Installation technology of precast reinforced concrete frame structure

Precast reinforced concrete frame structure components are installed

1 scope

This technology is applicable to general industry and civil construction of multistory frame of precast beams, columns, slabs of concrete components are installed.

2 construction preparation

2.1 materials and equipment:

2.1.1 widget: precast reinforced concrete elements, such as beams, columns, slabs, is given a factory certificate. Component specifications, models, embedded parts location and quantity, appearance and so on, should comply with the design requirements and the standard for quality inspection and assessment of prefabricated concrete member (GBJ321-90) of the.

2.1.2 steel bar and steel: size, shape, the drawing requirements and should be steel factory certificate.

2.1.3 cement: No. 425, should be adopted, No. 525 ordinary Portland cement. Seams in the column should be used, No. 525 expansive cement, or at least No. 525 ordinary Portland cement. Should not be adopting slag cement or Pozzolanic cement.

2.1.4 stone: size 5~32mm. , Sediment is less than 2%.

2.1.5 sand: sand or coarse sand, clay is less than 5%.

2.1.6 electrode must be according to the design requirements and welding is the process of selection of the relevant provisions. Packaging order, no rust no tides, certificates and instructions for use.

2.1.7 template: according to structural requirements and specifications needed to prepare complete, brush release agents. 100mmx100mm,100mmx50mm wood as well. 50mm plank.

2.1.8 main machinery: lifting machinery, welding machines and related equipment, welding rod drying boxes, wire ropes, rings, baskets of correctors, post lock clamps, slip line, supports, hooks, theodolite, level, leveling rod, foot boards, iron pole, Jack, chains and crowbars. Tools and so on.

2.2 operating conditions:

2.2.1 familiar drawings: drawings, especially structure diagrams, component fabrication, joint construction detail drawing, related to the Atlas should thoroughly understand and be familiar with. Carefully grasp the component model, quantity, weight, joint practice, construction operations, safety technologies, Spider-man-related provisions and the interaction between components.

2.2.2 preparation method: according to the structural characteristics of the building and construction process, based on the actual conditions, the fabric carefully lifting plan. Safety, quality and construction personnel, technology gives the low-down.

2.2.3 main components for pre-screening: based on the structure construction drawing and component processing, verification entry type, quantity, specification of components, concrete strength, embedded reinforcing iron, reserved position, number of conformance to design drawings, whether the component factory certificate.

2.2.4 line: the embedded parts and exposed on the reinforcement of cement paste and clean of rust and other debris management. On the members to play axis (centerline) is to say, the positioning line, indicate directions, axes and elevations. Axis of the columns should be playing on three sides. Axis post, first floor in addition to playing out, and mark 0.00mm horizontal lines on three sides. Embedded cross centre line of play. Play at both ends of the beam axis, axis control of positioning.

2.2.5 control floor installation elevation: the component connection anchoring the structure after construction, good floor column grid axial and elevation control lines, good post connection of superimposed layers, embedded positioning and leveling plates and calibrate their elevation. Floor column grid axis as clear and accurate.

2.2.6 adjust upper part of composite beams with exposed steel bars, welded at the ends of the main bars straighten buried along, check the connecting parts according to design requirements, length, location main bar. In the case does not affect the normal installation, upper part of the basket of flowers Leung of beam main bars fastened, head positioning embedded parts can also be welded composite beams of steel, but must ensure that their elevation, location accuracy.

2.2.7 in accordance with selected construction organization design of hoisting machinery comes into play, and the commissioning of identification in accordance with safety procedures ready for lifting appliances, lifting shall be put into operation.

2.2.8 erection of scaffolding, safety protection: in accordance with the provisions of the construction organization design in the lifting job putting up lifting scaffolding and platforms, and security guards. And associated personnel inspection, inspection, certification, compliance with safety regulations, to be fully operational. No security and safety measures, shall not carry out the job.

