Inspection Specification for Prefabricated Slab Houses

The inspection specification for prefabricated slab houses covers inspection items, instruments and equipment, inspection methods and procedures, as well as relevant technical standards, as detailed below:

1. Inspection Items and Scope

Inspection items include appearance quality (surface flatness, cracks, honeycombing, and other defects), geometric dimension deviations (length, width, thickness, diagonal difference, etc.), concrete strength (compressive and tensile strength), steel reinforcement configuration (cover thickness, reinforcement spacing, diameter), structural performance (bearing capacity, deflection, crack width), and durability indicators (impermeability, frost resistance). The inspection scope should cover products of the same type produced using the same process and from the same raw material source, and sampling inspection should be conducted by batch to ensure representative results.

2. Inspection Instruments and Equipment

Professional instruments are required:

• Concrete Strength Inspection: Non-destructive testing is performed using a concrete rebound hammer or an ultrasonic-rebound combined method tester; for abnormal areas, concrete core drilling machines can be used for sampling verification.
• Steel Reinforcement Configuration Inspection: A steel reinforcement scanner is used to measure cover thickness, spacing, and diameter.
• Geometric Dimension Measurement: Laser rangefinders and digital level gauges are used for measuring dimensions such as length and width.
• Surface Defect Analysis: Crack observation instruments and digital microscopes are used to observe cracks, honeycombing, and other defects.
• Structural Performance Testing: Static strain acquisition systems monitor strain, while jack loading systems and displacement sensors are used for bearing capacity testing.
• Auxiliary Equipment: Carbonation depth testers, etc. All equipment must be regularly calibrated to ensure accurate data.

3. Standard Inspection Methods and Procedures

1. Appearance and Geometric Dimension Inspection: Full or sampling inspection is conducted to record defects and dimensional deviations.
2. Non-destructive Testing: Rebound testing is used to measure concrete strength, and steel reinforcement cover thickness is scanned.
3. Core Drilling Method Verification: Cores are taken from areas with abnormal non-destructive testing results to verify concrete compressive strength.
4. Structural Performance Testing: Support devices, loading equipment, and measuring instruments are set up according to standards. Loading is performed in stages, and deflection changes and crack development are recorded until the test load or ultimate state is reached.
5. Report Issuance: Inspection data is comprehensively analyzed, and environmental conditions, instrument status, and abnormalities are recorded in detail to form an inspection report.

4. Relevant Technical Standards and Specifications

The main references are the Code for Acceptance of Construction Quality of Concrete Structures (GB 50204), the Technical Specification for Prefabricated Concrete Structures (JGJ 1), and the Standard for Dangerous Building Appraisal (JGJ 125-2016). Among them, JGJ 125-2016 classifies building danger levels into Class A (safe), Class B (individual components are dangerous), Class C (part of the load-bearing structure does not meet safety requirements), and Class D (overall danger), providing a basis for the safety assessment of prefabricated slab houses.