Anti-Wind Device for Seismic-Isolated Buildings: Solve Wind-Induced Sway for Base-Isolation Structures

This conflict between seismic isolation efficiency and wind-load service performance can be well solved by a professional anti-wind device (wind restraint device). It is a matched mechanical component for isolation layers, either integrated inside isolator units or installed as independent steel assemblies between upper and lower support piers. It provides additional lateral stiffness under wind and minor earthquake conditions, and automatically yields or releases restraint when seismic force exceeds design threshold, so the original isolation function will not be sacrificed during real earthquakes.

Working Mechanism

The anti-wind device operates in two distinct working stages:

1. Wind load & minor earthquake stage: The device bears horizontal wind force, supplies extra stiffness to limit isolation-layer displacement, suppress wind-induced vibration and guarantee human comfort. At this stage, seismic isolators keep elastic state without excessive shear deformation.

2. Moderate & major earthquake stage: Once horizontal force surpasses pre-designed yield or shear-off force, the anti-wind component yields plastically or shear pins break. The restraint function fails in a controlled way, and the full deformation capacity of the isolation layer is completely released. The isolators restore their core functions of period elongation, energy dissipation and displacement, protecting the superstructure from seismic damage.

Two mainstream structural types are widely applied in global projects. The shear-pin type embeds machined shear pins inside bearings; pins break under earthquake excitation and need replacement after strong shocks. The independent metallic yield-type anti-wind device adopts low-yield-point steel plates as energy-carrying parts, mounted separately on isolation piers. It is convenient for inspection and post-earthquake replacement, which becomes the preferred solution for modern isolated construction projects.

Core Technical Requirements

The device must follow strict design logic to avoid interfering with seismic-isolation performance. First, its design wind-resisting capacity shall not be less than total horizontal wind force on the isolation layer. Second, its yield or shear-off force must be lower than the yield force of matched seismic isolators, ensuring anti-wind parts fail prior to isolators during earthquakes. Full-scale prototype tests are compulsory to verify force-displacement curve, low-cycle fatigue and cooperative performance with isolators. Products comply with GB/T 51408-2021, referenced with EN 15129 and ISO 9001 quality-management system requirements.

Typical Application Scenarios

Anti-wind devices are necessary for these engineering cases:

- High-rise base-isolated buildings in high-wind-speed regions;

- Projects adopting natural rubber bearings (LNR), which have no self-anti-wind capability;

- Isolation schemes where isolation-layer yield force is lower than wind-caused horizontal force;

- Important public buildings, hospitals and lifeline facilities pursuing both seismic safety and daily comfort.