Dynamic Pedestrian Access Terminals for Vehicle Penetration Control
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Solution Overview
Problem
Existing pedestrian access terminals in roadside barriers face issues such as increased gap length for vehicle penetration, hazardous spearing risks, high installation and maintenance costs, and aesthetic concerns, while failing to effectively absorb varying impact energies from vehicles.
Innovation Solution
A dynamic pedestrian access terminal system with translatable terminal blocks and parallel attenuators, anchored by foundation posts and tensioning members, which absorb energy through compressible materials to prevent collapse and ensure safe pedestrian passage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If gating terminal systems are used to provide pedestrian access through roadside barriers, then pedestrian access is enabled, but the effective gap length increases significantly allowing vehicles to penetrate through the barrier system
Solution Approach 1:
The terminal block is designed to be dynamic rather than static, capable of translating laterally upon vehicle impact. The foundation post allows controlled movement of the terminal block from its initial position to a stopped position, transforming the rigid gating system into a dynamic energy-absorbing system that maintains barrier integrity while permitting pedestrian access.
Solution Approach 2:
An attenuator is positioned between the terminal block and the foundation post to provide predetermined energy absorption capability. This cushioning element is pre-installed to absorb impact energy, preventing the terminal block from transferring excessive force to the foundation post while limiting the translation distance to maintain barrier effectiveness.
2Reliability
If standard crashworthy terminal systems are used on either side of access points, then barrier performance is improved, but roadway widening and grading requirements increase installation complexity and cost
Solution Approach 1:
The terminal system is segmented into distinct functional components: a terminal block for vehicle impact, a foundation post for anchoring and guiding movement, an attenuator for energy absorption, and a tensioning member for pre-loading. This segmentation allows each component to be optimized independently and simplifies installation compared to monolithic terminal systems requiring extensive roadway modification.
Solution Approach 2:
The system changes the operational parameters of the terminal block from static to dynamic by introducing controlled translational capability. The foundation post geometry and attenuator properties are specifically designed to allow the terminal block to translate a predetermined distance while absorbing impact energy, eliminating the need for extensive roadway widening and grading.
3Object-affected harmful factors
If the terminal block is designed to absorb impact energy through translation, then vehicle impact safety is improved, but the system complexity and installation requirements increase
Solution Approach 1:
The foundation post is pre-designed with specific geometric features and the tensioning member is pre-installed to provide predetermined translation capability and pre-loading. The attenuator is pre-positioned between the terminal block and foundation post, establishing the energy absorption mechanism before impact occurs. This preliminary configuration simplifies the overall system while ensuring reliable impact energy absorption.
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 absorbs a greater amount of energy, reduces reliance on vehicle absorption, prevents destructive collapse, and maintains safety and cost-effectiveness, while meeting crash test requirements and aesthetic standards.
Implementation Method 1
an attenuator positioned between the terminal block and the foundation post to absorb impact energy
Data Source
AI summary
A dynamic pedestrian access terminal is disclosed having a pair of spaced apart terminal blocks for pedestrian passage along a roadway. The bottom portions of the terminal blocks are set beneath the surface. Foundation posts are vertically positioned below the surface and extend upward into each terminal block. A tensioning member extends between the foundation posts and beneath the terminal blocks to increase resistance to lateral movement. Soil plates may be attached to the foundation posts to further resist lateral movement. An internal attenuator is positioned in a compression chamber within each terminal block. An external attenuator may be positioned in a recess positioned at the bottom rear of each terminal block.