CN1318678A

CN1318678A - Transverse drawing formwork construction process for large span hollow concrete beam

Info

Publication number: CN1318678A
Application number: CN 00110331
Authority: CN
Inventors: 陈万利; 方荣乐
Original assignee: HEILONGJIANG PROV LAND RECLAMATION CONSTRUCTION CORP
Current assignee: HEILONGJIANG PROV LAND RECLAMATION CONSTRUCTION CORP
Priority date: 2000-04-19
Filing date: 2000-04-19
Publication date: 2001-10-24

Abstract

A construction process of transverse drawing formwork for making large span concrete hollow beam includes depositing and tamping 3-3.5 m of concrete on the base plate with the concrete level as the base plate thickness, inserting the base formworking for 2.5-3 m and mounting a section of top core formwork. After levelling and calibrating, and then the concrte depositing will be engaged on two sides base formwork and the top plate and then as concrete depositing as the base formwork and the mounted top formwork drawing by the pulling device. The drawing speed of base formwork is normally 3-5 m per hour and the pulling length of each time is about 0.5-1.0m with the interval of a half hour to maintain it until concrete deposition finish.

Description

Transverse drawing formwork construction process for large span hollow concrete beam

The present invention relates to a kind of transverse drawing construction technology of large-span concrete hollow beam.

At present, construction market solves construction to be had multiple in the job practices that type gives the system hollow beam, lattice type portal frame outsourcing iron sheet is wherein arranged, use impermeable material (as Polypropylence Sheet then, five colours cloth etc.) core of parcel, be generally two joints, every joint length is 1/2nd beam lengths, the core that this kind method is made, its outstanding weakness is that the rigidity of structure is poor, weight is big, very inconvenience is installed, and the physical dimension in core hole is difficult for guaranteeing, the concrete beam deadweight of shaping is strengthened, and it is real that the concrete of beam base plate is difficult for puddling, they are two years old, steel supports, and the board-like housing core of folding is though this job practices can guarantee physical dimension preferably than last a kind of method, yet, have and be difficult for to install and be unfavorable for that concrete floor weakness such as builds.Its three, the air filling type rubber mandrel, though that this method has is in light weight, advantage such as easy for installation, but the core come-up is difficult to control when fatal weakness is concreting, is difficult for guaranteeing concrete pouring quality.

The object of the present invention is to provide a kind of speed of application fast, save the job practices of the large-span concrete hollow beam of material.

In order to achieve the above object, the technical solution used in the present invention is: at first water from an end of beam and smash underplate concrete, building length is 3-3.5 rice, tamping and leveling are to designing base plate thickness, bed die is penetrated 2.5-3 rice, and lay one and save the top core, begin to build soffit formwork both sides and concrete roof after the leveling calibration, spur bed die and the top backform is installed with draw-gear with concreting then, the speed of pulling bed die generally is advisable with 3-5 rice per hour, and each pull length is advisable with 0.5-1.0 rice, and blanking time should not be above 0.5 hour, construct repeatedly by above-mentioned job practices and to extract out fully, remove backform more successively until the concreting bed die that finishes.

The present invention compares with prior art, has following advantage:

(1) saves material;

(2) template is in light weight, and is easy for installation;

(3) form cycling rate height uses economy, and the beam underplate concrete is tamping;

(4) speed of application is fast, and recruitment is few;

(5) be easy to building of beam underplate concrete, guarantee construction quality.

Description of drawings:

Fig. 1 is a drawing-die device schematic diagram of the present invention;

Fig. 2 is the backform sectional schematic diagram;

Fig. 3 is the bed die sectional schematic diagram.

Below in conjunction with accompanying drawing inventive embodiment is described in further detail.

