Key points of civil air defense engineering supervision and control:
1. Quality control of reinforced concrete
1. 1 Quality control of reinforcement
1. 1. 1 When steel raw materials enter the site, the quality certification documents, including factory certificate, quality warranty and inspection report, must be sampled by the supervisor and sent to a qualified testing unit for inspection before use.
1. 1.2 If brittle fracture, poor welding performance or obvious abnormal mechanical properties are found during the processing of steel bars, the chemical composition inspection or other special inspection shall be carried out for this batch of steel bars.
1. 1.3 In the process of steel binding and installation, the supervision engineer should follow up and inspect the site, find problems, point them out in time, and ask the construction unit to correct them. After the steel bar binding is completed, and the self-inspection by the construction unit is qualified and reported to the supervisor for acceptance, the supervision engineer shall check whether the specification, quantity, spacing, length, anchorage length and joint setting of the binding steel bar meet the design requirements according to the structural construction drawing. In addition, we should also focus on checking some structural measures, such as stirrups in the stirrup encryption area of frame joints and hanging bars or stirrups attached to the beam where concentrated loads are applied, and no leakage is allowed; For thick plates and double-ribbed wall panels, lacing and retractor shall be provided as required; Control the strength, thickness and position of reinforced protective layer pad should meet the specification requirements; The position of embedded parts and embedded holes should be correct and reliable, and the reinforcement around the holes should meet the design requirements.
1.2 concrete pouring quality control
1.2. 1 In the process of concrete pouring, it is necessary to strengthen on-site supervision, strictly control the pouring quality, check the slump of concrete, and it is forbidden to add water to concrete. Unqualified concrete shall be returned to the mixing station.
1.2.2 Check the vibration, and do not leak or over-vibrate. Pay attention to the position and firmness of formwork and reinforcement. At the same time, the construction unit is required to assign personnel to look at the template. If any formwork leakage or steel bar displacement is found, it should be dealt with in time, with special attention to the concrete pouring treatment of construction joints, settlement joints and post-pouring zones.
1.2.3 Strictly check the pouring sequence of different grades of concrete at the nodes and the pouring grade of concrete to prevent low-grade concrete from being injected into high-grade concrete.
1.2.4 supervise the construction unit to make test blocks on site and maintain them according to the specification requirements. After reaching the curing age, it will be sent to the laboratory for testing under the supervision of the supervisor.
1.2.5 mass concrete shall be poured in a reasonable way and temperature control measures shall be taken at the same time. Mass concrete should be poured in layers to make the concrete rise evenly along the height, and pouring should be carried out when the outdoor temperature is low; The temperature difference between inside and outside of mass concrete shall not exceed 25℃.
1.2.6 for winter and summer construction, the supervision engineer should make clear the key parts and contents of winter and summer construction according to the actual situation of the project, and strengthen on-site monitoring. Pay attention to the monitoring of the actual mold-entering temperature, internal and external temperature and temperature difference of concrete to prevent concrete from freezing and cracking; Control the time of form removal and heat preservation and maintenance after form removal.
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