Local underground works are fully buried undergroundstructureIt is undoubtedly very beneficial to control the temperature deformation and post shrinkage deformation caused by concrete structure;The temperature difference between day and night in Foshan is relatively small, generally within 10 ℃, and the annual extreme maximum and minimum temperature difference is also smaller than that in the north, which is also a favorable factor for preventing temperature cracks in reinforced concrete structures.
Mass Concrete Construction Scheme of Foshan Youbang Financial Center - Figure 1
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Proper selection of high efficiency water reducing agent and air entraining agent plays an extremely important role in reducing the unit water consumption and cementitious material consumption of mass concrete, improving the workability of fresh concrete, and improving the mechanical, thermal, deformation, durability and other properties of hardened concrete.
Concrete is a heterogeneous brittle material formed by mixing sand aggregate, cement, water and other external materials.Due to a series of problems such as concrete construction, deformation and constraint, there are many micropores, air pockets and microcracks in hardened concrete. It is precisely because of the existence of these initial defects that concrete presents some heterogeneous characteristics
Abstract: Concrete is an artificial stone made of cementitious materials, water, fine aggregate, coarse aggregate, admixtures and mineral admixtures when necessary, mixed in proper proportion, uniformly mixed, compacted, shaped and cured.In the construction process, it is often found that various cracks appear in the concrete structure after forming.This paper discusses the causes and measures of cracks in mass concrete as follows.
Abstract: This paper analyzes the causes of cracks in mass concrete from the aspects of cement hydration heat, internal and external constraints, external temperature, and plastic shrinkage of concrete, and introduces effective technical measures that should be taken in the construction process to reduce or avoid cracks.
With the rapid development of economy, there are more and more mass concrete in infrastructure construction. Engineering practice has proved that the construction of mass concrete is more difficult, and there are more chances of concrete cracks. Slight mistakes will cause incalculable losses
There are many reasons for cracks in concrete, mainly the changes in temperature and humidity, the brittleness and unevenness of concrete, and the structural form.
Abstract: This paper gives an overview of the causes of cracks in mass concrete construction, focusing on the prevention and treatment of cracks in mass concrete.
Abstr: In mass concrete, temperature stress and temperature control have important practical significance.However, no matter what measures are taken, mass concrete will produce temperature cracks, which will not only affect the aesthetics, but also may affect the integrity and durability of the structure
There are three main reasons for cracks in concrete structures: one is caused by external loads, that is, the main stress of conventional calculation;The second is caused by the secondary stress of the structure, that is, due to the difference between the actual working state of the structure and the calculation assumption model;The third is caused by deformation stress, that is, deformation caused by temperature, shrinkage, expansion and uneven settlement. The tensile strength of concrete is the lowest among various strengths, which is 7%~11% of the compressive strength. When the stress generated by deformation exceeds the tensile strength of concrete, cracks will occur.
Through years of on-site construction management experience, observation and thinking of some mass concrete engineering examples, and combined with monographs and data on concrete cracks, tests, internal stress and control, this paper expounds the causes of concrete temperature cracks, control of concrete temperature stress, and measures for prevention and control of cracks.
The net width of the main power house is 17m, including the auxiliary power house and the water inlet and outlet structures. The excavation area of the foundation pit is 70m × 48m, and the maximum excavation depth is 21.5m. The base is an interbed of mud and shale. The saturated compressive strength is 6.6~37.8MPa. The rock foundation is sealed with C15 plain concrete after excavation, with an average thickness of 35cm. The thickness of the foundation bottom plate is 4~7m, and the concrete volume is about 20000 m3.The highest monthly average temperature in general years is 28.6 ℃, and the annual average temperature is 18.1 ℃.The foundation concrete shall be poured in the middle of March, and the pouring shall be completed in May of the same year and the superstructure shall be constructed successively.The average temperature during pouring is about 17.4 ℃.Technical requirements for concrete construction: R60, C20 concrete, cement consumption not more than 260kg/m3, strength assurance rate of 90%, ultimate tensile value not less than 0.85 × 10-4, and the maximum temperature of concrete during construction must be controlled between 38~44 ℃.
Abstract: Through construction examples, this paper analyzes the original solid caused by cracks in mass concrete, and how to control the measures to avoid them.
