Prefabricated House Performance Inspection Report

The prefabricated house performance inspection report is a professional document that systematically evaluates the structural safety, usability, and potential risks of a building. Its core contents include inspection items, assessment methods, and grading criteria for the assessment results.

Inspection Items

1. Structural Safety Assessment: Focus on checking the integrity of load-bearing components (beams, slabs, columns, and walls), such as concrete cracking, steel bar corrosion, and masonry weathering. For prefabricated slab houses, special attention should be paid to the firmness of slab connections, the aging of waterproof layers, the degree of steel bar corrosion, and changes in structural load-bearing capacity. For example, cracks at the joints of prefabricated slabs or corrosion of connecting elements may affect overall stability.
2. Foundation and Substructure Stability: Evaluate the foundation's bearing capacity by observing whether the house exhibits uneven settlement (e.g., window and door deformation, wall cracks), checking the condition of apron drains and drainage systems, and inspecting basements for water seepage or structural deformation. If the tilt measurement data exceeds the allowable limits specified in regulations (e.g., those stipulated in the 'Code for Design of Building Foundation'), further analysis of the causes is required.
3. Building Envelope System Inspection: This covers the aging of roof waterproof layers, the hollowing and peeling of exterior wall finishes, and the airtightness of windows and doors. Although these defects do not directly threaten structural safety, they may accelerate the deterioration of the main structure's durability, such as waterproof failure leading to rainwater infiltration and subsequent steel bar corrosion.
4. Equipment and Pipeline Safety: Investigate the aging of water and electricity pipelines, the risk of gas leaks, and the effectiveness of fire protection facilities. For older houses, special attention should be paid to checking the insulation performance of wiring and the corrosion of pipelines to avoid secondary disasters caused by equipment failures.

Assessment Methods

1. On-site Inspection Techniques: Use a rebound hammer to test concrete strength, a steel bar scanner to locate the distribution of internal reinforcement, and a crack observer to record the width and development trend of damage. Suspected deteriorated materials (e.g., severely carbonated concrete) should be sampled and sent to a laboratory for compressive and tensile strength analysis.
2. Computational Analysis: Establish a structural finite element model based on inspection data to simulate the load-bearing capacity and deformation of components under load. Seismic assessment should verify whether the structure meets the requirements of 'remaining intact under minor earthquakes, being repairable under moderate earthquakes, and not collapsing under major earthquakes' in conjunction with the local seismic fortification intensity (e.g., an 8-degree fortification area).
3. Comparison with Historical Data: Retrieve original design drawings, construction records, and annual maintenance files to compare the current condition with the original design deviations. For example, if a house has undergone an additional floor construction without structural verification, safety hazards may arise due to increased loads.

Grading Criteria for Assessment Results

According to the 'Standard for Dangerous Building Appraisal' (JGJ 125-2016), the danger level of a house is divided into four grades:

• Grade A: The structural load-bearing capacity meets normal usage requirements, with no dangerous points.
• Grade B: There are individual dangerous components (e.g., local concrete spalling), but they do not affect the safety of the main structure.
• Grade C: The load-bearing capacity of some structural components is insufficient, posing a local danger (e.g., a through-crack appearing in the prefabricated slabs on a certain floor).
• Grade D: The overall structural load-bearing capacity is severely insufficient, constituting a dangerous building for the entire structure (e.g., a two-story brick-concrete prefabricated slab house in Xiangyang City, Hubei Province, was rated as Grade D due to extensive wall cracking caused by foundation settlement).

The grading of the assessment results should be determined based on a comprehensive consideration of the foundation, substructure, superstructure, and the number and degree of dangerous components, rather than solely based on the construction year.