CN112726517A - Construction method of aqueduct above bridge - Google Patents

Abstract

The aqueduct construction method above the bridge comprises support arrangement, process flow, construction method, support prepressing, aqueduct support frame dismantling, support construction safety precaution, template engineering construction method, steel bar engineering, concrete construction, template dismantling and road bridge support; the road and bridge support comprises I-shaped steel, a chain block and a support, wherein the I-shaped steel is arranged on two sides of an upright post, the I-shaped steel is provided with two layers, the I-shaped steel on the lower layer is tensioned and fixed on the upright post through the chain block, the I-shaped steel on the upper layer is vertically arranged on the I-shaped steel on the lower layer, and then the support is lapped on the I-shaped steel on the upper layer; the support arrangement comprises two steps of super-load template technical parameters and support system design; the process flow is that aqueduct columns, longitudinal and transverse beams and a tank body are separately constructed; the construction method comprises the following steps: basic processing of a supporting system, erection of a support and inspection and acceptance of the support; the template construction method is to install longitudinal and transverse templates; the steel bar engineering comprises two steps of steel bar storage and steel bar installation.

Description

Construction method of aqueduct above bridge

Technical Field

The invention relates to the technical field of civil engineering construction, in particular to a construction method of a aqueduct above a bridge.

Background

The aqueduct is an overhead water conveying building for conveying water flow of a channel to cross a canal, a road, a mountain rush, a valley opening and the like, is one of cross buildings which are most widely applied in canal buildings, and the concrete arch type aqueduct can fully exert the compression performance of concrete by virtue of the concrete arch type aqueduct, has low manufacturing cost and is widely applied. With social demands, the arch aqueduct is developing in the direction of large-span arch connection at present. The aqueduct is built in a local debris flow landslide section, so that debris flow landslide on a side slope in rainy season can be prevented from influencing normal road passing, and the passing safety of vehicles is ensured. Since the easy-to-break debris flow section of the road is usually steep in mountain conditions, the majority of the road is a bridge, and the aqueduct is constructed on the bridge, so that the construction difficulty is greatly increased; hospitals, schools, armies, public institutions, commercial facilities, passenger and freight transportation hubs and the like are distributed along roads, and the living of local residents cannot be influenced by aqueduct construction. And moreover, the debris flow rushes down from the debris flow sliding groove above the aqueduct in rainy season, the field road traffic influence is large, the aqueduct construction needs to be completed before the rainy season comes, and the aqueduct construction needs to be completed quickly so as to avoid the damage of the debris flow. The road surface below the aqueduct is usually a bridge surface, which can not bear thousands of tons of pressure, thus greatly increasing the construction difficulty of the aqueduct above the bridge.

Disclosure of Invention

In order to solve the problems, the invention provides a method for constructing a aqueduct above a bridge; the method has the advantages that the construction period of constructing the aqueduct is short, the door opening is arranged, the road is not blocked in the midway of construction, the passage of the road can be ensured during construction, the life of surrounding residents is facilitated, the aqueduct can be conveniently constructed on the bridge, the construction is simple and efficient, the bridge deck construction is facilitated, and the construction difficulty is reduced.

In order to achieve the technical purpose and achieve the technical effects, the invention is realized by the following technical scheme:

the aqueduct construction method above the bridge comprises support arrangement, process flow, construction method, support prepressing, aqueduct support frame dismantling, support construction safety precaution, template engineering construction method, steel bar engineering, concrete construction, template dismantling and road bridge support; the road and bridge support comprises I-shaped steel, a chain block and a support, wherein the I-shaped steel is arranged on two sides of an upright post, the I-shaped steel is provided with two layers, the I-shaped steel on the lower layer is tensioned and fixed on the upright post through the chain block, the I-shaped steel on the upper layer is vertically arranged on the I-shaped steel on the lower layer, and then the support is lapped on the I-shaped steel on the upper layer; the support arrangement comprises two steps of super-load template technical parameters and support system design; the process flow is that aqueduct columns, longitudinal and transverse beams and a tank body are separately constructed; the construction method comprises the following steps: basic processing of a supporting system, erection of a supporting frame and checking and acceptance of a support; the template construction method is to install longitudinal and transverse templates; the steel bar engineering comprises two steps of steel bar storage and steel bar installation; the template dismounting comprises the dismounting time of the template and the preparation work before the bottom die and the template are dismounted.

Furthermore, the technical parameters of the super-load template comprise parameters of a longitudinal beam, a cross beam, a aqueduct solid plate, a 1# door opening and a 2# door opening.

Furthermore, the design of the supporting system comprises a vertical rod foundation, a vertical rod of a longitudinal and transverse beam supporting frame, an upper support, a lower support, a sweeping rod and a horizontal rod.

Further, the basic processing of the support system comprises the step of manufacturing a motor vehicle pavement structure layer.

Further, the support frame sets up the step, 1, measures laying-out 2, lays adjustable base, 3, indulge, horizontal pole setting installation 4, embrace post 5, gravity type abutment and support body drawknot 6, the adjustable top layer holds in the palm installation 7, lays top layer main joist, distribution secondary joist, 8, horizontal bridging sets up, 9, the connection of different support body heights.