By Fig. 1-Fig. 3 as can be known, the present invention at first waters from an end of beam and smashes underplate concrete, building length is 3-3.5 rice, tamping and leveling are to designing base plate thickness, bed die 1 is penetrated 2.5-3 rice, and lay one and save the top core, begin to build soffit formwork both sides and concrete roof after transferring calibration, spur bed die and top backform 2 is installed with draw-gear with concreting then, the speed of pulling bed die 1 generally is advisable with 3-5 rice per hour, and each pull length is advisable with 0.5-1.0 rice, and blanking time should not be above 0.5 hour, construct repeatedly by above-mentioned job practices and to extract out fully, remove backform 2 more successively until the concreting bed die 1 that finishes.

Described drawing-die speed also can be adjusted speed of application according to the temperature and the concrete coagulation speed in when construction.

It is fixing that described backform 2 usefulness are fixed on the gooseneck 4 and the stay-bolt 5 of exterior sheathing 3, is with hard sleeve on the stay-bolt 5 so that the dismounting of stay-bolt 5.

Process of the present invention is to produce the core that gives system large-sized concrete hollow beam to adopt the transverse drawing construction technology, and existing is example with anistree core.

By Fig. 1-shown in Figure 3, the physical dimension that requires adopts the 2-2.5mm steel plate to divide two parts making core under bed die and the backform, its top is divided into the splayed backform, the elongated setting of per 2 meter one joint, it is long that the bottom is divided into bed die 5-7 rice, bed die is for drawing the sliding template corner angle plane should be straight, and structural strength should be firm, forbids the pull of torsional deformation in order to core.

The present invention is specially adapted to strength grade of concrete greater than C30, the construction production of the hollow beam in the circle that span is bigger, ellipse or polygon, straight core hole.Utilize on concrete initial setting strength and the circular core hole concrete arch action to support concrete deadweight, make it with concreting with the pull core, until finishing building of concrete hollow beam.

The present invention makes with (anistree polygon is an example) core: make of two parts about the 2mm steel plate branch according to the physical dimension that diagram requires, its top is divided into the elongated setting of 2 meter one joint, it is long that the bottom is divided into 5-7 rice, bed die corner angle plane should be straight, structural strength should be firm, forbids torsional deformation in order to the pull of core (as figure).

Job practices of the present invention and flow process:

At first water and smash underplate concrete from an end of beam, building length is 2-2.5 rice, tamping and leveling are to designing base plate thickness, bed die is penetrated 2-2.5 rice, install the part backform then, leveling is proofreaied and correct and is begun to build central layer both sides and top concrete with jig after fixing, then with concreting with slowly spurring core with hoist engine and the top core being installed, the speed of pulling bed die is generally with 3-5 rice (deciding according to temperature and concrete coagulating time) per hour, each pull length is advisable with 0.5-1.0 rice, and construction process is for watering underplate concrete → installation bed die and backform → water both sides and concrete roof → water underplate concrete → pull bed die → peace backform → circulation.

Extract and then remove successively top core (accompanying drawing: with 20 meters beams is example) fully out until building the concrete core that finishes so repeatedly.

Working measure of the present invention and key points for operation:

1., control core come-up:

Because concrete can produce bigger buoyancy to core in watering the process of smashing, and core floats more easily, must be controlled with following several respects:

A, the concrete slump of strict control are to reduce the buoyancy of concrete to core;

B, vibrate layering and vibration tamper insert the lower-layer concrete degree of depth should not be greater than 5cm;

C, utilize exterior sheathing that jig is installed, block the core head when smashing watering, behind pull, go jig to carry out the surface layer levelling treatment process (accompanying drawing) of beam.

2., the control core wanders off: the reason that general core wanders off has two kinds: the one inclined to one side because core is made error, core is not straight, produces sidesway power when making the core pull, causes the pull track not linearly, so it is straight to require core processing to guarantee; The 2nd, because casting and compacting of concrete is asymmetric or habitually always water the concrete of smashing a certain side earlier, the lateral pressure that produces when making casting and compacting of concrete is pushed core on one side to, carry out so must symmetrically interlock when requiring casting and compacting of concrete, can also utilize exterior sheathing and cage of reinforcement to add guide rail in addition and force the unlikely skew of core.

