Development of a Next-generation Non-proprietary Portable Concrete Barrier

Development of a Next-generation Non-proprietary Portable Concrete Barrier
Author: Riley J. Ruskamp
Publisher:
Total Pages: 0
Release: 2022
Genre:
ISBN:

Portable concrete barriers (PCBs) are segmented barriers made of precast concrete units that are connected by various load-bearing hardware. PCBs are typically used to shield work zones by redirecting errant vehicles upon impact with the barrier system. Most commonly-available PCBs have demonstrated performance issues arising from the sloped face of the barrier, which encourages vehicles to pitch and roll during impact, potentially resulting in vehicle rollover. Concerns also exist regarding the large dynamic deflections exhibited by these systems that can encroach upon the protected work zone or require anchoring to prevent large displacements. In addition to these concerns, the American Association of State Highway and Transportation Officials (AASHTO) updated the Manual for Assessing Safety Hardware (MASH) in 2016, which improved the criteria for evaluating roadside safety devices and required the re-evaluation of barrier systems developed before the updated standards were published. Thus, an opportunity existed to develop a next-generation PCB system capable of meeting the new MASH 2016 criteria while addressing the concerns of the current generation of PCBs. The objective of this research effort funded by the Mid-America Transportation Center (MATC) was to further develop and investigate PCB concept designs that were brainstormed under a parallel research effort at the Midwest Roadside Safety Facility (MwRSF) funded by the Wisconsin Department of Transportation. This research consisted of the development of finite element models of the PCB design concepts for use in LS-DYNA simulations, followed by the comparison of the simulation results to a current PCB system that has been previously modeled and validated. The simulation analysis identified three PCB concepts as viable designs, while three other PCB concepts were not recommended based on the simulation performance. Upon completion of the simulation analysis, the simulation results of the six PCB concepts were presented to Midwest Pooled Fund Program member states. Finally, a single concept, that used interlocking and staggered precast concrete segments without the need for connection hardware, was selected for further design and full-scale crash testing in the next phase of the research.

Development of a Non-pinned Low-profile End Treatment

Development of a Non-pinned Low-profile End Treatment
Author: Felicia Jean Desorcie
Publisher:
Total Pages: 84
Release: 2014
Genre:
ISBN:

In the early 1990s, the Low-Profile Portable Concrete Barrier (PCB) system, including both the sloped Low-Profile PCB segment and Low-Profile PCB end treatment, were developed. The original Low-Profile PCB end treatment was designed with steel pins inserted along the barrier centerline, through precast holes, and anchored to the pavement or subgrade. The purpose of these pins was to reduce lateral deflection of the end treatment during an impact. For various reasons, users of the Low-Profile PCB system have stated that the system would be more easily deployed if the vertical pins were not used in situations where lateral deflections can be permitted. The primary objective of the research presented herein was to determine the feasibility of removing the vertical, steel pins from the Low-Profile PCB end treatment in certain applications and if necessary make modifications. The secondary objective of the research presented herein was to demonstrate the applicability of the finite element analysis (FEA) to unpinned barrier systems. The research objectives were achieved through the use of sound engineering judgment, FEA, and a full-scale crash test. Based on sound engineering judgment and approximate strength analyses of the original Low-Profile PCB design, the author determined the system would most likely function acceptably but would have large lateral deflections. In order to increase connection rigidity and thus control lateral displacement, a plate washer was added to the barrier connection. The modified non-pinned Low-Profile PCB system was tested for strength in a full-scale crash test under Manual for Assessing Safety Hardware (MASH) test 2-35. Additionally, the recommended system was analyzed under similar test conditions with LS-DYNA, a finite element code. The recommended system passed the MASH test 2-35, in both a full-scale crash test and FEA. While this does not replace the original barrier, it does provide another option for use of the Low-Profile PCB in situations where sufficient room for deflection outside of the length of need exists. If this room does not exist, the barrier must remain pinned. The electronic version of this dissertation is accessible from http://hdl.handle.net/1969.1/151825

Deflection Limits for Temporary Concrete Barriers

Deflection Limits for Temporary Concrete Barriers
Author: Dean Sicking
Publisher:
Total Pages: 15
Release: 2002
Genre: Road work zones
ISBN:

Whenever a traffic control plan is developed that utilizes temporary barriers, it is important to define acceptable barrier deflection criteria. However, the acceptable deflection criteria can be expected to vary, depending on the application. When temporary concrete barriers are used on the edge of a bridge, the risk of the entire line of barriers falling off of the deck required that deflection limits be selected to preclude such behavior in almost all impact scenarios. Hence, it is recommended that at the edge of a bridge deck, design deflection limits should be selected to contain more than 95% of all crashes. In all other barrier applications, the consequences of a barrier exceeding the design deflection criteria are not severe. In these situations, a more modest deflection limit criterion based on an 85th percentile impact condition is more appropriate. Computer simulation was used to estimate the deflection of barriers impacted under the 85th percentile impact conditions. Finally, recommendations were made pertaining to the two different design deflection limits that should be used for the Iowa temporary concrete barrier.

Development of an NCHRP Report 350 TL-3 New Jersey Shape 50-inch Portable Concrete Barrier

Development of an NCHRP Report 350 TL-3 New Jersey Shape 50-inch Portable Concrete Barrier
Author: Chuck A. Plaxico
Publisher:
Total Pages: 198
Release: 2006
Genre: Concrete
ISBN:

For roadside work-zones in areas that have opposing traffic flow, safety is enhanced if the temporary barriers incorporate a "glare-shield" that blocks headlight glare from opposing traffic. Currently-available 32-inch portable concrete barriers require the use of an add-on glare shield attached to the top of the barrier. The add-on glare shields are an extra expense and complicate barrier set-up and handling. An alternative solution was to develop a 50-inch high portable concrete barrier which is tall enough to serve as its own glare-shield. Finite element analysis was used to investigate various barrier shapes and connection schemes to identify a successful crashworthy design that would meet requirments of NCHRP Report 350 Test level 3. A 50-inch portable concrete barrier design was developed based on the results of the finite element analyses and was crash tested at the Transportation Research Center in East Liberty, Ohio. The system successfully met all safety criteria of NCHRP Report 350 and has been approved by the Federal Highway Administration for use on the National Highway System as a test level 3 device.