2.2.9 the floors need of beams and columns, Board member of plane position close to flat. To prevent post flip when lifting, little stigma lifting touchdown crack or bend reinforcement, security leg can be used, or the addition of wood column end reinforcement to prevent bending deformation of main bars for lifting.

2.2.10 welder certificate and designation, official before brazing welding trials will be required to adjust the welding parameters, providing simulated weld and qualified through test and operation.

3 operational processes

3.1 process:

Column lifting (correction, positioning → welding) → girder lifting (correction, reinforcement welding) → beam-column joint core →

Shear wall construction → installed

3.2 pillars lifting:

3.2.1 structure hoisting hoisting in the order provided, generally along the longitudinal axis push, segmented flow layer by layer, each floor from end to started to reduce repetitive task when a transverse axis of the column after the installation is complete, and then hung the next post on the horizontal axis.

3.2.2 clean up post mounting area of debris, loose concrete and high position of embedded steel plates bonded clean, check the columns axis, position location, elevation, and anchorage and meet the design requirements.

3.2.3 hanging main bar up and down to check out the posts, according to the designed length will exceed the part cut off, ensure that the positioning of small pillars head steadily and is located in the joint position on the plate. Will lower out of the main bars straighten, smooth, and pledge to lower pillars reinforced overlap Nestled close, easy to weld.

3.2.4 pillars lifting: pillars hanging points location and hanging points number by pillars length, and section shape decided, General selection are buckle lashing, hanging points selected in from column top 600mm at card good special of column Hoop, in column hoop below lock good clasp wire rope, lifting mechanical of hook rope and clasp phase hook district with clasp card live, hanging rope should in hanging points of are above. Slow lifting, tense pause after lifting rope up, check the reliability of automatic clasp in a timely manner to prevent tripping on their own, to control the lift in place without swinging back and forth, in the lower part of the column hung well slip rope, check all connections, right before the lift.

3.2.5 pillars in place: when post lifted from the 500mm pause, remove the protective pillar reinforcement of wood and leg, clear the stigma in mud, and then by the signalman command, column lifted onto a floor in place. In place, slowly over the landing to the installation location, stop, check the post number, adjust the direction, controlled by the two make small stigma full range line is correct, before falling on to the installation location. Post check-check the shear wall inserted iron (steel), completion of directional seat, sided with hanging flower baskets bolted, oblique cord, additional temporary support fixed to ensure safety.

3.2.6 correction and positioning:

3.2.6.1 column vertical correction: hanging plates, and set up in the two mutually perpendicular directions Theodolites, vertical axis aligned with the installation location grid on the column axis, vertically. Corrects the time to find a two axis axis of the surface, then align on the third axis of the last pillar axis alignment in the middle or on the three axes. Pillars were in place well, careful theodolite calibration axis and vertical, confirm that does not exceed the deviations, stigmas positioning plate welding can be carried out.

3.2.6.2 column (pillar) installation calibration and orientation: the column centerline shall prevail, in place after four supports. Using two Theodolites are adjacent on the cylinder axis, at the pillar axis, vertical deviation correction. Observe the correct column axis, full height from bottom to top through. When two Theodolites calibration from two directions after a good, then check the other two axis of the plane, surrounded by supporting strong, small pillar steel plate and welded steel plate fixed on the head, and then welded reinforcement, the second correction.

3.2.6.3 side columns, corner post installation, calibration and location: edge, corner post installation wood only on the 2~3 from the floor taut basket correction correction. Except when installing the corner post after correction for three-axis positioning, and check on the fourth axis on the surface, ensure that the upper and lower pillar does not produce twisted, dislocation and migration at the nodes.

3.2.7 indispensable prior to positioning the main bar and the stigma, spot-fix to prevent support in prison, tighten TURNBUCKLE tie in with each other without coordination, resulting in posts to tip over.

