacent pedestals are connected by section steel to ensure the overall rigidity). Considering the gradual change of the cross-section of the curved section of the pier body, the width of the pedestal on one side of the curved section can be adjusted∟ The 100×10 angle steel is hinged with the pedestal, and the other side is set according to the line of the pier body. The ∟100×10 angle steel is consolidated with the pedestal. The ×10 angle steel is hinged, and at the same time, the height of the tire frame supporting steel in the curve section is also gradually changed. The sides of the ∟100×10 angle steel on both sides of the membrane are welded according to the distance between the main ribs. The positioning nuts used to fix the main ribs and the pull-out positioning ribs are used to complete the 4m fixed curve. The production of long-line tire molds for segmental + variable straight segment pier body skeletons, this bench is suitable for the production of steel skeletons for middle piers and side piers of different heights.

The reinforced skeleton of the pier body is made in sections and bound as a whole. Firstly, the adjustable ∟100×10 and ∟50×5 angle steels are installed, and the 50×5 angle steels are fixed to the other side. 100×10 angle steel is installed with the main reinforcement support reinforcement to form an integral membrane. Place the main reinforcement on the tire model steel and the support reinforcement according to the logo. The main reinforcement of the pier body is connected by a rolling straight thread sleeve. The number of reinforcement joints at the same section does not exceed the number of section reinforcement The joints of adjacent steel bars are staggered at a distance of not less than 35d. The main bars in the curved section must be placed in strict accordance with the design position. The orientation of the main bars in the curved section should be precisely adjusted and locked with lock nuts. A total of three stiffening stirrups (with the same diameter as the main reinforcement) are welded on the tail end, and the stiffening stirrups and the main reinforcement are spot-welded firmly one by one to ensure the lifting stiffness of the finished steel skeleton, the separation of the skeleton and the butt joint accuracy of the sleeve during on-site installation. The construction process of the reinforcement forming method is to bind the stirrups of the pier body at the end, and the stirrups are bound closely to the main reinforcement, the grids of the upper and lower layers are aligned, and the spacing between layers is accurate, and the steel skeleton is completed.

After the steel frame matching of the pier body is completed, paint the connection marks on the corresponding steel bars of the two adjacent steel bar frames, number the segments, and set lifting rings at the stiffening stirrups of the segmental steel bar frames to ensure that the steel bar frames can be hoisted properly. To avoid twisting and deformation, complete the drawing of the main reinforcement support of the pier body on both sides, and release the connection between the movable ∟100×10, ∟50×5 angle steel on one side and the ∟100×10 angle steel on the other side, so as to facilitate the distribution The section steel frame is disassembled, hoisted and moved, and the section steel frame is hoisted and moved to the specified place for standard storage.

Steel frame installation: The steel frame that passes the inspection shall be transported to the site in sections according to the installation sequence of the front field, and the flat transport vehicle shall be equipped with a steel frame supporting platform with the same spacing as the tire film to prevent the steel frame from being deformed during stacking and transportation .

The crane adopts the method of "two-point lifting" to install in sections, and the hoisting ceiling is set to connect the steel wire rope shoulder beam with the stiffening hoisting point to ensure the verticality of the steel frame, and the manual coordination of the steel frame is accurate.

The main reinforcement of the pier column adopts a rolling straight thread sleeve with a lock nut, and the segmental reinforcement skeleton and the main reinforcement of the pre-embedded identification mark of the cap are seated in alignment, and are connected one by one. The steel bar and the sleeve are locked with a lock nut, and the connection quality is checked with a torque wrench.

In order to ensure the plane position and verticality of the steel reinforcement skeleton of the pier body, the plane position of the pier body is set out on the cap platform, and measured by dropping the hammer, a main reinforcement is erected on the scaffold every 2-4m in height using steel pipes to install the outer frame to form a rigid skeleton pair A reinforced skeleton has been installed for verification and protection.

After the installation of the section-by-section reinforcement skeleton is completed, a plum blossom-shaped concrete protection layer pad that matches the net protective layer thickness of the steel reinforcement required by the design and has the same label and color as the pier body concrete is bound on the side of the pier body reinforcement skeleton.

The upper tie beams are installed at the ends of the pier body columns on both sides of the curved section, and the bottom formwork of the upper tie beams is installed first, and then the reinforcement of the upper tie beams is installed.

After the pier column reinforcement is installed, if the formwork cannot be installed in time, wind ropes should be set around to fix it and wrapped with colored strips to prevent dirt and rust.

6. Formwork processing and installation Before the formwork is installed, the formwork is configured and numbered according to the height of the pier body, and the whole is pre-assembled to complete the formwork seam, staggered platform, and flatness adjustment.

