I. Overview of the Project
This project consists of two-story basement and three-story podium, with 34 storeys of shops and office buildings, with a total construction area of 89264m2, of which the above-ground area is 67702m2, the underground area is 2 1562m2, the building height is 1.58m, and the elevation of the natural floor on site is about-0.8m. 0.00 is equivalent to the absolute elevation of 5.80m Concrete.
The structural concrete of this project adopts commercial concrete in accordance with regulations, and the sampling and inspection plan of concrete block shall be prepared separately for approval. Other main materials used in this project are Q235, HRB335 and HRB400 steel bars, in which the vertical steel bars of the column and the end column of the shear wall are connected by electroslag pressure welding, and the binding edge members of the shear wall, the structural edge members and the vertical steel bars of the wall and the horizontal steel bars (d & gt28mm) are connected by overlapping; The through bars on the upper part of the frame beam are connected by equal strength butt welding. Cement has 32.5 ordinary portland cement; MU 10 shale perforated brick is used as the infilled wall in the basement. The outer wall of frame infilled wall adopts M5.0 sand aerated concrete block, and the inner wall adopts M5.0 mixed mortar to build A5.0 light sand aerated concrete block. The underground waterproofing and use function of this project is Grade I ... The strength grade of structural concrete is C60~C35, and the foundation concrete adopts C35 impermeability grade P8. Due to the large scale of the basement in both directions, in order to reduce the shrinkage cracks caused by concrete hardening, the concrete of the bottom plate and retaining wall was replaced with cement, and HEA micro-expansive agent and UNS polypropylene fiber were added in a certain proportion to increase the crack resistance.
Second, the principle of sampling inspection
The re-inspection and various tests of other materials shall be carried out according to the national acceptance standards, the sampling inspection regulations of Hangzhou construction engineering quality inspection and the raw material inspection regulations of the company.
Third, the structural entity
According to the principles stipulated in GB50300-200 1 Unified Standard for Acceptance of Construction Quality of Building Engineering and the requirements stipulated in GB50204-2002 Code for Acceptance of Construction Quality of Concrete Structure Engineering, this project carries out structural entity inspection on important structural members such as columns, walls and beams related to the safety of concrete structures; Structural entity inspection shall be organized and implemented by the technical director of the construction project under the witness of the supervision engineer. Laboratories undertaking structural entity inspection should have corresponding qualifications.
Structural entity inspection is not a re-inspection before the acceptance of partial projects, but a confirmatory inspection of important projects based on the acceptance of corresponding partial projects and process control, so as to ensure the quality, thus strengthening the construction quality acceptance of concrete structures, truly reflecting the quality indicators such as concrete strength and steel bar position, and ensuring structural safety. At the same time, the inspection record of concrete structure entity is also an integral part of the quality control data of construction quality acceptance of concrete subdivisional works.
The structural entity inspection items of this project are concrete strength, the thickness of protective layer of reinforcement of important structural members and the thickness of floor slab.
1, concrete strength
(1) The inspection of concrete strength in the structural entity inspection project of this project is based on the strength of the specimen made at the concrete pouring site and maintained under the same conditions as the structural entity.
(2) Under the same conditions, the retention mode and sampling quantity of the curing specimens.
1) The retention method and sampling quantity of specimens cured under the same conditions shall meet the following requirements:
A. The structural members corresponding to the specimens with the same condition maintenance shall be jointly selected by the supervision (construction), construction and other parties.
B for each concrete strength grade of concrete structure engineering, all specimens shall be cured under the same conditions;
C. The number of retained specimens with the same strength grade and conditions shall be determined according to the quantity and importance of concrete, and shall not be less than 10 group and not less than 3 groups;
D. After the specimen is dismantled, it should be placed in an appropriate position near the corresponding structural members or structural parts, and the same curing method should be adopted.
2) According to the above requirements, combined with the structural characteristics of each unit project of this project, after consultation with the construction and supervision units, the structural parts corresponding to the specimens cured under the same conditions in each unit project are selected as follows:
See attached table for concrete test blocks with the same conditions in each unit project.
(3) When the specimen cured under the same conditions reaches the equivalent age, the strength test shall be carried out. The equivalent age should be determined according to the principle that the strength of specimens cured under the same conditions is equal to the strength of specimens cured for 28 days under standard curing conditions.
(4) The representative values of equivalent age and corresponding specimen strength under natural curing conditions shall be determined according to the local temperature and curing conditions according to the following provisions:
1) The age corresponding to the daily cumulative average temperature of 600℃ can be taken as the equivalent age, excluding the age of 0℃ and below; The equivalent age cannot be less than 14 days, nor longer than 60 days;
2) The representative strength value of specimens cured under the same conditions should be determined according to the strength test results and the current national standard "Standard for Inspection and Evaluation of Concrete Strength" (GBJ 107), and the multiplication factor should be 1. 10, which can also be adjusted appropriately according to the local test statistics.
2, structural entity reinforced protective layer thickness inspection
(1) The number of components for thickness inspection of reinforced protective layer shall meet the following requirements.
