Reinforcement of Three-Story Prefabricated Panel Houses
Common methods for reinforcing three-story prefabricated panel houses include comprehensive reinforcement, section enlargement reinforcement, structural load path modification reinforcement, replacement of prefabricated panels, and frame reinforcement and elevation methods. The specific measures are as follows:
Comprehensive Reinforcement Plan
For issues such as cracks and deflections at the bottom of the panels, carbon fiber sheets can be bonded to the panel bottom. Select Class I 300g/m² unidirectional carbon fiber sheets (tensile strength ≥ 3400MPa) to limit crack development by improving flexural bearing capacity. For areas where the concrete at the panel end supports is spalling or has insufficient bearing capacity, Q235B steel plate supports (thickness ≥ 10mm) can be added to distribute loads and enhance stability. On the top of the panels, HPB300 grade φ8 steel mesh (spacing 150mm × 150mm) can be laid and C30 fine aggregate concrete can be poured to improve the overall stiffness, waterproofing, and wear resistance of the floor.
Section Enlargement Reinforcement Method
Add a reinforced concrete overlay not less than 40mm thick on the surface or bottom of the prefabricated panels to form a rigid floor. If choosing to pour an overlay on the panel bottom, the panel bottom should be roughened and the spraying method should be used for construction to ensure tight bonding between the new and old concrete. This method improves structural bearing capacity by increasing the cross-sectional area and is suitable for cases where the original panel thickness is insufficient or the long-term load is excessive.
Structural Load Path Modification Reinforcement Method
Reduce the bending moment of the panels by adding beams and columns, such as adding new load-bearing columns or increasing the cross-sectional size of beams at the bottom of the prefabricated panels to transfer loads to the foundation. In a reinforcement case of a three-story prefabricated panel house in Anhui, adding columns and enlarging beams significantly enhanced structural stability, suitable for cases with localized concentrated loads or unreasonable structural systems.
Replacement of Prefabricated Panels
Select high-strength, high-performance prefabricated panels to replace the original panels, focusing on strengthening weak connection areas. For example, increase connecting reinforcement or use mechanical connection joints to ensure coordinated force between the new and old panels. This method is suitable for cases where the original panels are severely aged, have excessive cracks, or have insufficient bearing capacity, but attention should be paid to the impact on house use during construction.
Frame Reinforcement and Elevation Method
Reconstruct the frame structure on the original foundation, such as raising the structural height by 60 centimeters in a case in Zhejiang. During construction, first construct the frame and allow it to set, then remove the original prefabricated panels and walls and replace them with cast-in-place concrete structures. This method can thoroughly improve the structural system but has higher costs and is suitable for cases where the overall seismic performance of the house is insufficient or significant renovations are required.
Construction Preparation Points: Familiarize with drawings and specifications, conduct technical briefings and pre-job training, and verify data such as crack width and deflection. Ensure the quality of materials such as carbon fiber sheets, steel, and concrete is qualified. Precautions: The reinforcement plan should be selected based on the house inspection report and actual needs, and the construction process should strictly follow specifications to ensure quality and safety.