The pre-assembled qualified formwork should meet the local unevenness of the board surface ≤ 1.0mm, the height difference between the adjacent two boards ≤ 1.0mm, the seam ≤ 1.0mm, the overall surface flatness of the formwork ≤ 3.0mm, and the back rib of the qualified formwork in the trial assembly Finally, use paint as an adjustment mark.

The pre-assembled and accepted templates are split into pieces, and the polishing machine is repeatedly polished to a bright metal color. A uniform release agent is used to spread evenly on the surface of the template, and it is slightly air-dried, and covered with a plastic film to prevent dust and prevent secondary pollution. Mirror finish on concrete surface.

The formwork is installed piece by piece by means of a crane and manual adjustment. The bottom section formwork is fixed by the pre-embedded reinforcement of the cap. When the formwork is assembled, it is adjusted in place according to the pre-assembled numbering sequence and marks. The joints are pasted with double-sided adhesive and polished to be flush , to achieve tight joints, no wrong platform, and the protective layer pads are vertically attached to the formwork without damage. After the formwork of each section is assembled, check the center deviation and verticality of the formwork, and fasten the connecting parts to ensure that the formwork has sufficient space. Strength and rigidity, assemble the template for the next section after passing the test.

After the formwork is installed and the verticality and center position are tested to be qualified, the four sides of the steel formwork are fixed firmly in the shape of an "eight" with a cable wind rope and a tensioner on the top of the formwork.

7. Concrete pouring Curved pier column pier body and tie beam concrete are integrally poured into shape. Due to the dense steel reinforcement of the pier body, there are many steel mesh pieces and pre-embedded parts for the pier top support pad stone, concrete pouring and vibration have always been difficult in its construction. , in order to ensure that the concrete enters the mold smoothly, the concrete of the pier body is vibrated and compacted, and the concrete pouring string tube is reserved at the main reinforcement of the upper and lower layers of the pier top tie beam extending into the pier column for installation and disassembly. Rolled straight thread sleeve connection, the upper and lower layers and adjacent steel bar joints are staggered by a distance of not less than 35d.

The vibrator goes through the reserved manhole and ladder at the top of the pier to the inside of the steel bar, and pours the concrete with the string tube. The car crane lifts the hopper, and the material is discharged in series. The layers are layered according to the horizontal 30cm, and the adjacent piers are poured in turn. Considering the dense steel bars in the mold and the inconvenience of the displacement of the vibrator, multiple vibrators are pre-installed around and in the middle of a single pier. On the one hand, it is beneficial to the vibration of the vibrator, and on the other hand, it speeds up the concrete vibration progress, avoids the formation of cold joints due to the long time of concrete pouring, and reduces the labor intensity of the vibrator. The vibrating operation follows the "first outside The principle of "back inside, fast insertion and slow extraction, but not less", when pouring the upper layer, the plug-in vibrator extends 5-10cm into the lower layer to ensure comprehensive vibration and compactness, and the formwork should be prevented from being deformed or collided by the vibrator Formwork, steel bars, embedded parts, etc., when it is found that the steel bars are trampled or the support parts are displaced, they should be corrected in time, and it is strictly forbidden for workers to walk around on the steel bars.

After the concrete pouring is completed, the grouting on the top of the pier shall be carried out in time to control the surface flatness, and the grouting shall be carried out a second time when the concrete is about to set initially, so as to prevent cracks on the concrete surface.

Before the formwork is removed, the concrete on the top of the pier body and the tie beam is immediately covered with geotextiles to store water and maintain its health.

After the concrete strength reaches 2.5MPa, the pier top support pad stone concrete is artificially chiseled.

8. Formwork removal and health preservation The crane cooperates with the manual to complete the removal of the formwork, and the dismantled formwork is sorted and piled up, cleaned up centrally, and the release agent is brushed for the next use.

Immediately after the formwork is removed at room temperature, sprinkle water for maintenance, and wrap it tightly with plastic film and transparent tape in time to keep the film tightly covered so that the surface of the component is always in a wet state.

In the high temperature season, drip irrigation barrels are installed on the top of the pier to connect the perforated water pipes to wrap the pier body with film-covered dripping for maintenance.

For winter construction, after wrapping with plastic film, add thick double-layer geotextile wrapping for heat preservation and maintenance, and add canvas covering inside the support for heating and curing to ensure that the concrete is not lower than 10°C in the first 7 days after pouring.

9. The operation frame can be removed after the removal of the scaffolding template. Before the removal of the scaffolding, a comprehensive inspection of the scaffolding is carried out to remove all remaining materials, utensils and sundries; a safe area is drawn during the removal, warning signs are set, and special personnel are assigned to take care of it; Components should be classified and stacked to facilitate transportation, maintenance and storage.

