Disc and spring isolation bearing for seismic displacement
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Solution Overview
Problem
Existing isolation bearing designs face challenges in accommodating large seismic displacements, leading to increased size, cost, and limited damping capabilities, particularly in high-seismicity regions, where traditional sliding and elastomeric bearings struggle to provide both damping and restoring forces efficiently.
Innovation Solution
The integration of a central sliding high-load bearing element with shear springs positioned at the periphery, where the shear springs provide damping and restoring forces, allowing for large displacements while maintaining a compact design, and utilizing a disc bearing core with elastomeric and substrate layers to optimize damping and restoring capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If compression springs are used to provide restoring force in sliding bearings, then the bearing can accommodate lateral displacements, but the plan dimension and height of the bearing increase significantly for large seismic displacements
Solution Approach 1:
The patent transitions from horizontal spring placement (increasing plan dimension) to vertical spring placement (increasing height dimension). The compression springs are positioned vertically above the sliding surface, allowing large lateral displacements without increasing the bearing's plan dimension. This dimensional reconfiguration resolves the contradiction by accommodating large seismic displacements while maintaining a compact footprint.
Solution Approach 2:
The springs are pre-compressed to a predetermined force before the bearing undergoes lateral displacement. This preliminary compression establishes the restoring force in advance, allowing the bearing to immediately counteract seismic forces without requiring additional space for spring extension. The pre-compressed springs provide immediate restoring force while maintaining a compact design.
2Length of moving object
If compression springs are used to provide restoring force, then the bearing can accommodate lateral displacements, but the cost of the bearing increases significantly
Solution Approach 1:
The patent combines the sliding bearing function and spring restoring force function into a single integrated assembly. The vertical spring arrangement allows the springs to work in conjunction with the sliding surface without requiring separate mounting structures or additional components. This merging of functions reduces overall bearing cost by eliminating redundant parts and simplifying the assembly process.
3Length of moving object
If the sliding surface is made larger to accommodate high displacements, then the bearing can handle larger seismic movements, but the vertical load support capability decreases
Solution Approach 1:
The patent maintains a compact sliding surface area by positioning springs vertically rather than horizontally. The vertical spring arrangement decouples the displacement capacity from the load-bearing area, allowing large lateral displacements without increasing the sliding surface dimension. This preserves high vertical load support capability while accommodating large seismic movements.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration effectively reduces seismic forces and accelerations transferred to structures, allowing for flexible design specifications and enhanced damping without the limitations of traditional designs, such as excessive size and vertical load constraints.
Implementation Method 1
The shear spring is configured to deform in shear along the layers of elastomeric material
Implementation Method 2
The shear spring provides damping and restoring forces
Implementation Method 3
The shear spring exerts a lateral return force on the upper base plate when the upper base plate is laterally displaced
Implementation Method 4
the disc bearing core allows the lower surface of the upper base plate to slide along the disc bearing core
Data Source
AI summary
The disclosed seismic isolation bearing includes an upper base plate, a lower base plate, a disc bearing core, and at least one shear spring. The upper and lower base plates each have an upper surface and a lower surface. The disc bearing core is centrally positioned with respect to the planes of the upper and lower base plates and is in contact with the lower surface of the upper base plate and the upper surface of the lower base plate, where the disc bearing core allows the lower surface of the upper base plate to slide along the disc bearing core. The shear spring is coupled to the lower surface of the upper base plate and the upper surface of the lower base plate, deforms in shear upon lateral movement of the upper base plate relative to the lower base plate, and exerts a lateral return force on the upper base plate when laterally displaced.