Shallow Security Barrier Post with Spring Steel Footing
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Solution Overview
Problem
Existing security barriers require deep concrete beddings, which are disruptive, interfere with underground utilities, and can be damaged by vehicle impacts, making them unsuitable for shallow installations like bridges and increasing the need for shallower footings that maintain structural integrity.
Innovation Solution
A security barrier post design featuring a shallow underground footing with a vertical tubular steel shaft, a steel foot box, and spring steel elements that allow for easy installation and replacement, distributing impact loads through a concrete bed with embedded steel reinforcement, enabling effective stopping of vehicles with minimal excavation and disruption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If deep concrete bedding is used to stop vehicles, then the barrier can effectively stop vehicles moving at 40-50 km/h, but the excavation depth interferes with existing buried services and increases installation complexity
Solution Approach 1:
The barrier system is divided into separate modular components: above-ground posts and a shallow underground footing. Each post can be independently installed and replaced without affecting others, eliminating the need for deep continuous excavation and allowing installation around existing utilities.
Solution Approach 2:
The invention transitions from a purely vertical depth-based solution to a multi-dimensional approach by adding horizontal spread of the shallow footing and creating a modular array of posts. This distributes the vehicle-stopping function across multiple shallow units rather than requiring one deep foundation.
2Strength
If deep concrete bedding is used to provide structural integrity, then the barrier can prevent punch-through by vehicles, but the concrete bed can be damaged by impact loads reducing strength against future impacts
Solution Approach 1:
Spring steel elements are pre-installed within the post structure to absorb and dissipate impact energy through elastic deformation. This cushioning mechanism protects the concrete footing from direct impact loads, preventing damage and maintaining structural integrity for subsequent impacts.
Solution Approach 2:
The invention changes the material parameter from rigid concrete alone to a composite system including flexible spring steel elements. This allows the structure to dynamically adjust its stiffness and energy absorption characteristics during impact, reducing peak forces transmitted to the concrete footing.
3Ease of operation
If shallow footing is used to reduce excavation disruption, then underground utilities are preserved, but the footing depth may be insufficient to meet security requirements
Solution Approach 1:
The barrier function is segmented into multiple shallow posts rather than one deep foundation. The collective resistance of several posts spaced apart provides equivalent or superior vehicle-stopping capability to a single deep footing, while minimizing excavation depth and disruption to utilities.
Solution Approach 2:
The post structure combines concrete footing with spring steel elements and reinforcement bars to create a composite system. This composite construction achieves high strength and energy absorption in a shallow configuration, meeting security requirements without deep excavation.
4Ease of operation
If stand-alone posts are used instead of interlinked posts, then installation is simplified and individual replacement is easier, but the load of impact must be borne by each individual post
Solution Approach 1:
Spring steel elements are pre-installed within each stand-alone post to provide inherent shock absorption. This cushioning mechanism enables individual posts to withstand full impact loads without requiring interlinking, while maintaining installation simplicity and ease of individual replacement.
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 design allows for stand-alone posts with footings as shallow as 200mm to effectively stop heavy vehicles, reducing disruption, preserving underground utilities, and meeting stringent impact testing criteria without the need for deep excavations or complex installations.
Implementation Method 1
a spring steel back plate arranged immediately adjacent to, substantially perpendicular to, and extending to at least one side of, the rear facing side of the shaft
Implementation Method 2
at least a first spring steel element comprising a substantially vertical section and a substantially horizontal section
Data Source
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AI summary
This invention presents a security barrier post (10) which has an underground footing (12) and an impact post (14) that extends above the surface. The underground footing (12) has a substantially vertical tubular steel shaft (16) having an opening at its lower end on an impact facing side and a steel foot box (18) aligned with the opening.A bottom plate (20) is provided to which the shaft (16) and said foot (18) box are attached. A spring steel back plate (22) is arranged adjacent and perpendicular to rear facing side of the shaft (16), and extends to at least one side of it. The back plate (22) is located at a position that is flush with or slightly below the surface in which the footing is buried. The impact post (14) has at least a first spring steel element (32) which is L shaped, and at least one packing element (34, 36, 38) located behind the first element (32) to retain it in a position in which it extends into the foot box(18).