Benefit analysis of this construction scheme: (1) Economic benefit analysis 1. The processing of the pier body reinforcement and the construction of the on-site cap platform are carried out in parallel, which effectively realizes the transformation of the process and improves the continuity and balance of the pier body construction.

2. The blanking, processing and overall production of pier body steel bars adopt factory standardized operations, which is convenient for quality control and acceptance, effectively improves work efficiency and machine utilization rate, and reduces waste of raw material resources.

3. The main reinforcement of the pier column is mechanically connected with a straight thread sleeve. According to the lifting capacity, the steel skeleton of the pier body on site can be lengthened in advance in sections, and the assembly-type overall installation is adopted to ensure the installation quality and efficiency, and reduce or cancel the erection of the reinforcement installation platform. Compared with the traditional pier body steel bar installation, steel pipes are used to erect the work platform layer by layer on site, and the main bars are welded and lengthened one by one by a crane, layered stirrups are tied, and compared with the reinforcement process, the construction difficulty is reduced and the labor intensity is reduced. The use time is greatly reduced, and the construction period is doubled.

4. The formwork of the pier body optimizes the assembly and reinforcement methods, which improves the accuracy and efficiency of formwork installation. The concrete of the pier body is poured at one time, which reduces the secondary concrete joint treatment, steel bar combing and lengthening, scaffolding operation platform erection and dismantling in conventional engineering construction. The secondary installation, support and dismantling process of the formwork improves the utilization rate of the turnover materials of the formwork and steel pipe support, and reduces the investment of personnel, lifting equipment and materials.

5. On the premise of ensuring the quality, the invention can effectively save the construction period, reduce material waste, improve work efficiency, reduce construction and management costs, and have good economic benefits.

Taking the construction of a single pier column (double column) as an example, compared with the conventional construction technology, it saves an average of 15 man-days of labor, 3 shifts of 25T truck cranes, shortens the construction period by 4-5 days, and improves the double-sided construction of formwork and pier body. The utilization rate of scaffolding steel pipe support turnover materials, labor and mechanical costs are reduced by about 8,000 yuan/seat, plus the benefits brought about by saving the construction period, the economic benefits are significant.

(2) Analysis of social benefits Curved piers are mostly used in projects with high urban and regional image requirements. Most of these projects have tight construction schedules and high requirements for quality, safety, and civilized construction. The present invention effectively improves the quality. It has improved the degree of industrialized construction, has few environmental constraints, and has low construction safety risks. It has made breakthroughs in improving work efficiency, shortening construction period, saving costs, and safe and civilized construction, which has good social benefits.

Claims (5)

1. an overhead road of city curvilinear style pier stud one-time-concreting molding construction method, is characterized in that:

Construction sequence is as follows:

The first step, the pre-buried main muscle location of pier stud:

Pre-buried main muscle, cushion cap reinforcing bar firm welding, colligation stirrup forms stiff skeleton;

Second step, pier shaft and cushion cap binding site dabbing:

After cushion cap concrete strength reaches 2.5MPa, dabbing is carried out to cushion cap end face concrete inside pier shaft embedded bar, cuts a hole to concrete face has stone to expose, and rinse well;

3rd step, surveying and locating;

Adopt total powerstation to put at cushion cap end face and establish Planar Contours inside and outside the longitudinal and transverse axis of pier stud and post mould, ink fountain ejects line, measures surrounding absolute altitude at the bottom of pier, as reinforcing bar binding, installation and formwork erection benchmark;

4th step, scaffold building;

Pier shaft surrounding adopt Φ 48mm × 3.5mm bowl button support or fastener type steel pipe set up double-pole scaffold tear open as pier shaft reinforcement installation, template peace and concreting time working platform; Scaffold surrounding closes, basis falls within cushion cap and processes on the ground that hardened, interior outside utilizes steel pipe and fastener to arrange brace or bridging by code requirement, reserving model sheetinstallat inside scaffold and between external mold, tearing open apart from removing spacing, within the scope of work layer, channel width, scaffold floor is paved with surely, and peripheral platform railing is than the superiors operation floor height 1.2m;

5th step, steel bar meter and installation;

1) main muscle silk head processing: the main muscle of pier shaft (>=Φ 25mm) adopts roll forming straight screw sleeve to connect;

2) semiproduct processing: semiproduct adopt classification processing, take by root numbering blanking processing, classify and pile up for the main muscle of variable cross-section section and stirrup;

