In aluminum curtain wall connections, the combination of mechanical connections and elastic buffer structures typically offers superior seismic performance. This method transmits loads through rigid components like bolts and angle brackets, while utilizing elastic materials such as rubber gaskets and seismic pads to absorb vibration energy, forming a balanced rigid-flexible seismic system. This connection method is widely used in the connection between the curtain wall and the main structure, the splicing of panels, and the treatment of expansion joints. Its seismic advantages are reflected in structural stability, energy dissipation capacity, and adaptability to deformation.
In the connection between the curtain wall and the main structure, mechanical connections securely fix the curtain wall frame to the building structure using bolts, angle brackets, and other components. For example, double-bolt connections are often used between columns and the main structure, with at least two bolts of at least 10mm diameter at each load-bearing point to ensure the connection strength meets seismic requirements. Simultaneously, elastic gaskets, such as nylon or rubber gaskets, with a thickness typically not less than 2mm, are installed at the connection points to isolate vibrations and compensate for deformation differences between different materials. This structure ensures the overall stability of the curtain wall under seismic loads while absorbing some vibration energy through elastic gaskets, reducing stress concentration.
The splicing nodes between panels also rely on the synergy of mechanical connections and elastic buffers. Taking a unitized curtain wall as an example, the keel of adjacent panels is connected by interlocking profiles, with a vertical overlap length of no less than 10mm and a horizontal overlap length of no less than 15mm, forming a stable structural whole. A 1-2mm gap is set at the splice, filled with sealant or flexible gaskets to ensure airtightness and watertightness while allowing for minor relative displacement between panels. For irregularly shaped panels or corner nodes, custom aluminum alloy core connections are often used, with a 0.5-1mm gap reserved between the core and the keel cavity wall to accommodate profile dimensional deviations while ensuring node strength through mechanical connections. Some innovative designs also embed seismic-resistant pads at the connection points to further enhance the energy dissipation capacity of the nodes.
Expansion joint nodes are a key aspect of the seismic design of aluminum curtain walls. During an earthquake, significant displacement occurs at the expansion joints of the building's main frame. Curtain walls must adapt to this deformation through expandable structures. A common practice is to install independent units on both sides of the expansion joint, with elastic materials such as accordion plates or rubber strips used for transition in the middle. For example, the distance between curtain wall studs must be consistent with the width of the civil engineering expansion joints to meet the third-level seismic requirements; the distance between easily crushed panels is determined according to the second-level calculations, with elastic materials or thin metal plates filling the gaps, allowing for horizontal sliding. This structure ensures the sealing performance of the curtain wall during normal use and releases energy through elastic deformation during an earthquake, preventing damage caused by inconsistent deformation.
The selection of materials and processing precision also significantly affect the seismic performance of joints. Aluminum alloy studs often use high-strength alloys such as 6063-T5 or 6061-T6, whose yield strength and elastic modulus meet seismic design requirements. Connectors such as bolts and angle brackets are preferably made of stainless steel to avoid strength reduction due to electrochemical corrosion. During manufacturing, the diameter of the column hole needs to be approximately 1mm larger than the bolt diameter to compensate for installation errors; the clearance between the sleeve and the keel must be strictly controlled to ensure that relative displacement is allowed during an earthquake while preventing loosening during daily use.
From practical application results, the node method combining mechanical connections and elastic buffers has performed excellently in various earthquakes. For example, in a high-rise building, the aluminum curtain wall using this connection method only experienced localized sealant cracking after an earthquake; the keel and connectors remained undamaged, and the overall curtain wall structure remained intact. This is attributed to its use of mechanical connections to ensure structural strength, while simultaneously utilizing elastic buffer structures to absorb vibration energy, forming multiple lines of earthquake resistance.
