Evaluation of Guardrail to Concrete Bridge Rail Transitions PDF Download
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Author: Roger P. Bligh
Publisher:
ISBN:
Category : Bridge railings
Languages : en
Pages : 76
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Book Description
In December 2001, the Design Division and Bridge Division of Texas Department of Transportation released a new standard for an approach guardfence to concrete bridge rail transition that complies with the testing requirements of National Cooperative Highway Research Program (NCHRP) Report 350 for use on high-speed roadways. The purpose of this research was to develop a transition that is suitable for use on lower speed roadways and that is less expensive and complex than the current high-speed design. A low-cost transition was successfully evaluated at 45 mph impact speeds under NCHRP Report 350 Test Level 2 conditions. A second objective of the project was to evaluate the need for the curb detail that is one of the design elements of the newly adopted thrie beam transition design. Elimination of the curb would greatly enhance installation flexibility and reduce installation cost. The assessment of the curb was accomplished through full-scale crash testing.
Author: Roger P. Bligh
Publisher:
ISBN:
Category : Bridge railings
Languages : en
Pages : 76
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Book Description
In December 2001, the Design Division and Bridge Division of Texas Department of Transportation released a new standard for an approach guardfence to concrete bridge rail transition that complies with the testing requirements of National Cooperative Highway Research Program (NCHRP) Report 350 for use on high-speed roadways. The purpose of this research was to develop a transition that is suitable for use on lower speed roadways and that is less expensive and complex than the current high-speed design. A low-cost transition was successfully evaluated at 45 mph impact speeds under NCHRP Report 350 Test Level 2 conditions. A second objective of the project was to evaluate the need for the curb detail that is one of the design elements of the newly adopted thrie beam transition design. Elimination of the curb would greatly enhance installation flexibility and reduce installation cost. The assessment of the curb was accomplished through full-scale crash testing.
Author: Tewodros Y. Yosef
Publisher:
ISBN:
Category : Bridge railings
Languages : en
Pages : 0
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Book Description
Author: Roger P. Bligh
Publisher:
ISBN:
Category : Bridge railings
Languages : en
Pages : 200
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Book Description
A recent study on the performance of guardrail-to-bridge rail transitions revealed that many widely used designs do not meet current safety standards. As a result, the Federal Highway Administration (FHWA) requested that the Arizona Department of Transportation verify the safety performance of its standard transition designs. Three transition designs currently being used by ADOT were evaluated through a combined program of computer simulation and full-scale crash testing. The standard ADOT wood post transition, incorporating a channel rubrail and two different sizes of timber posts at a reduced post spacing near the bridge rail end, was found to be in compliance with National Cooperative Highway Research Program (NCHRP) Report 230 performance criteria. The standard ADOT steel post transition with channel rubrail was also found to be in compliance with NCHRP Report 230 requirements when impacted near the end of the bridge rail. However, the upstream end of the steel post transition required modification to eliminate deficiencies identified during testing. The modified design, which terminated the channel rubrail behind a W6x9 guardrail post, was successfully crash tested. A recent study on the performance of guardrail-to-bridge rail transitions revealed that many widely used designs do not meet current safety standards. As a result, the Federal Highway Administration (FHWA) requested that the Arizona Department of Transportation verify the safety performance of its standard transition designs. Three transition designs currently being used by ADOT were evaluated through a combined program of computer simulation and full-scale crash testing. The standard ADOT wood post transition, incorporating a channel rubrail and two different sizes of timber posts at a reduced post spacing near the bridge rail end, was found to be in compliance with National Cooperative Highway Research Program (NCHRP) Report 230 performance criteria. The standard ADOT steel post transition with channel rubrail was also found to be in compliance with NCHRP Report 230 requirements when impacted near the end of the bridge rail. However, the upstream end of the steel post transition required modification to eliminate deficiencies identified during testing. The modified design, which terminated the channel rubrail behind a W6x9 guardrail post, was successfully crash tested.
