Author: Publisher:
ISBN:
Category : Concrete construction
Languages : en
Pages : 66
Book Description
Development of Low-deflection Precast Concrete Barrier
Author: Publisher:
ISBN:
Category : Concrete construction
Languages : en
Pages : 66
Book Description
Development of a Retrofit, Low-deflection, Temporary Concrete Barrier System
Author: Robert W. BielenbergPublisher:
ISBN:
Category : Roads
Languages : en
Pages : 384
Book Description
Development of a Next-generation Non-proprietary Portable Concrete Barrier
Author: Riley J. RuskampPublisher:
ISBN:
Category :
Languages : en
Pages : 0
Book Description
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
Author: Felicia Jean DesorciePublisher:
ISBN:
Category :
Languages : en
Pages : 84
Book Description
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
Development of a Transition Between Free-standing and Reduced-deflection Portable Concrete Barriers - Phase I
Author: Mojdeh Asadollahi PajouhPublisher:
ISBN:
Category : Roads
Languages : en
Pages : 59
Book Description
Deflection Limits for Temporary Concrete Barriers
Author: Dean SickingPublisher:
ISBN:
Category : Road work zones
Languages : en
Pages : 15
Book Description
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 a Low-profile Portable Concrete Barrier
Author: Todd R. GuidryPhase I Development of an Aesthetic, Precast Concrete Bridge Rail
Author: Traffic Control Design for Portable Concrete Barriers
Author: Aesthetic Concrete Barrier Design
Author: Delbert Lance BullardPublisher: Transportation Research Board
ISBN: 0309088496
Category : Bridge railings
Languages : en
Pages : 87
Book Description
This report contains guidelines for aesthetic treatment of concrete safety shape barriers. The report will be of particular interest to design and safety practitioners with responsibility for roadside safety improvements. The increasing application of context-sensitive design solutions for highway projects has created a national need for aesthetic improvement of typical highway features. Requests for concrete barrier treatments and bridge rails that contribute to the overall aesthetic experience are increasing. Concrete barriers (e.g., New Jersey, F-shapes, single-slope, and vertical-face designs) are often the barriers of choice in urban and suburban environments. Many transportation agencies and communities have expressed a desire for aesthetic treatments for these standard shapes. To date, there has been limited evaluation to determine which aesthetic treatments are safe and practical. Designers need guidance regarding the safety implications of aesthetic treatments for concrete barriers.