Construction technique of prefabricated reinforced concrete pile

1 scope

This technology is applicable for industrial and civil construction of prefabricated reinforced concrete piles.

2 construction preparation

2.1 materials and equipment:

2.1.1 precast reinforced concrete piles: quality specifications must meet the requirements of specification for design and construction, and factory certificate.

2.1.2 electrode (piles): model, performance must comply with the design requirements and the relevant provisions of the standards, should be treated with E4303.

2.1.3 plate (piles): materials, specifications comply with the design requirements, to use low-carbon steel.

2.1.4 main tools are: diesel hammer, electric welding machines, pile caps, carry cars. Sling, wire rope, steel plate or steel, as well as Pocket rule.

2.2 operating conditions:

2.2.1 pile axial and elevation have been completed, and after checking the pre-screening procedure. Axis and elevation control of pile-pile, should be set up in places not affected by pile driving and should be properly protected.

2.2.2 processing of aerial and underground obstacles. Affect the use or security of neighbouring buildings or structures, effective measures should be taken in conjunction with the relevant authorities, to deal with it.

2.2.3 released axis line, with chunks of wood or steel head nails pile and lime as a marker, so that shot.

2.2.4 sites should be rolled flat, smooth drainage to ensure vertical pile movement and stability.

2.2.5 test piles. Test pile construction must play, the number of wood less than 2. Determine penetration and verify piling equipment, construction technology and technical measures are appropriate.

2.2.6 to select and rank pile driver access routes and piling, and formulate programmes, make technology gives the low-down.

3 operational processes

3.1 process:

Pile hoisting precast pile → → → → → piling pile stabilization →

Intermediate inspection → pile to the next pile position

3.2 in place pile: pile in place, should be aligned to ensure vertical stabilizer, the construction does not tilt, move.

3.3 lifting prefabricated pile: first tied good hanging pile with of wire rope and cable with, then application cable with bundle live pile top rings near at, General should not be over 30cm, again up moving machine lifting prefabricated pile, makes pile pointed vertical alignment pile bit Center, slowly down plug buried in the, location to accurate; again in pile top buckle good pile CAP or pile Hoop, can removed cable with.

3.4 stability. After pile insert, use a smaller drop-distance cold hammer 1~2, pile into a certain depth, then makes the vertical stabilizer. 10m line for short pile can be Visual or bi-directional correction; 10m or playing pile must be in line or theodolite bidirectional calibration, not Visual. Insert vertical deviation must not exceed 0.5%. Pile in front of the access should be set on the side of the pile or pile the ruler, so that construction of observation, record.

3.5 driving: with a hammer or hammer driving, hammers the maximum fall distance should be less than 1.0M. ; Driving diesel hammer, hammer should be beating normally.

3.5.1 weight piling should be low, hammer weight should be selected based on engineering geology condition of pile type, structure, intensity and construction conditions to choose.

3.5.2 piling orders based on the underlying design of the elevation, deep-shallow; according to pile size after the first small, long before they are short. Due to the different intensity of the pile, from the Center to two hearts to the symmetry or around; or by the side of a single direction.

3.6

3.6.l in the case of long enough, by welding by pile, embedded part of its precast pile on the surface should be clean, gap between the upper and lower sections of iron Tablet pad solid solid; welding, should take measures to reduce weld deformation of welds shall be continuous welds.

3.6.2 pile, generally from when the ground around the LM. Center line of the upper and lower sections of deviations not greater than 10MM, joints flexed rise-high-‰ length shall not be greater than l.

3.6.3 before the pile the soil, exposed iron, make up brush paint again.

3.7 pile: when design requirements pile, the centerline of the pile shall be consistent with the line of the pile, pile. If uneven, sacks or thick paper pads that are available. The pile immediately backfill compaction pile left.

3.8 checking: each piles to penetration requirements, elevation of pile tip into bearing layer, when close to the elevation, or while he was playing to the design level, intermediate inspection should be carried out. In control, General requirements for the last sancishi average penetration of the hammer does not exceed the values prescribed by, or using a pile until elevation to control, comply with the design requirements and fill construction record. Such as when he found the position and requirements are different, and should be studied in conjunction with the relevant authorities. Then moves to a new position.

3.9 during piling, meets the following conditions should be suspended, and timely and relevant units dealing with:

3.9.1 penetration upheaval;

3.9.2 tilt and displacement or suddenly had serious rebounding;

3.9.3 piles or pile when serious crack or break.

3.10 all the piles after the excavation to the design level, do a final check and acceptance. And submit the technical data the total package.

3.11 pile in permafrost area in winter when there are difficulties, it should first be removed or after thawing of frozen soil.

4 quality criteria

4.1 project:

4.1.1 the precast reinforced concrete pile quality must comply with the design requirements and specifications provided, and has a factory certificate.

4.1.2 the piling of elevation or penetration, piles of connector, you must meet the requirements of specification for design and construction.

4.2 allowable deviation, as shown in table 2-5.

Precast reinforced concrete pile tolerance table 2-5

Project tolerance (mm) test method

Vertical center line of Foundation beam 100

Along the center line of Foundation beam 150

Number of 2 piles for 1~3 or single-row piles 100

3 number of piles for 4~16 root d/3

Edge d/3

Middle d/2

Note: d for the diameter of the pile length or cross section.

5 finished product protection

5.1 shall meet the design strength of the 70% before he can lift, above 100% to transport.

5.2 lifting and handling, you must do the lifting point meets the design requirements, should be smooth and not damaged.

5.3 pile piled up, the following requirements:

5.3.1 venues should be smooth, firm, shall not give rise to uneven sinking.

5.3.2 wood with hanging points should be the same, and should be in the same plane.

5.3.3 pile, the pile should be put together, and pointed to the end.

5.3. more than 4 storey wood should align the bottom wood should be appropriately widened. Stacking layer is generally not more than 4 floors.

5.4 properly protect the axis and elevation control of pile-pile. No displacement due to collisions and vibrations.

5.5 data differ from the driving data provided does not comply, it should stop the construction and joint research with relevant units.

5.6 on the slopes close to buildings or to shore, driving, effective measures should be taken in conjunction with the relevant authorities. Should be observed at any time during construction to ensure that avoids accidents because of piling vibration.

5.7 piling is completed during excavation, should formulate a reasonable construction and technical measures in order to prevent displacement and tilt.

6 quality problems to be noticed

6.1 advance order processing prefabricated pile, driving strength must meet the design strength of precast concrete pile of 100% and conservation period by one month behind the shot should be added.

6.2 pile break. Due to excessive bending, strength of the pile and the underground obstructions caused, or fracture in the stacking, lifting, transport, did not find consensus. Should be checked in a timely manner.

6.3 fragmentation, due to pile on pile top intensity and insufficient reinforcement mesh, reinforcement from the top of the pile, or the pile caused by injustice, wrong choice of construction machines and other reasons. Inspection at time of preparation should be strengthened.

6.4 piles tilted. Due to the uneven, space pile drivers chassis not level or steady not vertical, pile in underground meeting caused by hard objects or other reasons. Should be strictly according to the process regulations.

6.5 pulling crack. Connected surface is not clean, connect welding quality uneven, iron does not meet the requirements, then pile vertical centre line is not in the same line of fine resulting. Should ensure the quality of piles.

7 quality records

This standard shall meet the following quality records:

7.1 of prefabricated reinforced concrete piles factory certificate.

7.2 test or test records.

7.3 filling pile floor map.