3., the end face concrete control of subsiding: because pulling template construction hollow beam is to smash with twitching core with watering, so the concrete when requiring depanning will have the deadweight of enough strength support itself, make again that core is unlikely is lived by concrete bonding, so must strictly control the concrete slump, pull blanking time, Admixture, speed of application and construction temperature, intensity during with the depanning of assurance concrete, should before formal construction, carry out simulated test, with the volume of determining Admixture and concrete definite depanning time (the general slump is controlled at 1-2cm) unlikely generation when the guaranteeing construction hole phenomenon of collapsing according to concrete conditions such as job site temperature and raw material for this reason.

4., accelerate the major measure of speed of application: work as mix proportion, after the volume of Admixture is determined by test, the principal element of control speed of application is exactly the temperature of construction environment, can take in the core hole and the way of top surface of the beam local warming for improving speed of application, to guarantee the unlikely hole of collapsing of concrete of depanning, local warming can establish two groups of covers of movably heating at top surface of the beam, heat at the concrete surface that has watered, the anti-avulsion water generates crackle but the concrete surface through heating must in time add water curing, heat two groups of iodine-tungsten lamps can be installed in core in the core hole, can in the core hole, heat effectively and can realize the hole intraoral illumination, so that peep hole inner concrete construction quality at any time.

The present invention requires:

(1) the core making must be straight, and enough rigidity should be arranged to guarantee unlikely under external force generation distortion.

(2) exterior sheathing, reinforcing bar and Concrete Construction quality should meet the regulation of " concrete structure engineering construction and standards of acceptance ".

(3) concrete depanning intensity should be controlled at 0.3-0.5MPa, and by unlikely generation slump of concrete and crack after the test assurance depanning.

(4) each core pulling blanking time must not be greater than 0.5h.

(5) concrete reaches to the needed time of depanning intensity and should be determined by simulated test under the construction condition.

(6) should check sliding trace after each core pulling at any time with assurance core position, and check that in time concrete has or not slump, drawing crack and pitted skin etc. are pinpointed the problems and are in time handled.

With regard to 20 meters hollow beams, pulling core and conventional core job practices compare below.

(1) weight: pulling core 300-500kg

Conventional core 800-1200kg

(2) length: pulling core 5-7m

Conventional core 20-21m

(3) set-up time: pulling core 5-10 minute

Conventional core 2-3 hour

(4) engineering time: the every cover of pulling core whenever can be finished 2 beams round the clock

The every cover of conventional core can be finished 1 beam at every turn

(5) turnaround time: pulling core every cover 9-10 hour on every side once

The every cover of conventional core 3-5 days on every side once

(6) turnover ability: the every cover number of turnover of pulling core is greater than 50 times

The every cover number of turnover of conventional core is less than 10 times

Claims

1, a kind of transverse drawing formwork construction process for large span hollow concrete beam, it is characterized in that: at first water and smash underplate concrete from an end of beam, building length is 3-3.5 rice, tamping and leveling are to designing base plate thickness, bed die (1) is penetrated 2.5-3 rice, and lay one and save the top core, begin to build soffit formwork both sides and concrete roof after the leveling calibration, spur bed die and top backform (2) is installed with draw-gear with concreting then, the speed of pulling bed die (1) generally is advisable with 3-5 rice per hour, each pull length is advisable with 0.5-1.0 rice, do not declare blanking time above 0.5 hour, construct repeatedly by above-mentioned job practices and to extract out fully, remove backform (2) more successively until the concreting bed die (1) that finishes.

2, according to the described transverse drawing formwork construction process for large span hollow concrete beam of claim 1, it is characterized in that: described drawing-die speed also can be adjusted speed of application according to the temperature and the concrete coagulation speed in when construction.

3, according to the described transverse drawing formwork construction process for large span hollow concrete beam of claim 1, it is characterized in that: described backform (2) is fixing with gooseneck (4) that is fixed on exterior sheathing (3) and stay-bolt (5), is with hard sleeve on the stay-bolt (5) so that the dismounting of stay-bolt (5).