3.2.8 adjust main bars, welding: during the lifting process is reinforced by collision in welded reinforcement before straightening and smoothing, so upper and lower reinforcement is correctly positioned, close to each other, easy to weld. When used for welding, steel bars should be used has the same gluten level when using lap welding, should meet the requirements of lap length, consists of two double-sided welds. Two welding machines for welding required, diagonal, symmetric, and so speed up the arc, ARC basic synchronization. The intermittent welding, to prevent thermal effects lead to uneven stress, excessive deformation are generated to avoid burns and reinforcement of concrete. Positioning small stigmas surrounding welding of steel plates on all sides. Welding post. Quality meets the specification for welding requirements, complete construction record, indicating the welder code. Pillar reinforcement after finishing welding, weld cooling in order to withdraw support. Review correction: theodolite review the verticality of column and line, controlled within tolerance range, found ultra deviations available chain for correction, may not be hit with a sledgehammer, pry hard, hard to pry, damaged main bar.

3.3 girder lifting:

3.3.1 the sling in place: in the programme provides for the construction of the installation order the relevant type, specifications of the beams supporting code, playing well at both ends of the axis (or the middle), straightening and straightening out the ends out of the bar. Hanging out in the Bay of pillars, beams for the crane main beam and then hung the first time, between the floors.

3.3.1.1 lift: in accordance with drawing on the provision or construction schemes identified in the hang point location, hook and rope lock. Pay attention to the angle between the slings must not be less than 45 degrees. If using the lifting rings, you must tie safety lines. When using the fallback when lifting, have to CLASP one prison. After hanging the hook-and-line upgrade slowly, tighten the hook-and-line, 500mm stop rise off the ground, carefully check spreader firmly tied hung safe and reliable, to be lifted into place. Lifting AWB or local pick side beams, to give serious consideration to its center of gravity, avoid eccentric to prevent tilting. Lifting point should be as close as possible to the rings or beam end position.

3.3.1.2 in place: check again before lifting the stigma pivot steel pad elevations, location meets the installation requirements, in place looking for good on the stigma of axis positioning and relationship between the beam axis, so that the beam is seated correctly. The pillars at both ends of the beam in prison.

3.3.2 beam correction and reinforcement welding: in place after a solid, elevation, position of the beam to make corrections. Finishing steel and corresponding Liang Tou main bar after you close to each other, for welding. In order to control the displacement of the beam, end of center line of both ends of the beam should be aligned with the top of the pole and line, and if the error is small, crowbars available minor chord so that it sharply when the error is large, don't pry roots hard to pry, or otherwise affect the pillars vertical changes. Beam should be lifted again, slightly off the base steady operation by officers from both ends, Visual alignment axis left hook to a smooth, slow seating and top end of the beam axis alignment axis. Vertical beam deviation correction is a wire pendant hanging from both ends, and standard deviation, and beam floor mats with crowbars, iron pad smooth tight, until the ends of the vertical deviation control within the allowed range, note in the entire calibration process, must also be observed with a theodolite vertical pillars have no change. Installation to make the post as a result of beam the vertical deviation exceeds allowed value must be adjusted. When the beam elevation and position correction right, top firm, weld, weld quality shall conform to the requirements.

3.4 core area of beam-column joints:

3.4.1 the practice of core area of beam and column in line with design drawings and building Atlas of seismic requirements. Prefabricated welded closed Stirrup stirrup, Stirrup spacing throughout the encrypted area, diameter, quantity, 135 ° hook, straight part length shall meet the requirements of specification for design and construction. In composite beam of iron part should be set 1 φ 12 welding on closed position Hoop, used to control the correct position of column main bars and joints.

3.4.2 edge, corner, capped columns node: Liang Hezhu main bar anchorage length and lap welds, design drawings, specifications and code requirements must be met. Top floor Corner column joint beam on the steel removed and rebar lap welding of beams in addition to remaining top reinforced with embedded anchor bar on welding in prison. Top anchorage reinforcement angles welded in prison.

3.4. the 3-node strength than concrete strength class of concrete should be level to 10MPa. Seams with dry concrete column joints (lighter than concrete face stiff bean), preferably by pouring cement, cement at 0.3 and increase its strength than the concrete strength 10MPa. Seams seams clean before using hemp ropes, sacks water fully wet; two-side template block. Both symmetrical side chisel action, with twist-filled reality. Construction finished maintenance 7d, to prevent shrinkage cracks. Prior to the installation of upper structure, columns should be joint construction is completed.

