Session 9 Guardrail Attachments to Bridge Ends

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Session 9Guardrail Attachments to Bridge Ends
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Common Deficiencies in Bridge Railings

• Inadequate Dynamic Strength
• Potential for Snagging
• Use of Safety Walk
• Inadequate Transition

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Transitions

• Guardrail Deflects Bridge Ends DONOT!!
• Bridge End Connections are an example of a change
  in the type of Barrier Deflection Characteristics
• Must Reduce the Deflection of the Guardrail
  before you reach the Bridge End from 3 to Zero
• Must have adequate Structural Connection

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Transition Considerations

• Adequate structural connection to the bridge
  railing
• Reduced post spacing and nested rail to increase
  stiffness gradually
• Block outs and rub rails used to minimize
  snagging

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How can you REDUCE DEFLECTION of Standard Strong
Post W-Beam Guardrail

• Normal Guardrail Post Spacing is 63
• Reduce Post Spacing to 3 1½ and reduce
  deflection by 50
• Nest the Guardrail (double thickness) and reduce
  deflection by 50
• Add a Guardrail panel to the back of the Post and
  reduce deflection by 50
• Add a Rub Rail and reduce deflection by nearly
  50 reduce snagging potential
• Combine 2 of the above and reduce deflection by
  75

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How can you REDUCE DEFLECTION of Standard Strong
Post W-Beam Guardrail
Reduced Post Spacing
Nested
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Gradually Increase Stiffness by Increasing the
number of Post
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Rub Rail Components - Std Draw RBC-001 002 003
Guardrail Connection to Bridge End Type A and
A-1 Components
Rub Rail
Not Island Curb
Rub Rail
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Standard Drawing RBC-001Guardrail Connector to
Bridge End Type A and A-1
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Inadequate Structural Connection or Stiffening of
Approach Rail
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Adequate Structural Connection Terminal Sect No 2
Plate A B
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Inadequate Reduction in Deflection and Structural
Connection
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Transition of Curb and Rub Rail to Bridges
Safety Shape
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Addition of a Spacer Tube
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Combination of all of the Proceeding for a
Successful Transition
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Std Draw RBC-001 Guardrail Connection to Bridge
End Type A and A-1
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Curb Inlet Type BShould have Island Curb in
Throat of the Inlet

• Std Draw RBD-280
• Match Adjacent Curb

• Std Draw RBC-001 Note 5 Island Curb

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Curb Inlet Type BShould have Island Curb in
Throat of the Inlet

• Lt Std Draw RBD-280 Curb Box Inlet Type B (Detail
  Drawing) Match Adjacent Curb
• Rt Std Draw RDB-281 Curb Box Inlet Type B (Steel
  Drawing) "Island Curb Detail

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Type B Drainage Box As-Builts vs. Std Draw
Construction memo No 5-11July 6, 2011

• Have not been getting Island Curb on Type B Inlet
  therefore a Const Memo was Issued
• See Std Draw RBC-001, RBD-280, RBD-281 Previous
  Slides
• Corrective Actions
• Retrofit by extending the double ply rail from 25
  linear feet to 50 linear feet
• Replace the drain box top with the correct one

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Std Draw RDB-280 Curb Box Inlet Type B 2012
Design Changed Detail to Show Island Curb instead
of Std Curb
Changed to Island Curb
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Normally getting Standard Curb instead of Island
Curb
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What makes this a good Guardrail Connection to
Bridge End? Q A Time