Basic provisions of 1

1. 1 The construction quality of a building project shall be checked and accepted according to the following requirements:

The construction quality of building engineering shall conform to this standard and relevant professional acceptance specifications.

1. 1.2 The construction of building projects shall meet the requirements of engineering survey and design documents.

1. 1.3 All personnel involved in the project construction quality acceptance shall have the required qualifications.

1. 1.4 engineering quality acceptance shall be conducted on the basis of self-inspection evaluation by the construction unit.

1. 1.5 Before the concealed works are concealed, the construction unit shall notify the relevant units for acceptance and form an acceptance document.

1. 1.6 The test blocks, test pieces and related materials related to structural safety shall be subjected to witness sampling test as required.

1. 1.7 The quality of the inspection lot shall be accepted according to the master control project and general project.

Important subdivisional works involving structural safety and use function shall be sampled and inspected by 1. 1.8.

1. 1.9 The unit undertaking witness sampling inspection and related structural safety inspection shall have corresponding qualifications.

1. 1. 10 The visual quality of the project shall be inspected by the acceptance personnel on site.

2 pipe pile quality acceptance

2. 1 unit (sub-unit) project quality acceptance shall meet the following requirements:

2. 1. 1 The engineering quality of the division (sub-division) included in the unit (sub-unit) project shall be accepted.

2. 1.2 Quality control data shall be complete.

2. 1.3 The unit (sub-unit) project contains the safety and function test data of the sub-projects and should be complete.

2. 1.4 The spot check results of main functional items shall comply with the provisions of relevant professional quality acceptance specifications.

2. 1.5 visual quality acceptance shall meet the requirements.

2.2 After repair or reinforcement, the divisional project or unit (sub-unit) project that still cannot meet the requirements for safe use shall not be accepted.

3 pipe pile acceptance procedures and organization

3. 1 After the unit project is completed, the construction unit shall organize relevant personnel to carry out inspection and evaluation, and submit the project acceptance report to the construction unit.

3.2 After the construction unit receives the project acceptance report, the person in charge of the construction unit (project) shall organize the person in charge of the construction (including subcontractors), design, supervision and other units (projects) to carry out the project acceptance of the unit (sub-unit).

3.3 After the unit project quality acceptance, the construction unit shall submit the project completion acceptance report and related documents to the construction administrative department for the record within the specified time.

4. Stress of pipe pile

4. 1 The pipe pile foundation shall be designed according to the following two limit states:

4. 1. 1 bearing capacity limit state: the pipe pile foundation reaches the maximum bearing capacity, and the whole pile foundation is unstable or deformed, which is not suitable for further bearing;

4. 1.2 normal service limit state: the pipe pile foundation reaches the deformation limit specified in the normal service of the building or reaches a certain limit of durability requirements.

4.2 The design grade of pipe pile foundation shall be determined according to Table 4.2 according to the existing problems of pipe pile foundation, the degree that it may damage buildings or affect normal use, and the building scale, functional characteristics, adaptability to differential deformation, complexity of site foundation and building shape.

The first-class pile foundation and the pile foundation with no more than 2 piles in the same pile cap shall be γ. = 1.2。

2. The safety level of pile foundation should not be lower than that of buildings.

4.3 The following bearing capacity calculation and stability checking calculation shall be carried out for pipe pile foundation according to specific engineering conditions:

4.3. 1 The vertical bearing capacity and horizontal bearing capacity of pile foundation shall be calculated respectively according to the use function and stress characteristics of pipe pile foundation;

4.3.2 The strength of pipe pile body and bearing capacity of cap structure shall be calculated; For engineering pipe piles with undrained shear strength of soil around the pile less than 10KPa and length-diameter ratio greater than 50, the buckling calculation of the pile body should be carried out; Check the strength and crack resistance of pipe piles during transportation, hoisting, knocking and static pressure;

4.3.3 Check the overall stability of the pipe pile foundation on the slope and the shore;

4.3.4 uplift bearing capacity of single pile and pile group shall be calculated for anti-floating and uplift pipe pile foundation;

4.3.5 Check the bearing strength of pile materials;

4.3.6 Check the vertical and horizontal seismic bearing capacity of pipe pile foundation in seismic fortification area;

4.3.7 When there is a weak substratum below the end face of the pipe pile, the bearing capacity of the weak substratum should be checked;

4.4 Settlement calculation should be made for the following building pipe pile foundations:

4.4. 1 non-rock-socketed pile and non-deep hard bearing layer building pile foundation, with design grade of Grade A;

4.4.2 Build a pile foundation with complex shape, obviously uneven load distribution, or the design grade of soft soil layer below the pile tip plane is Grade B.

4.5 For the building pipe pile foundation with large horizontal load or strict restrictions on horizontal displacement, the horizontal displacement should be calculated.

4.6 The crack resistance and crack width of the normal section of piles and caps shall be checked according to the environmental categories of pipe piles and pile foundations and the corresponding crack control levels. For pipe piles in corrosive environment and Grade III environment, there should be no cracks according to Grade I strict requirements; In the second-class environment, according to the general requirements of the second class, cracks may not appear. For corrosive environment and Class III environment, the crack width of low pile cap should be ≤ 0.2 _; The secondary environment should be ≤0.3_

4.7 When designing pipe pile foundation, the combination of action effect and corresponding resistance adopted shall meet the following requirements:

4.7. 1 When determining the number and arrangement of piles, the standard combination of load effects transmitted to the bottom of the cap should be adopted; The corresponding resistance should adopt the characteristic value of bearing capacity of foundation pile or composite foundation pile.