Further, the step of pre-pressing the bracket comprises the following steps: 1. before prepressing, a measurer selects an observation point at the top of the support, and marks and numbers the observation point; 2. pre-pressing and loading are carried out for 4 times, the weight of the first time of loading is 60 percent of the total weight, the observation is carried out for 12 hours in a stable way, and when the average value of the settlement difference of the support measuring points for 2 times is less than 2mm, the loading can be continued; loading for the second time to 80% of the total weight, stabilizing for 12 hours, and continuously loading when the average value of the settlement difference of the support measuring points for 2 continuous times is less than 2 mm; loading for the third time until the total weight is 100%, stabilizing for 12 hours, and continuously loading when the average value of the settlement difference of the support measuring points for 2 continuous times is less than 2 mm; loading for the fourth time to 110% of the total weight, stably observing for 12 hours, and unloading step by step once after the settlement is stable when the average value of the settlement difference of the support measuring points is less than 2mm for 2 consecutive times; 3. pre-pressing measurement data observation, recording and sorting the result of each loading observation so as to better master foundation treatment and support erection parameters of the control box girder; 4. and pre-camber setting, wherein in order to enable the superstructure to meet the design requirements after the frame is disassembled, a reasonable and accurate pre-camber value needs to be set during construction, and the pre-camber is temporarily controlled by +10mm according to the design of the box girder in the pre-pressing stage.

Further, the aqueduct support frame is dismantled: 1. the strength of the cast-in-situ aqueduct bracket reaches 100 percent, and the construction bracket is dismantled; 2. the dismantling process follows the principle of firstly assembling and then dismantling from top to bottom, namely, firstly loosening the jacking to separate the bottom die of the bottom beam plate from the beam body; 3. observing the camber of the aqueduct and the change of the abutment by using an instrument, carefully recording, and additionally arranging a special person to observe whether a crack phenomenon exists; 4. when the vertical rod is detached, the vertical rod is firstly held, and then the last plate opening of the connecting cross rod is detached, so that the vertical rod is prevented from falling.

Further, the method for installing the longitudinal and transverse beam template comprises the following steps: (1) the ground is flat, foot plates are laid, when a multi-layer support formwork is adopted, the vertical rods are vertical, the vertical rods on the upper layer and the lower layer are on the same vertical central line, and the stability of the multi-layer supports in the vertical direction and the horizontal direction is ensured; (2) determining the arrangement and the spacing between the vertical rods and the keels in the template design according to the concrete weight and the construction load of the longitudinal and transverse beams; (3) the height of the supporting top is adjusted through the line, and the large keel is leveled.

Further, the steel bar installation step: 1. installing the longitudinal beams and the transverse beams one by one, installing a bottom die when the template is constructed, and constructing side molds after the construction of the longitudinal beams and the transverse beams is finished;

2. when the reinforcing steel bar is installed, a protective layer cushion block is installed according to requirements, and the design requirements of the protective layer are met;

3) in the steel bar installation process, the reserved steel bars are installed according to the requirements of design drawings, and the accurate installation position of the embedded part and the firm positioning are guaranteed.

Further, the concrete construction adopts an automobile pump for pouring, and concrete is poured strictly according to a set sequence; the concrete is layered from the middle to the two sides and is poured evenly.

Further, the template removing step: 1. the method comprises the following steps that (1) when the template is removed, the strength of concrete of the side-form shear wall reaches more than 2.5MPa, and the surface and edges and corners of the concrete are not damaged due to template removal and can be removed; 2. the bottom die can be disassembled when the dismantling time of the bottom die meets the specified strength requirement according to the strength of the concrete test block at the position under the same condition; 3. the template dismounting procedure is that the template is dismounted according to the template dismounting sequence of the template design, and the template dismounting sequence from top to bottom is followed after the template is dismounted when no template is designed; the support is that the lateral support is dismantled before dismantling vertical support.

The invention has the beneficial effects that: the aqueduct construction method above the bridge has the following advantages:

the method has the advantages that the construction period of constructing the aqueduct is short, the door opening is arranged, the road is not blocked in the midway of construction, the passage of the road can be ensured during construction, the life of surrounding residents is facilitated, the aqueduct can be conveniently constructed on the bridge, and the construction is simple and efficient. The aqueduct can prevent mud-rock flow landslide on the side slope in rainy season, influence the normal traffic of the road, and guarantee the traffic safety. The bridge pier is provided with the I-shaped steel, the I-shaped steel is fixed on the upright post, the I-shaped steel is tensioned and fixed through the chain block, the support is lapped on the I-shaped steel, the support is not pressed on the bridge floor, force is transmitted to the upright post pier through the I-shaped steel, and the problem that construction above the bridge floor is difficult is solved.

Of course, it is not necessary for any product in which the invention is practiced to achieve all of the above-described advantages at the same time.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is an elevational view of a aqueduct support;

FIG. 2 is a cross-sectional view of a aqueduct support;

FIG. 3 is a schematic view of a aqueduct configuration;

FIG. 4 is a construction process flow diagram;

FIG. 5 is an elevational view of the arrangement of diagonal members of the unit truss;

fig. 6 is a schematic structural diagram of the road bridge support.

