Recommended Guidelines for the Selection of Test Levels 2 Through 5 Bridge Railings (2021) / Chapter Skim
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71 RESULTS OF SURVEY OF PRACTICE Introduction A survey of practitioners was distributed via e-mail to about 2,800 roadside safety researchers, bridge engineers, DOT engineers, and highway design consultants both within the US and abroad. This survey was conducted to determine the current policies for deciding which test level bridge railing to use in particular situations and to obtain data which could be used in this research.
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72 1. Alabama 2.
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73 Table 22. Question 2 Average Values.
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74 Question 3: As part of this work, the research team is collecting in-service crash records for bridge railings. If you or your agency has data available to help with the development of these guidelines, please list the best way to contact you and the nature of the data in the box below.
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75 and maintenance practices all contributed to the observed deterioration. In addition to the reports listed above, one respondent suggested that the research team make direct contact to obtain information.
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76 traffic, then TL4 railing is used." Other respondents indicated that Alabama specifies a minimum of TL4 railing; WSDOT requires "TL5 at T-intersections on a bridge or structure or when the barrier is on the outside curve of a structure with radius of curvature less than 500 ft." WSDOT also requires TL5 "where approach speeds are 50 mph or greater." "Some standards call for the use of TL5 bridge rails for horizontal curved bridge with high speeds while allowing for TL3 bridge rails to accommodate historic bridge needs." Many States rely on the 1989 AASHTO Guide Specifications for Bridge Railing in combination with the AASHTO LRFD Bridge Design Specifications, AASHTO Roadside Design Guide, and the AASHTO Task Force 13 barrier guide. Some States, including Utah and New Mexico, are in the process of updating design standards to include guidelines for the selection of bridge rails and median barriers.
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From page 77... ...
77 http://www.mhd.state.ma.us/default.asp? pgid=content/bridgeman_new02&sid =about • NYSDOT Bridge Manual: https://www.nysdot.gov/divisions/engineering/structures/repository/manuals/b rman-usc/Section_6_US_2010.pdf • http://www.dot.state.oh.us/Divisions/HighwayOps/Structures/standard/Bridge s/test/railing%20selection%20procedure.pdf • NCDOT Design Manual, Section 6.2.4: http://www.ncdot.org/doh/preconstruct/highway/structur/designmanual/lrfd/L RFDManual(December2010)
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From page 78... ...
78 • ADT, • Percent Trucks, • Posted Speed Limit, • Design Speed, • Number of Lanes, • Accident data, • Cost/benefit, • Roadway type, • Horizontal alignment, • Vertical alignment, • Land use around the structure, and • Other. Design speed, traffic characteristics (i.e., volume and truck percentage)
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79 concerns. "Aluminum rails are being stolen at an alarmingly high rate, so the state of Iowa is proactive about replacing them with the lightest functional rail available." One survey respondent noted "all of the above criteria are considered, however, there are not any published guidelines that cover all of the possible combinations ….
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80 Question 12: What testing has been done to support the retrofitting of substandard bridge rail policy? Respondents indicate that retrofitting policy is based on materials found in NCHRP Report 350, the 2005 FHWA/CALTRANS Bridge Rail Guide, and historic crash tests.
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81 construction methods (e.g., extrude the railing)
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