The curved surface sliders or Friction Isolation Pendula (FIP) are sliding isolators based on the working principle of the simple pendulum. In a structure that is isolated by means of curved surface sliders, the period of oscillation mainly depends on the radius of curvature of the curved sliding surface, i.e. it is almost independent from the mass of the structure. The energy dissipation is provided by the friction encountered during the movement of the sliding surfaces, and the re-centring capability is provided by the curvature of the sliding surface.
The Friction Isolation Pendulum can be designed and manufactured in two main types, with one or two primary spherical sliding surfaces that accomodate the horizontal displacement, respectively classified as FIP or +FIP-D series as follows.
The FIP-D series or double concave curved surface sliders are characterised by two primary concave sliding surfaces with the same radius of curvature; both surfaces accomodate for horizontal displacement and rotation. In this case each single sliding surface is designed to accomodate only half of the total horizontal displacement, so that the dimensions in plan of the devices may be significantly smaller in comparison with FIP series. Another advantage of FIP-D series versus FIP series is that the eccentricity of the vertical load (P-Δ effect) is halved, i.e. is equal to half the displacement, while in FIP series devices it is equal to the displacement (on one side).
Standards
The curved surface sliders (both series FIP and FIP-D) are usually designed according to the European Standard EN 15129:2009 Anti-seismic devices. On request, they can be designed to satisfy other standards or technical specifications.
Design Features
The standard FIP-D isolators whose geometrical and mechanical characteristics are listed in the enclosed tables, are designed for seven different values of maximum displacement, from 100 to 400 mm.
Quality Control
FIP MEC’s internal quality control system ensures the conformity of the product to the various requirements thus guaranteeing the quality both of materials and manufacturing processes.
Anchoring systems
The curved surface sliders are fixed on to the structure by means of mechanical anchoring systems providing 100 % of the horizontal load transfer (despite the European Standard EN 15219:2009 allows that only 75 % of the horizontal load is supported by mechanical anchorages when the minimum vertical load on the isolators during the seismic action has been determined by non-linear dynamic analysis).
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Anti Seismic Devices
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Anti Seismic Devices
Anti Seismic Devices