Pull-out Test for Prefabricated Panel Houses

The pull-out test for prefabricated panel houses is a crucial inspection method to verify the tensile pull-out resistance of connection joints between prefabricated components and ensure structural safety. The key points are as follows:

I. Test Purpose and Core Objects

The pull-out test simulates actual stress conditions to verify the tensile performance of connection joints between prefabricated components (such as wall panels and floor slabs). It focuses on inspecting two types of objects:

1. Embedded Part Systems: Including lifting embedded parts, installation connectors, etc., to ensure their anchoring strength meets design requirements.
2. Reinforcement Connection Areas: Such as connection points of longitudinal stressed reinforcements like sleeve grouting connections and grout-anchored lap connections, to prevent structural failure due to connection defects.

The test can expose construction hazards, such as inadequate grouting density, insufficient anchoring depth, incomplete chemical anchor bolt injection, or incomplete cleaning of drilling residues. Although these issues are concealed, they can significantly weaken the tensile bearing capacity of components and are difficult to detect with the naked eye.

II. Inspection Content and Process

1. Ultimate Pull-out Bearing Capacity Test: Apply axial tension through step-by-step loading until the component fails or reaches the designed bearing capacity, and record the maximum bearing value.
2. Load-Displacement Curve Plotting: Monitor the displacement changes of the component during the loading process in real-time to analyze its stiffness and ductility.
3. Failure Mode Observation: Record abnormal phenomena such as component fracture, slippage, or loosening, and determine the failure mode (e.g., brittle failure or plastic failure).
4. Compliance Determination: Compare the measured values with the design values. If the component does not fracture but the bearing capacity does not meet the standard or slippage or loosening occurs, it is still judged as unqualified.

The test must strictly follow standards such as the Technical Specification for Post-installed Fastenings in Concrete Structures (JGJ 145) and the Technical Specification for Applications of Grouted Sleeve Connections for Reinforcements (JGJ 355). Data is collected through professional equipment, and an authoritative report is issued.

III. Application Scenarios and Importance

The pull-out test is a direct means of quality control for prefabricated panel houses, especially suitable for verifying the quality of post-installed construction processes. For example:

• Exterior Wall Insulation Layers and Decorative Tiles: Verify the anchoring strength of adhesion to prevent falling risks.
• Ceiling Hanging Rods and Equipment Brackets: Ensure bearing stability to avoid safety accidents caused by loosening.

Through the test, connection joint defects can be identified and repaired in advance, avoiding structural safety hazards and ensuring the safety of the building throughout its lifecycle.