Joints can also be pouring UEA shrinkage-compensating concrete, its strength than concrete strength grade should also improve 10MPa, design of mix proportion and pouring method, with the consent of the Department.

3.5 installation (floor or roof): rigid frame formwork can be used directly or in-place method.

3.5.1 position of line: on the side beams according to the design drawings drawn panels and Panel seam line, indicating the type of plate.

3.5.2 Board in place: clean up the beam or wall epithelial, check level, review the axis. The required hoisting. On board the Setup begins on installation technology of prestressed concrete hollow plate standard.

3.6 shear wall construction: on the floor after installation is complete all the beams, columns, slabs, interspersed within the hollow beams with vertical reinforcement, and insert the horizontal ribs and pillars embedded in iron (steel) welding in prison. Connector locations should comply with the provisions of the code. The construction organization design requires a good template, vibration compacting of concrete poured, and strengthen conservation.

4 quality criteria

4.1 project:

4.1.1 hoisting structure concrete strength, lower internal forces of structures subjected to joint (joint) strength of concrete or mortar must comply with the specification for design and construction requirements. Check the component factory certification and the test of sample cured in same condition report.

4.1.2 component anchoring must comply with the design requirements and no damage. Observed or standard checks and inspection lifting records.

4.1.3 joints (joints) of the concrete (mortar) must be measured accurately, pouring dense, careful conservation, which must meet the design requirements or provisions of the code. Visual check and 28D sample test report and check construction records.

4.2 Basic project:

4.2.1 beams, columns, slabs in place anchorage: axis position, elevation, pulp and node construction practices, end plug holes, Board-end anchor, Board width, should comply with the design requirements.

4.2.2 joints welding practices should comply with the design requirements and the provisions of the code. Component main bars and plates are connected with the weld length, width, thickness, and shall meet the requirements of specification for design and construction. Weld surfacing, soldering wave uniform, no dents, welding tumor and burns, joint crack and blowhole, slag and the undercut. Clean welding slag, covering and spatter.

4.3 allowable deviation, as shown in table 4-39.

5 finished product protection

5.1 axis to maintain through the floor of the column grid, clear installation node level to indicate that need to be addressed should be clearly marked, and not any apply, change, and pollution.

5.2 installation locating buried parts of the beams and columns to ensure accurate elevation cannot be reached, any move, hit and shift.

Prefabricated frame components installation tolerances and inspection methods table 4-39

Project tolerance (mm) method

1 column centerline axis positioning position offset 5-foot check

2-column interface up and down center line position offset 3 foot check

3 5M in column 5

>5M vertical 4 column column-10 using a theodolite or hanging and foot check

5 >10m column 1 ‰ high and <20

6 5M +0,-5 level or standard of inspection

7 >5m +0,-8

5 foot 8 axis displacement deviation check

9-storey ± 0 level or standard of inspection

10 Board shelving ± 10 feet in length check

Plastering at 5 feet and feeler gauges check

Don't plaster 3

12 center line axis positioning wire 5 foot check

13 +0,-5 surface of the beam elevation level or wait and check

14 vertical deviation of 3 hanging and foot check

15 stairs, offset 10 feet of horizontal displacement check

16 terrace elevation ± 5 with the level, standard checking

5.3 the reinforcement may not be crooked, bent at the nodes, removal of rust and dirty in the process not knocked down. Φ 12 before the pouring of concrete steel welding into closed position hoop fixed-column main reinforcement position. Node encrypted area hoop welded closed, the amount in line with design and seismic provisions of the Atlas, binding firm.

5.4 Installing the beams, columns, plates shall be arbitrarily bracing and tie rod removal, all cooling needs to be welded reinforcement rear detachable calibration facilities. When installing a beam, shall at all times observe the verticality of column changes, offset should be stopped or remedied.