In the drawings, the components represented by the respective reference numerals are listed below:

1-aqueduct, 2-upright post, 3-door opening, 4-bracket, 401-upright post, 402-horizontal rod, 403-vertical diagonal rod, 404-horizontal diagonal rod, 5-mortar anchor rod, 6-antiskid groove, 7-I-steel and 8-chain block.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the 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.

Referring to fig. 1-5, the aqueduct construction method above the bridge comprises support arrangement, process flow, construction method, support prepressing, aqueduct support frame dismantling, support construction safety precaution, template engineering construction method, steel bar engineering, concrete construction, template dismantling and road bridge support; the road and bridge support comprises I-shaped steel, a chain block and a support, wherein the I-shaped steel is arranged on two sides of an upright post, the I-shaped steel is provided with two layers, the I-shaped steel on the lower layer is tensioned and fixed on the upright post through the chain block, the I-shaped steel on the upper layer is vertically arranged on the I-shaped steel on the lower layer, and then the support is lapped on the I-shaped steel on the upper layer; the support arrangement comprises two steps of super-load template technical parameters and support system design; the process flow is that aqueduct columns, longitudinal and transverse beams and a tank body are separately constructed; the construction method comprises the following steps: basic processing of a supporting system, erection of a supporting frame and checking and acceptance of a support; the template construction method is to install longitudinal and transverse templates; the steel bar engineering comprises two steps of steel bar storage and steel bar installation; the template dismounting comprises the dismounting time of the template and the preparation work before the bottom die and the template are dismounted.

Example 1

And (3) field plane arrangement: adopting a plane arrangement principle;

(1) the plane arrangement is scientific and reasonable, and the occupied area of the construction site is small;

(2) transportation is reasonably organized, and secondary transportation is reduced;

(3) the division of the construction area and the temporary occupation of the site are in accordance with the requirements of the overall construction deployment and the construction flow, and the mutual interference is reduced;

(4) the existing structures and the existing facilities are fully utilized to reduce the construction cost of temporary facilities for project construction service;

(5) meets the requirements of energy conservation, environmental protection, safety, fire fighting and the like.

Example 2

Technical parameters of the super-load template: the maximum height of the bracket is 12 m; width of the bracket: 16.5 m; the single span length of the bracket: 13.2 m; pole setting: 3m/2 m; transverse span of longitudinal beam of aqueduct: 13.2 m; transverse span of aqueduct: 4.6 m; cross bar: setting the steps in a layer with the step pitch of 1.5 m; b, bridging: setting the steps in a layer according to 4 steps; gravity type abutment wall connecting piece: setting according to 3 m; embracing the column: setting according to 3 m; vertical diagonal draw bar: the unit truss combination mode of the truss type supporting structure adopts a matrix type; steel pipe fastener # style of calligraphy frame cohesion column: setting according to 3 m; the maximum longitudinal distance of the main keel (double-limb 12# channel steel) is 0.9 m; the spacing between the secondary keels (100mm square timber) is 0.1 m.

Designing a supporting system:

(1) pole setting basis: the left side is an asphalt pavement which is newly built, 300 × 6cm of a green stone slab is paved under the feet of the vertical rods before the formwork support frame is erected, the green stone slab is paved and stably paved, the right side spans the twentieth span of the k5+601.3 bridge, and the wet joint of the bridge plate is a weak position;

(2) vertical rod of longitudinal and transverse beam support frame: a disc buckle type full-hall support frame is adopted, a vehicle running door opening is arranged below the support frame, a corresponding vertical rod interval is selected by a cast-in-place aqueduct full-hall support system according to the beam height and the erection height, and the horizontal rod interval is 1500 mm;

(3) supporting: the top support of the bracket adopts an adjustable jacking with the outer diameter of 48 mm;

(4) supporting: the bottom support of the bracket adopts an adjustable lower support with the outer diameter of 48 mm;

(5) a floor sweeping rod: arranging a floor sweeping rod at the height of 500mm from the ground at the bottom of the vertical rod according to the program of the vertical rod, the horizontal rod and the vertical rod;

(6) horizontal rod: the horizontal rods have the step pitch of 1.5m and are arranged vertically and horizontally. The step distance of the horizontal rods at the topmost layer is adjusted in real time and is controlled within 500mm from the bottom of the beam or the bottom of the plate, the bottom of the adjustable support is provided with a horizontal rod, and the end part of the adjustable support is tightly propped against the side of the peripheral beams;

example 3

Basic processing of the support system; through the checking calculation of the vertical rod foundation, the bearing capacity of the vertical rod foundation of the longitudinal and transverse beams is greater than 101Kpa, the bearing capacity of the vertical rod foundation of the aqueduct groove body is greater than 176Kpa, the bearing capacity of the vertical rod foundation of the door opening is greater than 70Kpa, 300 x 6cm of the green stone plate is paved under the foot of the vertical rod, through the test detection, the compression strength of the green stone plate reaches 60Mpa, and the bearing capacity meets the requirement.