(2) For the selected beam members, check the protective layer thickness of all longitudinal reinforcing bars, and for the selected plate members, check the protective layer thickness of not less than 6 longitudinal reinforcing bars. For each steel bar, 1 point shall be inspected at the representative position.
(3) The inspection of reinforced protective layer can adopt nondestructive or local destructive methods, and can also adopt nondestructive and local destructive methods; When the nondestructive testing method is adopted, the testing instruments used shall undergo metrological inspection, and the inspection operation shall comply with the provisions of the corresponding regulations; The detection error of reinforced protective layer thickness inspection is not greater than 65438±0mm；;
(4) When inspecting the thickness of steel bar protective layer, the allowable deviation of longitudinal steel bar protective layer thickness:+10MM and-7mm for beam members; Plates are+8mm and-5mm.
(5) The thickness of steel protective layer of beam and plate members shall be checked and accepted respectively; Structural entity reinforced protective layer thickness acceptance shall meet the following requirements:
1) When the qualified rate of all reinforced protective layer thickness inspection exceeds 90%, the inspection result of reinforced protective layer thickness is judged as qualified;
2) When the qualified rate of all reinforced protective layer thickness inspection is less than 90% but not less than 80%, the same number of members can be selected for inspection. When the qualified rate calculated by the sum of the two samples is 90% or above, the inspection result of the thickness of the protective layer of steel bars should still be judged as qualified;
3) The maximum deviation of unqualified sampling results shall not be greater than 1.5 times of the allowable deviation specified in Article 4 above.
3, the floor thickness and height detection
The number of structural members and components for floor thickness and floor height inspection shall meet the specification requirements.
The floor detection position is determined by the construction, supervision and construction unit. See the attached table for details.
The design unit is required to verify the unqualified parts, the qualified parts can be accepted, and the unqualified parts will not be accepted.
The basement is divided into six parts according to the post-cast strip, and the specific axis is expressed as:
I # plot: 2700 south of Q -C axis-1-8 axis-4380 west;
Plot 2 #: axis 8 is west of axis 2380- 13 and south of axis 3600 -2700;
Plot III #: 2600- 13 axis west /2700 axis Q -C axis south.
Ⅳ # block: 65438+3380-8 axis north of axis 0-3700 axis south of axis A.
ⅴ # plot: 8/3600 south of axis A-C/2380- 13 west of axis A.
ⅵ # block: 2600- 13 axis west /3700 axis A -C axis south.
Four, the standard sample block
According to the principles stipulated in the Unified Standard for Acceptance of Construction Quality of Building Engineering (GB50300-200 1) and the requirements of Code for Acceptance of Construction Quality of Concrete Structure Engineering (GB50204-2002), the number of lien groups in the standard maintenance test of this project is determined according to the actual site concrete quantity.
The strength grade of structural concrete must meet the design requirements. Specimens used to check the concrete strength of structural members shall be randomly selected at the concrete pouring site, and the sampling and specimens shall meet the following requirements:
1, every mixed 100 disc and not more than 100m? With the mixture ratio of concrete, sampling shall not be less than once;
2. When the concrete of the same mixture ratio is less than 100 plate per shift, sampling shall not be less than once;
3, when a continuous casting more than 1000 m? , the same mixture ratio of concrete every 200 m? Sampling shall not be less than once;
4, each floor, the same mixture ratio of concrete, sampling shall not be less than once;
5. At least one set of standard curing specimens shall be retained for each sampling, and the number of groups of specimens with the same conditions shall be determined according to actual needs.
According to the Code for Quality Acceptance of Underground Waterproofing Engineering (GB50208-2002), concrete specimens of concrete structures with impermeability requirements should be randomly sampled at the pouring site. The same project, the same mixture ratio of concrete, sampling should not be less than once, the number of lien groups can be determined according to actual needs.
1, the same concrete strength grade, impermeability grade, and the same mixture ratio, the production process is basically the same, and each unit project shall not be less than two groups of impermeability test blocks (6 blocks in each group);
2, every 500 m continuous pouring concrete? A set of impermeability test pieces (a set of 6 impermeability test pieces) shall be kept, with no less than 2 sets for each project. The number of retained groups of impervious specimens using ready-mixed concrete should depend on the scale and requirements of the structure;
3. The compressive strength specimen should be kept at the same time as the impermeability specimen, and should be taken from the same plate of concrete mixture.
4. The test block shall be made at the casting site.
After the standard curing specimen is formed, the surface should be covered to prevent water evaporation, and it should be allowed to stand at 20 5℃ for one day and two nights, and then the formwork should be removed (both sides of the impermeable specimen should also be brushed off). Immediately after form removal, the specimen shall be placed in a standard curing room with a temperature of 20 2℃ and a humidity higher than 95%, or the temperature is 20 2℃. In the "standard curing room", the specimen shall be placed on a shelf with a spacing of 10~20㎜, and the surface of the specimen shall be kept moist, and it shall not be directly washed with water. The standard curing period is 28d (counting from mixing and adding water).
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