This data is for the mass concrete pouring project of the bottom plate, including construction preparation, construction technology, quality requirements, etc., for reference.
The net width of the main power house is 17m, including the auxiliary power house and the water inlet and outlet structures. The excavation area of the foundation pit is 70m × 48m, and the maximum excavation depth is 21.5m. The base is an interbed of mud and shale. The saturated compressive strength is 6.6~37.8MPa. The rock foundation is sealed with C15 plain concrete after excavation, with an average thickness of 35cm. The thickness of the foundation bottom plate is 4~7m, and the concrete volume is about 20000 m3.The highest monthly average temperature in general years is 28.6 ℃, and the annual average temperature is 18.1 ℃.The foundation concrete shall be poured in the middle of March, and the pouring shall be completed in May of the same year and the superstructure shall be constructed successively.The average temperature during pouring is about 17.4 ℃.
The mass concrete construction organization design includes the "Changyuan · Holiday Harbor" office base project with a large scale and a building area of 49211.73 ㎡, including 37040.62 ㎡ above ground and 12171.11 ㎡ underground.The project is a high-rise office building, of which 1 # building covers an area of 1477.7m2, with one floor underground and 15 floors above the ground, and the building height is 64.20m. The foundation form is a whole slab foundation in the basement, with the slab bottom elevation of -7.1m and the slab surface elevation of -5.5m. The foundation size is a=53.4m long, b1=27.211m wide, b2=33.587m, and h=1.6m thick.The concrete strength is C35, and the impermeability grade is S8. The total volume is about 2600m3, which is a typical mass concrete.The construction of this mass concrete floor has the characteristics of high hydration heat, large shrinkage and easy cracking, so the mass concrete pouring of the floor should be taken seriously as a construction focus and difficulty.The key point of mass concrete construction is to minimize the adverse effects of temperature stress and prevent and reduce the generation and development of cracks.In order to ensure the smooth construction of mass concrete of foundation slab, sufficient preparations should be made in terms of material selection, technical measures and other related links.For reference and download
The project specification clearly stipulates the requirements for structural crack control. Therefore, at the beginning of the project, we will select Portland cement with lower hydration heat according to the project specification. The coarse aggregate will be continuously graded stone with less needle flakes, and the fine aggregate will be natural medium sand. The lower sand ratio will be used to reduce the consumption of cement and water in the concrete.In the design of concrete mix proportion, fly ash and granulated blast furnace slag are added to replace part of cement, and high efficiency water reducer and air entraining agent are added to reduce water consumption and minimize the heat generated by cement hydration.
Guide: by adopting reasonable mix proportion of concrete, one-time pouring construction method of inclined plane layer by layer, finishing treatment measures after concrete pouring, concrete surface heat storage, heat preservation and moisture conservation measures and temperature measurement control
Guide: prevent cracks due to dry shrinkage in the early stage.Temperature stress is generated.TMT-101 electronic thermometer is used for temperature measurement.Crack, mass concrete cooling construction measures.
Heshan Road is planned to be an urban trunk road leading directly to Taihu Lake in Suzhou, connecting Yuping Road to the south line of Taihu Avenue in the long term.The west extension project of Heshan Road in this bid section is east-west direction. The starting point of the bid section is connected with 2 marked dug tunnels, which is located at NK2+207 (SK2+213) between Longchi East Road and Baimajian Hetang. It extends westward in a two-way six lane scale to Longchi West Road, reserves a six lane break of the main line in the long term, and sets a branch ramp to turn north to connect Longchi West Road to Majian Road.
In order to ensure the compact and reasonable layout of the construction site and the smooth progress of the site construction, the construction plane layout principle of the project is as follows: the layout meets the requirements of site health, safety, fire prevention and environmental protection.The protection facilities are enclosed by municipal steel barriers to ensure normal construction in the site.
**No. 43~53 (F type duplex) villas in Huayuan * * Garden are of frame structure. The building has 4 floors (3 floors). The design life of the building is 50 years. The design grade of the civil building is Grade II. The seismic fortification intensity of this project is Grade 6, and the fire resistance rating is Grade II. The natural foundation alone is used in this project. The foundation is embedded in strongly weathered rock. The strength grade of the concrete of the project structure is C25-C35,The thickness of the external wall and wall of the building infill wall is 180, the thickness of the partition wall is 120 ', and the standard floor height of the building is 3m. The external decoration is mainly made of external wall tiles. The indoor decoration is rough, and the roof is paved with west tiles.