4.7.2 When calculating the settlement and horizontal displacement of pile foundation under load, the quasi-permanent group of load effect should be adopted.

Close; When calculating the horizontal displacement of pile foundation under horizontal earthquake and wind load, the standard combination of horizontal earthquake and wind load should be adopted.

4.7.3 When checking the overall stability of the pile foundation of buildings on slopes and banks, the standard combination of load effects should be adopted; The standard combination of seismic action effect and load effect should be adopted in the seismic fortification area.

4.7.4 When calculating the bearing capacity of pile foundation structure, determining the size and reinforcement, the basic combination of load effects transmitted to the top surface of pile cap should be adopted. When checking the crack control of pile cap and pile body, the standard combination of load effect and quasi-permanent combination of load effect should be adopted respectively.

4.7.5 The safety grade of the pile foundation structure and the reasonable design service life of the structure should be adopted according to the current building structure code; The design grade and importance coefficient of pile foundation structure shall be determined according to Article 4. 1.2 of this Code.

4.7.6 During the seismic calculation of pile foundation structure, the adjustment coefficient of its seismic bearing capacity is γRE, which should be adopted according to the current national standard Code for Seismic Design of Buildings (GB500 1 1).

4.7.7 For the building pile foundation whose settlement is calculated according to Article 4. 1.4 of this specification, systematic settlement observation shall be conducted during construction and after completion until the settlement is stable.

1. Production quality inspection

First, the production deviation (see table below)

B, the appearance of the pile quality inspection

The appearance quality of piles shall meet the following requirements:

1) The pile surface shall be smooth and dense, the depth of corner drop shall not exceed 10mm, the total area of local honeycomb and corner drop defects shall not exceed 0.5% of the total pile surface area, and it shall not be excessively concentrated.

2) The depth and width of cracks caused by concrete shrinkage are not more than 20mm and 0.5mm respectively.

3) There shall be no honeycomb, pits, cracks and edges at the top and tip of the pile.

The general defects of piles can be repaired, but the defects that affect the structural performance must be studied and dealt with in conjunction with the design and other relevant units.

2. Pile sinking quality control

Pile sinking inspection, including pile joint, pile position deviation, elevation deviation, inclination deviation and pile appearance quality, etc.

A, joint quality inspection, should according to the joint type inspection joint appearance quality, joint or cementing material, welding or cementing quality, in line with the concrete structure engineering construction quality acceptance specification GBJ50204—2002 and the steel structure engineering construction quality acceptance specification gbj50205-200 1 quality requirements.

B, pile location deviation inspection, should according to the characteristics of the pile foundation structure inspection pile location deviation, the following table:

C, pile top elevation deviation inspection, according to the elevation control pile, the allowable deviation of pile top elevation is -50.

D, pile inclination inspection, straight pile inclination shall not be greater than 65438+/-0%, inclined pile inclination deviation shall not be greater than 65438+/-05% of the tangent value of the included angle between the pile centerline and the vertical line.

E, the appearance inspection of the pile, including the fracture and crack of the pile body, the exposed corner of the concrete of the pile body, the cracking of the pile extension, etc.

3. Pile foundation engineering acceptance

The acceptance of piling works shall check whether it meets the design requirements and construction specifications. Before acceptance, the pile top shall not be removed.

A, pile foundation engineering acceptance shall be carried out in accordance with the following provisions:

1) Before piling, pile making, lifting and stacking quality inspection shall be carried out.

2) When the design elevation of the pile top is the same as that of the construction site, the acceptance of the construction quality of the pile foundation project shall be carried out after the completion of piling.

B, when the design elevation of the pile top is lower than the construction site elevation, when the pile top of each pile reaches the site elevation, intermediate acceptance shall be conducted, and a comprehensive inspection shall be conducted after all piles are completed and excavated to the design elevation.

1 1, piling engineering quality control:

The quality standard of precast piles in this project meets the national acceptance standard. When piling, the following requirements shall be met:

① Choose precast pile products with good quality for construction. The fabrication, hoisting, stacking and transportation of piles must conform to the standard of pretensioned prestressed pipe piles (Zhejiang G22, 2002).

② The verticality error of piling shall not exceed 0.5%.

(3) The allowable error of pile top elevation is 50 mm.

(4) The allowable deviation of pile construction plane position must meet the requirements in the following table:

12. In case of any of the following conditions during piling, the supervisor shall be informed in time, and the relevant units shall study and handle them.

(1) The pile body is seriously inclined during initial pressure;

(2) sudden change of pile pressing force during pile pressing;

(3) The soil squeezing during pile pressing affects the verticality of the pile or the surrounding structure.

13, intermediate acceptance

In the process of construction, intermediate acceptance is carried out, and strict operation requirements are carried out for each process to ensure the engineering quality with the process quality. The contents and standards of intermediate acceptance are as follows:

14, completion acceptance

After the completion and acceptance of the pile pressing project, four sets of complete technical data should be arranged in time for verification and filing.

(1) Measuring and setting-out record

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