5.5 members while in transport and stacking, wood mat location shall conform to the provisions, generally close to the rings, the pad thickness should be above the ring, and wood into a straight line up and down. Preventing cushion unreasonable, cause damage to the components. Piling yard should be smooth, solid, not water. 100mmx100mm timber at the bottom or double feet smooth hand pad. Each duo construction organization design provides a high degree of code should be neatly stacked.

5.6 when the pipeline is installed, shall be arbitrarily picking cut component. Construction shall be arbitrarily cut rebar or bend to bend in damaged products.

6 quality problems to be noticed

Defects 6.1 component: the component model, specification error. Component factory has yet to achieve the required strength, causing breakage or damage. During transport and installation, check the component quality, the strength of concrete. Using the correct methods of handling and transport. Damaged or defective component without technical department identification, may be used.

Displacement deviation 6.2 component: component models and parts should be marked before installation, check wire size were installed to prevent setting errors caused by component offset. Different climate change adjustment of measuring error. When serious and responsible, careful correction. Component location, elevation, vertical, met the requirements.

6.3 above and below the axis does not correspond to any affected components are installed: construction on line, top of the line should be from the bottom up, using theodolite vertical, axis of the determination of the correct floor. Guarantee perfect match between the upper and the lower axis.

6.4 node concrete pouring is not compact: node template does not run pulp. Node template should be sewn block before pouring. Denser core reinforcement, pouring should be careful when vibrated. Has a good workability of concrete and genuine slump. Template to leave a clean out, carefully cleaning to avoid inclusions.

6.5 displacement of main bars: reinforcement displacement nodes lower pillars, causing difficulties to lap welding. Because components production without taking measures to control where the main bar; component reinforcement caused deformation in the process of transportation and installation. Therefore measures should be taken when production, guarantees the proper beam main reinforcement position, lifting the collision avoidance, before installing straightened out.

6.6 the core structure does not meet the requirements: because the core steel more, so when should seriously look at the pictures, according to the joint requirements. Steel connection position accurately, lapping each other close, easy to weld. Stirrups quantity shall conform to the drawings.

6.7 floor high: mainly the lifting process of elevation control is lax, drove up installation elevation. Starting from the first floor, measuring actual relative elevation of plinth epithelium, find the right column bottom screed's elevation. When you install the floor pillars, to adjust the locating plate to control the floor elevation above sea level, positioning plate leveling application level, according to the post's actual situation, set by column positioning plate negative deviation. Negative deviation to 3~5mm, available steel plate adjustment.

6.8 column are skewed: the cause is poor welding methods. Improvement is the joint of beam and column with two or more than two welding points, conveying welding method should be used. Hard to pry bars are not allowed in the welding process, welding of reinforcement in the process of using the theodolite to observe a vertical deviation, find the problem corrected.

6.9 pillars displacement: stigma in place only in accordance with small cross line in place, rather than controlled axis on the pillar; reinforcement welding, thermal deformation effects distort, led to post them.

6.10 pillars vertical overload and unbalanced, pillar is not straight: when installing, in the adjacent of two surfaces that are perpendicular to the fall line of correction. After column connection on the steel sheet spot welding, pillars and corrector for the second correction. Main bar with symmetrical, such as speed, intermittent welding. Arrange the welding sequence from Plum point should be applied as a whole to stagger the framework welding method to prevent the welding process, effects of stress, avoid frames have varying degrees of deformation.

6.11 quality does not meet the requirements, should be strictly observed welding procedures.

7 quality records

This standard should have the quality records

7.1 component factory certificate.

7.2-steel factory certificate.

7.3 steel factory certificate and retest report of mechanical performance.

7.4 certificate of welding electrode factory.

7.5 welding operation certificate.

7.6 test report.

7.7 cement factory certificate and retest report.

7.8 test reports for sand and stone.

7.9 structure hoisting records (pre inspection records).

7.10 reports 28D strength of concrete block.

7.11 components install section for quality inspection and assessment records.

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