The area where the project belongs has abundant rainfall, especially 2-3 typhoons in the tropical climate zone in summer and autumn, accompanied by heavy rain, which makes the surface runoff strong and rainy in early spring, often constituting highway water disasters and inducing highway water damage.
Splicing steel sheet piles according to the design length: with the cooperation of crane, set a platform in the workshop or site, fix the pile sections to be spliced on the same axis, and then use fishplate welding method to connect the piles to the design pile length.
The installation content of this project is mainly the low-voltage power distribution system, and the lighting system has a large workload. It must be carefully organized, closely coordinated, and strictly required by the quality standards of excellent model projects to ensure a satisfactory and comfortable lighting environment.
On the basis of careful investigation of the actual situation of the project, careful study of the bidding documents and relevant regulations, the construction shall be organized scientifically and reasonably according to the characteristics and construction conditions of the bid project and the actual situation of our construction force, machinery and equipment.
Our company has organized relevant technicians to carefully read the drawings, carefully understand the site conditions and prepare the Construction Organization Design.The Construction Organization Design is a programmatic document for guiding the construction of the project. During the preparation, the construction period, quality objectives, project management organization setting and labor organization, construction schedule control, mechanical equipment and revolving materials allocation, main technical scheme, safety, civilized construction, environmental protection, seasonal construction, general contracting management and other factors have been fully considered,Highlight scientificity, applicability and pertinence.Before the implementation of the project, detailed construction organization design or construction scheme, measures and operation instructions shall be prepared to guide the project construction and ensure that all construction contents of the project are completed within the specified construction period.
The project aims to create "excellent project and double civilization model project", so when organizing the construction, especially in the structural and decoration stages, it should be strictly controlled, carefully organized and constructed.
The foundation pit support scheme of this project is designed by Guangdong Overseas Architectural Design Institute Co., Ltd., a Class A design institute. The foundation pit support structure adopts deep mixing pile water stop curtain and natural sloping.The design safety level of foundation pit is Level III, and the safe service life is 1 year.See the Appendix Design Institute Calculation Sheet for slope stability checking calculation
The construction scheme for earthwork excavation of a project in Foshan is rich and detailed, and can be downloaded for reference and study by netizens.
**The resin plant project is located in ***** Industrial Zone, Foshan City. The project is composed of office buildings, dormitory workshops and warehouses. It is invested by * * Resin (Foshan) Co., Ltd. and designed by the * * District Architectural Design Institute, Guangzhou. The total building area is 29483m2, including 3645 m2 for dormitory buildings, 3648 m2 for office buildings, and 18434 m2 for workshops and warehouses,
Plant area project, which is composed of office building, dormitory workshop and warehouse, with a total construction area of 29483m2, including 3645m2 for dormitory, 3648m2 for office building and 18434m2 for workshop and warehouse.
Foshan Nanhai Jiuzhou Pratt&Whitney Fan Co., Ltd. is a professional fan manufacturer, which was founded in 1996. It is a member of China General Machinery Fan Industry Association, China Electrical Appliance Industry Association fractional horsepower motor branch, Guangdong Quality Association, and Guangdong Environmental Protection Industry Association.The factory covers an area of 115000 square meters, the standard factory covers an area of 60000 square meters, and more than 800 employees. It has general and numerical control equipment such as machining, sheet metal, stamping, shearing, riveting, dynamic balancing, and various precision measuring tools and testing equipment;There are fan assembly, automatic spray drying and motor production lines,
The construction scheme of a plant area project in Foshan City, * * Resin Plant Area Project, is located in ***** Industrial Zone, Foshan City. The project is composed of office buildings, dormitory workshops and warehouses. It is invested by * * Resin (Foshan) Co., Ltd. and designed by Guangzhou * * District Architectural Design Institute. The total building area is 29483m2, including 3645m2 of dormitory building area and 3648m2 of office building building area,Workshop and warehouse building area 18434 m2