Guardrail Posts With Sliding Fasteners
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Solution Overview
Problem
Existing roadway guardrail systems using wooden support posts are prone to deterioration and costly to maintain, while traditional steel breakaway posts require significant resources for fabrication and installation, and their designs have remained largely unchanged for improved safety.
Innovation Solution
A roadway guardrail system featuring steel support posts with longitudinally extending channels and block-outs that allow fasteners to slide upon impact, dissipating energy and redirecting vehicles, while reducing material costs and installation complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If wooden support posts are used in guardrail systems, then installation is simpler, but they are susceptible to deterioration and require costly maintenance with chemical treatments
Solution Approach 1:
The patent replaces durable but expensive and complex steel posts with simpler, potentially replaceable wooden posts that can be treated with chemicals to extend their service life. The block-out device with sliding fasteners simplifies installation and potential replacement, accepting that wooden posts have limited lifespan compared to steel but offering easier installation and lower initial cost.
Solution Approach 2:
The patent changes the material parameter from steel to wood, and applies chemical treatment to the wooden posts to alter their durability parameter. The chemical treatment transforms wood from a rapidly deteriorating material to one with extended service life, balancing the trade-off between simplicity and durability.
2Reliability
If steel support posts are used instead of wooden posts, then durability and maintenance are improved, but material costs and installation complexity increase
Solution Approach 1:
The patent reverses the typical approach by choosing less durable but simpler and cheaper wooden posts over durable but expensive and complex steel posts. The system accepts reduced durability in exchange for simplified installation and lower material costs.
Solution Approach 2:
Instead of using steel posts to achieve durability (the conventional approach), the patent inverts the logic by using wooden posts and accepting their limitations, compensating through the simplified block-out fastening system that facilitates easier installation and potential replacement.
3Reliability
If traditional break away steel support posts with cutouts or multi-section designs are used, then safety is improved, but fabrication time, money, and resources increase substantially
Solution Approach 1:
The patent segments the fastening system into a block-out device and sliding fasteners, separating the safety function (energy absorption through fastener sliding) from the post structure itself. This allows using simple, easily fabricated wooden posts while maintaining safety through the segmented fastening mechanism.
Solution Approach 2:
The block-out device acts as an intermediary between the rail and the post, providing the safety function through controlled fastener sliding during impact. This intermediary absorbs the complexity of safety mechanisms, allowing the posts themselves to remain simple and easy to fabricate.
4Strength
If larger posts are used in guardrail systems, then impact resistance is improved, but material costs and installation complexity increase
Solution Approach 1:
The block-out device with sliding fasteners acts as an intermediary that provides impact resistance through controlled movement and energy absorption. This allows using smaller, simpler posts while maintaining impact resistance through the intermediary fastening mechanism rather than relying on large post size.
Solution Approach 2:
The fastening system transitions from a static rigid connection to a dynamic system where fasteners slide within the block-out during impact. This dynamic response provides impact resistance through controlled movement and energy dissipation, allowing smaller posts to withstand impacts that would require much larger static posts.
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 system effectively dissipates vehicle impact energy, redirects vehicles safely, and meets safety standards with reduced material and labor costs, offering improved durability and maintenance efficiency.
Implementation Method 1
the fasteners are adapted to slide along the slot in the support post
Implementation Method 2
The guardrail systems may act to contain and redirect an errant vehicle along such roadways. Such guardrail systems may dissipate some of the vehicle's energy through deformation of the rail or post
Data Source
AI summary
A roadway guardrail system including a rail, a plurality of support posts, and a plurality of fasteners assembly to redirect an impacting vehicle and dissipate a portion of the impacting vehicle's energy. Block-outs may be positioned in between the rail and support posts. A plurality of support posts each includes a slot extending along its length aligning with apertures in the rail and engaging with the rail through the apertures with fasteners including reinforcing members slidable along the slots in the posts. Alternatively, the rail has a plurality of laterally extending slots aligning with apertures in support posts and engaging with the support posts through the apertures with fasteners including reinforcing members slidable along the slots.