community Service Centre Final version of project supervision outline
2、 Characteristics and key control points of the project (I) Characteristics of the civil works of the project 1. Characteristics of the foundation and foundation works: the foundation works of the project use prestressed reinforced concrete pipe piles, which are end bearing friction piles. The design grade of the building pile foundation is Grade C, and PHC-500 (110) AB-C80-14 pile type and C-type steel pile tip are used; The pile end bearing stratum is 11 layers of strongly weathered gneiss. The pile end enters the bearing stratum no less than 1.0m, and the pile length is 14m. The characteristic value of the vertical bearing capacity of a single pile is Ra=1400KN, and the total number of piles is 208. Static pressure pile sinking construction is adopted. Prestressed concrete pipe pile is a kind of precast concrete pile that adopts the principle of centrifugal dewatering and compaction molding process, applies prestress by pretensioning method, stretches the prestressed reinforcement after reaching the specified strength, and then performs autoclave curing (or immersion curing). Prestressed pipe pile (static pressure type) has the characteristics of low noise, high bearing capacity of single pile, easy quality assurance, short construction period, etc., but the compaction effect is obvious, and pile sinking will have certain difficulties. 2. Main structure engineering characteristics: the main body of the project is a frame structure, which is cast-in-place with reinforced concrete, with a large amount of work. 2.1 Features of reinforcement subdivisional works The reinforcement of this project adopts HPB300 and HRB400, and the ratio of the measured tensile strength value to the measured yield strength value of the reinforcement should not be less than 1.25, and the ratio of the measured yield strength value to the standard yield strength value of the reinforcement should not be more than 1.3. At present, HPB235 reinforcement still exists in the market, and the construction unit may continue to use HPB235 reinforcement according to the old ideas and methods. We pay attention to the subdivisional works of reinforcement, and check the model and specification when the raw materials of reinforcement enter the site. Steel bar engineering is an important part of reinforced concrete structure. Steel bar and concrete constitute an important load-bearing component, which is an important load-bearing structure of housing construction. There are many reinforcement processes: reinforcement processing, reinforcement connection and installation. The process requirements are strict. Grasping each process is the key to completing the quality requirements. Close cooperation and coordination are needed to improve the quality standards that meet the specifications. 2.2 Features of formwork subdivisional works Wood formwork and steel support system are adopted for the formwork of the project. Formwork sub project is the general term of a series of technical works and completed entities such as the design, installation and removal of formwork and its support for concrete pouring. Due to the large amount of use in this project, the formwork can be used continuously. We should check the painting of the isolation agent on the formwork surface and the damage degree of the formwork to ensure the use quality of the formwork and the apparent quality of the concrete. 2.3 Features of concrete subdivisional works Due to the large demand for concrete in the project, it is recommended to use commercial concrete in priority. The concrete grade used for the main frame structure of the project is: C40 (P6) for basement floor, cushion cap, external wall, pool, frame column and roof; C30 is used for frame columns, beams, slabs, stairs, etc. above ± 0.00; C20 concrete is used for secondary pouring components such as structural columns and lintels. Because commercial concrete has the characteristics of factory production, commercial supply and mechanized construction, it not only improves the mechanization level and production efficiency of construction, but also improves the quality of concrete engineering. At the same time, it can shorten the construction period of high-rise building structural engineering. Its advantages are very significant. 2.4 Features of masonry subdivisional works The project is a frame structure, and the wall is a non bearing infilled wall. 200 thick MU7.5 hollow blocks and M5 special mortar are used for the external wall; The interior wall is constructed with NALC aerated concrete blocks (A2.5) and M5 special mortar. The wall is made of hollow cut blocks and aerated concrete blocks. The wall material is light and the apparent quality after forming is good. The quantity of masonry works in this project is large, and the quality control goal of this project is excellent. The quality control of masonry works in construction is also an important part of the project quality. Therefore, in terms of material procurement such as masonry works, strict quality control is required to overcome the construction difficulties caused by material procurement itself. Ensure that the wall masonry meets the expected control objectives. 3. Decoration engineering characteristics: 3.1 General plastering engineering characteristics The wall of the project shall be plastered with mortar, and the internal and external walls shall use medium coarse sand with mud content less than 2% and fineness modulus not less than 2.3. The project is a public building, and the wall painting quality requirements are high. Therefore, in the face of hollowing, cracks, and uneven plastering surface, we should take priority control measures for the common quality problems existing in the plastering process. According to the construction characteristics of the project, the construction period is tight, the amount of plastering work is large, and the construction processes are relatively concentrated. It is suggested that professional plastering teams should be preferentially selected for construction to fully ensure the construction of this sub project. 3.2 Features of door and window subdivisional works Customized fireproof doors (Class A, B and C series) and aluminum alloy hollow glass window series are used for the doors and windows of the project. The wind pressure resistance performance of the external doors and windows of the building is Level 3, and the air tightness is Level 6. Plastic steel doors and windows are widely used in the construction process in China. They have the advantages of environmental protection, energy conservation, beauty, good function, strong decoration, durability, easy processing, etc. The installation of plastic steel doors and windows is an important link in the process of building construction. The quality of installation is not only related to the overall facade effect of the building, but also directly affects the use function of the building. We should control the construction process, construction quality control, finished product protection and construction cooperation of plastic steel windows.