3) pier shaft cage of reinforcement processing: pier stud cage of reinforcement is overall loose tool long line method integral manufacturing on employing level land, steel bar meter workshop, adopt shaped steel that fixed curve section+long line loose tool of length-adjustable standard paragraphs pier shaft cage of reinforcement is set, arrange according to the main muscle of pier shaft, loose tool adopts adjustable support shaped steel frame;

6th step, template processing, installation;

Number according to the good template of the level configurations of pier shaft before model sheetinstallat, entirety is assembled in advance, complete formwork edge joint, faulting of slab ends, planeness adjustment;

Pre-splicing qualified template reaches local, plate face injustice≤1.0mm, adjacent two plate surface difference of height≤1.0mm, piece≤1.0mm, formwork integral surface finish≤3.0mm, and adopts paint to adjust mark after the template back of the body rib of examination split lattice;

The template of pre-splicing acceptance(check) splits into block, and sanding machine is polished repeatedly to metal light tone, adopts unified release agent, at template surface uniform application, slightly air-dry, and adopts covered rearing with plastic film dust-proof;

7th step, concreting;

Curvilinear style pier stud pier shaft and binder concrete monobloc cast shaping, pier shaft concrete vibrating is closely knit, reserve concreting tumbling barrel peace to tear open at the main muscle place of levels that pier top binder stretches into pier stud, vibrate personnel's lower channel, the reinforcing bar disconnected adopts rolling straight thread sleeve connection, and levels and adjacent bar splice are staggered and be not less than the distance of 35d;

Personnel of vibrating reserve manhole through Dun Ding and cat ladder is inner to reinforcing bar, connect tumbling barrel concreting, it is suitable for reading that tumbling barrel adopts the lumps of wood, steel pipe becomes groined type to be supported on template, end mouth distance concrete end face is no more than 2.0 meters, concrete adopts mobile crane to promote hopper, tumbling barrel blanking, by horizontal 30cm layering, adjacent pier stud is built in turn, single pier stud surrounding and middle part pre-set multiple stage vibrating spear and vibrate, when building upper strata, poker vibrator extend into lower floor 5 ~ 10cm, after concrete strength reaches 2.5MPa, completes pier topmast seat cushion stone concrete artificial chiseling;

8th step, form removable, health;

Crane coordinates and manually completes the dismounting of template, and the template classification of dismounting is stacked, and concentrates cleaning, brushes release agent and get ready and time to use; Normal temperature lower bolster to be sprinkled water maintenance after removing immediately, adopts plastic sheeting and adhesive tape closely to swathe covering, keeps plastic film covering tight, makes component surface be in moisture state all the time;

9th step, scaffold is removed;

Dismantling operation frame after form removable, before scaffold is removed, do to check to scaffold, clear all surplus material, and utensil and foreign material, mark place of safety during dismounting, arranges warning mark comprehensively.

2. a kind of overhead road of city curvilinear style pier stud one-time-concreting molding construction method as claimed in claim 1, is characterized in that:

In the first step, to long-term exposed steel bar brushing aqueous rust preventive mud, main muscle connecting filament head screws in mechanical sleeve or protective cap, and overall parcel carries out corrosion protection.

3. a kind of overhead road of city curvilinear style pier stud one-time-concreting molding construction method as claimed in claim 2, is characterized in that:

In 6th step; template adopts crane to coordinate the mode of artificial adjustment to carry out block-by-block installation; coxopodite template is fixed by cushion cap embedded ribs; adjust to the right place by pre-splicing number order and mark during template assembly; adopt sticking double faced adhesive tape between piece and polish and flush; topping cushion block is vertical with template closely connected; every sections template assembly well checks center off normal and the verticality of template afterwards; be fastenedly connected accessory; model sheetinstallat completes; verticality and center detect qualified after, it is splayed fixation that the very useful cable wind rope of template joins tension device by steel form four limit.

4. a kind of overhead road of city curvilinear style pier stud one-time-concreting molding construction method as claimed in claim 3, is characterized in that:

In 7th step, after concreting completes, once slurry is received to pier jacking row, control surface planeness, until concrete want initial set also non-initial set time carry out secondary receive slurry, before form removable, after pier shaft and binder top concrete receive light, geotextiles is utilized to carry out covering retaining health to end face concrete.

5. a kind of overhead road of city curvilinear style pier stud one-time-concreting molding construction method as claimed in claim 4, is characterized in that:

In 8th step; high temperature season; Dun Ding arranges drip irrigation bucket tape splicing hole water pipe and is wound around pier shaft overlay film and drips pouring and carry out maintenance; winter construction; add the double-deck geotextiles of thickening after plastic sheeting swathes and swathe insulated curing; and inside support, increase canvas cover, carry out heating curing, guarantee that concrete is not less than 10 DEG C in 7 days after building.