Author: William F. Williams (Transportation engineer)
Publisher:
ISBN:
Category : Automobiles
Languages : en
Pages : 0
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Book Description
Texas Transportation Institute (TTI) researchers performed an extensive literature review of bridge railing transitions crash tested to Manual for Assessing Safety Hardware (MASH) TL-3, and incorporated the information obtained from this review into the design and details for the new transition testing developed for this project. TTI researchers developed concepts for the new transition anchored to a concrete wing wall. TTI researchers developed a full-scale, three-dimensional finite element model of the guardrail transition. The modeling effort included developing and validating a subcomponent level model of the post installed on concrete. Upon completion of the simulations, TTI researchers processed the results and assessed the likelihood of the transition system passing the required MASH crash tests. TTI researchers noted the design deficiencies and recommended design modifications to the system to mitigate those deficiencies. TTI researchers developed full-scale test installation drawings of the design after the finite element model simulations were completed and all the results were reviewed with favorable results. After approval of the test installation drawings by Texas Department of Transportation (TxDOT), construction of a full-scale test installation for crash testing commenced, and crash tests were performed on the full-scale test installation. The Guardrail to Rigid Barrier Transition Attached to Bridge or Culvert Structure, used on the upstream and downstream ends, performed acceptably for MASH TL-3 transitions.
Author: Roger P. Bligh
Publisher:
ISBN:
Category : Bridge railings
Languages : en
Pages : 152
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Book Description
This report describes the development and testing of a guardfence-to-rigid bridge rail transition. The transition consists of a tubular W-beam supported on 7 inch diameter round wood posts. It is designed to transition to a vertical wall or to the concrete safety shaped barrier. It can be used on new construction or as a retrofit for existing installations. Based on a full-scale vehicular crash test program, the design was judged to be in compliance with recommended impact performance criteria as presented in NCHRP Report 230. Also described is a tentative design for approach guardfence at bridge ends near an abutting roadway. The design consists of short radius, curved guardrail supported on weakened round wood posts.
Author: Karla A. Polivka
Publisher:
ISBN:
Category : Roads
Languages : en
Pages : 95
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Author: Eugene Buth
Publisher:
ISBN:
Category : Bridge railings
Languages : en
Pages : 172
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Book Description
An assortment of retrofit bridge railings and a retrofit transition were evaluated through full-scale crash testing. The assortment included: (1) a W-beam retrofit railing for a concrete baluster bridge railing (AASHTO performance level one); (2) a W-beam transition for the bridge railing above (NCHRP Report 350 test level two); (3) a double-tube pedestrian/bicycle railing mounted on the Illinois 2399-1 traffic railing (AASHTO performance level one); (4) a vandal protection fence on the New Jersey concrete safety shape bridge railing (AASHTO performance level two); and (5) a thrie beam retrofit railing, a Delaware design, mounted on a 203-mm-high safety curb (AASHTO performance level two and NCHRP Report 350 test level four). All of the designs demonstrated acceptable performance.
Author:
Publisher:
ISBN:
Category : Impact
Languages : en
Pages : 172
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Book Description
Two approach guardrail transitions for use with concrete safety shape barriers were developed and crash tested. For this study, the transition systems were attached to the New Jersey safety shape concrete barrier; however, it is believed that these transition systems could be easily adapted to the F-shape barrier with no need for further crash testing. Both transition designs were constructed with two nested thrie beam rails measuring 2.66-mm thick. The first transition design was supported by nine W150x13.5 steel posts measuring, 1,981-mm long, while the second transition design was supported by nine 152-mm x 203-mm wood posts measuring 2,134-mm long. For both systems, post spacings consisted on one at 292 mm, five at 476 mm, and three at 952 mm. A triangular-shape concrete curb was constructed below the thrie beam rail on each approach guardrail transition system. The two transition systems successfully met the Test Level 3 requirements specified in NCHRP Report 350, "Recommended Procedures for the Safety Performance Evaluation of Highway Features."
Author: Malcolm H. Ray
Publisher:
ISBN:
Category : Automobiles
Languages : en
Pages : 172
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Book Description
This synthesis will be of interest to state department of transportation (DOT) roadway design, traffic, structural, maintenance, and research engineers and others concerned with highway safety issues. This synthesis describes the current state of the practice for the use of guardrails and median barriers and their crashworthiness. It includes information about the crashworthiness and typical applications of the most common, permanently installed, nonproprietary guardrail and median barrier systems used in the United States today. A significant amount of detail is included in the text to aid the design, selection, and locating processes for safe and effective guardrails and median barriers. The report presents data obtained from a review of the literature and a survey of state DOTs. The synthesis presents a description of the typical longitudinal barriers in use today, including drawings, the extent of their use, and the most recent testing on each guardrail and barrier system, with particular emphasis on NCHRP Report 230 and 350 requirements. In addition, it discusses the maintenance issues, cost constraints, and common problems with each type of barrier. The synthesis only discusses the crashworthiness of guardrails and median barriers; their transitions and terminals are not discussed.
Author: Brian G. Pfeifer
Publisher:
ISBN:
Category : Bridge railings
Languages : en
Pages : 68
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Book Description