The vertical rod foundation of the longitudinal beam and the aqueduct trough body is arranged on a left asphalt pavement and a right bridge floor which are built, the side (right side) facing the river is a river bank slope, the right pavement is made of 80cm thick soil and stones, 16cm thick graded broken stone, 45cm thick cement stable layer and 18cm thick asphalt layer, the bearing capacity of the foundation below a road bed is more than 200Kpa through a foundation bearing capacity experiment, and the bearing capacity of the vertical rod foundation meets the requirement.

Method for manufacturing road surface structure layer of motor vehicle

The right bridge deck is a 7.5-meter traffic lane and a 5-meter facility working belt, a wet joint of the bridge deck is 1 meter wide and 0.15 meter thick, belongs to a post-pouring section, and has weaker bearing capacity than that of a thin bridge, and the bearing capacity is enhanced by paving a 2cm thick steel plate in the traffic lane range in a processing mode; the facility belt is composed of a green belt with the width of 1.5 meters and a green slow-moving road with the width of 3.5 meters, an anti-collision wall and four slow-moving road pad beams are respectively arranged, and because the facility belt is not arranged on a plane and the height difference is large, different combination forms can be caused on the frame body, and unstable factors are increased; in order to reduce different combinations of the frame bodies as much as possible, the gaps among the cushion beams are filled and tamped by using the stone dust sand, so that the whole facility belt is on the same plane, and then a layer of steel plate with the thickness of 2cm is fully paved on the top surface.

The outer foundation of the bridge falls on the bearing platform and the outer side artificial filling, the soil body is loose, and the bearing capacity is low. The basic method comprises the following steps: removing loose soil mass 5 meters outside the bearing platform, excavating to a bearing layer, pouring a C20 concrete gravity type retaining wall, wherein the length of the retaining wall is 2 meters longer than that of each side of the projection position of the frame, the top of the wall is preferably 20cm higher than the bottom of the bearing platform, the back of the wall is backfilled to 20cm below the top of the wall by adopting rubbles, a C20 concrete cushion layer with the thickness of 20cm is poured on the surface, and a 10 x 10cm phi 10 steel mesh is laid in the cushion layer.

The method for constructing the door opening foundation is that a C30 foundation with the width of 2000mm and the height of 500mm is arranged on the two sides of the door opening along the path direction, an asphalt pavement is arranged under the door opening foundation, the pavement is made of 80cm thick soil and stones, 16cm thick graded broken stones, 45cm thick cement stabilizing layers and 18cm thick asphalt layers, the bearing capacity of the pavement under a roadbed is more than 200Kpa through a foundation bearing capacity experiment, and the bearing capacity of the upright stanchion foundation meets the requirement.

Example 4

The support frame is set up, and this aqueduct is cast-in-place aqueduct, and the support material chooses for use various, needs to carry out the inspection of entering the field respectively according to the performance requirement of each material.

1. Survey lofting

The support system is pre-arranged before being installed, a warrior is used for carrying out field positioning according to the longitudinal and transverse distances of the vertical rods in the scheme, and a control line or a pull line is sprung on the ground for controlling, so that the purpose of ensuring the accurate erection position of the support body is achieved.

2. Lay adjustable base

Adjustable bases are arranged at transverse and longitudinal intervals, the heights of the bases and the heights of the bases are determined by the on-site actual measurement of the level gauge, the positions of adjustable nuts on the bases are adjusted, and the same ground frame body is guaranteed to be on a unified plane. The kneading length of the adjustable base screw rod and the nut is not less than 4-5 buttons, the length of the adjustable base screw rod inserted into the vertical rod is not less than 15cm, and the exposed length of the screw rod is not more than 30 cm. The maximum height of the first-layer longitudinal and transverse sweeping rod of the bracket from the ground is not more than 55 cm.

3. Longitudinal and transverse upright rod installation

Before installation, the scaffold is checked to see whether the scaffold has the phenomena of bending, joint welding, fracture and the like, and the scaffold system can be assembled without errors.

When the support is erected, the vertical deviation of the vertical rods is not larger than 1/500 of the total height of the support body and is not larger than 50mm, after the first-step support body assembly is completed, the verticality and the flatness of the horizontal rods of all the vertical rods are adjusted, and after all the vertical rods are adjusted, the support of the previous step can be assembled.

The vertical rods are connected through vertical rod connecting sleeves, and the positions of the joints of the adjacent vertical rod connecting sleeves in the same horizontal height are staggered by 500mm or more.

4. Hug column

Close to pier stud department and set up the support horizontal pole and hold tightly with the pier stud to support the jail with adjustable steel pipe, the staple bolt of every 3 meters on the height, steel pipe fastener card has three card with the body frame body at least, and the synchronous construction is embraced the post measure in the support work progress, and the junction wood pattern support pad protection pier stud concrete does not receive an ancient egg-shaped, leans on in river one side steel pipe scaffold for the tie beam and coils to detain the fastener for the frame body horizontal pole and be connected, increases the whole antidumping nature of support body, detailed template support plane schematic diagram.

