Shear Element Fastening Device for Bollard Foundation Protection
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Solution Overview
Problem
Existing fastening devices for public space elements like bollards and street lamps are prone to destruction when hit by vehicles, leading to the need for new installations and costly foundation repairs, with existing solutions being complex and difficult to assemble or repair.
Innovation Solution
A fastening device featuring a mounting ring anchored to the ground with a shearing element between the ring and foot, designed to shear off under excessive stress, allowing for secure, play-free mounting and easy repair, using a shearing element made from materials that fail under supercritical loads and geometric designs influencing failure points.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the barrier or retaining element is firmly attached to the foundation, then the stability and security of the element is improved, but the foundation is destroyed when the element is hit by a vehicle
Solution Approach 1:
The connection between the barrier element and foundation is segmented into two independent parts: the foundation-side fastening ring and the element-side mounting foot, connected by a replaceable shear element. This segmentation allows the shear element to fail and be replaced without damaging the foundation or the barrier element itself.
Solution Approach 2:
The shear element is designed as a sacrificial, replaceable component made of shearable material that is intended to fail under excessive load. This disposable element protects the expensive and permanent foundation and barrier element from damage, requiring only the replacement of the relatively inexpensive shear element after a collision.
2Ease of repair
If a sacrificial shear element is used to protect the foundation, then the ease of repair is improved, but the device complexity increases due to additional components
Solution Approach 1:
The sacrificial function is extracted into a separate, dedicated shear element that can be independently replaced. This extraction simplifies the repair process by isolating the replacement task to a single component while maintaining a relatively simple overall structure through the use of a single receptacle and direct-fit mounting foot.
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 prevents foundation damage and allows for easy repair of fastening devices by shearing the element under stress, maintaining structural integrity and reducing repair costs, while providing a secure and rigid connection under normal loads.
Implementation Method 1
a shear element (11) made from materials that fail under supercritical loads and geometric designs influencing failure points
Data Source
Figure 1
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AI summary
The device (3) has a double-side fixing base (2) forming a fixing ring (14), and a fixing stand (4) insertable into the ring for holding a blocking- and holding element (8). The stand is detachably connected with the base, and a recess (40) is provided between the ring and the stand and extends in a circumferential direction. A shear element (11) is arranged in the recess in an assembly condition, and bridges a gap (17) between the ring and stand. The fixing stand has two lower and upper fixing stand elements (5, 6) releasably connected with each other.