00802525

Component

https://doi.org/10.3141/1720-07

http://scholar.google.com...Reid&publication_year=2000

The current generation of NCHRP Report 350-compliant guardrail terminals all use wooden breakaway posts in the terminal section. The first two end posts are typically breakaway cable terminal posts inserted into steel foundation tubes that are joined with a ground strut to provide the anchorage capacity. Wood is readily available and inexpensive, but it also has many drawbacks. The quality of the wood and the associated breaking forces vary widely. The strength of a wooden post is affected by many factors, including post size, ring density, knot location and size, cracks and checks, species, and moisture content. Results are presented of an effort to design and develop steel breakaway posts for guardrail terminals. The breakaway steel post system described has been successfully tested for use in a tangent terminal. The post exhibited consistent strength for redirection impacts and failed at very low loads during head-on impacts. The breakaway steel post actually improved the redirective performance of the SKT-350 during a 2020-kg (4,450-lb) pickup truck impact at the beginning of the length of need. These breakaway steel posts have been shown to meet NCHRP Report 350 performance criteria and should provide highway agencies with an alternative where wood posts are unacceptable.

This appears in Transportation Research Record No. 1720, Roadside Safety Features and Hydraulic, Hydrology, and Water Quality Issues.

English

p. 59-66

2000

Transportation Research Record

0309066980

Figures; Photos; References (4)

Breakaway supports; Crash tests; Guardrail terminals; Performance tests; Pickup trucks; Posts; Steel; Wood

NCHRP Report 350

Breakaway cable; Redirection (Impacting vehicle)

Design; Highways; Research; Safety and Human Factors; I85: Safety Devices used in Transport Infrastructure

TRIS, TRB, ATRI

Nov 15 2000 12:00AM

• CALIFORNIA DEPARTMENT OF TRANSPORTATION STATEWIDE STORM WATER MANAGEMENT PROGRAM
• ESTIMATION OF TIME OF CONCENTRATION FOR MARYLAND STREAMS
• EVALUATING HUMAN RISK IN SIDE IMPACT COLLISIONS WITH ROADSIDE OBJECTS
• EVALUATION OF PORTABLE CONCRETE BARRIERS USING FINITE ELEMENT SIMULATION
• IMPACT PERFORMANCE OF THE G4(1W) AND G4(2W) GUARDRAIL SYSTEMS: COMPARISON UNDER NCHRP REPORT 350 TEST 3-11 CONDITIONS
• IN-SERVICE, PERFORMANCE-BASED ROADSIDE DESIGN POLICY: PRELIMINARY INSIGHTS FROM WASHINGTON STATE'S BRIDGE RAIL STUDY
• LONG-SPAN GUARDRAIL SYSTEM FOR CULVERT APPLICATIONS
• PERFORMANCE OF BREAKAWAY CABLE AND MODIFIED ECCENTRIC LOADER TERMINALS IN IOWA AND NORTH CAROLINA: IN-SERVICE EVALUATION
• SAFETY EFFECTIVENESS OF UPGRADING GUARDRAIL TERMINALS TO NCHRP REPORT 350 STANDARDS
• TEMPORAL VARIATIONS IN HEAVY METAL PARTITIONING AND LOADING IN URBAN HIGHWAY PAVEMENT SHEET FLOW: IMPLICATIONS FOR IN SITU TREATMENT DESIGN
• TEST LEVEL 4 BRIDGE RAILS
• TRANSITIONS FROM GUARDRAIL TO BRIDGE RAIL THAT MEET SAFETY PERFORMANCE REQUIREMENTS