Bidirectional Collapse-Proof Damper for Bridge Seismic Freedom
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Solution Overview
Problem
Existing bridge collapse-proof devices are either too damaging to structures during earthquakes or overly restrictive for other vibrations, leading to high repair costs and limited deformation freedom.
Innovation Solution
A bidirectional collapse-proof damper with a macroscopic NPR structure, featuring a sleeve with a reducing part and a sliding rod connected by an elastic element, allowing for bidirectional sliding and energy absorption through elastic and frictional forces, preventing collapse and enabling resetting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If steel damper pull rods are used to consume seismic energy, then damage to girders is avoided, but the dampers are too restrictive to building structures or bridges under aeolian vibration, environmental vibration, train vibration and temperature deformation
Solution Approach 1:
The damper employs a dynamic limiting body that can slide freely within the reducing part under small vibrations (aeolian, environmental, train vibrations) but becomes locked under large seismic displacements. This dynamic behavior allows the system to adapt its constraint level based on the intensity of the applied force, providing freedom of deformation for minor vibrations while offering strong protection during earthquakes.
Solution Approach 2:
The damper changes its mechanical parameter (constraint stiffness) based on the displacement magnitude. Under small displacements, the limiting body slides freely with low constraint, allowing thermal and vibration-induced deformations. Under large seismic displacements, the limiting body engages with the reducing part to create high constraint, providing collapse-proof protection. This parameter change resolves the contradiction between protection strength and deformation freedom.
2Loss of energy
If anti-collision blocks or shear walls are used to reduce energy, then seismic energy is consumed, but damage is caused to the girders or the parts connected with the girders, increasing repair cost
Solution Approach 1:
The invention extracts the energy dissipation function from the bridge structure itself and places it in a separate, dedicated damper device. The limiting body and reducing part constitute a specialized energy-consuming mechanism that isolates the seismic energy dissipation process from the girders and connected parts. This extraction allows energy consumption without damaging the main bridge structure, thereby reducing repair costs.
Solution Approach 2:
The limiting body is designed as a sacrificial component that undergoes controlled plastic deformation or friction during seismic events to consume energy. This disposable-like component can be replaced more easily and cheaply than the main bridge girders, allowing energy dissipation through controlled damage to a replaceable part rather than permanent damage to critical bridge infrastructure.
3Reliability
If conventional dampers are used to consume seismic energy, then girder damage is reduced, but the structure is overly restrictive under normal vibrations and temperature deformations
Solution Approach 1:
The damper is segmented into distinct functional components: the limiting body for bidirectional sliding, the reducing part for geometric constraint, and the elastic element for energy storage. This segmentation allows each component to perform its specific function independently, enabling the system to provide collapse-proof protection through the locking mechanism while remaining simple and non-restrictive under normal operating conditions.
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
The solution provides effective protection against various vibrations and deformations, minimizing damage and repair costs while maintaining structural stability and freedom of deformation.
Implementation Method 1
the rod body of the sliding rod located at both sides of the limiting body is connected with the inner side wall of the sleeve through an elastic element so that the limiting body and the rod body can realize bidirectional sliding displacement in the sleeve
Implementation Method 2
in the event of large deformation and vibration caused by small and moderate earthquakes, the motion of the limiting body expands the reducing part of the sleeve to provide main resistance, which consumes vibrational energy under the combined action of the elastic force provided by the elastic element
Data Source
AI summary
The present invention discloses a bidirectional collapse-proof damper with a macroscopic NPR structure and a bridge structure having the same, comprising a sleeve and a sliding rod; by adding a structure of a reducing part and a limiting body, a sliding gap exists between both ends of the limiting body and both inner ends of the reducing part; the rod body is connected with the inner side wall of the sleeve through an elastic element; the limiting body and the rod body can realize bidirectional slip in the sleeve, which have multi-level seismic performance.