5. Gravity type bridge abutment and frame body tie

When the gravity type abutment is constructed, the pulling embedded parts are embedded in the abutment position, the frame body and the gravity type abutment are pulled together according to 3m, and the overall stability of the frame body is guaranteed.

6. Adjustable top support installation of top layer

After the top layer vertical rods are assembled, the top layer adjustable jacking supports can be assembled, and the top surfaces of the jacking supports are adjusted to the designed elevation positions according to the designed elevation. The exposed length of the adjustable jacking screw rod is strictly limited to be more than 40cm, and the distance of the jacking extending out of the top horizontal rod is not more than 65 cm.

7. Laying top main keel and distributing secondary keel

After the top surface of the top support is adjusted to the designed elevation position, double-limb channel steel is laid, and the double-limb 12# channel steel is mutually transversely connected end to end by utilizing the connecting piece (the bolt of the connecting piece must be locked), so that the double-limb channel steel becomes a whole, and seams which are staggered are arranged along the bridge direction. And paving square timbers in the transverse direction, wherein the paving intervals are strictly carried out according to the design, a level gauge is used for checking the elevation, and the bottom formwork can be assembled after the elevation is free of errors.

8. Horizontal scissor brace erection

After the frame body vertical rod and the horizontal rod are erected, horizontal cross braces are erected, one steel pipe and a fastener are erected at every 4 steps, the fastener steel pipe is connected with the horizontal rod, and the distance between the first layer of cross braces and the ground is not larger than 55 cm.

9. Connections of different frame heights

Because the ground elevation is inconsistent, the support body is composed of groups with different heights, the support body is erected and is adjusted by the adjusting rod from the low side to the high side, the horizontal rod is arranged on the same plane as far as possible, and when the horizontal rod is inevitably arranged on the same horizontal plane, the steel pipe fastener and the horizontal rod are used for horizontal pulling, if the door opening support body and the adjacent support body, the integral stability of the support body is ensured, and the vertical surface of the inside of the support body is supported by the template.

Example 5

Support prepressing

The aqueduct concrete adopts full framing cast-in-place construction, the support is pre-pressed before concrete pouring, so that the rigidity and the bearing capacity of the support are checked, meanwhile, the inelastic deformation of the support is eliminated, the rule of the elastic deformation of the support is mastered, the strength, the rigidity and the stability of a support system are ensured, and the elastic deformation of the support is eliminated in a mode of setting the pre-camber of the support. The pre-pressing load of the bracket is not less than 1.1 times of the weight of the cast-in-situ aqueduct concrete. The aqueduct bracket can be disassembled after the construction of the aqueduct (the strength of concrete of the aqueduct body reaches 100 percent), the disassembly sequence of the bracket is that the bracket is firstly spanned and then pivoted, and simultaneously, the principle of symmetry, a small amount of brackets, multiple times and gradual completion is followed.

1. Purpose of prepressing

(1) Eliminating inelastic deformation and foundation settlement;

(2) measuring the elastic settlement of the foundation to provide reference data for determining the elevation of the bottom die;

(3) eliminating inelastic compression of the stent;

(4) and measuring the elastic compression of the support to provide reference data for determining the elevation of the bottom die.

2. Pre-pressing area

The pre-pressing area is an integral aqueduct.

For guaranteeing construction progress and pre-compaction quality, consider to adopt the sand bag pre-compaction, meet weather and need adopt waterproof tarpaulin to cover the sand bag, prevent to cause the loading numerical value to change because of sleet etc..

Observing the vertical settlement deformation of the loaded bracket, the template and the foundation by using a level gauge, and observing the displacement deformation of the bracket by using a total station, wherein the specific observation method comprises the following steps:

(1) and (4) selecting an observation point at the top of the support by a measurer before prepressing, marking and numbering.

(2) Pre-pressing and loading are carried out for 4 times, the weight of the first time of loading is 60 percent of the total weight, the observation is carried out for 12 hours in a stable way, and when the average value of the settlement difference of the support measuring points for 2 times is less than 2mm, the loading can be continued; loading for the second time to 80% of the total weight, stabilizing for 12 hours, and continuously loading when the average value of the settlement difference of the support measuring points for 2 continuous times is less than 2 mm; loading for the third time until the total weight is 100%, stabilizing for 12 hours, and continuously loading when the average value of the settlement difference of the support measuring points for 2 continuous times is less than 2 mm; and loading for the fourth time to 110% of the total weight, stably observing for 12 hours, and unloading step by step once after the settlement is stable when the average value of settlement differences of the support measuring points for 2 continuous times is less than 2 mm.

100% prepressing weight (self-adding item)

110% prepressing weight (self-adding item)

3. Observation of pre-compaction measurement data

(1) The observation uses a level gauge and a total station, only one observation station is arranged, and errors are not accumulated;

(2) after the field is hardened, arranging observation points on each span of field, and observing the original ground; observing a hardening field and the top of the support after the support is installed;

(3) observing at intervals of 2 hours after each time of loading is finished, and continuously loading when the average value of the settlement difference of the fulcrum measuring points for 2 continuous times is less than 2 mm; observing for 2 hours after the last loading is finished until the sedimentation and deformation are stable;

(4) observing the bracket and the field after unloading;

(5) and recording and sorting the observation result of each loading so as to better master the foundation treatment and support erection parameters of the control box girder.

