摘要: |
Portable concrete barriers (PCBs) are frequently used on to shield motorists where limited deflection is desired during vehicle impacts, such as bridge decks and work-zones. The impact performance of PCBs is influenced by several variables, including barrier shape/profile, height, segment length, joint rotation, joint moment capacity and tensile strength. Most non-proprietary, portable barrier systems on the nation’s highways consist of safety-shape or single-slope barrier segments comprised of reinforced concrete and simple pinned connections. General problems exist with these existing barrier configurations: (1) the sloped barrier geometry allows impacting vehicles to climb the front face and roll into the barrier, thus potentially causing unstable vehicle behavior or vehicle rollover; (2) the barrier joints allow significant rotation prior to transferring load across the joint, thus resulting in large lateral barrier displacements. There exists a critical need to develop a high-performance portable barrier system that meets the Manual for Assessing Safety Hardware (MASH) safety criteria while addressing large deflection, stability, and durability concerns of current portable barrier designs. Development of this new, non-proprietary optimized PCB will also lead to a uniform standardization of portable barriers throughout the nation. The objective of this research project along with a current project at Midwest Roadside Safety Facility (MwRSF) at UNL is to develop a new generation of non-proprietary, high-performance portable barrier capable of meeting the MASH TL-3 safety requirements with reduced free-standing barrier deflections as well as increased vehicle stability as compared to existing, widely used PCB systems. Other design criteria include cost, durability, construction and transportability, ease of installation and removal. Design concepts including various geometries, connections, and/or materials will be developed and evaluated using advanced computer simulations. Selected design(s) need to be crash tested to MASH safety criteria at full-scale in separate studies (e.g., Midwest Pooled Fund program) prior to implementation. |