Terry Chism FHWA Safety Engineer

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Terry Chism FHWA Safety Engineer

• Feb 21, 2007
• Residents Engineers Conf.
• 2006 Guardrail Process Review
• Terry.chism_at_fhwa.dot.gov
• 502-223-6750

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Team Members

• Terry Chism FHWA Transportation Safety Engineer
• Mary Murray FHWA Transportation Engineer
• Nasby Stroop KYTC Div of Construction
• Jeff Jasper KYTC Div of Highway Design
• Tim Gatewood KYTC Div of Highway Design
• Various REs and Inspectors

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Guardrail Process ReviewPurpose

• Conducted a Process Review of Guardrail to
  evaluate current KYTC Design Standards and
  compliance with the design standards and
  construction specifications during construction

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Guardrail Process ReviewScope

• Active or recently completed projects
• I-64, I-65, I-71, US 119 and KY 11
• 11 Projects
• Existing roadside barriers on southern I-75 and
  various Kentucky Parkways

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Guardrail Process ReviewScope Current Barrier
End Terminal Types

• Type 1 (energy absorbing, ET-2000, SKT)
• Type 2A (solid rock cut)
• Type 3 (buried in the back slope)
• Type 4A (flared and gating, SRT)
• Type 7 (KY Turndown)
• Type IX (telescoping median barrier, CAT)
• Cable median barriers

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Guardrail Process ReviewScope Outdated and Non
Standard Terminals

• Texas Twist
• Buried in the Back Slope into man made mounds
• Double Texas Twist in median
• Mounded earth median bridge pier protection
• Type 7 (KY Turndown)

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Guardrail Process ReviewKYTC Best Practices

• Kentuckys use of pre-tensioned Cable Median
  Barrier.
• KYTC has good Standard Drawings for guardrail end
  terminals.
• KYTC has improved efforts to upgrade roadside
  safety appurtenances on 3R projects.
• KYTCs Type 1 Guardrail Energy Absorbing End
  Terminal has a phenomenal performance record
• AASHTO Roadside Design Guide 5 Sessions

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Six items in Executive Summary

• Elimination of Texas Twist and Type 7 Turn Down
• Type 2A End Terminal must be placed against a
  solid rock cut
• Type 1 energy absorbing end terminal
• Field reviews of 3R projects concerns
• Roadside Safety Training needs
• Consideration of Contractor and Inspector
  Certification for guardrail installation

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1. Elimination of Texas Twist and Type 7 Turn
Down

• Turndown end terminals have been prohibited by
  FHWA since 1990
• Vaulting and rollover concerns
• Still existing on Interstates and Parkways
• FHWA pushing for a quick removal timetable

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Texas Twist and Type 7 Turndown End Terminals
on Interstates and Parkways
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Texas Twist and Type 7 Turndown End Terminals
on Interstates and Parkways
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2. Type 2A End Terminal must be placed against a
solid rock cut

• The Type 2A is a non-breakaway, generic device
  which can spear an impacting vehicle if it is not
  snugly placed against a solid rock cut.
• Often incorrectly placed in cuts with partial
  rock.
• Could/should use Type 3
• Designers need to check in field
• Construction can change End Terminal Types
• KYTC looking at rock anchors other alternates

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Good Type 2A End Terminal
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Misuse of Type 2A End Terminal All could have
been Type 3 Buried in the Back Slope
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Misuse of Type 2A End Terminal All could have
been Type 3 Buried in the Back Slope
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Type 2A End Terminal can spear a vehicle not KY
photo
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Type 2A End Terminal can spear a vehicle not KY
photo.
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3. Type 1 energy absorbing guardrail end terminal

• Phenomenal track record
• Over 135 recorded hits and zero fatalities
• The easiest end terminal to properly install and
  least earthwork required
• This device could be utilized more often
• Considering changes to Standard Drawings
  allowing in cuts

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3. Type 1 energy absorbing end terminal
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4. Field reviews of 3R projects concerns

• New end terminals were generally placed at the
  same location as the old end terminal
• This can result in improper length of need
• Each end terminal needs to be reviewed by the
  designer in the field to assure that new end
  terminals are placed at proper locations.
• NOTE Construction can change end terminal
  locations!!! May check design.

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Pad and new terminal placed at old location but
side slope to steep before after rollover
potential
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5. Roadside Safety Training needs

• Need for training in AASHTO Roadside Design Guide
  and Guardrail Installation in all Districts for
  Design, Construction, Operations, Consultants,
  Contractors
• KYTC has held 5 sessions of the AASHTO Roadside
  Design Guide Training in the last 2 years
  Excellent but need more
• FHWA has offered to present guardrail training
  for Central Office and all District Offices

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6. Consideration of Contractor and Inspector
Certification for guardrail installation

• Review Team discussed this concept
• INDOT has this type of certification
• The KYTC has similar certification for Grade and
  Drain, Painting, Structures and Asphalt Lay Down.

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Field Installation Problems Type 4A flared and
gating end terminal

• Field reviews revealed problems with properly
  installing the Type 4A flared gating guardrail
  end terminal
• Improper parabolic flare rates
• Can result in spearing vehicles
• Field measurements found none that met the flare
  rates in Standard Drawing RBR-035
• KY exploring straight flare terminal

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One Good and three poor Type 4A flares and
measuring demo
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Syro-Trinity Straight Flare SRT-350 6 Post Design
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Other construction safety concerns found during
field reviews

• Type 3 end terminal without required concrete
  anchor
• Non- breakaway steel I beam guide sign in clear
  zone
• Breakaway slip bases covered with DGA
• Frangible luminaire bases covered by DGA
• Inadequate length of need
• Uncompleted terminal work

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Type 3 end terminal without required concrete
anchor ramping possibility
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Type 3 end terminal without required concrete
anchor
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Type 3 end terminal without buried in back slope
anchor
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Non- breakaway steel I beam guide sign in clear
zone
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Breakaway slip bases covered with DGA
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Frangible luminaire bases covered by DGA
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Inadequate length of need
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Uncompleted terminal workRecommend lay down 4
sections
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For Installation GuidesWeb sites phone numbers

• www.Energyabsorption.com
• 1-888-32-ENERGY
• www.roadsystems.com
• 815-464-5917
• SYRO Trinity www.highway-safety.com
• 1-800-644-syro (7976)
• FHWA NCHRP 305 Approval Web site
  http//safety.fhwa.dot.gov/roadway_dept/road_hardw
  are/index.htm