4. Pre-camber setting

When pouring superstructure concrete on the support, the superstructure sinks to a certain extent and deflects to a certain extent during construction and after unloading. Therefore, in order to enable the superstructure to meet the design requirements after being disassembled, a reasonable and accurate pre-arching value needs to be set during construction, and the pre-arching stage is temporarily controlled according to the box girder design pre-arching degree +10 mm.

5. Qualification standard

(1) When one of the following conditions is satisfied, the support pre-pressing is judged to be qualified:

(2) the average value of the initial 24h settlement of each monitoring point is less than 1mm

(3) The average value of the initial 72h settlement of each monitoring point terminal point is less than 5mm

(4) In the process of pre-pressing the representative region of the stent, when the specification of the 5 th item of the specification is not met, all the stents of the same kind are processed after the reason is found out, and the representative region of the processed stent is re-selected for pre-pressing.

(5) And debugging the support frame after the pre-pressing and unloading, and performing the next construction after no error.

Example 6

Longitudinal and transverse beam formwork installation

(1) The ground is smooth and the foot plate is laid. When a multi-layer support formwork is adopted, the vertical rods are vertical, the vertical rods on the upper layer and the lower layer are on the same vertical central line, and the stability of the multi-layer supports in the vertical direction and the horizontal direction is ensured.

(2) The arrangement and the distance between the vertical rods and the keels are determined in the design of the formwork according to the concrete weight and the construction load of the longitudinal beams, and the arrangement of the vertical rods is considered to be provided with passing door openings.

(3) The height of the supporting top is adjusted through the line, and the large keel is leveled.

(4) The longitudinal and transverse beam template adopts a wood template

(5) The formwork support erection meets the requirement of a high support, and the support erection requirement is detailed.

(6) When pouring, the pouring and tamping are symmetrically pushed to the periphery according to the middle of the beam, and the pushing is carried out from the place with low elevation to the place with high elevation. The reserved position of the construction joint is designed in advance according to the time interval of concrete casting and tamping and the concrete supply condition.

Example 7

1. Steel bar storage and processing

(1) All the steel bars need to provide factory quality guarantee certificates and can be used after corresponding mechanical property and weldability performance tests are qualified and agreed by supervision engineers.

(2) The reinforcing bars are stored in a movable reinforcement cage, placed on a concrete strip foundation support, and should be protected from mechanical damage. The steel reinforcement should be free of harmful defects such as cracks and glass layers.

(3) The technical requirements of the steel bar joint are as follows:

before the construction of the steel bar welding, rust spots, oil stains, sundries and the like on the steel bar welding part and the surface of the contact part of the steel bar and the electrode are removed; when the end of the steel bar is bent or twisted, the end of the steel bar is straightened or cut off.

When the main rib adopts straight thread bush connection, the professional quality inspector of the project department randomly samples and inspects, and unqualified thread ends are left off through self-inspection qualified thread ends, so that the reason is found out, and the thread is machined again after the reason is solved. And (4) protecting the qualified thread ends, adding protective caps or screwing the thread ends by using sleeves, and sorting and stacking the thread ends according to specifications. When connecting the reinforcing steel bar, the reinforcing steel bar specification must be unanimous with telescopic specification, and the screw thread of reinforcing steel bar and sleeve should be clean, intact. When the embedded joint is adopted, the position, specification and quantity of the connecting sleeve meet the design requirements. The steel bar with the connecting sleeve is firmly fixed, and the exposed end of the connecting sleeve is provided with a protective cover. The rolled straight thread joint is constructed by using a pipe wrench and a torque wrench, two steel bar screw heads are mutually tightly jacked at the middle position of a sleeve, and the precision of the torque wrench for screwing the joint is +/-5%.

2. Installation of reinforcing bars

(1) Principle of installing reinforcing bars

Installing the longitudinal beams and the transverse beams one by one, installing a bottom die when the template is constructed, and constructing side molds after the construction of the longitudinal beams and the transverse beams is finished;

(2) technical requirements for installing reinforcing steel bars

1) After the reinforcing steel bars are processed into semi-finished products in a processing field, the semi-finished products are transported to a construction site by using an automobile and are lifted to a groove body by using a crane to be bound and formed.

2) When the reinforcing steel bar is installed, a protective layer cushion block is required to be installed according to requirements so as to meet the design requirements of the protective layer; the protective layer cushion block has enough strength and rigidity, and the concrete cushion block produced by a manufacturer with quality assurance is adopted and firmly bound by using reinforcing steel bars.

3) In the process of installing the steel bars, the reserved steel bars are installed according to the requirements of design drawings, and therefore the accurate installation position of the embedded part is guaranteed, and the positioning is firm.

Example 8

The engineering adopts commercial concrete and adopts an automobile pump for pouring, and concrete pouring is strictly carried out according to a set sequence.

