Kinematic Anti-Seismic Device for Structural Isolation
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Solution Overview
Problem
Current anti-seismic solutions, such as Lead Rubber Bearings and Buckling-Restrained Axial Dampers, are costly and reactive, primarily addressing seismic vibrations through stiffness and irreversible deformation, failing to effectively manage seismic vibrations beyond certain thresholds and limiting their applicability.
Innovation Solution
An anti-seismic device comprising a system of interconnected supports with constant reciprocal distances and hinges, allowing for dynamic absorption of seismic stresses through kinematic mechanisms, reducing the degrees of freedom of structural movement and providing stable equilibrium without relying on deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If Lead Rubber Bearings with lead core are used to dissipate seismic energy, then dissipative capacity is improved (up to 30% equivalent viscous damping), but device complexity increases due to extremely complex structures with alternate layers of steel and elastomer
Solution Approach 1:
The device segments the seismic energy dissipation function into multiple independent hinges (at least three hinges) that can individually absorb rotational movements. Each hinge acts as a separate energy dissipation unit, simplifying the overall structure compared to the integrated complex Lead Rubber Bearing while maintaining dissipative capacity through the cumulative effect of multiple hinges
Solution Approach 2:
The invention replaces the complex mechanical system of Lead Rubber Bearings (alternate layers of steel and elastomer connected by vulcanisation) with a simpler hinge-based mechanical system. The hinges provide rotational freedom and energy dissipation through controlled movement, substituting the viscoelastic material-based dissipation mechanism with a pure mechanical articulation system
2Strength
If Buckling-Restrained Axial Hysteretic Dissipaters are used, then structural deformability is improved, but cost increases and the system remains reactive beyond certain earthquake thresholds
Solution Approach 1:
The device introduces dynamic adaptability through hinges that can rotate and adjust to seismic movements in real-time. Unlike the static Buckling-Restrained Axial Hysteretic Dissipaters that react beyond certain thresholds, the hinge system continuously adapts its configuration to match the dynamic nature of seismic forces, providing ongoing energy dissipation throughout the earthquake event
Solution Approach 2:
Instead of restricting deformation as in Buckling-Restrained Axial Hysteretic Dissipaters, the invention inverts the approach by embracing controlled deformation through hinge rotation. The hinges allow and guide structural deformations in a controlled manner, dissipating energy through the rotational movement itself rather than resisting the deformation, thereby simplifying the system while maintaining deformability
3Ease of manufacture
If anti-seismic devices work only on the stiffness of joints and support structures, then manufacturing is simplified, but the ability to reduce degrees of freedom of structural movement is limited
Solution Approach 1:
The invention merges the functions of joint stiffness provision and movement degree reduction into a single hinge element. The hinges simultaneously provide the necessary structural support (stiffness) and constrain movements to specific rotational degrees, combining what were previously separate functions into one integrated component that maintains manufacturing simplicity while enhancing movement control capability
Data Source
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AI summary
An anti-seismic device (1 ) is provided for seismically isolating a structure (2) relative to the ground (3) comprising a first support (4) defining a first support plane (4a) integrally connectable to an upper portion and comprising at least two first hinges (40) defining a first constant reciprocal distance (d'), a second support (5) defining a second support plane (5a) comprising at least two second hinges (50) defining a second constant reciprocal distance (d"), a third support (6) defining a third support plane (6a) integrally connectable to a lower portion and comprising at least two third hinges (60) defining a third constant reciprocal distance (d'"), and connection means (7) defining a connection plane (7a) perpendicular to the third support plane (6a) and comprising at least two first rigid bars (70), each defining a first non-deformable direction of connection (70a) and two second rigid bars (71 ), each defining a second non-deformable direction of connection (71 a), wherein the first bars (70) are transiently constrained to a first hinges (40) and a second hinge (50) so that said first directions of connection (70a) of the first bars (70) cross in said connection plane (7a), and wherein the second bars (71 ) are transiently constrained each to a second hinges (50) and a third hinge (60) so that said second directions of connection (71 a) of said second bars (71 ) cross in said connection plane (7a).