Gravity type abutment, pier stud, longitudinal girder, cell body concrete part are pour, and gravity type abutment, pier stud pour the construction earlier, reach 75% design strength after, carry out the construction of vertical and horizontal roof beam again and pour, after vertical and horizontal roof beam intensity reached 100%, the cell body was constructed again. The concrete pouring is carried out by adopting an automobile pump. Considering that the concrete pouring can generate larger horizontal thrust, pouring is started from the lowest end of the longitudinal slope, the horizontal structure beam concrete is uniformly and symmetrically poured as far as possible, continuous material distribution at the same position is not needed, material distribution is horizontally moved within the range of 2-3 m, the pouring speed is not too high, the horizontal thrust is smaller after the pouring of the low-end beam concrete is completed and initial setting is achieved, the vertical pressure is mainly used, and the overall stability of a frame body in the pouring process is ensured. The cross section height and the span of the engineering beam slab are large, so that the balanced load in the construction process of the formwork support is ensured, a pouring mode of expanding from the middle part to two ends is adopted, in the concrete pouring process, a specially-assigned person is sent to the lower part to see the formwork, the pouring is stopped immediately when a problem is found, and the formwork support is reinforced.

When concrete is poured and tamped, operators can not concentrate on one concrete, and the free falling height of the concrete is required to be not more than 1.5m, so that the impact force on the formwork support is reduced; the concrete distribution is uniform, the thickness of the concrete distribution is controlled to be 200-300 mm, and the slump of commercial concrete is strictly controlled in the construction process.

Example 9

1. Demolition time of a formwork

The strength of the concrete when the formwork of the cast-in-place structure and its support are removed, when the design has no special requirements, must comply with the following regulations:

the strength of the side-form shear wall concrete reaches more than 2.5MPa, and the surface and edges of the side-form shear wall concrete are not damaged by form removal and can be removed.

2. Bottom die

The bottom die can be disassembled when the strength of the concrete test block reaches the specified strength requirement under the same condition of the part. The concrete strength meets the following regulation:

formwork removal procedure

The form should be removed according to the form removal sequence of the form design, if no design is available, the form removal sequence of first support and then removal, then removal and from top to bottom should be followed. The support is that the lateral support is dismantled before dismantling vertical support.

3. Preparation work before removal of form

(1) Constructors and safety personnel should carry out technical interaction with workers for removing the formwork;

(2) a concrete strength report is provided before the formwork is dismantled;

(3) before the template is removed, a quality inspector provides a template removal application report, and a project technical responsible person signs and confirms that the rear part can be removed;

(4) before the form removal, whether the supporting system is firm or not and whether a working surface exists or not should be checked;

(5) after the conditions are met, the template can be dismantled.

4. Safety measures for the removal of formworks

(1) Before the template is dismantled, carrying out technical bottom crossing on an operator, and carrying out construction according to the content of the bottom crossing strictly; when the mold is removed, a specially-assigned person is required to conduct, and a warning line is set to clearly divide the boundary range;

(2) the self protection of workers and the enclosing around the operation surface are well done before the form removal, when the beam slab bottom die is removed, the removed form is manually transferred to the floor surface in time for stacking and tidy, and the turnover material stacking part is cleaned in time after an area is removed;

(3) the form is removed without over-force, over-force and over-urgency, the removed material is timely carried away, the non-bearing part is firstly removed, and then the bearing part is removed.

(4) When the lower support of the beam with larger span is dismantled, the lower support is firstly dismantled from the span to the two ends respectively.

(5) The templates are cleaned after being detached and stacked orderly for the next use.

In the description herein, references to the description of "one embodiment," "an example," "a specific example" or the like are intended to mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example.

The preferred embodiments of the invention disclosed above are intended to be illustrative only. The preferred embodiments are not intended to be exhaustive or to limit the invention to the precise embodiments disclosed. Obviously, many modifications and variations are possible in light of the above teaching. The invention is limited only by the claims and their full scope and equivalents.

Claims (10)

1. The aqueduct construction method above the bridge is characterized by comprising support arrangement, process flow, a construction method, support prepressing, aqueduct support frame dismantling, support construction safety precaution, template engineering construction method, steel bar engineering, concrete construction, template dismantling and road bridge support; the road and bridge support comprises I-shaped steel, a chain block and a support, wherein the I-shaped steel is arranged on two sides of an upright post, the I-shaped steel is provided with two layers, the I-shaped steel on the lower layer is tensioned and fixed on the upright post through the chain block, the I-shaped steel on the upper layer is vertically arranged on the I-shaped steel on the lower layer, and then the support is lapped on the I-shaped steel on the upper layer; the support arrangement comprises two steps of super-load template technical parameters and support system design; the process flow is that aqueduct columns, longitudinal and transverse beams and a tank body are separately constructed; the construction method comprises the following steps: basic processing of a supporting system, erection of a supporting frame and checking and acceptance of a support; the template construction method is to install longitudinal and transverse templates; the steel bar engineering comprises two steps of steel bar storage and steel bar installation; the template dismounting comprises the dismounting time of the template and the preparation work before the bottom die and the template are dismounted.

2. The method for constructing the aqueduct above the bridge according to claim 1, wherein the technical parameters of the super-load template comprise parameters of a longitudinal beam, a cross beam, an aqueduct solid plate, a No. 1 door opening and a No. 2 door opening.

3. The method for constructing the aqueduct above the bridge according to claim 1, wherein the design of the supporting system comprises the design of vertical rod foundations, vertical rods of cross beam supporting frames, upper supports, lower supports, sweeping rods and horizontal rods. The basic processing of the supporting system comprises the step of manufacturing a motor vehicle pavement structure layer.

4. The aqueduct construction method above the bridge according to claim 1, wherein the support frame is erected, 1, measuring and lofting 2, placing adjustable bases, 3, installing vertical and horizontal vertical rods 4, holding columns 5, connecting gravity type abutment and frame body drawknot 6, installing top layer adjustable jacking 7, laying top layer main keel, distributing secondary keel, 8, erecting horizontal cross braces, 9, and connecting different frame body heights.

5. The bridge overhead aqueduct construction method as claimed in claim 1, wherein the step of pre-pressing the bracket is as follows: 1. before prepressing, a measurer selects an observation point at the top of the support, and marks and numbers the observation point; 2. pre-pressing and loading are carried out for 4 times, the weight of the first time of loading is 60 percent of the total weight, the observation is carried out for 12 hours in a stable way, and when the average value of the settlement difference of the support measuring points for 2 times is less than 2mm, the loading can be continued; loading for the second time to 80% of the total weight, stabilizing for 12 hours, and continuously loading when the average value of the settlement difference of the support measuring points for 2 continuous times is less than 2 mm; loading for the third time until the total weight is 100%, stabilizing for 12 hours, and continuously loading when the average value of the settlement difference of the support measuring points for 2 continuous times is less than 2 mm; loading for the fourth time to 110% of the total weight, stably observing for 12 hours, and unloading step by step once after the settlement is stable when the average value of the settlement difference of the support measuring points is less than 2mm for 2 consecutive times; 3. pre-pressing measurement data observation, recording and sorting the result of each loading observation so as to better master foundation treatment and support erection parameters of the control box girder; 4. and pre-camber setting, wherein in order to enable the superstructure to meet the design requirements after the frame is disassembled, a reasonable and accurate pre-camber value needs to be set during construction, and the pre-camber is temporarily controlled by +10mm according to the design of the box girder in the pre-pressing stage.

6. The aqueduct construction method above the bridge according to claim 1, wherein the aqueduct support frame dismantling step is as follows: 1. the strength of the cast-in-situ aqueduct bracket reaches 100 percent, and the construction bracket is dismantled; 2. the dismantling process follows the principle of firstly assembling and then dismantling from top to bottom, namely, firstly loosening the jacking to separate the bottom die of the bottom beam plate from the beam body; 3. observing the camber of the aqueduct and the change of the abutment by using an instrument, carefully recording, and additionally arranging a special person to observe whether a crack phenomenon exists; 4. when the vertical rod is detached, the vertical rod is firstly held, and then the last plate opening of the connecting cross rod is detached, so that the vertical rod is prevented from falling.

7. The method for constructing an aqueduct above a bridge according to claim 1, wherein the method for installing the longitudinal and transverse beam templates comprises the following steps: (1) the ground is flat, foot plates are laid, when a multi-layer support formwork is adopted, the vertical rods are vertical, the vertical rods on the upper layer and the lower layer are on the same vertical central line, and the stability of the multi-layer supports in the vertical direction and the horizontal direction is ensured; (2) determining the arrangement and the spacing between the vertical rods and the keels in the template design according to the concrete weight and the construction load of the longitudinal and transverse beams; (3) the height of the supporting top is adjusted through the line, and the large keel is leveled.

8. The bridge overhead aqueduct construction method according to claim 1, wherein the steel bar installation step is: 1. installing the longitudinal beams and the transverse beams one by one, installing a bottom die when the template is constructed, and constructing side molds after the construction of the longitudinal beams and the transverse beams is finished; 2. when the reinforcing steel bar is installed, a protective layer cushion block is installed according to requirements, and the design requirements of the protective layer are met; 3. in the steel bar installation process, the reserved steel bars are installed according to the requirements of design drawings, and the accurate installation position of the embedded part and the firm positioning are guaranteed.

9. The bridge overhead aqueduct construction method according to claim 1, wherein the concrete construction is performed by adopting an automobile pump, and concrete is poured strictly according to a set sequence; the concrete is layered from the middle to the two sides and is poured evenly.

10. The method for constructing an aqueduct above a bridge according to claim 1, wherein the step of dismantling the formwork comprises the following steps: 1. the method comprises the following steps that (1) when the template is removed, the strength of concrete of the side-form shear wall reaches more than 2.5MPa, and the surface and edges and corners of the concrete are not damaged due to template removal and can be removed; 2. the bottom die can be disassembled when the dismantling time of the bottom die meets the specified strength requirement according to the strength of the concrete test block at the position under the same condition; 3. the template dismounting procedure is that the template is dismounted according to the template dismounting sequence of the template design, and the template dismounting sequence from top to bottom is followed after the template is dismounted when no template is designed; the support is that the lateral support is dismantled before dismantling vertical support.

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